Front Cover
 Title Page
 Technologies to sustain tropical...
 OTA staff on technologies to sustain...
 Technology transfer workshop
 Systems analysis workshop
 Table of Contents
 Part I: Background
 Part II: Technology assessment
 Part III: Options for congress
 Back Cover

Title: Technologies to sustain tropical forest resources
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00053855/00001
 Material Information
Title: Technologies to sustain tropical forest resources
Physical Description: vii, 344 p. : ill., maps ; 26 cm.
Language: English
Creator: United States -- Congress. -- Office of Technology Assessment
Publisher: Congress of the U.S., Office of Technology Assessment :
For sale by the Supt. of Docs., U.S. G.P.O.
Place of Publication: Washington D.C
Publication Date: 1984
Subject: Rain forests   ( lcsh )
Reforestation -- Tropics   ( lcsh )
Forest conservation -- Tropics   ( lcsh )
Genre: federal government publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references and index.
General Note: "OTA-F-214"--P. 4 of cover.
General Note: "March 1984"--P. 4 of cover.
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
 Record Information
Bibliographic ID: UF00053855
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 001283206
oclc - 10609530
notis - AGD3867
lccn - 84601018

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Page i
        Page ii
        Page iii
    Technologies to sustain tropical forest resources advisory panel
        Page iv
    OTA staff on technologies to sustain tropical forest resources
        Page v
        Page vi
    Technology transfer workshop
        Page vi
    Systems analysis workshop
        Page vi
    Table of Contents
        Page vii
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
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        Page 26
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        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
    Part I: Background
        Page 33
        Page 34
        Importance of tropical forests
            Page 35
            Page 36
            Page 37
            Page 38
            Page 39
            Page 40
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            Page 55
            Page 56
            Page 57
            Page 58
            Page 59
            Page 60
        Status of tropical forests
            Page 61
            Page 62
            Page 63
            Page 64
            Page 65
            Page 66
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            Page 78
            Page 79
            Page 80
            Page 81
            Page 82
        Causes of deforestation and forest resource degradation
            Page 83
            Page 84
            Page 85
            Page 86
            Page 87
            Page 88
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            Page 98
            Page 99
            Page 100
            Page 101
            Page 102
        Organizations dealing with tropical forest resources
            Page 103
            Page 104
            Page 105
            Page 106
            Page 107
            Page 108
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            Page 120
            Page 121
            Page 122
            Page 123
            Page 124
        U.S. tropical forests: Caribbean and Western Pacific
            Page 125
            Page 126
            Page 127
            Page 128
            Page 129
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            Page 153
            Page 154
    Part II: Technology assessment
        Page 155
        Page 156
        Technologies for undisturbed forests
            Page 157
            Page 158
            Page 159
            Page 160
            Page 161
            Page 162
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            Page 171
            Page 172
            Page 173
            Page 174
        Technologies to reduce overcutting
            Page 175
            Page 176
            Page 177
            Page 178
            Page 179
            Page 180
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            Page 188
            Page 189
            Page 190
            Page 191
            Page 192
        Forestry technologies for disturbed forests
            Page 193
            Page 194
            Page 195
            Page 196
            Page 197
            Page 198
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            Page 211
            Page 212
            Page 213
            Page 214
            Page 215
            Page 216
        Forestry technologies to support tropical agriculture
            Page 217
            Page 218
            Page 219
            Page 220
            Page 221
            Page 222
            Page 223
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            Page 235
            Page 236
            Page 237
            Page 238
            Page 239
            Page 240
        Resource development planning
            Page 241
            Page 242
            Page 243
            Page 244
            Page 245
            Page 246
            Page 247
            Page 248
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            Page 250
            Page 251
            Page 252
            Page 253
            Page 254
        Education, research, and technology transfer
            Page 255
            Page 256
            Page 257
            Page 258
            Page 259
            Page 260
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            Page 270
            Page 271
            Page 272
            Page 273
            Page 274
        Forestry technologies for U.S. tropical territories
            Page 275
            Page 275a
            Page 275b
            Page 276
            Page 277
            Page 278
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    Part III: Options for congress
        Page 297
        Page 298
        Options for congress
            Page 299
            Page 300
            Page 301
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            Page 320
        Page 321
        Page 322
        Appendix A: Status of tropical forests - Tables
            Page 323
            Page 324
            Page 325
            Page 326
            Page 327
            Page 328
            Page 329
            Page 330
            Page 331
        Appendix B: Glossary
            Page 332
            Page 333
            Page 334
            Page 335
        Appendix C: Commissioned papers
            Page 336
            Page 337
            Page 338
        Page 339
        Page 340
        Page 341
        Page 342
        Page 343
        Page 344
    Back Cover
        Back Cover 1
        Page 347
Full Text
C1,q, /q,


SOffice of Technology Assessment
v Washlngton, D C 20510
. .......n.- ... "

Office of Technology Assessment

Congressional Board of the 98th Congress

MORRIS K. UDALL, Arizona, Chairman

TED STEVENS, Alaska, Vice Chairman

South Carolina
Rhode Island

Midwest Research Institute
University of Alaska
General Accounting Office
California Land Commission


Advisory Council

University of Pittsburgh
Tennessee Valley Authority
Congressional Research Service
University of Arizona


University of Wisconsin
Hambrecht & Quist
General Motors Corp.
Memorial Sloan-Kettering
Cancer Center



The Technology Assessment Board approves the release of this report. The views expressed in this report are not
necessarily those of the Board, OTA Advisory Council, or of individual members thereof.




Office of Technology Assessment
Washington, D. C. 20510

OTA Reports are the principal documentation of formal assessment projects.
These projects are approved in advance by the Technology Assessment Board.
At the conclusion of a project, the Board has the opportunity to review the report,
but its release does not necessarily imply endorsement of the results by the Board
or its individual members.

Recommended Citation:
Technologies to Sustain Tropical Forest Resources (Washington, D.C.: U.S. Congress,
Office of Technology Assessment, OTA-F-214, March 1984).

Library of Congress Catalog Card Number 84-601018

For sale by the Superintendent of Documents
U.S. Government Printing Office, Washington, D.C. 20402


The United States has a stake in the sustained economic development of tropical
nations for humanitarian, political, and economic reasons. To a great extent, the
development of these nations depends on increasing production from their poten-
tially renewable soil, forest, and water resources. But tropical forest resources, which
cover nearly one-half of the tropical nations' land, are being consumed at a rate
that may make them nonrenewable. They are exploited for timber and cleared for
pasture and cropland with little regard for their abilities to produce-in a long-
term sustainable fashion-important goods, maintain soil productivity, regulate
water regimes, or regenerate themselves. Much of the recent deforestation occurs
where the new land uses cannot be sustained and it causes productivity losses that
tropical nations and the world can ill afford.
International recognition of the importance of tropical forests, and efforts to
sustain the productivity of these resources, have increased significantly in the last
decade. In 1980, the House of Representatives Committee on Foreign Affairs, Sub-
committee on International Organizations, held hearings on tropical deforestation.
The committee then requested the Office of Technology Assessment (OTA) to con-
duct a more thorough assessment of the problem, the technologies that could help
sustain tropical forest resources, and possible options for Congress. The Subcom-
mittee on Insular Affairs of the House Committee on Interior and Insular Affairs
and the Subcommittee on Environmental Pollution of the Senate Committee on
Public Works endorsed the request. The Senate Committee on Energy and Natural
Resources asked that the assessment specifically address forest resources of the
U.S. insular territories in the Caribbean and western Pacific. The report and its
two background papers (Reforestation of Degraded Lands and U.S. and Interna-
tional Institutions) identify and discuss in-depth some of the constraints and op-
portunities to develop and implement forest-sustaining technologies.
OTA greatly appreciates the contributions of the advisory panel and workshop
participants assembled for the study, the authors of the commissioned technical
papers, and the many others who assisted us, including liaisons from other Govern-
ment agencies. As with all OTA studies, however, the content of the report is the
sole responsibility of OTA.


Technologies to Sustain Tropical Forest Resources Advisory Panel

Leonard Berry, Panel Chairman
Center for Technology, Environment, and Development
Clark University

Eddie Albert
Hugh Bollinger
Vice President
Native Plants, Inc.
Robert Cassagnol
Technical Committee
Robert Cramer
Former President
Virgin Islands Corp.
Gary Eilerts
Appropriate Technology International
John Ewel
Department of Botany
University of Florida
Robert Hart
Winrock International
Susanna Hecht
Department of Geography
University of California
Marilyn Hoskins
Department of Sociology
Virginia Polytechnic Institute
John Hunter*
Michigan State University
Norman Johnson
Vice President, North Carolina Region
Weyerhaeuser Co.

*Resigned in July 1982.

Jan Laarman
Department of Forestry
North Carolina State University
Charles Lankester
U.N. Development Programme
Robert Owen
Chief Conservationist (retired)
Trust Territory of the Pacific Islands
Christine Padoch
Institute of Environmental Studies
University of Wisconsin
Allen Putney
West Indies Lab
Jeff Romm
Department of Forestry
University of California
John Terborgh
Department of Biology
Princeton University
Henry Tschinkel
Regional Office for Central American Programs
Agency for International Development
U.S. Department of State

OTA Staff on Technologies to Sustain Tropical Forest Resources

H. David Banta* and Roger Herdman,** Assistant Director, OTA
Health and Life Sciences Division

Walter E. Parham, Program Manager
Food and Renewable Resources Program

Analytical Staff

Susan Shen, Forester
Alison Hess, Resource Economist
Chris Elfring, Science Journalist
Eric Hyman, Environmental Planner***
Denise Toombs, Resource Policy Analyst***
Jim Kirshner, Resource Policy Analyst***
Bruce A. Ross-Sheriff, Geographer,
Project Director

Administrative Staff

Phyllis Balan, Administrative Assistant
Nellie Hammond, Secretary
Carolyn Swann, Secretary

OTA Publishing Staff

John C. Holmes, Publishing Officer
John Bergling Kathie S. Boss Reed Bundy Debra M. Datcher
Joe Henson Glenda Lawing Linda A. Leahy Cheryl J. Manning

*Until August 1983.
*From Dec. 26, 1983.
**Temporary staff (4-month period).

Technology Transfer Workshop

Ron Stegall, Chairman
Development Consultant
Washington, D.C.

Anil Agarwal
Centre for Science and Environment
New Delhi, India
Jose Roberto Castillio
Merrill Conitz
Agency for International Development
Nairobi, Kenya
Robert Fishwick
World Bank
Washington, D.C.

Gerald Murray
Pan American Development Foundation
Gunnar Poulsen
Tropical Forestry Consultant
David Richards
Appropriate Technology International
Washington, D.C.
Skip Stiles
Office of Congressman George E. Brown, Jr.
Washington, D.C.

Marilyn Hoskins
Virginia Polytechnic Institute
Blacksburg, Va.

Systems Analysis Workshop

Donella H. Meadows, Chairwoman
Resource Policy Center, Dartmouth College

Jeffrey Gritzner
Board on Science and Technology
for International Development
National Academy of Sciences
Jeff Romm
Department of Forestry
University of California

John Terborgh
Department of Biology
Princeton University
Frank Wadsworth
Institute of Tropical Forestry
Puerto Rico

Technology Transfer Workshop

Ron Stegall, Chairman
Development Consultant
Washington, D.C.

Anil Agarwal
Centre for Science and Environment
New Delhi, India
Jose Roberto Castillio
Merrill Conitz
Agency for International Development
Nairobi, Kenya
Robert Fishwick
World Bank
Washington, D.C.

Gerald Murray
Pan American Development Foundation
Gunnar Poulsen
Tropical Forestry Consultant
David Richards
Appropriate Technology International
Washington, D.C.
Skip Stiles
Office of Congressman George E. Brown, Jr.
Washington, D.C.

Marilyn Hoskins
Virginia Polytechnic Institute
Blacksburg, Va.

Systems Analysis Workshop

Donella H. Meadows, Chairwoman
Resource Policy Center, Dartmouth College

Jeffrey Gritzner
Board on Science and Technology
for International Development
National Academy of Sciences
Jeff Romm
Department of Forestry
University of California

John Terborgh
Department of Biology
Princeton University
Frank Wadsworth
Institute of Tropical Forestry
Puerto Rico

Technology Transfer Workshop

Ron Stegall, Chairman
Development Consultant
Washington, D.C.

Anil Agarwal
Centre for Science and Environment
New Delhi, India
Jose Roberto Castillio
Merrill Conitz
Agency for International Development
Nairobi, Kenya
Robert Fishwick
World Bank
Washington, D.C.

Gerald Murray
Pan American Development Foundation
Gunnar Poulsen
Tropical Forestry Consultant
David Richards
Appropriate Technology International
Washington, D.C.
Skip Stiles
Office of Congressman George E. Brown, Jr.
Washington, D.C.

Marilyn Hoskins
Virginia Polytechnic Institute
Blacksburg, Va.

Systems Analysis Workshop

Donella H. Meadows, Chairwoman
Resource Policy Center, Dartmouth College

Jeffrey Gritzner
Board on Science and Technology
for International Development
National Academy of Sciences
Jeff Romm
Department of Forestry
University of California

John Terborgh
Department of Biology
Princeton University
Frank Wadsworth
Institute of Tropical Forestry
Puerto Rico


Introduction ............................................................

1. Summary ................................... .......................

2. Importance of Tropical Forests .............................

3. Status of Tropical Forests ..................................

4. Causes of Deforestation and Forest Resource Degradation ......

5. Organizations Dealing With Tropical Forest Resources .........

6. U.S. Tropical Forests: Caribbean and Western Pacific..........

7. Technologies for Undisturbed Forests .......................

8. Technologies to Reduce Overcutting .........................

9. Forestry Technologies for Disturbed Forests ..................

10. Forestry Technologies to Support Tropical Agriculture .........

11. Resource Development Planning ............................

12. Education, Research, and Technology Transfer ...............

13. Forestry Technologies for U.S. Tropical Territories ............

14. Options for Congress......................................

............ 37

............ 63

. ........... 85

............ 105

............ 127

............ 159

........... 177

............ 195

............ 219

............ 243

............ 257

............ 275

............ 301

A. Status of Tropical Forests: Tables .................................... .

B. Glossary ....................... ...................... .......... ....

C. Commissioned Papers ...............................................

Index ..................................................................







Each year, 11.3 million hectares of the
Earth's remaining tropical forests (an area
roughly the size of Pennsylvania) are cleared
and converted to other land uses or to unpro-
ductive land. Where the land can support sus-
tainable agriculture, deforestation may be ben-
eficial. But most of the Tropics' remaining for-
est land cannot sustain continuous farming or
grazing using current practices and so is soon
abandoned. The abandoned land has lost much
of its inherent productivity-a loss the tropical
nations and the world can ill afford. The
United States, however, can contribute exper-
tise to develop and disseminate technologies
that could reduce the need to convert forests
to unsustainable land uses.
Forest land and former forest land in tropical
areas can be classified as undisturbed forest,
disturbed forest (secondary forest and man-
made forest), converted land (cropland and
grazing land), and unproductive land.* The
products from these lands differ, with the most
actively managed lands-cropland and man-
made forest-generally yielding the highest
economic value. Secondary forest is often per-
ceived as relatively unproductive. Yet all for-
ested land provides important services includ-
ing climate and runoff regulation, water reten-
tion, and maintenance of an enormous, still-un-
cataloged stock of species.

*Undisturbed forest-natural tropical forest with at most a
few small areas cleared by natural or human-induced events,
regenerating by natural stages of succession.
Disturbed forest-includes:
Secondary forest or forested land that has been cleared in large
areas within the last 60 years, commonly for crops or pasture.
Usually it is sufficiently degraded or harvested so often that
it does not return to its original state. Trees may be managed
or left to natural succession, and
Manmade forest planted and maintained in trees, often in ex-
otic species, often a tree monoculture and sometimes also
with a useful understory.
Converted Land-includes:
Cropland planted annually or every few years with food or
fiber crops, and
Grazing land covered permanently with grasses, legumes, and/
or herbaceous species, harvested by grazing animals.
Unproductive land-land that has been so degraded that it pro-
duces few useful products and provides minimal environ-
mental services (e.g., erosion and flood control). It usually
supports very little growth of useful species and does not
return naturally to any of the previous categories.

Depending on the methods of management,
these natural resources may be sustained or un-
sustained. Sustained resources are those in
which the inherent productivity is not dimin-
ished over time. Conversely, unsustained re-
sources suffer declining or degraded produc-
tivity. Productivity of almost any land can be
sustained by applying substantial inputs (e.g.,
fertilizer, water), but this is not the general
practice on tropical lands.
Undisturbed forest is the only productive
form that maintains itself without human man-
agement. Four of the land types-cropland,
grazing land, secondary forest, and manmade
forest-potentially are interchangeable. For ex-
ample, cropland can be fallowed into grazing
land, which can be planted with trees. In some
cases, several land uses can be realized simul-
taneously-e.g., agroforestry can combine
agriculture, forestry, and grazing. Little, if any,
land changes back into undisturbed forest or
out of unproductive land, although in theory
undisturbed forest might be regenerated from
other land types or unproductive land might
be made productive if given enough investment
or time to recuperate (fig. 1).
Because this process moves tropical land
from forest to unproductive land rapidly and
from unproductive land back to forest more
slowly, the area of unproductive land is grow-
ing steadily. Thus, serious land degradation is
taking place, but the change may not be felt im-
mediately in terms of price or availability of
products. This is because the intermediate
levels of land use are being maintained by con-
tinually clearing undisturbed forest to replace
land that becomes unproductive. Figure 2 de-
picts the trend of land-use changes over time
typical of tropical areas.*

*This discussion does not present documented trends in land
class but provides a general discussion of concepts. The inter-
actions implied by the diagrams are derived from the principles
and experience of members of the Advisory Panel and of a
workshop attended by Dr. Donella Meadows, Dr. Jeff Gritzner,
Dr. Frank Wadsworth, Dr. Jeff Romm, Dr. John Terborgh, and
the OTA project staff. Thus, figures 2 and 3 present no scales,
nor are specific countries or regions classified by position on
the curves.

4 TANeptigw to Sustain Troploal Forest Resources

Figure 1.-Trend of Change Among Tropical Forest Land Uses

SOURCE. Office ol Technology Assessment

Figure 2.-Conceptual Diagram Indicating Land-Use Changes Typical of Tropical Asia

- I uiii -

SOCF p Offl ooft-echnology Assessment.

If ntfiag Wviere done to change the system,
the .-~iisia which the amount of undisturbed
lad unproductive land stabilize for
'a i would be, in theory, where the
co Ahe next acre of undiPtiobed
facst of reclaiming ansace of
Af-d Since that cost is high for
this equilibrium implies
Li disturbed forest, a great deal
l and, and extremely low levels
-. -

: .- i

of production. The actual equilibrium may be
delayed until even more undisturbed forest is
cleared because costs and benefits accrue to
different groups of people, skewing both mo-
tivations to invest and to exploit,

Many technologies exist but are not fuly
used to prevent conversion of productive land
to unproductive land, to increase yields on it-
termediate lands, or to harvest from undis-

,,, ..- ;- ,

Introduction 5

turbed forest without converting it to a less
sustainable land type. There are also social
changes both possible and desirable to re-
duce the driving forces behind conversion to
unsustainable uses.
Because different countries or regions of
countries fall at different points along the
curves in figure 2, the actions needed to halt
this degradation would be most effective if de-
signed for the urgency of the situation in each
country. For example, regions with low rain-
fall and/or dense populations probably follow
this process more rapidly than countries with
moist forest and large areas of currently inac-
cessible land. Categorization of countries or
major regions to indicate the urgency for ac-
tions to address loss of tropical forest resources
and degradation of land productivity might
take the form indicated in figure 3:
Countries where the problem is latent but
not compelling: A considerable amount
of original forest land remains, but with-
out appropriate measures, population
pressures and development needs can be
expected eventually to propel these coun-
tries into the next categories.
Countries where the problem is critical:
Much original forest land has been con-
verted into the four intermediate uses, in-

cluding most of the land capable of sus-
taining continuous agriculture. Further
clearing is occurring and technologies to
sustain productivity on these lands gen-
erally are not applied.
Countries where emergency measures are
required-the ratio of unproductive land
to original undisturbed forest is high and
increasing, severe shortages of locally pro-
duced forest products are occurring, and
the amount of intermediate land types is
declining rapidly because technologies are
not adequately used to sustain land pro-
An improved division of countries into cate-
gories might account separately for urgency of
human needs (e.g., food, fuelwood, materials
for shelter, fodder, etc.) and urgency of ecolog-
ical need (e.g., loss of genetic diversity). The
Food and Agriculture Organization has cate-
gorized countries by need for action to ame-
liorate fuelwood deficiencies, but scales to
measure other dimensions of forest resource
value have not been created.
The loss of tropical forest resources is not
new, and its effects are not restricted to those
who live within the forests. Part I of this report
describes the Background of tropical forest
resource changes, including who is affected,

Figure 3.-Conceptual Diagram Indicating Possible Categorization of Countries or Regions
by Urgency of Land Degradation Problems

Latent condition

Critical condition

Emergency condition

- I iFrle -

SOURCE: Office of Technology Assessment.

6 Technologies to Sustain Tropical Forest Resources

the current status, the visible agents and un-
derlying causes of change, and the organiza-
tions-United States, national, and internation-
al-involved. This section also describes the
tropical lands of most direct concern to the
U.S. Congress: the U.S. tropical territories.
Part II of this report, Technology Assess-
ment, discusses various technologies for re-
source-sustaining development of tropical for-
est lands. The technologies considered cover
a broad range. Some are techniques to manage
the forests-undisturbed and disturbed-and
some are technologies to use forests to protect
related resources such as agriculture and wa-
ter. Others are techniques to prepare people for
the various tasks involved in sustaining tropical
forest resources, such as resource development
planning, education, research, and technology
Within each technology discussion, actions
are suggested to promote development of sus-
tainable tropical forest use. In general, actions
can enhance the stability and productivity of
tropical lands if they:

reduce degradation of the resource base,
reduce demand on the ecosystems,
provide more timely and accurate infor-
mation to decisionmakers or reduce the
time necessary to implement decisions.
A final chapter in this section discusses appli-
cation of the various kinds of technologies to
the U.S. tropical forests.
Part III describes Issues and Options for
Congress to promote development and use of
technologies that can sustain tropical forest re-
sources globally and within U.S. tropical ter-
ritories. The organization of options for the
Congress does not indicate the relative impor-
tance of the various measures. If long-term ac-
tions are not taken to build institutions con-
cerned with the sustainable use of tropical for-
ests, short-term actions will be overwhelmed.
And conversely, if short-term measures are not
taken, development of institutions to manage
the forest resources in the long term may be

Chapter 1


Introduction ........................................ ..... ........... 9
Importance of Tropical Forest Resources .................................... 10
Status of Tropical Forests ................................................. 10
Technology Assessment.......................... ...................... 14
Technologies for Undisturbed Forests ..................................... 14
Maintaining Sample Ecosystems .................................... .. 14
Making Undisturbed Forests More Valuable .............................. 14
Technologies to Reduce Overcutting .................................... 15
Industrial W ood .................... .......... ....... .............. 15
Fuelw ood ....................................... .... .............. 16
Technologies for Disturbed Forests ...................................... 17
Management of Secondary Forests ...................................... 17
Reforestation of Degraded Lands ....................................... 17
Forestry Technologies to Support Tropical Agriculture ...................... 18
A groforestsry ........................ ........... ............ 18
W atershed M anagem ent ................................. ............. 19
Resource Development Planning ....................................... 20
Education, Research, and Technology Transfer ............................. 20
E education ............................................. ............ 20
R research ............................. ......... ... ............ .... 21
Technology Transfer .................................................. 22
Issues and Options for Congress ......................................... 23
Expand and Coordinate Development Assistance ........................... 24
Encourage Resource Development Planning. ............................... 25
Improve Tropical Forest Research and Market Development ................. 25
Protect Biological Diversity ......................................... ..... 26
Expand U.S. Expertise in Tropical Forest Resources ........................ 26
U .S. Tropical Forests .............. .................. ... ........... 27
Introduction ............................. ................ ........ ... .27
The U.S. Caribbean Territories: Puerto Rico and the U.S. Virgin Islands ....... 28
The U.S. Western Pacific: Micronesia and American Samoa ................. 29
Issues and Options for Congress ....................................... 31

List of Tables
Table No. Page
1. Estimates of Closed Forest Areas and Deforestation Rates in
Tropical Africa, America, and Asia ................ .................... 13

List of Figures
Figure No. Page
4. Global Areas of Tropical Woody Vegetation .............................. 9
5. Areas of Woody Vegetation in 76 Tropical Nations ......................... 11
6. A Typical Biosphere Reserve .............................. ............. 15
7. Location of Puerto Rico and the U.S. Virgin Islands ........................ 29
8. Location of the U.S. Western Pacific Territories ........................... 30

Chapter 1



Forests of various kinds cover 42 percent of
the tropical nations' land (fig. 4). To support a
population of 2 billion, these nations must use
the natural resources found in these forests:
soil, water, plants, and animals. The produc-
tivity of these resources can be renewable, but
only if tropical people use resource-sustaining
Some tropical nations are experiencing se-
vere shortages of forest products and services.

Figure 4.-Global Areas of Tropical Woody
Land surface of the Earth

forests Plantations
SOURCE: M. Hadley and J. P. Lanley, "Tropical Forest Ecosystems: Identifying
Differences, Seeking Similarities," Nature and Resources UNESCO,
19(1):2-19, 1983.

To avoid even more acute problems, they need
to restore resource productivity. Other nations,
even those with adequate forests, need to sus-
tain their forest resources to avoid future prob-
lems. In just 30 years, the population of tropical
nations is expected to double to 4 billion peo-
ple. Thus, the importance of tropical forest pro-
ductivity is increasing as more and more peo-
ple depend on forest products and services for
basic needs such as fuel, materials for shelter,
and a reliable water supply.
Substantial institutional activity is occurring
worldwide that directly or indirectly benefits
tropical forest resources. The U.S. Agency for
International Development (AID), the United
Nations agencies, the multilateral development
banks, and others have increased their atten-
tion to forestry in recent years. Private corpora-
tions and nonprofit organizations also have
been involved in the search for solutions to
tropical forest problems. Most importantly,
tropical nations' governments have come to
recognize that deforestation and forest re-
source degradation constrain their economies
and their development options.
The large number of organizations that have
some responsibilities in forestry might imply
that an adequate level of activity is under way.
But the total amount of expertise and funding
available to forestry still remains small relative
to the scope of the problem. International de-
velopment assistance organizations cannot
fund enough forest conservation to offset de-
forestation because the underlying institutional
causes can only be resolved by the tropical
countries themselves.


25-287 0 84 2

10 Technologies to Sustain Tropical Forest Resources


For tropical nations, forests and shrublands
provide wood for lumber and paper, building
materials, and fuel, and are an important
source of foreign exchange. Forests help main-
tain soil quality, limit erosion, stabilize hill-
sides, modulate seasonal flooding, and protect
waterways and marine resources from accel-
erated siltation. In addition, many millions of
people living in and near the forests depend
directly on them for food, medicines, and other
basic needs.

The benefits from tropical forests are not lim-
ited to tropical nations. World trade in tropical
wood is significant to the economies of both
the producing and consuming nations. The
United States is the second largest importer of
tropical wood products, and U.S. demand for
tropical wood has been growing at rates well
above our population and gross national prod-
uct growth rates. Tropical forests also provide
a broad array of nonwood products such as
oils, spices, and rattan that are valuable for
both subsistence and commerce. The annual
world trade in rattan, for example, is estimated
to be $1.2 billion. Thus, industrial wood and
other forest product exports earn substantial
foreign exchange for nations that trade with
the United States.

The productivity of renewable resources in
the Tropics affects both the economic viabili-
ty of U.S. investments overseas and political
stability in the tropical nations. Many devel-
opment projects funded by the U.S. Govern-

ment or the U.S. private sector are being under-
cut by flooding, siltation of reservoirs, pest out-
breaks, and other problems associated with de-
forestation. Food and jobs, both critical for po-
litical stability in developing nations, can be
reduced by the consequences of deforestation.
The highly diverse tropical forests contain
plants, animals, genetic material, and chemi-
cals that have great potential value for medi-
cine, agriculture, and other industries. The
Tropics are thought to contain two-thirds of the
world's approximately 4.5 million plant and an-
imal species. An estimated 2.5 million of the
tropical species are yet unknown to science.
Considering the value to society that has come
from those tropical species that have been stud-
ied (e.g., many major agricultural crops, anti-
cancer drugs, insects used in integrated pest
management), it is very likely that some of the
remaining unstudied species offer potentially
important resources, particularly for pest con-
trol, plant breeding, genetic engineering, and
other biotechnologies. Biologists are already
using new techniques for cloning plants and
micro-organisms to screen for their production
of useful chemicals.
Tropical forests also provide habitats for
many of the world's migratory birds and vari-
ous endangered species. About two-thirds of
the birds that breed in North America migrate
to Latin America or the Caribbean for winter.
Some of these migratory birds play an impor-
tant role in controlling agricultural pests in the
United States.


Some 76 nations located entirely or largely
within the tropical latitudes contain about half
the world's population (approximately 2 bil-
lion). These nations are characterized by rapid-
ly growing populations, low per capital in-
comes, and predominantly agrarian econo-
mies. Near forest lands, much of the agricul-
ture is subsistence farming, often in upland

areas where soils are dry or have low fertility.
Commercial agriculture, on the other hand,
generally is sited on the more fertile and often
irrigated alluvial plains of major river valleys.
Both types of agriculture are strongly affected
by the 1.2 billion hectares* of moist tropical

*One hectare equals 2.47 acres.

Ch.1-Summary 11

forest and 800 million hectares of drier open

The type and distribution of forests vary con-
siderably across regions in the Tropics (fig. 5).
Two-thirds of the closed forests* are found in
tropical America, while Africa has two-thirds
of the open forests.** Even within regions,

*Closed forest means that trees shade so much of the ground
that a continuous layer of grass cannot grow.
**Open forest has trees that cover at least 10 percent of the
ground but still allow enough light to reach the forest floor so
that a dense, continuous cover of grass can grow.

forest types are unequally distributed among

Data on the extent and condition of tropical
forests are widely scattered and often inac-
curate. Overall figures for deforestation* mask

*Deforestation is the conversion of closed or open forest to
nonforest. A distinction should be made between deforestation
and degradation; the latter refers to biological, physical, and
chemical processes that result in loss of the productive poten-
tial of natural resources in areas that remain classified as forest
This distinction explains some of the confusion in estimates of
change in forest resources.

Figure 5.-Areas of Woody Vegetationa in 76 Tropical Nations (thousands of hectares, 1980 estimates)
Tropical America

forests4,620 Closed forest
4,60 fallow
Open woodland 108,612
61,650 Open woodlands
Tropical Africa

Tropical Asia

O /Open woodland
Closed forest

Closed forest

35,503 /


Open woodlands
Open woodland

aClosed forest has dense tree canopies and no continuous grass cover. Open forest has scattered trees and continuous grass cover. Forest fallow is land
used for or abandoned from agriculture. Shrubland has wood vegetation under 7 meters high.
SOURCE: Office of Technology Assessment.

12 Technologies to Sustain Tropical Forest Resources

considerable differences among the rates at
which individual countries are using and alter-
ing their forest resources (table 1). If present
trends were to continue, nine tropical coun-
tries would eliminate practically all of their
closed forests within the next 30 years and
another 13 countries would exhaust theirs
within 55 years.
Estimates of overall deforestation rates also
conceal significant differences in the types of
tropical forest affected. The loss of species is
probably greatest in the broad-leaved humid
lowland forests as these are biologically the
most complex and diverse. But the tropical
conifer forests cover much smaller areas and
have been severely degraded by logging and ag-
riculture. Direct impacts on people are greatest
in dry regions where degradation of open for-
ests leads to severe shortages of wood for fuel.
But the loss of mountain watershed forest may
affect even more people by making river flows
more erratic.
Each year approximately 11.3 million hec-
tares of the Earth's remaining tropical forests
-an area roughly the size of Pennsylvania-
are cleared and converted to other uses. Where
cleared land is developed for sustainable agri-
culture, deforestation can be beneficial. But
most land being cleared cannot sustain farm-
ing or grazing with available technologies. So
it is abandoned after a few years. Often, com-
mercially valuable trees do not grow back
quickly because of highly weathered soils,
harsh climates, and recurring fires. Thus, pro-
ductive but underused forest resources are giv-
ing way to low productivity grasslands and
Deforestation and degradation of tropical
lands are not new. Losses of forest resources
have been reported as early as 450 B.C. in the
African Sahel and 1000 A.D. in South China.
For centuries, tropical deforestation has been
associated with poverty and with patterns of
economic development that result in inequit-

able access to farmland. People displaced by
development in the lowlands often have been
the direct agents of deforestation because they
have little choice if they are to survive.
The main agents of tropical deforestation and
forest resource degradation continue to be sub-
sistence agriculturalists, livestock raisers, fuel-
wood collectors, and people who set fires to
facilitate clearing or gathering activities. Com-
mercial agriculture plays a smaller role in de-
forestation today than it has in the past, al-
though in some areas (e.g., Central America
and Brazil) clearing tropical forests for cattle
ranching causes a large part of the forest re-
source loss. Commercial logging is also an im-
portant cause of forest degradation.

Both subsistence and commercial use of for-
est lands can cause deforestation. Combined,
they form particularly pernicious relationships.
For example, loggers build roads through un-
disturbed forests to remove timber. Slash-and-
burn cultivators use the roads to gain access
to the forests and clear patches for temporary
agriculture. Ranching or commercial agricul-
ture may follow the farmers, exploit the land's
remaining productivity, then move on into new
areas. These agents of tropical forest change
vary in prominence among tropical America,
Africa, and Asia.

Alternative techniques exist that could be
substituted for these destructive practices.
However, sustainable forestry and agriculture
practices generally are not being developed
and applied. The underlying causes of this fail-
ure lie in political, economic, and social forces
(e.g., undefined property rights) that cause peo-
ple to use forests in ways that are inappropriate
to ecological conditions. Deterioration of the
forest resources seems likely to continue until
combinations of improved technologies and en-
forced resource development policies make
sustaining the forests more profitable than de-
stroying them.

Ch.1-Summary 13

Table 1.-Estimates of Closed Forest Areas and Deforestation Rates in Tropical Africa, America, and Asia

Closed forest
Country (1,000 ha)

Tropical Africa:
Ivory Coast .................
N igeria ....................
Burundi ....................
Benin ...................
Guinea-Bissau .............
G uinea ....................
Kenya .....................
Madagascar ...............
Angola ....................
Zam bia ............. .....
Ghana ....................
Mozambique .............
Sierra Leone ...............
Togo ......................
Sudan ....................
C had ......................
Ethiopia ...................
Som alia ...................
Equatorial Guinea...........
Zaire ......................
Central African Republic .....
Gabon .....................
Congo .....................
Zimbabwe ..................
Nam ibia ...................
Mali ......................
Upper Volta ................
Senegal ...................
M alaw i ..................
Gam bia ....................


Totals .................... 216,634
Tropical America:
Paraguay .................. 4,070
Costa Rica ................. 1,638

per year"



Haiti ............ ....... .
El Salvador .................
Jam aica ...................
Ecuador ...................
Honduras ..................
Guatemala .................
Colom bia ..................
M exico ....................
Belize .....................
Dominican Republic........
Trinidad and Tobago ........
Peru .......................
Venezuela ..................
C uba ......................
French Guiana..............
Surinam ............. .....
Guyana ....................
Totals ...................
Tropical Asia:
Nepal ............. ... .....
Sri Lanka ..................
Thailand ...................
M alaysia ...................
Laos ....................
Philippines .................
Bangladesh ................
Viet Nam ..................
Indonesia ..................
Pakistan ...................
Burma .....................
Kampuchea ................
India ......................
Bhutan ....................
Papua New Guinea..........
Totals ...................

Closed forest
(1,000 ha)



per yeara



aFrom 1981-85.
bNo data; in most cases this is where the areas are very small.

SOURCES: Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources Assessment Project (GEMS): Tropical Africa, Tropica'
Asia, Tropical America, 4 vols., Rome, 1981.

14 Technologies to Sustain Tropical Forest Resources


This report discusses various technologies to
develop tropical forest resources. Some are
techniques to manage forests-undisturbed and
disturbed-and some are technologies to use
forests to protect related resources such as ag-
riculture and water. Others are techniques to
prepare people for the various tasks involved
in developing and implementing technologies
to sustain the resources.

Technologies for
Undisturbed Forests
Undisturbed forests produce many valuable
products and services, usually with little or no
human management. One way to reduce the
rate at which undisturbed forests are converted
to other, nonsustainable uses is through sys-
tematic preservation of sample ecosystems in
parks and protected areas. Another approach
is to enhance the value of the forest by develop-
ing its resources other than timber-the non-
wood products and forest food sources. For
either approach to succeed, willing involve-
ment of local people and political commitment
from government decisionmakers are essential.

Maintaining Sample Ecosystems
Parks and protected areas can be managed
for direct income (e.g., tourism) and for indirect
benefits, such as preventing siltation of reser-
voirs. Some of these benefits can be estimated
for resource allocation decisions. Other major
benefits provided by protected areas-e.g.,
preservation of biological diversity-cannot be
measured in dollars. Thus, in the past, the loca-
tions of protected areas have been determined
more for watershed protection or tourist poten-
tial than for conserving of biological diversity.
A marked disparity exists in the worldwide
distribution of parks and protected areas, with
some types of ecosystems well represented and
others not represented at all. Many legally pro-
tected areas lack firm commitments from local,
national, and international agencies. Conse-
quently, they receive little actual protection or
are inadequately managed.

Strict preservation with total exclusion of
economic activity is not practical for many
sites where protection of undisturbed forests
is important. Recognizing the growing de-
mands to develop rural land, protected area
planners and managers have begun to pay
more attention to socioeconomic and institu-
tional factors. They seek participation from
both the people who will affect or be affected
by forest resources and the people and agen-
cies that must support management programs.

Some innovative plans that include the sur-
rounding biophysical and socioeconomic set-
ting have been developed for protected areas.
One such activity is the UNESCO Man and the
Biosphere (MAB) program's worldwide net-
work of biosphere reserves (fig. 6). The man-
agement of these reserves considers the needs
of local populations and seeks ways to make
benefits available to local people. More field
experience and monitoring are needed to eval-
uate the successes of existing biosphere re-
serves. However, the MAB effort is constrained
by a lack of strong, consistent commitments
from U.S. and other governments.

Making Undisturbed Forests
More Valuable
Few deliberate attempts have been made to
harvest forest products other than timber and
fuelwood in a sustainable, organized way. In-
centives to maintain unlogged forests would
be greater if methods were developed to use
forest resources other than timber more fully-
either by discovering new, valuable products
or by encouraging collection and processing
of existing products.

Products obtained from animals and from
wood, bark, leaves, or roots of trees and other
forest vegetation offer significant opportunities
for tropical countries to develop cottage indus-
tries. Employment and incomes for people liv-
ing in or near forests could be improved while
encouraging maintenance of the natural eco-
systems. Improved assessment of the role of

Ch.1-Summary 15

Figure 6.-A Typical Biosphere Reserve

X -
/ x x X

/\ x I
/ \

\ 1-] -. /

Core area [ Research station
Buffer zone 1 [T Tourism
D Buffer zone 2 X X Human settlements
A biosphere reserve considers the needs of the local people by incorporating
biophysical and socioeconomic factors into its management plan.
SOURCE: M. Batisse, "The Biosphere Reserve: A Tool for Environmental Con-
servation and Management," Environmental Conservation, vol. 9, sum-
mer 1982.
forest products in subsistence economies and
development of markets for nonwood products
could help decisionmakers recognize the value
of undisturbed forests. U.S. scientific and
managerial expertise could be applied to this
problem, especially from the fields of ecology,
botany, business, and forest management.
Few technologies exist today that can extract
selected renewable resources from a tropical
forest while leaving the forest nearly intact.
Crocodile and butterfly farming are two ex-
amples that are being implemented. The devel-
opment of other such resource-conserving sys-
tems is needed.

Technologies to Reduce Overcutting
Much resource degradation is caused in
closed tropical forests by inappropriate wood
harvesting methods and in mountain and dry

forests by cutting more wood than grows each
year. Development of improved wood process-
ing technologies and markets for more of the
many tree species and sizes growing in the
closed forests would reduce the area that must
be logged to satisfy timber demand. Where too
much wood is being cut, it may be necessary
to reduce demand by increasing the efficien-
cy of woodstoves and charcoal kilns or by sub-
stituting alternative energy sources.

Industrial Wood
Intensive forest harvesting could give in-
creased output per unit area, thus reducing de-
mand to cut elsewhere. But this approach can
have both positive and negative impacts. It can
make reforestation planting more feasible. On
the other hand, it increases the potential for
damage to the site from poor road engineer-
ing, inadequate site protection, and tardy res-
toration of forest stands. Intensive harvesting
would require strict enforcement of regulations
to prevent adverse impacts on the land's long-
term productivity.
Intensive harvesting depends on the availa-
bility of profitable technologies to extract, proc-
ess, and market a wider range of tree species
and sizes. Grouping species according to their
uses (e.g., construction material) is an approach
that has been successful in Africa. However,
many unused species have sizes, shapes, or
wood characteristics that make them difficult
to harvest and process and that limit their use-
The use of smaller trees would require cost-
ly replacement of existing equipment, which
has been designed for large logs. Portable saw-
mills and small units that could be carried easi-
ly and set up to mill logs at the stump could
make logging much more efficient. Such tech-
nologies might minimize adverse environment-
al effects from hauling logs but might encour-
age logging of currently inaccessible areas.
The greatest progress toward making inten-
sive harvest profitable has occurred where mul-
tispecies wood chips are produced for wood
pulp or fuel. The "press-dry paper process"
developed at the U.S. Forest Products Labora-

16 Technologies to Sustain Tropical Forest Resources

tory promises to increase the world market for
hardwood chips. However, chipping can have
adverse impacts because in moist tropical for-
ests most of the plant nutrients are located in
the trees rather than in the soil. Thus, wood
chip harvesting that removes most trees can
severely reduce the fertility of the site.
For little known but potentially marketable
lumber species, cost-effective preservation and
drying technologies are needed to improve use
characteristics. Many types of wood are sus-
ceptible to attack by termites, other insects, or
fungi under tropical conditions. Although
wood preservatives are available, they gener-
ally are costly. Some less expensive techniques
exist but their effectiveness has not been

Approximately 80 percent of the estimated
1 billion cubic meters of wood removed annual-
ly from tropical forests is used for fuel. The ef-
fects of excessive fuelwood cutting are seen
first near cities and towns where fuel demand
is concentrated. But overcutting does not
always remain a local problem. Mangrove
forests of Thailand and dry forests of Kenya,
for example, are overcut to produce charcoal
that is transported by ship to other nations.
Most wood fuel is used in homes for cook-
ing, though tobacco drying and other rural in-
dustries also consume substantial quantities.
Common domestic stoves waste much of the
wood energy, as do traditional methods of mak-
ing charcoal. Therefore, it should be possible
to reduce fuelwood demand significantly and
consequent overcutting by disseminating more
efficient stoves and charcoal kilns.
Attempts to introduce such technologies in
tropical nations have had mixed success. Im-
proved stoves are not quickly and widely ac-
cepted. Though cheap by U.S. standards, they
often cost too much. Some reduce the range
of fuels that can be used. Further, improved
charcoal production sometimes does not lead
to less wood cutting because charcoal makers
may use the time or profits they gain to make
even more charcoal. Techniques to reduce de-

Photo credit: OTA staff
Since most wood fuel in tropical nations is used in
homes for cooking, disseminating more efficient and
low-cost stoves should significantly
reduce fuelwood demand

mand require especially careful planning,
monitoring, and evaluation.
Nonwood fuels such as kerosene can some-
times be used to reduce wood demand tempo-
rarily while fuelwood plantations are estab-
lished and while natural forests recover from
exploitation. But the costs of obtaining and
distributing nonwood fuel substitutes are often
prohibitive, especially to the rural poor. Small-
scale, renewable energy technologies such as
solar dryers have more potential for long-term
use, but their adoption is inhibited by finan-
cial and managerial constraints.
Substituting plantation-grown wood for na-
tural forest wood clearly is an important op-
tion in many tropical regions. Investment in
plantations is constrained, however, where ac-

Ch.1-Summary 17

cess to "free-for-the-taking" forest wood is not
restricted. Thus, regulatory controls on fuel-
wood gathering from the natural forest must
be enforced if the fuelwood plantation option
is to be used before all the accessible natural
forests are destroyed. Where fuelwood has
commercial value above the cost of cutting and
transportation, there is a possibility that farm-
ers and business will invest in planting trees.
Securing future wood supplies is a social,
political, and economic problem. Investments
of land, labor, and capital in tree growing are
constrained by problems with land ownership,
laws, and social organization. Until these are
resolved and woodfuel supplies are being effec-
tively replenished, measures to reduce demand
will fail to reach the root of the problem. De-
mand reduction creates no incentives for in-
creased supply; it may achieve the reverse.

Technologies for Disturbed Forests
An estimated 400 million hectares of poten-
tially productive secondary forest* exist in
closed tropical forest areas. Approximately 2
billion hectares of tropical lands are in various
stages of degradation. Investment in the im-
provement of secondary forests and reforesta-
tion of degraded lands offers opportunities to
meet needs for materials, substitute domestic
production for imports, and provide new
sources of employment in wood production
and processing.

Management of Secondary Forests
Many tropical countries could sustain pro-
duction of all the wood they will need for dec-
ades if adequate investments were made to de-
velop and manage cutover secondary forests.
However, such investments are seldom made.
Land tenure can be a constraint, but even
where the forests are clearly owned and con-
trolled by government forestry agencies or
private landowners, investments are usually in-
adequate. Technologies for sustained forest

*Secondary forest includes both residual forest that has been
cut once or several times during the past 60 to 80 years and sec-
ond growth forests that invade after periodic cultivation.

production exist, but for most of these the time
lag before payback begins is too long and re-
turn on the investments is too low to attract
adequate private and public capital. Opportu-
nities to improve this situation include:
resolution of land tenure issues,
public and private investments in research
and development to make sustainable sec-
ondary forest management more profit-
increased technology transfer of profitable
resource-sustaining forest management
methods, and
implementation of resource use regula-
tions, tax laws, or subsidies to make in-
vestments in secondary forest manage-
ment more profitable.
Simply reducing logging damage by using ap-
propriate or improved harvesting equipment
can increase the number of trees available for
a future crop as well as increase natural regen-
eration and facilitate enrichment planting. But
to ensure that this occurs, regulations to con-
trol logging practices must be enforced.

Reforestation of Degraded Lands
Technologies are available to reforest certain
degraded lands. But tree planting sometimes
does not compete well, in economic terms,
with other land uses. The solutions to this di-
lemma include reducing reforestation costs, re-
ducing plantation failure rates by enlisting sup-
port of local people, increasing plantation
yields, and developing methods to quantify the
indirect benefits of reforestation.
Reforestation costs can be reduced if land
preparation is used to reduce weed invasion
and ensure a favorable environment for seedl-
ing growth. Plantation yields can be increased
by selecting high-yielding, fast-growing, soil-
enriching, and stress-tolerant tree species.
Developing and implementing tree breeding
and improvement programs can produce vari-
eties with high yields and other desired char-
acteristics. Careful provenance testing-match-
ing the appropriate variety to a particular
site-should improve species performance and
reduce mortality.

18 Technologies to Sustain Tropical Forest Resources

To achieve successful reforestation, several
constraints must be overcome:
shortage of planting stock and lack of qual-
ity control in seed and clone production,
inadequate knowledge of tropical site con-
ditions, and
lack of information dissemination.
The coordination of collection, certification,
and international distribution of high-quality
seeds in commercial quantities needs to be im-
proved. Information on proven silvicultural
techniques must be disseminated to the local
These technical problems can be solved
given adequate funding and time. A more sub-
tle problem is to get local people to maintain
tree plantations. First of all, they must clearly
understand the reasons for planting trees. The
trees should produce products local people
want, and the people must be convinced that
substantial benefits from the trees will accrue
directly to them. Often this means using spe-
cies selected by local people rather than species
selected by foresters.

Photo credit: J. Bauer
Mahogany seed. Shortage of planting stock and lack of
quality control in seed production are constraints to
reforestation. Systematic collection, certification, and
distribution of seeds in commercial quantity
could facilitate tree planting

Forestry Technologies to Support
Tropical Agriculture
Medium- and long-term maintenance of trop-
ical forest resources may depend more on sus-
taining the land already under cultivation than
on refining use of the remaining forest. Intro-
ducing woody perennials into farming and pas-
toral land (agroforestry) and improving farm-
ing techniques for upland watershed areas
could help sustain the productivity of lands
under cultivation and so reduce the need to
clear additional forest lands.

Agroforestry encompasses many well-known
and long-practiced land-use methods. The aim
is to create productive farming systems able to
supply a higher and more sustainable output
of basic needs and saleable products than oc-
curs without trees. Agroforestry is most impor-
tant on lands with serious soil fertility prob-
lems and lands where inadequate rural infra-
structure makes it vital for people to produce
most of their own basic needs for fertilizers,
food, fodder, fuel, and shelter.
Agroforestry is a newly recognized field and
could benefit from a critical examination of
practices and quantification of information.
Since agroforestry cuts across several disci-
plines, its research and development requires
an interdisciplinary approach. Because of frag-
mented institutional jurisdiction, however,
agroforestry is not receiving adequate support
from either forestry or agricultural institutions.
Great technological potential for agroforestry
seems to lie in genetic improvement (systema-
tic breeding and selection) of multipurpose tree
and shrub species. Selection of appropriate
provenances, subspecies, and varieties can
greatly enhance the success of agricultural
systems designed for particular land require-
The potential for farmers and pastoralists ac-
tually to adopt agroforestry system improve-
ments is more difficult to assess. Peasant farm-
ers can ill afford the risks of innovation. Large-

Ch.1-Summary 19

Photo credit: H. Bolllnger
Production agroforestry system (planting Eucalyptus fuelwood trees, coffee, fodder grasses, and sisal fiber crops on
terraces) in Kenya. Such land-use systems could have great impact on sustaining tropical forests

scale adoption of new agroforestry systems
would require creating incentives for people
to implement new practices in spite of the ini-
tial risks and delayed returns.

Watershd Mn uage.n
The greatest problems in tropical watersheds
occur where subsistence farmers and their live-
stock move onto steep uplands. Excluding
farmers and livestock from such areas can al-
low vegetation time to recover, but enforcing
such policies is difficult. Mechanical structures
and replanting methods can restore water flow
stability from some deforested slopes. Further,
conservation practices exist that allow farm-
ing and grazing on many moderate watershed
slopes. However, the watershed management
techniques are unlikely to become widespread

until farmers and herders in upland areas have
incentives to stop destructive land-use prac-
tices. To provide upland farmers with nondes-
tructive land-use alternatives necessitates:
developing methods of land use that are
more profitable to the local community
and at the same time improve control of
water flows;.
developing improved techniques to meas-
ure and predict tradeoffs of different man-
agement actions; and
testing new technologies and getting the
useful ones adopted by the local communi-
ty. Subsidies from downstream benefici-
aries of the watershed protection may be
necessary. Sociological studies could help
define the type of incentives needed to ob-
tain farmers' cooperation.

20 Technologies to Sustain Tropical Forest Resources

Resource Development Planning
Most conversions of tropical forests to other
land uses take place without adequate consid-
eration of whether the natural and human re-
sources available can sustain the new land use.
Sometimes, destructive forest conversions are
an unplanned result of some other, narrowly
planned development. For instance, poorly
sited logging roads can open highly erodible
forest land to unplanned clearing for slash-and-
burn agriculture.
This problem can be ameliorated through the
use of resource development planning tech-
niques that match land development activities
to the natural and human capabilities of specif-
ic sites. These techniques can identify which
sites can sustain crop production, grazing, res-
ervoirs, new settlements, intensive forestry or
agroforestry, and which will be most produc-
tive if retained as natural forest.
Ideally, resource development planning in-
cludes four components: biophysical assess-
ment, financial (investor's viewpoint) and eco-
nomic (society's viewpoint) assessment, social
assessment, and project monitoring and eval-
uation. Biophysical assessment is used more
often than the others, although it still is under-
used. Furthermore, the techniques commonly
are used to find the best site for a particular
development purpose rather than to develop
a comprehensive strategy for all sites in a
Use of each of the four planning components
is constrained by a lack of information on
cause-and-effect relationships. Economic as-
sessment encounters difficulty measuring non-
market values. Further, the analyses may con-
sider the forest values only of a small site,
disregarding the interrelationships between
that site and the surrounding area. For exam-
ple, loss of the genetic resources in a small
patch of a large forest may seem unimportant
because nearby forested areas contain the same
biological diversity. Consequently, individual
economic analyses may justify clearing the for-
ested region piece by piece without accounting
for the overall genetic loss incurred.

Finally, even well-planned development may
prove unsustainable if planning stops after im-
plementation begins. Most planning is done be-
fore projects begin when least is known about
biophysical and human resources at the site.
Continuous planning, monitoring, and evalua-
tion are necessary during and after the project.
The major development assistance organiza-
tions have begun to institute such procedures
but have not yet determined how to use the re-
Opportunities to enhance the use of resource
development planning include improving data
availability, more demonstration of the tech-
niques' potentials, better communication of
planning successes, increasing the number of
trained planners, improving techniques for
economic and social analysis, and assuring that
projects remain open to redirection after imple-
mentation begins.

Education, Research, and
Technology Transfer
Forest resource development is constrained
in most tropical nations by a shortage of pro-
fessional and technical personnel who know
about appropriate technologies and who also
understand the institutional, economic, and
cultural aspects of forest resource systems. In
the near term, expatriates, including U.S. pro-
fessionals, can provide some expertise. But this
is not likely to be sufficient because the scope
of tropical forest resource problems is so large
and the number of expatriate experts is few.
Further, expatriates lack the political and cul-
tural ties necessary to influence policy. Sustain-
ing tropical forest resources requires develop-
ment of indigenous expertise in all aspects of
resource development. Education, research,
and technology transfer are the means to de-
velop expertise both in the United States and
in tropical nations.

U.S. universities can act to sustain tropical
forests in two ways: educating professionals
who will work in tropical forestry related fields

Ch.1-Summary 21

and strengthening tropical nations' universi-
ies. However, tropical forestry is peripheral to
the interests of most U.S. forestry schools and
the experts are scattered widely among institu-
tions. Consequently, efficient mechanisms
must be developed to bring together multidis-
ciplinary teams of researchers and educators
and connect them with students, foreign uni-
versities, and others seeking to develop tropical
forest expertise.
Twinning, which creates associations be-
tween tropical nation institutions and individ-
ual developed nation institutions, has worked
with a few university forestry schools. Consor-
tia of U.S. universities can provide tropical in-
stitutions access to a wider range of expertise
and experience than twinning arrangements.
However, this approach still does not resolve
several of the fundamental deficiencies that re-
duce the effectiveness of U.S. institutions. U.S.
forestry schools lack a tropical setting for
teaching and research. Further, their curricula
do not prepare students to solve the social and
institutional problems that confront tropical
forest resource development.
The development of one or more U.S. cen-
ters of excellence in tropical forestry might
resolve these deficiencies. For example, a
center of excellence in Puerto Rico could focus
on Latin American forest development needs,
providing the necessary tropical setting as well
as benefiting the U.S. tropical forests.
A major objective of U.S. efforts to enhance
tropical forest education could be to strengthen
schools in the Tropics. Some 138 universities
and 220 technical schools in tropical nations
provide forestry education and training. Near-
ly all these schools are new. Most are small and
produce few graduates each year. Thus, sub-
stantial support is needed to provide in-service
faculty training, to produce locally relevant
course materials, and to modernize basic edu-
cation facilities such as herbariums, library col-
lections, and computers.
Resource development professionals, the sci-
entists who develop technologies, and the tech-
nicians who implement them are ineffective
without strong support from the many people

who make decisions about the use of natural
resources. Environmental education aims to
change people's attitudes and behavior by pro-
viding them with the motivation and the knowl-
edge necessary to make decisions and take ac-
tions that will sustain natural resource pro-

Environmental education efforts can be di-
rected at the general public using mass media
or programs in primary and secondary schools.
Or the efforts can be directed more narrowly
at higher level decision makers. Unfortunate-
ly, the behavioral science basis for environmen-
tal education is not well established, so the
techniques must be developed by unscientific
trial and error. This development could be ac-
celerated if significant investments were made
to evaluate, document, and communicate the
environmental education efforts that are under
way. Having neither a strong scientific foun-
dation nor substantial documentation of the
causes of program success and failure, envi-
ronmental education projects have a difficult
time competing with other projects for funds
and personnel.

Technologies intended to develop renewable
resources are likely to fail if they are based on
inadequate knowledge. Thus, both fundamen-
tal and applied research are necessary compo-
nents of any strategy to sustain tropical forest
resources. Fundamental research is the foun-
dation for applied research, while applied re-
search is needed to improve existing forestry
technologies and develop new ones.

Many experts conclude that sustaining trop-
ical forests is not so much a technical problem
as it is an institutional problem. Thus, research
is especially needed to determine the interac-
tions between the social and biophysical fac-
tors of tropical forest systems. Some knowledge
about social and institutional factors is being
used in resource development projects sup-
ported by U.S. agencies. However, this knowl-

22 Technologies to Sustain Tropical Forest Resources

edge usually is based on personal experience,
not on careful research. A substantial increase
in truly interdisciplinary research could en-
hance the likelihood that institutional changes
would result in sustainable forest resource
The techniques used to manage tropical for-
est resources are generally based on trial-and-
error experience gained in past centuries. They
have benefited little from the rapid advances
in fundamental and applied biology that have
occurred recently. For most tropical forest
types, techniques have not been developed
that can:
produce the products, environmental serv-
ices, and employment opportunities that
local people need, and
sustain the productivity of the resource
base, and
be profitable enough to motivate people to
risk their scarce capital, labor, and land.
Applied research to improve existing technol-
ogies probably will not suffice to meet these
goals. Innovations based on new fundamental
research will also be necessary.
Low levels and short periods of funding are
major constraints on fundamental research in
tropical areas, but these are not the only rea-
sons why basic knowledge is inadequate to sus-
tain tropical forests. Most fundamental re-
search in tropical biology has been designed
to develop evolutionary theory, and relatively
little work has been done or is being done on
ecological theory.
Another problem is poor communication
among researchers and between researchers
and technology users. Most forestry and biol-
ogy research organizations reward scientists,
including those working on applied research,
for publishing in journals that technology users
seldom read. In fact, few journals exist that are
designed to communicate research results to
resource developers. The U.S. Forest Service
periodical The Caribbean Forester once served
this purpose but has been discontinued. As a
result of poor communication, the pace of in-
novation is slower than it needs to be, tech-
niques are reinvented, some mistakes are con-

tinually repeated, and potentially successful
technologies spread slowly, if at all.
Technology Transfer
The experience of U.S. forestry organizations
shows that many potentially profitable tech-
niques languish for lack of effective technology
transfer among scientists, between scientists
and technology users, and among technology
users. Thus, it is appropriate that international
development assistance organizations focus
their efforts not on promoting particular tech-
nologies but rather on building local institu-
tions' capacities to choose, receive, adapt, and
deliver technologies appropriate to local cir-
An important constraint on development as-
sistance effectiveness in forestry is the lack of
coordination among many bilateral and multi-
lateral projects. Coordination of resource de-
velopment projects so that each project contrib-
utes the appropriate actions at the appropriate
time to accomplish long-range plans should be
the responsibility of tropical governments. But
donor agencies usually fund the projects they
identify rather than projects identified in some
longer term planning process. One approach
to improve planning and coordination of tech-
nology transfer is the use of ad hoc interna-
tional committees that are separate from the
policies and problems of individual govern-
ment agencies or development assistance or-
ganizations. Committees such as the newly in-
stituted Coordination for Development in Af-
rica could assist tropical governments in de-
veloping long-range plans and in identifying
and recommending projects for the various in-
ternational organizations.
The OTA assessment identified a number of
necessary conditions for successful technology
transfer.* For most technologies, the lack of
these conditions seems to be constraining
wider adaptation and adoption:
Technology is transferred most effective-
ly by direct people-to-people actions. Peo-
ple who are to adapt and apply the tech-
*These conditions were a result of discussions among OTA
staff; Roger Moeller, AID; and Gary Eilerts, Appropriate
Technology International.

Ch.1-Summary 23

nology need to learn it directly from peo-
ple who have experience applying it.
* The technology needs to be adapted at the
users' end to local biophysical and socio-
economic conditions.
* Well-qualified people with knowledge
about the technology are needed on the
source end of the transfer, and receptive,
capable people are needed on the receiv-
ing end. These people may be local trans-
fer agents or they may be the end users.
* Another type of actor, the "facilitator," is
also necessary. Facilitators understand the
technology transfer process, including the
market for the technology and its products
and the political, social, and economic
constraints and opportunities that affect
all the other actors.
* Users and transfer agents should be in-
volved in choosing the technologies and
in planning and implementing the transfer
process so that the technology and the
transfer meet actual needs and are appro-
priate for the local situation.
* All parties involved-source, transfer

agents, facilitators, and end users-must
feel that they are winners and must, in
fact, be winners. Each actor's self interests
should be identified at the start of the tech-
nology transfer process so that they can
be addressed.
e* Each participant must be aware of subse-
quent steps in the transfer process so his
or her actions are appropriate to the later
steps. This requires early definition of
roles for each person involved.
The environment for technology demon-
strations should be similar to the environ-
ment that will exist during subsequent
steps of the transfer process. Pilot transfer
projects should not be unrealistically easy.
The initial commitment of resources to the
process should be sufficient to carry the
technology transfer until it is self-support-
The transfer process must include mech-
anisms through which all participants can
contribute effectively to interim evalua-
tions and improvements.


Tropical forest resources represent a great
opportunity for sustained development because
they are fundamentally renewable. However,
too little such development is occurring. In-
stead, the productivity of the forests continues
to be diminished. The U.S. Congress has al-
ready helped to sustain tropical forests by
directing AID and the U.S. representatives to
international organizations to give forest re-
source development higher priority in devel-
opment assistance programs. To expand this
progress, Congress could take actions that
would enhance tropical governments' abilities
to plan and coordinate resource development
The underlying causes of forest resource de-
terioration are institutional, social, and eco-
nomic. Consequently, the reforms needed to
support sustainable resource development can
only come from the governments and people

of the tropical nations. However, the United
States can help stimulate such reforms. Some
U.S. technologies, such as Landsat imagery, al-
ready supply vital information to improve re-
source development decisions. U.S. diploma-
cy-for example, supporting the United Na-
tions Environment Program and UNESCO's
MAB program-also can help to foster under-
standing of resource problems and coordinate
international efforts to resolve them.

Congress can address technical constraints
more directly. U.S. and international organiza-
tions that Congress can influence have the ca-
pability to: 1) develop technologies to produce
goods and services for local people while con-
serving forest productivity, and 2) assist trop-
ical organizations and individuals in develop-
ing, adapting, and implementing such technol-
ogies. U.S. agencies that are applying this type

24 Technologies to Sustain Tropical Forest Resources

of expertise include AID, the Forest Service,
the National Academy of Sciences, the Nation-
al Park Service, the Fish and Wildlife Service,
and the Soil Conservation Service. Some com-
mercial firms, private voluntary organizations,
and U.S. universities also have expertise rele-
vant to sustaining tropical forest resources.
Congress has ways to influence multilateral
banks and U.N. agencies, some obvious (e.g.,
through allocation of funds) and some subtle
(e.g., using the prestige of Congress to give
credibility to a new idea). The final chapter de-
scribes opportunities for congressional action
expand and coordinate development
encourage resource development plan-
improve tropical forest research and de-
velopment efforts,
protect biological diversity, and
expand U.S. expertise in tropical forest re-
The U.S. tropical forests are discussed sepa-
rately in this summary.

Expand and Coordinate
Development Assistance

Issue (Projects)
Development assistance progress is slow
and the gains are insufficient to sustain trop-
ical forest resources. Many opportunities ex-
ist to enhance gains already made, but con-
gressional vigilance is necessary to ensure
that forestry projects receive an appropriate
share of U.S. development assistance funds
and that other types of projects complement
the forestry efforts.
The Foreign Assistance Act directs develop-
ment assistance organizations in which the
United States participates to give higher priori-
ty to protecting against the loss and degrada-
tion of tropical forests. Accordingly, AID, the
World Bank, the U.N. Food and Agriculture
Organization (FAO), and some other multilat-
eral organizations have increased funding in

recent years for forest related projects. How-
ever, many opportunities for use of develop-
ment assistance to sustain tropical forest re-
sources are not being pursued adequately. Ex-
amples of such opportunities are:
emphasize agroforestry, innovative crops,
and other techniques to sustain permanent
agriculture on relatively poor soils;
promote reforestation and management of
natural forests to sustain environmental
services and produce fuelwood, construc-
tion wood, polewood, and nonwood prod-
stress institution-building to enable tropi-
cal governments to exercise improved con-
trol over timber concession operators; and
support livestock projects that do not re-
sult in deforestation or forest degradation.

To encourage expanded support for forestry
projects, committees of Congress could contin-
ue oversight hearings requesting AID officials
and U.S. representatives to multilateral devel-
opment assistance organizations to testify on
the extent to which assistance practices accom-
plish the objectives set forth in section 118 of
the Foreign Assistance Act.

Issue (Coordination)
Development assistance agencies general-
ly do not coordinate their projects effective-
ly at the country or regional level. To improve
their effectiveness, projects could be orga-
nized as steps in comprehensive strategies de-
signed to develop sustainable forest resource
use systems. Individual development assist-
ance agencies have neither developed nor co-
ordinated such strategies.
The reasons why host governments and in-
ternational assistance organizations do not
coordinate activities more effectively are com-
plex. But coordination could play a key role in
improving the cost effectiveness of U.S. assis-
tance. If the Congress decides that improving
cost effectiveness is worth relinquishing some
degree of U.S. control over what projects are
funded, it could mandate increased U.S. effort

Ch.1-Summary 25

to enhance the tropical nations' abilities to
coordinate the work of development assistance

One way to begin such a fundamental shift
in the development assistance process would
be to direct the Department of State to assess
whether various tropical nations are able and
politically ready to develop long-term action
plans for sustained forest resource develop-
ment. Another mechanism is to create ad hoc
committees of experts from donor nations and
tropical nations to work together to identify
problems and plan regional forest development

Encourage Resource Development
Although resource development planning
technologies can improve the sustainability
of tropical forest development, they are sel-
dom applied to their full potential.
Resource development planning techniques
can be used to identify development activities
that match the available human and natural re-
sources. The techniques can give decisionmak-
ers a clearer picture of the social, economic,
and environmental implications of a particular
type of development on a particular site. Also,
they can be used to determine the best locations
for protection of natural areas to maintain bio-
logical diversity while providing tangible ben-
efits. But the application of planning is ham-
pered by shortages of information on how bio-
physical, social, and economic factors interact.

To encourage the use of resource develop-
ment planning, Congress could maintain the
availability of low-cost Landsat images to trop-
ical governments. Congress also could direct
AID to expand its Environmental Profiles to
include macro-level land classification and col-
lection of information for social and institu-
tional analyses. Further, Congress could direct
U.S. representatives to multilateral develop-

ment banks to promote environmental assess-
ments at an early stage of project planning.
This request could be followed up with hear-
ings to determine whether the banks are using
environmental assessment procedures effec-

Improve Tropical Forest Research
and Market Development

Issue (Research)
Fundamental research, applied research,
and technology implementation related to
tropical forests are not well coordinated.
Moreover, interactions among factors that
constrain forest resource development are
poorly understood. Consequently, resource
development projects often fail and technol-
ogies that seem to succeed in trials fail to
spread beyond demonstration areas. Re-
search on tropical forest resources needs to
be more interdisciplinary and more closely
related to technology implementation.
Much work remains to develop profitable
technologies that can supply local people's
needs while simultaneously sustaining forest
productivity. New techniques need to be based
on improved understanding of the biological,
economic, and cultural factors affecting forest
resources. This calls for interdisciplinary re-
search based on an adequate understanding of
the needs of technology implementors.

Initially, Congress could conduct hearings to
determine whether the research organizations
that receive U.S. funds give adequate priority
to interdisciplinary tropical forestry that links
research and development. Special attention
should be paid to disseminating research re-
sults. Congress could increase support for
agencies where such research and develop-
ment is stressed.
The other approaches would be for Congress
to appropriate funds specifically to support
UNESCO's MAB program or to amend the For-
eign Assistance Act to include funds for the

25-287 0 84 3

26 Technologies to Sustain Tropical Forest Resources

United Nations University. Both promote in-
terdisciplinary research. Additionally, Con-
gress could amend the existing legislation that
allocates funds for tropical agriculture to in-
clude tropical forestry and agroforestry explic-
itly. Congress also could determine the feas-
ibility of establishing a forestry research pro-
gram at existing Consultative Group on Inter-
national Agricultural Research (CGIAR) institu-
tions. Congress could establish a trust fund for
the Forestry Department of FAO of the United
Nations specifically to support improved com-
munication among researchers and technology

Issue (Market Development)
In many areas sustaining tropical forest re-
sources will depend on local markets for for-
est products. People seldom attempt to sus-
tain the productivity of natural resources
used for subsistence products because these
appear to be "free." Government agencies
typically are not aware of the natural forest's
potential to support rural communities.
Tropical forest ecosystems house complex
associations of vegetation, wildlife, and other
potential resources that could be developed.
Development of markets, along with research
on ways to manage the unused resources for
sustained yields, could help motivate local peo-
ple and local resource agencies to manage the
forests effectively. It could be possible in some
places to maintain biological diversity and si-
multaneously support profitable rural develop-
ment. However, such market development is
likely to reduce subsistence opportunities for
landless poor people.

Congress could direct and fund the U.S. For-
est Products Laboratory to develop new prod-
ucts and market information to use tropical
tree species and increase its efforts to trans-
fer technologies. Similarly, AID could be di-
rected to expand its support for synthesis and
dissemination of information on underused
tropical forest resources and to assist in devel-
oping markets for those products that can be
produced on a sustainable basis.

Protect Biological Diversity

Benefits from preserving the biological di-
versity of tropical forests accrue to society as
a whole, including future generations in the
U.S. and elsewhere, yet the costs are borne
by the people of the tropical countries.
Developing new markets and ways of har-
vesting and using tropical forest species even-
tually may make it possible to manage natural
forests profitably and sustainably. But until the
markets and technologies are developed, it is
necessary to protect and maintain undisturbed
portions of these biologically diverse ecosys-
tems for future generations.

Congress could take two approaches to help
maintain biological diversity. First, it could
conduct hearings on its recent amendment to
the Foreign Assistance Act which directs AID,
in concert with other appropriate agencies, to
develop a comprehensive U.S. strategy to main-
tain biological diversity.
Additionally, Congress could support the
creation of an international fund to subsidize
the establishment and maintenance of tropical
parks and protected areas. Money for such a
fund could be contributed by a variety of
sources, including transfers from existing
assistance agencies (e.g., AID, multilateral
development banks, and U.N. agencies), in-
creased export taxes and import duties on trop-
ical forest products, and donations from pri-
vate foundations and multinational corpor-

Expand U.S. Expertise in Tropical
Forest Resources

U.S. tropical forest resource expertise is
widely scattered and is not being developed
or used effectively.
The United States has recognized expertise
(both individuals and organizations) in many
resource fields, including reforestation, water-

Ch.1-Summary 27

shed management, commercial forestry, re-
source inventory and mapping, resource devel-
opment planning, and information collection,
processing, and dissemination. But only a few
of these experts or organizations have the ex-
perience or training to apply their skills directly
to the increasingly important field of tropical
forest resources.

Congress could modify the organic legisla-
tion of those U.S. agencies whose actions af-
fect the tropical nations or the U.S. tropical ter-
ritories to say that tropical forests are valuable
renewable resources and to direct each agen-
cy to conduct its activities without contributing

to the unplanned or unmanaged conversion or
degradation of tropical forests. Further, Con-
gress could direct Federal agencies to encour-
age employees to participate in international
assistance efforts under existing laws or it
could amend legislation to encourage such in-
terchange. Congress could encourage partici-
pation of the U.S. private sector to develop and
implement technologies to sustain tropical for-
est resources. Congress could contribute to the
United Nations Associate Experts Program
whereby young U.S. professionals can gain
field experience in tropical forestry. Congress
also could designate U.S. centers of excellence
in tropical forest resources to develop and
make available U.S. expertise in tropical re-
source issues.


Less than 1 percent of the world's tropical
forests fall under U.S. jurisdiction. These for-
ests are located primarily in Puerto Rico, the
U.S. Virgin Islands, Hawaii, and the U.S. west-
ern Pacific territories of American Samoa and
Micronesia (which includes Guam, the Com-
monwealth of the Northern Mariana Islands,
and the Trust Territory of the Pacific Islands).
As Congress becomes more involved in efforts
to sustain tropical forest resources worldwide,
it has reason to pay particular attention to the
tropical forests in territories under its care.
Despite their small total land area, the U.S.
tropical forests are important resources to local
people and economies: they supply food, fod-
der, fuel, and employment; reduce erosion; and
protect ocean fisheries. Most wood products,
however, are imported to these areas. For ex-
ample, Puerto Rico imported $400 million
worth of wood products in 1981. Perhaps the
most important value of forests on these trop-
ical islands is regulation of water regimes. For
instance, because of deforestation the U.S. Vir-
gin Islands no longer has permanent streams.
Most other islands also have experienced prob-
lems with water quality and quantity.

Only in Hawaii has forestry been made an
integral part of the region's economic develop-
ment. To protect watershed values, most for-
ested land in Hawaii is classified under con-
servation zoning which restricts or prohibits
conversion to land uses other than forest. Near-
ly half of Hawaii's designated "commercial for-
est land" is owned by the State. Since 1962, the
Hawaii Department of Land and Natural Re-
sources has followed multiple-use programs for
managing water, timber, livestock forage, rec-
reation, and wildlife habitat on these lands. In
addition, two of the three programs of the U.S.
Forest Service Institute of Pacific Islands For-
estry are dedicated to research on Hawaiian
Even though forestry problems still exist in
the Hawaiian islands (e.g., the recent dieback
of native forests, endangered status of numer-
ous native plants and animals) considerable ef-
fort has been made to mitigate these problems.
A number of organizations working to sustain
tropical forest resources are based in Hawaii,
including the Nitrogen-Fixing Tree Associa-
tion, the Bioenergy Development Corp., the
East/West Center, and the College of Tropical
Agriculture and Human Resources at the Uni-
versity of Hawaii. These are among the sources

28 Technologies to Sustain Tropical Forest Resources

of expertise housed in Hawaii that can be ap-
plied to the U.S. tropical territories and to the
world's tropical forest resources.
Forest resources in the U.S. Caribbean and
Pacific tropical territories are not receiving a
similar level of attention. The forests have suf-
fered degradation in the past as a result of poor
land-use practices. More recently, incentives
for local people to undertake and improve agri-
cultural or forestry activities have been re-
duced by dependence on U.S. Federal income
supports and by economic development focus-
ing on industrial growth. This has resulted in
a movement away from agriculture and cor-
responding increases in abandoned agricultur-
al land and unmanaged secondary forests. In
many places, runoff and erosion resulting from
past forest loss threaten water supplies and
coastal marine resources. With forest resource
development technologies, much of the pro-
ductivity of this degraded and abandoned land
could be restored to support economic growth.
Although current overexploitation of forest
resources is not a problem in most of the ter-
ritories, the remaining forests are vulnerable
as populations and expectations rise. Future
problems could be averted, however, if sustain-
able forest use techniques could be integrated
into strategies for regional economic develop-

The Caribbean Territories: Puerto Rico
and the U.S. Virgin Islands
The Commonwealth of Puerto Rico is the
largest contiguous tropical area under U.S.
jurisdiction (see fig. 7). At least one-third of its
land area is under forest cover-mostly second-
growth trees, fruit tree plantations, and shade
trees in coffee-growing regions. Because Puerto
Rico has a relatively large forest area, a relative-
ly well-developed road system, and secure land
tenure, it has significant potential for commer-
cial forestry to supply its domestic economy.
About 200,000 acres in Puerto Rico have been
identified as suitable for commercial forestry.
However, large-scale forestry is hindered by
high land prices and a law limiting the acreage

that can be owned by an individual or corpora-
Opportunities exist to develop small-scale
forest industries to serve domestic markets
using technologies that require comparative-
ly low capital outlay, such as the portable
sawmills now used in Puerto Rican Common-
wealth forests. The sawmills are one compo-
nent of a Puerto Rico Department of Natural
Resources program to bring private landhold-
ers into commercial forestry. This program
relies heavily on U.S. Federal cost-sharing pro-
grams and on funding from the U.S. Forest
Service's State and Private Forestry grants. In-
creased support for these activities could en-
courage plantation forestry and increase Puer-
to Rican self-sufficiency in forest products.
The U.S. Virgin Islands have little remain-
ing forest and no forest industry but are used
extensively for tourism. Lack of forest manage-
ment and a growing population in the U.S. Vir-
gin Islands have disturbed local water regimes.
Thus, water must be shipped from Puerto Rico
or desalinized from sea water at great expense.
Reforestation and management of island water-
sheds could reduce runoff rates, decrease ero-
sion, and enhance aquifer recharge.
The main constraints to sustaining tropical
forest resources in the U.S. Caribbean are lack
of support for existing forest resource develop-
ment institutions and lack of a skilled cadre of
local resource managers. The U.S. Forest Serv-
ice maintains a forestry research station, the
Institute of Tropical Forestry (ITF). It also
manages the Caribbean National Forest and
supports a State and Private Forestry cooper-
ative program with the Puerto Rico Depart-
ment of Natural Resources and the Virgin
Islands Department of Agriculture. At a time
when U.S. Forest Service research needs to be
expanded to include agroforestry, watershed
protection, and other areas of importance to
landholders and the public, its research funds
and staff size have been reduced.
In the short term, people with general tropi-
cal forestry expertise can be attracted to work
in the U.S. Caribbean, but in the long term an

Ch.1-Summary 29

Figure 7.-Location of Puerto Rico and the U.S Virgin Islands

uitted States



U.S. Virgin
Puerto Islands

DP aae





SOURCE: Office of Technology Assessment.

established method to train people to manage
tropical natural resources specific to that re-
gion is needed. Increased environmental edu-
cation, scholarships, and creation of a natural
resource management curriculum at the Uni-
versity of Puerto Rico could help train the nec-
essary resource managers. In the meantime,
adequate Federal support of Puerto Rico and
U.S. Virgin Islands forestry programs through
the State Forestry Grants of the State and Pri-
vate Forestry Division of the U.S. Forest Serv-
ice are needed to stimulate development, dem-
onstration, and coordination of desirable for-
estry practices.

The Western Pacific: Micronesia
and American Samoa

U.S. tropical forests exist on some 2,000
islands spread over 3 million square miles in
the western Pacific (see fig. 8). Forest cover var-

ies with the nature of each island. Few truly
undisturbed forests exist, but considerable
areas of secondary forest have regenerated. Lit-
tle of this is managed to provide forest prod-
ucts. Fuelwood and some nonwood forest
products are harvested for local use, but most
wood products are imported.
As in the U.S. Caribbean, the major value of
forest resources in the U.S. western Pacific is
not timber but regulation of water regimes and
protection of biologically rich coastal ecosys-
tems. Island people in this region depend heav-
ily for both subsistence and trade on marine
organisms that feed and spawn in mangrove
habitats, lagoons, and coral reefs. Unplanned
exploitation of upland forests can substantial-
ly reduce the productivity of these coastal
areas. This already is occurring on some is-
Transportation costs, limited land areas, and
insecure or communal land tenure limit the re-



Costa Rica

30 Technologies to Sustain Tropical Forest Resources

Figure 8.-Location of the U.S. Western Pacific Territories


Trusl lerritory ol ihe
Pacilc Islands

^Z Philippines
J. 0
lM r!


O Samoa

gion's industrial forestry opportunities. How-
ever, small-scale management, harvesting, and
processing technologies could be applied to the
secondary forests and abandoned coconut
plantations to increase their provision of food,
fuel, employment, and other goods. For exam-

pie, improved small-scale charcoal production,
if developed and promoted wisely, could in-
crease the importance of wood as a sustainable
energy source in the U.S. Pacific. Production
from existing agroforestry lands could be en-
hanced with new techniques. Coconut shell


Ch.1-Summary 31

Photo credit: C. Whitesell
Opportunities exist for small-scale forestry operations
oriented toward domestic markets. This small sawmill
operates on Ponape, Federated State of Micronesia

charcoal can be used as a filter in various in-
dustrial and pharmaceutical uses and could be
exported from these islands.
Any forest development in the U.S. western
Pacific territories, however, will require careful
planning and management to avoid further
degradation of the resources and to ensure the
sustainable production of both goods and serv-
ices provided by the forests. This requires up-
to-date and comprehensive data bases on trop-
ical forest resources, their uses, and the poten-
tials for their development. U.S. Federal agen-
cies can play a major role in creating these data
Integrating forestry into development plan-
ning in the U.S. western Pacific will require
personnel with substantial knowledge in trop-
ical resource management and strong local in-
stitutions through which they can work. Yet,
no natural resource management education
programs exist in the U.S. western Pacific ter-
ritories, and few of the students who receive
training at U.S. or other institutions return to
work in their own regions. Actions to help sup-
ply needed expertise include creating a natural
resource management curriculum at the Uni-
versity of Guam and increasing scholarships
for potential resource managers.

Additional extension services also could be
useful. Developing a group of local, grass roots
naturalists with generalized training to assist
scientists, spread information on appropriate
land uses, and help integrate new technologies
with local customs could be a joint undertak-
ing of U.S. and local western Pacific organi-

Issues and Options for Congress
The primary requirement for sustaining trop-
ical forest resources in the U.S. tropical ter-
ritories is the development of indigenous orga-
nizations capable of managing the islands' re-
sources. Because the territories' governments
still depend on U.S. support and their natural
resource agencies are generally new, small,
and undersupported, the U.S. retains a sub-
stantial role in both the development of the
resource organizations and in the development
and implementation of forest-sustaining tech-
Congress could direct the U.S. Forest Serv-
ice to 1) expand the scope of research and
technology development in its research insti-
tutions with jurisdiction in the U.S. tropical
territories and 2) increase cooperative efforts
with local governments.
Development of forestry management plans,
in the short run, will require technical assist-
ance provided by U.S. expertise. Similarly,
adaptation of technologies to conditions in the
U.S. tropical territories requires Federal assist-
ance. In the long run Federal aid could be re-
placed when more people are trained in natu-
ral resource management at local institutions.
Development of programs to encourage private
forestry appropriate for each island probably
also will require Federal assistance. The Fed-
eral organizations responsible for assisting
forestry development in the U.S. tropical ter-
ritories are too small and their focus is too lim-
ited to give the impetus needed for local de-
velopment. More research, more forestry tech-
nology transfer, and greater response to the
changing needs of the territories are required.

32 Technologies to Sustain Tropical Forest Resources

Congress could support natural resource
agencies in U.S. territories by increasing
funding for the cooperative State and Private
Forestry programs of the U.S. Forest Service
institutes in Puerto Rico and Hawaii. Con-
gress could also create a program of grants
to territorial governments to encourage in-
vestment in privately owned forests.
The Federal Government subsidizes private
forestry with cost-sharing and direct payments

to forest owners. Replacing these subsidies
with a program of grants administered by the
territorial governments would provide the flex-
ibility needed to respond to each island terri-
tory's unique cultural, economic, and ecologi-
cal characteristics. Furthermore, it would en-
courage the development of a constituency
concerned with sustaining the forest resources.


Chapter 2
Importance of Tropical Forests


H highlights .............................................................. 37
Social and Economic Context ............................................. 37
Water and Climate .................................................... 40
Hydrology in Tropical Regions ........................................... 40
Local Clim ate .......................................................... 42
Tropical Agriculture .................................................... 42
Basic Human Needs .................................................... 44
Wood for Fuel ......................................................... 44
Other Basic Human Needs .............................................. 45
Employment .......................................................... 47
Com m ercial Forest Products .............................................. 48
Wood................................................................ 48
Products for M medicine .................................................. 50
Other Forest Products .................................................. 51
Environment ...................................... ..................... 52
Endangered Species .................................................... 52
M igratory A nim als ..................................................... 52
Clim ate ............................................................... 52
Political Im plications ..................................................... 53
Importance to Future Generations .......................................... 53
Chapter 2 References .................................................... 56

Table No. Page
2. Estimated Annual Person-day Requirements for Various Forestry Operations .. 47

List of Figures
Figure No. Page
9. Tropical Forests and Woodlands Are Located at Latitudes South of 23.50 N
and North of 23.50 S, and at Other Frost-Free Localities ................... 38
10. Age-Sex Composition of More Developed
and Less Developed Regions, 1980 and 2000 .............................. 39
11. The Role of Forests ................................................... 41

Chapter 2

Importance of Tropical Forests


* The potentially renewable productivity of
tropical forests will become increasingly im-
portant over the next 30 years as the tropical
nations' population grows from 2 billion to
4 billion people.
* Tropical forests support economic develop-
ment. They sustain production on land that
rapidly loses productivity if they are re-
moved and they can restore the productivity
of degraded land.
* Economic development in tropical nations
is important to the people of the United
States for humanitarian reasons and because
of our economic ties with these nations.
* Industrial wood and other forest products

earn substantial foreign exchange for tropi-
cal nations that trade with the United States.
* Tropical forest resources provide food, fuel,
medicines, and other basic human needs for
millions of people who live in and near them.
* Where fuel wood is not available, agricultur-
al lands are damaged as people have to burn
crop residues and manure that would other-
wise be used as fertilizer.
* The highly diverse tropical forests contain
plants and animals that have great potential
value for medicine, agriculture, and other
industries. These will be more valuable as
industries come to rely more on biotech-


Tropical nations face a dilemma. Forests
must be cut and cleared to increase production
in the near term, but the loss of forests can
reduce productivity in the long term.
About 76 nations, containing about half the
world's population (2 billion), are located en-
tirely or largely within the tropical latitudes
(fig. 9). These nations are characterized by fast-
growing populations, low per capital incomes,
and agrarian economies: Some of their agricul-
ture is subsistence farming in upland areas
where soils have low fertility or are dry. Some
is commercial agriculture on the more fertile
and generally irrigated alluvial plains of major
river valleys. The success of both types of agri-
culture is linked to the status of 1.2 billion hec-
tares (ha) of moist tropical forest and 800 mil-
lion ha* of drier open woodlands.
*This report refers to land area in hectares (ha). One hectare
equals 2.47 acres. One square kilometer equals 100 ha. One
square mile equals 259 ha. Thus 1.2 billion ha of moist tropical
forest is 3 billion acres or 4.6 million square miles.

Because the population structure in tropical
countries is dominated by young people, food
and other needs are growing faster than popu-
lation (fig. 10). For example, food production
in developing nations needs to increase by
about 4 percent per year, while population is
growing at about 2 percent. The age structure
also means that population growth has a built-
in momentum that will prevent the numbers
from stabilizing until well into the next cen-
tury, if then (80).
Part of the needed gains in agricultural pro-
duction can come from improved irrigation,
crop breeding, and technical inputs that en-
hance agricultural yields. But average yields
probably cannot increase every year by 4 per-
cent. Two percent gains may be possible, but
to sustain even that rate over several decades
will be very difficult. Consequently, the amount
of land farmed and grazed will have to be
expanded and people will continue to clear for-
ests to produce food and other goods.

Figure 9.-Tropical Forests and Woodlands Are Located at Latitudes
South of 23.50 N and North of 23.5o S, and at Other Frost-Free Localities



V Egypt -. C
ESIp tI-

C. Bed

Uppn Volta _r Isud.

Menlo Centra

Oteta t lyy tny

Ugana Kny
*yU ~C
*U U Tydenr


Unitla Stat



Figure 10.-Age-Sex Composition of More Developed and Less Developed Regions, 1980 and 2000

300 260 220 180 140 100 60 20 0 20 60 100 140 180 220 260
SOURCE: U.S. Bureau of the Census, Illustrative Projections of World Populations to the 21st Century. Special Study Series, table 2, pt. B, p. 23, no. 79, January 1979.
In: U.S. Congress, Office of Technology Assessment, World Population and Fertility Planning: The Next 20 Years, OTA-HR-157, February 1982.

40 Technologies to Sustain Tropical Forest Resources

Population growth rates and the number of
young people in tropical populations also result
in a rapidly growing labor force. But in most
tropical nations, it does not seem likely that
industry and commercial agriculture will be
able to sustain growth of over 2 percent per
year in job opportunities. Thus, substantial
numbers of people will turn to the forests-
either clearing them for conventional farming
and grazing, or managing them for forestry and
agroforestry production.
The need for food and jobs is direct and com-
pelling, while the environmental services pro-
vided by tropical forest resources affect tropi-
cal people indirectly and forest loss becomes
apparent slowly. In the long term, tropical peo-
ple need the watershed protection, preserva-
tion of habitat and genetic diversity provided
by the forests (fig. 11).

One approach to accommodate the conflict-
ing needs of tropical people is to accelerate eco-
nomic development of resources outside the
forest to provide food, goods, jobs, and foreign
exchange. This would reduce the need to ex-
ploit and clear tropical forests. While this may
have the greatest effect in the long run, these
types of technologies (e.g., improving tropical
agriculture) are outside the scope of this
A second approach is to direct the use of for-
est resources so that both sets of needs-pro-
vision of food, jobs, and national income and
maintenance of the forests' environmental
services-are fulfilled.


Hydrology in Tropical Regions
Most rainfall in the Tropics occurs where the
northeast and southwest trade winds converge.
This Inter-Tropical Convergence Zone is intrin-
sically unstable, oscillating to the north and
south of the Equator, causing an erratic rain-
fall pattern with sharp seasonal contrasts (49).
When tropical rains do fall, storms are more
violent than those in temperate areas. More
water falls per storm, quickly saturating the
soil. Consequently, a larger proportion of the
rainfall runs off the soil surface. Furthermore,
in tropical storms raindrops are larger, thus
having great kinetic energy and high erosive
power (1,59). For example, in areas of the
Amazon Basin where annual rainfall averages
2,100 millimeters per year and land slope is
about 15 percent, erosion removes only about
360 kilograms of soil per hectare per year from
forested land. But after the forest is cleared,
erosion increases 100 times (43).
Tropical forests protect soil and modulate
water flows in several ways. The canopy of
leaves intercepts rainfall and provides tempor-

ary water storage. In addition, organic litter on
the soil surface and the porous topsoil store
water. The organic litter in closed tropical for-
ests is typically 10 to 30 centimeters thick and
the topsoil has a high organic material content
(49,61). These mechanisms minimize the im-
pacts of intense rainstorms, reduce peak storm-
flows, and help mitigate flooding.
The effects of forest cover on streamflow
have been measured in tropical regions. In a
moist montane forest in Kenya, for example,
water measurements were taken on two adja-
cent 600 ha valleys for over 25 years. When one
valley was cleared for a tea plantation-leaving
the steeper slopes and riverbanks under forest
-the immediate effect was a fourfold increase
in peak stormflow. Even after installing con-
servation practices (e.g., contour planting, cut-
off drains, cover crops), stormflows remained
double that measured in the undisturbed forest,
although the total flows were small (49). Simi-
larly, an experiment was conducted in India
on a forest which had been reduced to waste-
land by fuelwood cutting and overgrazing.
When the severely eroded Siwalik hills of

Ch. 2-Importance of Tropical Forests 41

Figure 11.-The Role of Forests

SOURCE: World Bank, Forestry Sector Policy Paper (Washington, D.C.: World Bank, 1978).

25-287 0 84 4

42 Technologies to Sustain Tropical Forest Resources

Chandigah were reforested, the peak rate of
flow from the watershed was reduced 73 per-
cent and total flow was reduced 28 percent (73).
In dry environments where tree canopies are
open, forests are less effective in protecting the
soil and modulating water flows, but their in-
fluence is still beneficial. Open forests provide
shade and act as windbreaks. They reduce soil
surface temperatures and wind erosion and sta-
bilize streambanks. They can anchor shifting
sand dunes that can otherwise destroy crop-
lands and irrigation systems. In coastal plains,
trees can prevent the rise of saline ground wa-
ter. Trees in arid areas, however, may through
evapotranspiration leave less water available
for human uses (49).

Local Climate
Tropical forests also can affect local climate.
In moist forests with closed canopies, tran-
spiration of water extracted from the soil and
the direct evaporation of intercepted rainfall
cool the surrounding air. The resulting cool-
ing effect is pronounced, increasing the occur-

rence and persistence of mists. Thus, the heat
flux from a closed tropical forest in the dry sea-
son is only half that from similar land covered
with subsistence crops or rough pasture (49).
Crops cultivated in and near the forest are like-
ly to enjoy greater soil moisture content than
those on cleared land, provided that they are
planted beyond the root-spread of the trees.
Similarly, windbreaks and shade trees can im-
prove microclimates for crops in dry areas.
Some mountain forests in low rainfall areas
collect useful amounts of water by condensation
from mists and release the water as "drip-fall,"
sometimes giving rise to perennial streams (49).
However, the belief that forests actually cause
rain is questionable. (One recent study in the
Amazon reports that a significant part of the
rain falling there is water evaporated from the
forest, but the results have not been verified
by other studies.) The dessication that is so fre-
quently a consequence of large-scale forest des-
truction is due to the hydrological damage
caused by loss of infiltration and underground
storage. In general, forests thus have a critically
important influence on the reception of rain-
fall, but not on its generation (49).


The populations of tropical nations generally
are concentrated on the coastal plains and in
the valleys of the great rivers. Most forests in
these areas already have been cleared for crop-
lands. Much of this land is irrigated by old
systems that control the drainage of seasonal
floodwaters. Land that is irrigated with newer
systems uses large dams to store excess flood-
water and can produce more than one crop per
The most productive tropical agriculture is
based on annual flooding, but it fails when the
floods are severe. New high-yielding crop vari-
eties of the Green Revolution are short-
stemmed and so require precise control of
water levels. Excessive flooding also can result
in shortages of reservoir water for irrigation
in the following dry season. Further, the ac-

celebrated siltation that accompanies abnormal
floods can fill reservoirs, canals, and stream
channels, reducing the precision of water con-
trol in subsequent years. Thus, the Green Rev-
olution not only increased production from the
best tropical croplands but also increased sus-
ceptibility to damage by floods and siltation.
This makes watershed protection provided by
tropical forests even more important.
Unfortunately, recent decades have been a
time of rapid deforestation in many tropical na-
tions. Consequently, river flows have become
more erratic, flood damage to crops and struc-
tures has been severe, and siltation of water-
ways and reservoirs has increased (49).
The modulating effect of forests on stream-
flow and the consequences for agriculture are

Ch. 2-Importance of Tropical Forests 43

Photo credit: WFP/FAO by Peyton Johnson
Ghana has invested heavily in the Volta River project. The long-term returns on this investment depend on the longevity
of the 3,275 mi2 reservoir, which in turn depends on watershed protection afforded by forests and agroforestry

most evident when the protective forests have
been destroyed. In Pakistan, for example, some
70 million people depend on 14 million ha of
irrigated land in the Indus Basin for food. The
irrigation depends on river flow, but deforesta-
tion on the Indus' headlands has resulted in in-
creased peak flows during the monsoons, fol-
lowed by water shortages during the dry sea-
son. With World Bank funding, two dams, the
Mangla and the Tarbella, were constructed for
hydropower, flood control, and irrigation.
Careful studies of sedimentation rates had
indicated that these dams would repay con-
struction costs by providing benefits for many
decades. However, parts of both watersheds
have suffered uncontrolled deforestation and

these reservoirs are filling with sediment at
twice the expected rate (49). Similarly, siltation
is expected to reduce the lifetime of the Hira-
kud reservoir in India from 110 years to 35
years (57).

In India, the area of agricultural land dam-
aged each year by floods continues to increase
as deforestation occurs. The area of moist for-
est cleared each year is about 147,000 ha (29),
and the area flooded has risen 18 percent over
the past 10 years, from 22 million to 26 million
ha (72). Clearing of forests over the past 20
years in India has caused flood and erosion
damage estimated at U.S.$36 billion in 1982.
This estimate includes loss of topsoil, loss of

44 Technologies to Sustain Tropical Forest Resources

nutrients, loss of property to floods, and short-
ened reservoir lifetimes (57).
Flood control and irrigation also are impor-
tant in Central America. By the year 2000,
Costa Rica and Panama plan to expand their
irrigated areas by 180 percent and 340 percent,
respectively (45). Yet, in these countries defor-
estation is rapid and uncontrolled. In many
Central American locations, water needs for
irrigation, consumption, industry, and naviga-
tion are reaching the limits of low-season flows.
Half of the region's forests have been cleared in
the past 25 years and water flows are becoming
more erratic as deforestation continues (26,45,
77). Similarly, in Africa along a broad belt bor-
dering the equatorial humid tropical forest and
along the Gulf of Guinea, the forests are being
destroyed. Consequently, several nations in the
region are expected to suffer agricultural water
shortages before the end of the century (77).
In addition to watershed protection for the
current year's crops, forests have longer term
values for agriculture. Farmers throughout the
world are using more high-yielding crop vari-
eties. In fact, about half the increase in agri-
cultural production in recent decades can be
attributed to plant breeding (81). The reliance
on high-yielding varieties has reduced the ge-
netic diversity of agricultural systems and so
increased the risk of catastrophic damage from
diseases, pests, and other stresses. Yet, no great
increase in crop failures has occurred. This is
due to new methods of crop protection and the
ability of crop breeders to respond to threats
quickly by breeding new traits into the crops-
traits sometimes obtained from wild relatives

in the tropical forests. For example, a recent
improvement in resistance of peanuts to leaf-
spot was derived from breeding crop varieties
with wild forms from the Amazon region. The
estimated benefit from this one improvement
is $500 million per year (47).

The peanut is just one of many crops with
ancestors in tropical forest areas (58). Other
cultivated tropical plants include plantains,
yams, taro, cassava, sugarcane, potatoes, and
cowpeas. Tree crops with tropical forest an-
cestors and relatives include oil palm, rubber,
coffee, cocoa, and many important fruits.
These tropical plants account for at least half
the calories consumed by people in the Tropics
(47), as well as many commodities important
to the U.S. economy. Future gains in produc-
tivity from breeding these important agricul-
tural crops may depend on the genes in their
wild progenitors and, thus, on the continued
existence of tropical forests and associated nat-
ural areas.

For the people of the Tropics, damage from
increased flooding and siltation and the poten-
tial loss of crop breeding opportunities mean
poorer nutrition, slower economic progress,
and less prospect of achieving prosperous,
stable economies. For the United States, this
means the affected nations are less able to trade
internationally. The developing nations already
are a major market-and the fastest growing
market-for U.S. exports. Their purchases
from the United States in 1982 were valued at
$82.7 billion, over one-third of all U.S. exports


Wood for Fuel
Wood is the most important source of fuel
in most tropical nations (two exceptions are
Brazil and Mexico, where oil and gas provide
a greater share of total fuel than wood). One
and one-half billion people in developing coun-
tries meet 90 percent of their energy needs with

wood and charcoal. Another billion people
meet at least 50 percent of their energy needs
this way (25).
Fuelwood, however, is becoming harder and
harder to find. Some 100 million people already
are experiencing acute fuelwood scarcity and
another billion are affected by lesser shortages

Ch. 2-Importance of Tropical Forests 45

Other Basic Human Needs
The exact number of people living in and
P near tropical forests, relying on the productivi-
ty of forests to supply their basic needs, is not
known. The U.N. estimates that about 28 mil-
lion people practice shifting cultivation in the
closed tropical forests of Asia, 20 million in
Africa, and 40 million in Latin America-total-
ing some 88 million people (31). This means
some 3 to 4 percent of the total agricultural
population in Asia, about 10 percent in Africa,
uand 35 percent in Latin America, work inside
the closed forests. These estimates include eth-
nic populations practicing shifting cultivation
as a traditional way of life. They do not include
nonagricultural people who are purely hunters
and gatherers, nor people who recently moved
into forests. This can be significant, since in
Tropical Asia, at least, squatters probably out-
ieg, number shifting cultivators.
iiMany millions of additional people live in
Sdrier, mixed tree and grassland environments
o o f (open woodlands). These people are typically
Photo credit: R. C. Ghosh livestock herders and dryland farmers; yet, they
Collecting firewood in the dry, open forests of Madhya too are directly dependent on the woodland en-
Pradesh, India, is arduous labor for women. Because the vironment. Their livestock feed on trees and
quantity collected is greater than the annual growth,
finding enough wood takes more and
more time each year

(30). In some countries, it can take up to 300 A/ '
person-days of work to satisfy one household's
annual fuelwood needs-forcing some dramat-
ic changes in lifestyle. For example, many fam- .
ilies in Upper Volta eat only one cooked meal 41
each day, and in Senegal, quick cooking cereal
(e.g., rice) has replaced more nutritious, but
slower cooking, foods (e.g., millets) (64). Fewer
families can avoid the "luxury" of boiling their
water (76) and some are forced to keep children
out of school to search for wood.
Fuelwood shortages are forcing increasing
numbers of people to burn animal dung and
agricultural wastes, with adverse impacts on
land productivity. It has been estimated that
if the cow dung burned for fuel in Asia, Africa, Ai N
and the Near East were used for fertilizer, grain Photo credit: U.S. Agency for (ptemational Development
production could increase by 20 million tons As fuelwood becomes more scarce, the burning of animal
a year (4). dung increases, depriving the land of nutrients

46 Technologies to Sustain Tropical Forest Resources

bushes, especially during dry seasons when
grasses provide poor fodder. People living in
open woodlands use wood for cooking, boiling
water, heating, drying crops, and as fuel for
small industries. Open woodland dwellers, like
the people of the closed forests, use trees and
wild plants for medicines, soaps, and many
other basic needs (86).
Food from the forests-both closed and
open-meets a significant part of the world's
nutritional needs. Meat from wild animals,
fruits, nuts, honey, insects, fungi, and foliage
are all important forest food sources. At least
500 species of edible leaves are used in Africa
alone (42). "Bush meat," including rodents and
reptiles as well as wild ungulates and other
mammals and birds, supply as much as 75 per-
cent of the animal protein consumed in some
tropical regions (20).
Forest trees and vegetation are the main ma-
terials used in the Tropics to build homes and
buildings. In many rural societies, wood fre-
quently is preferred even when other materials
are available (91). Local wood also serves as
poles, fences, stakes, furniture, tools, and uten-
sils. Substitutes for these products are rarely
available in subsistence cultures. Various fibers
derived from forest vegetation are also impor-
tant, especially for household use. Rattans, for
example, are climbing palms used for cane fur-
niture, baskets, mats, and similar uses.
In the northwestern Amazon forest alone, at
least 1,300 plant species have been used by
native people as medicines and drugs (62). Tra-
ditional healers in Southeast Asia use some
6,500 plants as treatments for malaria, stomach
ulcers, syphilis, and other disorders, and also
as sedatives and emetics (50). A number of
these plants identified and tested by native peo-
ple through generations of trial and error yield
exceptionally promising compounds when
screened in modern laboratories (21,24).
Forests also protect both inland and coastal
waters, providing another important benefit to
people. After deforestation, increased runoff
accelerates erosion and carries excessive
amounts of sediment to nearby lakes, reser-
voirs, and streams. For example, as early as

1904 erosion resulting from deforestation was
responsible for clogging the once-navigable Rio
das Velhas in Brazil to such an extent that even
canoes ran aground (87). Today, deforestation
is much more widespread in Brazil, and other
navigable rivers such as the Cuiaba and Sao
Francisco have large parts filled with silt from
eroded forest soils (3,8). Inland waterway trans-
portation is further damaged by the seasonal
drying up of local streams that can be a con-
sequence of deforestation (18,88).
Increased erosion caused by deforestation
has accelerated siltation of the Panama Canal's
system of reservoirs at the same time that accel-
erated runoff has diminished water storage in
the Canal's watershed. During a 1977 drought,
the canal was closed to large vessels because
of low water, a situation that experts believe
may occur with increasing frequency unless
watershed forest cover is restored (85).
Another impact of deforestation on tropical
waterways relates to the release of nutrients
from the forest biomass and soil. Organic mat-
ter production is sharply reduced under non-
forest conditions. Further, the soluble nutrients
from the ash of burned forests and from rapidly
decomposing soil organic matter are easily
leached from soil by heavy rainfall. The result-
ing increased nutrient content of runoff can
accelerate the growth of noxious plants and
algae in nearby lakes, canals, and rivers. Aquat-
ic weeds block canals and pumps in irrigation
projects. Also, they interfere with hydroelectric
production, waste water through evapotran-
spiration, hinder boat traffic, increase water-
borne disease, interfere with fishing and fish
culture, and clog rivers and canals so that
drainage is severely retarded and floods result.
In India, for example, plants reduce water
flow in some large irrigation projects by as
much as four-fifths. Rafts of water hyacinth
weighing as much as 300 tons float over rice
paddies in Bangladesh during floods. When the
water recedes, the weeds settle and kill the ger-
minating rice. Maintaining forested water-
sheds would reduce erosion and runoff, reduce
populations of aquatic weeds, and reduce the
cost of maintaining waterways.

Ch. 2-Importance of Tropical Forests 47

Forests also act as a buffer against the force
of typhoons and other violent storms in coastal
zones. Tropical Asia, for example, suffers an
average of 57 typhoons each year, causing
storm damage that averages $2.8 billion (92).
Forests reduce the destructive energy of these
storms by deflecting wind and reducing the
occurrence of landslides and other environ-
mental damage.
Tropical storms are most violent in coastal
areas, typically the areas that are most popu-
lated. Yet coastal forests are being eliminated
more rapidly than most other types of tropical
forests, with sometimes devastating effects (45).
For example, Bangladesh has a coastal zone of
20,000 square kilometers that supports 20 mil-
lion people. This nation's coastal areas were
extensively cleared in the 1960's, leaving little
protective forest. When a severe typhoon
struck in 1970, 150,000 Bangladeshis drowned
(35,65). Each year, typhoons and floods to-
gether claim the lives of 200,000 people and
destroy many hundred thousand hectares of
crops (92). A portion of these lives and crops
could be saved if forest cover were maintained
and enhanced (45).
About 15.5 million ha of mangrove forests
grow along coastlines and in estuaries in trop-
ical America, Asia, and Africa (31). These for-
ests have several important functions aside
from acting as a coastal buffer against storms,
seawash, and floods. They also process sewage,
absorb nutrients and heavy metals, and precip-
itate sediments. Most importantly, they provide
ideal breeding and nursery grounds for various
fish, molluscs, and crustaceans. Many valuable
shrimp species breed at sea, after which the
young move into mangroves where they seek
food and protection. Mangroves also provide
nurseries for such commercially important
fishes as mullet, grunts, and milkfish (66).

Forest management and forest products in-
dustries can be a major source of employment
in tropical countries. Industrial wood harvest
in tropical forests takes about 60 person-days
per hectare. Planting trees takes even more

labor because site preparation usually involves
more cutting and tree removal than does har-
vest (63). Table 2 is a summary of estimated
annual person-day requirements for various
forest plantation operations in World Bank
Some tropical governments view tree plant-
ing as a way to reduce unemployment (33). For
example, planting programs are planned with
employment as a major benefit in various areas
of Brazil. In the states of Minas Gerais and
Espirito Santo, a large work force plants
100,000 ha/yr by hand, and in the Amazon re-
gion two large companies only do hand-plant-
ing. Similarly, large-scale, labor-intensive pro-
grams have been developed in Colombia, Vene-
zuela, the Philippines, the Republic of Congo,
and other Asian and African countries, and
smaller programs are under way in Guatemala
and Honduras (89).
Forestry and agroforestry require protection
and management and so provide even more
employment opportunities. Using agroforestry
systems including cultivated crops, several tree
crops, and livestock on a 100-ha farm in India,
employment is estimated to rise from 20 to 50
people at the final, sustained yield stage. Thus,
agroforestry systems to reclaim 5 million ha of
India's degraded lands might employ 2 million
people (57). Furthermore, forest products could
serve as the basis for cottage industries, provid-
ing more employment and producing goods for
domestic use and export.

Table 2.-Estimated Annual Person-day Requirements
for Various Forestry Operations
Plantation design
Spacing: 600-2,000 trees per hectare (ha)
(more for energy plantations)
Task Person-days
Nursery work/1,000 plants....................... 7-13
Land clearing and burning/haa................... 10-50
Pitting for planting/ha ............. .............. 3-15
W eeding/ha/yra ................................. 6-36
Pruning/ha. .................................... 5-15
Thinning ...................................... 8-11
aThese measures vary greatly according to site conditions.
SOURCE: P.J. Wood, J. Burley, and A. Grainger, "Technologies and Technology
Systems for Reforestation of Degraded Tropical Lands," OTA com-
missioned paper, 1982.

48 Technologies to Sustain Tropical Forest Resources

ad volume of freshwater rsiff
: a iitfrdgi t :t*tc - ch, r cts; coastal .aineer ptaic-
^Nal wgbsl~iPsio major. stresses iiaddepf
^ A^aiL^i eaarl' iaJitep~ ssi egieiclatnelpitolects anauiecurlog$ sjuis af duo

Le n we" t wagktr s .l-s--.-- .Ib e t*
shcpwawlhWr &if~iaa-dng*iii Charcoal for caE cibr&
agLoub_ ensSzmngrov-pols are used e.sasily for nra"
kb me,,and-Ocaffolt~bd pbecausp the woodnewny mangrove

'qa4nB~ipdsaldo ponds increasing, whidchcoui~k~ve-
= 0to iprte foductia. Hloriveetimprprsite selection.aondpeondesign dcou~ave
as- ftett-n atwe ialpets.,
Ianagpieianove forgets paEn bueimpacgtedz In cleaacut mangrov areas, increased
taltiUs andBap aEion con ai8ssile saliity sokthat meaagoveuaraabltteorgrca.mltd
Splaai." ,deedings is poss$tle but cosy. Sqtive efi.g .systaB trdtqi .w itml s bilo* certain
<^ s, abatiet^rathe cotBaehttkiansiat aay be4iffieut-to damiister. Natusal
Fag1.s1ti e -a. iieaby Aaowtipsstotha*niby treseas preglomeids.

-- g -_on ..es --W.,.tc i-ad_.._ codf and "poles* ire S hot ad

'opate t aluu tpa CO aes p own, for Sataena PwRtt Utextn 9te
ra -".-a.. COMM.RfCuAL ,OR4S.Td PRODUCTS .: .


The principal commercial products of trop-
ical forests are timber and fuelwood. Tropical
hardwoods are used to produce lumber for con-
struction, poles, pilings, railway ties, props in
mines, and panel products such as plywood,
veneer, fiberboard, and particle board. Hard-
wood is also important for finished goods such
as furniture and paper products. In addition,
some softwoods from tropical forests are used
for lumber and pulp.
Most tropical forest wood is used within the
country of origin and the economic value of
this domestic consumption is difficult to assess.

Value estimates exist for the 6 percent of the
commercial tropical wood harvest that is ex-
ported. The total value of wood and wood prod-
uct exports from the tropical nations has in-
creased by about 500 percent in the past 10
years (32). Indonesia's wood exports in 1980
earned some $1.9 billion. The value of wood
exports for Malaysia was $2 billion in 1980; for
the Philippines, $415 million; for Brazil, $816
million; for the Ivory Coast, $415 million (32).
World trade in tropical wood is significant
to the economies of both the producing and
consuming nations. The largest single importer
is Japan. Several other large importers-e.g.,
Singapore, Hong Kong, and South Korea-

Ch. 2-Importance of Tropical Forests 49

reexport most of the wood to industrialized na-
tions after partial or complete processing.

The United States is the second largest im-
porter of tropical wood products and little of
this wood is reexported. U.S. hardwood im-
ports in 1978 amounted to $682 million, with
tropical countries (principally Southeast Asia)
supplying 82 percent of the total. Imports of
tropical wood (logs, lumber, plywood, and ven-
eer) averaged $430 million annually from 1974
to 1978. Although the dollar value of these im-
ports seems high, on a volume basis they ac-
count for only 1 to 2 percent of all wood used
in this country (85). U.S. demand for tropical
wood has been growing at rates well above our
population and the gross national product
growth rates.

Both in the Tropics and in the importing na-
tions, industrial hardwood is used mostly in the

housing industry, so industrial demand for
tropical wood has grown at a rate that generally
follows housing starts. The paper industry is
the other major wood user, but it primarily uses
softwoods, for which the United States and
Canada are major producers. Many tropical na-
tions import paper, and the papermills located
in the Tropics still import most of their soft-
wood pulp from the temperate zone. Some
tropical nations have begun to use their own
natural pine forests, pine plantations, and, in
a few cases, hardwoods as a source of pulp.
But tropical forests still produce no more than
10 percent of the world's paper and paper-
This is likely to change in the next few dec-
ades. New technologies, some developed by the
U.S. Forest Products Laboratory and U.S. for-
est industry, make it possible to produce high-
quality paper pulp from 100 percent hard-
. ...... .. -.. .


Photo credit: H. Bollinger
Wood, a major export item for Malaysia, is no longer restricted to sawlogs. Here 8-year-old Albizia falcataria trees
(a legume species) are harvested for export to the Japanese pulp and paper market

50 Technologies to Sustain Tropical Forest Resources

woods and from a mixture of many hardwood
species (84). International demand for tropical
hardwood chips is expected to rise substantial-
ly as the new technologies are installed in
papermills in wood-scarce Japan and in Eur-
ope, where wood shortages are anticipated.
Japan already uses hardwood chips for over
half of its pulpwood needs (46).
Demand for hardwoods for paper production
also will increase within those tropical nations
that have growing economies. As income in-
creases, demand for paper products rises rapid-
ly among relatively poor consumers as long as
wood supplies are abundant (17).
Fuelwood and charcoal enter commerce for
both household use and industry. Wood fuels
have become much more important for indus-
tries in tropical nations since the rapid rise in
fossil fuel costs. Wood is the least expensive
energy source available for many cottage in-
dustries and charcoal the highest quality local
source for some uses. For example, Brazil has
1.5 million ha of eucalyptus plantations estab-
lished to supply charcoal to the iron and steel
industry in the state of Minas Gerais (31).
The Philippine Government is planning two
large wood-consuming industrial facilities in
the province of Ilocos Norte. The first of a num-
ber of 3-megawatt "dendrothermal" electric
powerplants dependent on wood from fast-
growing trees as boiler fuel is under construc-
tion. Another project that will involve two large
pig-iron blast furnaces and will rely on char-
coal from local wood is being planned (36).

Products for Medicine
The importance of the tropical forests, espe-
cially the moist forests, as a source for medi-
cines is largely a result of their high biological
diversity. Some of these forests contain com-
munities of species that have existed for 60 mil-
lion years, making them the oldest continuous-
ly established land ecosystems known. Their
great age and ecological stability have allowed
evolution to proceed in a relatively undisturbed
manner, and it is probably due to this stable
history that tropical moist forests developed
their extreme biological richness (45).

Because tropical moist forests contain so
many species, each species must compete with
and defend itself against many potential ene-
mies, and one way to do this is by developing
alliances (e.g., symbiosis) with other species.
Thus, tropical forest species are highly interac-
tive. The millions of plant and animal species
also have had time to develop complex chemi-
cals that help them interact with other species.
It is because of these "biologically active"
chemicals that the tropical forests are consid-
ered Earth's richest storehouses of potential
Today, medical science is highly dependent
on chemicals produced naturally by plants.
One-fourth of all U.S. prescriptions contain
ingredients from higher plants (27). In 1974, the
United States imported $24.4 million worth of
medicinal plants to produce about $3 billion
worth of drugs. The commercial value of these
products is over $8 billion per year. When non-
prescription items are included, the value
doubles (28).
Although chemical screening has been done
on less than 1 percent of the tropical species,
already some 260 South American plants have
been identified as having potential for fertility
control. Some 1,400 tropical forest species are
believed to have anticancer properties (7,16,
21,68,70). The National Cancer Institute has
screened about 35,000 higher plant species for
activity against cancer. As of 1977, about 3,000
of these had demonstrated reproducible activi-
ty and a smaller number were appropriate for
clinical trials (23). Rotenoids from the roots of
tropical trees, for example, are being tested
clinically in the United States as antitumor
One tropical plant, the rosy periwinkle, has
had a profound effect on treatment of leuke-
mia. In 1960, people suffering this disease
faced one chance in five of remission. But be-
cause of two drugs developed from the rosy
periwinkle, the chances of remission are now
four in five (41). Tabebuia serratifolia, Jacaran-
da caucana, and Croton tiglium are tropical
trees, and each produces a unique anti-cancer
compound whose effectiveness has been
proved in the laboratory (51).

Ch. 2-Importance of Tropical Forests 51

Tropical forest plants are significant in treat-
ing other medical problems, notably hyperten-
sion (2,41,44,67). D-tubocurasine, made from
the South American vine Chondrodendron to-
mentosum, is widely used as a muscle relax-
ant in surgery in the United States. Chemists
have been unable to produce it synthetically
in a form having all of the characteristics of
the natural product (52). The drug's supply,
therefore, continues to rely on extracts from
wild plants.
Tropical forest animals are also necessary to
medical science. Primates are the most impor-
tant group. They are used widely in medical
research and pharmaceutical trials.' Tropical
primates are especially important because of
their similarity to humans. For example, re-
search into malaria, cardiovascular diseases,
cancers, hepatitis, and other diseases common-
ly uses rhesus monkeys, longtail macaques,
squirrel monkeys, chimpanzees, African green
monkeys, and owl monkeys.
Some 34,000 primates were imported into the
United States in 1977 for drug safety tests and
drug production (5). Virus-free polio vaccine
perhaps is the most important of the drugs pro-
duced this way, using many thousands of trop-
ical forest African green monkeys. The Cen-
tral and South American owl monkey is the
only known nonhuman animal suitable for ma-
laria chemotherapy and immunology studies
(5). Few of these important animals are raised
in captivity; most are captured, and they are
becoming scarce as their forest habitat is be-
ing destroyed.

'See ongoing OTA assessment "Alternatives to Animal Use
in Testing and Experimentation."

Other Forest Products
Tropical forests provide a broad array of non-
wood products.2 Some are produced in planta-
tions of selected tree species. Others are gath-
ered in natural forests and brought to market
through a diffuse system of collectors and
middlemen. These are often called "minor for-
est products," although their importance fre-
quently is greater than that term implies. For
example, tropical forests provide essential oils,
exudates, gums, latexes, resins, tannins, sterols,
waxes, esters, acids, phenols, alcohols, edible
oils, rattans, bamboos, flavorings, sweeteners,
spices, balsams, pesticides, and dyestuffs.
Few nations have collected data on the com-
mercial value of these nonwood forest prod-
ucts. One exception is India, where nonwood
forest products are worth about $135 million
per year, equivalent to one-fifth of the value of
industrial timber (48,69). Indian forests also
produce a substantial quantity of animals used
for food, scientific research, and other pur-
poses. In Indonesia, rattans generate an export
trade worth up to $5 million per year. The
world trade in rattan end products now totals
$1.5 billion (22,37).
World trade in essential oils and spices from
tropical forest plants, such as camphor, cassia,
cardamon, citronella, and cinnamon, exceeds
$1 billion per year. The United States now im-
ports about 10,000 tons per year of these kinds
of oils and spices, with a value of over $100
million (24,54,55). A systematic investigation of
the many nonwood forest products used by the
forest-dwelling people of the Tropics might
lead to increased use of these materials and fur-
ther enhance the economic importance of the

'See Workshop Proceedings on Plants: The Potentials for Ex-
tracting Protein, Medicines, and Other Useful Chemicals (Wash-
ington, D.C.: U.S. Congress, Office of Technology Assessment,
OTA-BP-F-23, September 1983), for additional information.

52 Technologies to Sustain Tropical Forest Resources


Endangered Species
Tropical habitats contain a significant num-
ber of the world's endangered species. As dis-
cussed earlier, tropical moist forests are both
the most biologically complex and species-di-
verse* biome on Earth. The complexity is both
dynamic (highly interactive) and stable (able to
maintain itself for long periods). Yet the stabil-
ity depends on an important provision-that
external forces do not exceed certain critical
thresholds. Human intervention may easily ex-
ceed these thresholds.
Because of geographic confinements and
specialized ecological requirements, tropical
moist forest species are unusually susceptible
to extinction (46). Many species are found in
only one small area, so even a limited amount
of deforestation can exterminate entire species.
Further, species are highly interdependent. For
example, Brazil nuts are probably the most
commercially significant food gathered from
forests. The nuts will grow only where a par-
ticular type of bee lives, as only this bee can
pollinate Brazil nut flowers. The bee, in turn,
lives only where a particular type of orchid is
found, because it must obtain a chemical from
the orchid to attract its mate. Thus, the tree has
not been domesticated away from the forest
where the bees and the orchids are found. Fur-
ther, for some of the nuts to serve as seeds, the
nuts must be chewed by a rodent to soften the
fruit, allowing seed germination. Thus, Brazil
nut tree reserves must be large enough to sup-
port a breeding population of this rodent. Such
complex systems of interdependence are
another reason why entire species can be
threatened by small changes (75).
At least three-quarters of the projected ex-
tinctions worldwide until the end of the cen-
tury are expected to occur in tropical moist
*Biological diversity includes two related concepts, genetic
diversity and ecological diversity. Genetic diversity is the amount
of genetic variability among individuals in a single species,
whether the species exists as a single interbreeding group or as
a number of populations, strains, breeds, races, or subspecies.
Ecological diversity (species richness) is the number of species
in a community of organisms. Both kinds of diversity are fun-
damental to the functioning of ecological systems (17).

forests. Degradation and destruction of tropi-
cal forests and woodlands could precipitate a
fundamental shift in the course of evolution
(45). Of more certain concern is the loss of
potential resources, not only chemicals and
animals that may be used directly in medicine,
agriculture, and other industries but also ge-
netic information with great potential for bio-
technology development.

Migratory Animals
Tropical forests provide habitats for many of
the world's migratory and endangered species.
About two-thirds of the birds that breed in
North America migrate to Latin America or the
Caribbean for winter (74). In general, forest
habitats are more important for migratory
species than was previously thought. Many mi-
gratory species winter in tropical highlands-
areas that have been rapidly preempted for
agriculture. Since migratory species concen-
trate often in smaller areas in winter, the ef-
fects of clearing 1 ha of forest in Mexico prob-
ably are equivalent to clearing 5 ha in the
Northeastern United States (74).
Migratory species have economic, environ-
mental, and esthetic values in the United
States. For instance, some migratory birds play
an important role in integrated pest manage-
ment systems for agriculture in the Eastern
United States, yet they could become more
scarce as their wintering grounds in the Trop-
ics are lost to deforestation.

The question of whether tropical deforesta-
tion can disrupt the stability of world climates
is highly controversial. The scientific under-
standing of the climate effects of deforestation
is still theoretical. When forests are removed,
more solar heat is reflected back into space (the
"albedo" effect). Some scientists believe that
this can lead to changes in global patterns of
air circulation, with potential impacts on agri-
culture (53,60).

Ch. 2-Importance of Tropical Forests 53

Another effect of forests on global climate is
their role as a carbon reservoir in the carbon
cycle. As large areas of forest are converted to
nonforest, the carbon that had been stored in
wood and in organic material in the topsoil is
released to the atmosphere as carbon dioxide.
When croplands, grasslands, or degraded
brush replace moist forest, the new vegetation
stores much less carbon. Thus, net annual de-
forestation adds carbon dioxide to the atmos-
phere (90).
The concentration of carbon dioxide in the
atmosphere has been increasing for several
decades, apparently more from burning fossil
fuels than from deforestation. Scientists agree
that continued increases in atmospheric car-

bon dioxide will produce a "greenhouse effect"
leading to a global warming trend. Doubling
of the atmospheric carbon dioxide would prob-
ably raise the average global climate by several
degrees centigrade. Some scientists hypothe-
size that increased cloud cover and other en-
vironmental change will confound the green-
house effect. The effects of such trends on
agriculture or on the world's hydrological sys-
tems are unknown. Likewise, the role of the
world's forests and the effect of substantial
deforestation are still uncertain. Some scien-
tists consider deforestation to be a significant
factor in the concentration of atmospheric car-
bon dioxide, while others do not (10,12,15,19,


Stability of the renewable natural resource
base in tropical countries affects both the eco-
nomic viability of U.S. investments overseas
and the political stability of the host nations.
Foreign assistance projects funded by the U.S.
Government and development projects funded
by the U.S. private sector are being undercut
by flooding, siltation of reservoirs, pest out-
breaks, and other problems associated with de-
forestation. For example, the reservoirs used
to operate the Panama Canal are rapidly filling
with silt (85), as are hydroelectric reservoirs in
Pakistan, Thailand, the Philippines, Indonesia,
and many other nations (49).
Food and jobs are critical for political stabil-
ity in developing nations and both are reduced
by inappropriate deforestation. Food supplies
and employment can be increased in the long
run, however, by reforestation of degraded
land and by forest management. Frontiers of

human settlement, with relatively untapped
supplies of natural resources, historically are
a source of new employment opportunities. To-
day, however, the remaining frontiers are most-
ly infertile or dry lands unable to support large
numbers of people using current technologies.
Thus, many rural unemployed persons migrate
to the cities. As unemployment climbs, changes
in the distribution of income within societies
further aggravate social inequities and political
stresses (11).
One consequence of the inability of develop-
ing country governments to create sufficient
jobs is that people emigrate to countries with
slower population growth and greater per capi-
ta resources. The flow of refugees from Haiti
to Florida is sometimes cited as an example of
the economic and social disruption caused, in
part, by tropical deforestation and consequent
environmental deterioration (9).


Tropical forests have particular importance
to future generations. With few exceptions
present agriculture systems cannot accomplish
sustained productivity on infertile or dry sites

without expensive inputs of irrigation water or
fertilizers. But scientific study of natural
ecosystems, in concert with applied research
to develop technologies, possibly can discover

54 Technologies to Sustain Tropical Forest Resources

how sustainable agriculture can be achieved
on this land. Such research has hardly begun
and it is a slow process. Thus, the tropical
forests serve future generations by the infor-
mation they reveal to science and by maintain-
ing the quality of the land until sustainable
systems for more intensive use are developed.
The Tropics are thought to be the repository
of two-thirds of the world's approximately 4.5
million plant and animal species, only about
500,000 of which have been named. That
means that about 2.5 million of the tropical
species are yet unknown to science (58).* These
unknown species are resources of incalculable
importance for the future. Undoubtedly, new
sources of food, drugs, fuel, and products lie
undiscovered in tropical forests.
Although vertebrates are generally thought
to be well known on a worldwide basis, only
about 60 percent of the estimated 5,000 species
of fish in the fresh waters of South America
have been scientifically described and named,
even though these comprise a large proportion
of the diet of local people. A principal source
of meat for Paraguayan farmers is a peccary,
made known scientifically only in 1977 (58).
Tropical forests offer potential resources for
plant breeding, genetic engineering, and other
biotechnologies. Because farming environ-
ments are constantly changing as pests or plant
diseases threaten or as weather changes, agri-
culture relies on the continued input of genet-
ic diversity for plant improvement. Germplasm
is the resource to which plant breeders turn for
desirable characteristics-resistance to pests or
stress, or improved growth qualities. A Peru-
vian species, for example, contributed "ripe
rot" resistance to American pepper plants and
a wild melon in India was the source of resist-
ance to powdery mildew that threatened de-
struction of California's melon crop (47). A
wild relative of the potato from Peru has been
known for decades to be highly resistant to in-

*No one knows how many species exist. Some estimates put
the figure as low as 2 million; many converge on a figure of 5
million to 10 million; if tropical insect species are included, the
number could be closer to 30 million (40).

sects because of sticky hairs on its leaves, but
this resistance has not been useful to agricul-
ture because the wild plant cannot be crossed
with domesticated kinds of potatoes. Now the
sticky-hair characteristic is expected to be
transferred with new biotechnology methods.
If it works, the result could be new potato
strains that have a much reduced need for pes-
ticide applications. This implies substantial
gains in production of this important food and
attendant environmental benefits from reduced
insecticide use. It is not possible to predict with
accuracy what germ plasm will be needed in
the future.
With the gradual consumption of fossil fuels
and other nonrenewable resources, the United
States and other nations are expected to turn
increasingly to biological systems for industrial
and chemical feedstocks and for solutions to
pollution and other environmental problems
(78,79). Some complex chemicals and some
more simple biological processes can be in-
vented in the laboratory, but most have to be
found in nature.
Genetic materials and basic systems found
in nature can be reproduced or adapted with
bioengineering techniques. New techniques for
cloning plants and micro-organisms already
are enabling laboratory biologists to screen ex-
isting organisms for their production of useful
chemicals much more rapidly and efficiently
than in the past. The newly developing tech-
niques for genetic manipulation offer oppor-
tunities to adapt existing organisms to new
uses (79).
For example, tropical forests have a greater
proportion of alkaloid-bearing plants than any
other biome (6,39,56). Many of the plant species
contain hydrocarbons as well as carbohydrates
in their tissues. These plant tissues can be re-
newable sources for many chemicals, includ-
ing fuels, now derived from nonrenewable fos-
sil sources (13,38). Since tropical forest species
usually are restricted to small geographic areas,
opportunities are lost wherever the forests are
removed before their unique biota has been
identified, screened, and assessed for useful-
ness (83).

Ch. 2-Importance of Tropical Forests 55




fiai#~sC~c6Lt'M~ ftr -P-it j~S~it~~~~

5-="" ,,

56 Technologies to Sustain Tropical Forest Resources


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25-287 0 84 5

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Ch. 2-Importance of Tropical Forests 59

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Chapter 3
Status of Tropical Forests


H highlights .........................

The Data Base ......................

Extent of Remaining Tropical Forest ..
Closed Forest .....................
Open Forests and Shrublands ......
Forest Fallow .....................

Forest Management .................
Forest Legislation and Policy .......
Forest Ownership .................
Wood Production .................
Natural Forest Management ........
Plantations .......................

Destruction of Forest Resources ..
Deforestation .................
Resource Degradation .........

Projection of Changes ...........
Chapter 3 References............

.............. ....... .. ........... 63

....... .... ... .. .... ....... ... 64
...................................... 64
. . . . . . . . . . 6 7
........ ....... ..... ... ............ 68

. . . . . . . . . . 6 9
. . . . . . . . . 6 9
.. ....... ................ ........... 70
... ..... .... ........................ 70
.... ...... ..... .... ... .............. 73
. ........................ ............ 74

.... ..... ............................ 79
.. .................. ............... ... 82

List of Tables

Table No.
3. Estimates of Per Capita Closed Forest Areas and Deforestation Rates in
Tropical Africa, America, and Asia ..................................
5. Annual Deforestation, 1981-85 ..................................... .
6. Forest Area Projections .............................................



List of Figures

Figure No. A
12. Classification of W oody Vegetation ....................................
13. Areas of Woody Vegetation in 76 Tropical Nations .......................
14. Overall Area of Tropical Woody Vegetation ... ....................
15. Comparative Production of Wood, 1980 ...............................
16A. Wood Production in Tropical Africa, 1969-80 ............................
16B. Wood Production in Tropical America, 1969-80 ..........................
16C. Wood Production in Tropical Asia, 1969-80 ..............................
17. Plant Nutrient Loss Caused by Logging in Tropical v. Temperate Forests....

111 11::

1:1111 1

' '

Chapter 3

Status of Tropical Forests


* The area planted with trees in tropical re-
gions each year is only about one-tenth of
the forest area cleared.
* Gradual resource degradation, especially in
the drier open forest areas, may have a
greater long-term impact on human welfare
than deforestation.
* Landsat imagery has greatly improved
knowledge of closed tropical forests and this
is enhancing forest management. However,
data on open forests and forest resource
degradation are still imprecise.
* Forest data aggregated by region may sug-
gest that no global problem exists. However,
country-by-country analyses show that rates
of deforestation are high and forest area per
capital is already low in many tropical na-

* The acreage within tropical forests that is
fallowed or abandoned is growing rapidly.
Some of this will naturally return to forest
cover, but most of it does not regain produc-
tivity without a concerted reforestation
* Most tropical forest is owned by national or
State governments, but locally recognized
rights to use the resources greatly complicate
management efforts.
* Tropical forestry historically has tended to
neglect the basic needs of people who live
in and near the forests. This is changing as
laws, policies, and forestry professionals' at-
titudes give more attention to fuelwood, and
to relationships between forestry and agri-


Data on the extent and condition of tropical
forest areas are abundant but widely scattered
and frequently inaccurate. Some of this infor-
mation is based on old, imprecise measure-
ments or estimates that have been updated
through simple extrapolation. Accuracy is fur-
ther impaired by lack of standard definitions
and classifications of forest types; thus, the data
are difficult to compare across studies. Micro-
level studies of project areas or watersheds con-
tain some of the most reliable and detailed in-
formation on forest resources and land use, yet
this information is hard to obtain because it is
poorly distributed.
A comprehensive synthesis of data about the
world's tropical forest resources was con-
ducted by the United Nations Food and Ag-
riculture Organization (FAO) with the assist-
ance of the United Nations Environment Pro-

gramme (UNEP) (3,4). The FAO/UNEP study
is the first where the definitions of forest types
and conditions are consistent across countries.
It covers 76 nations; 73 nations are tropical or
partly tropical, and 3 nations are outside the
Tropics but are directly influenced by tropical
monsoons. It does not include the tropical
regions of China, Australia, islands off the
coasts of Africa, the Pacific islands, or Puerto
Rico. Some of the forests included are in places
where the climate is more temperate than trop-
The FAO/UNEP study relies mainly on data
supplied by governments. Most measurements
and estimates in various categories of forest
were made in the 1970's. Then, using the
estimated rates of change from one category
to another, the figures were projected to rep-
resent the situation in each nation as of 1980.

64 Technologies to Sustain Tropical Forest Resources

Several nations did not have complete data,
and for 13 of these FAO commissioned new
Landsat analyses. Some of the government
estimates used by FAO are also based on Land-
sat data.
Data gathered from the U.S. Landsat pro-
gram has greatly enhanced the accuracy of in-
formation on the extent of forests. By using
computers to study Landsat data, investigators
can distinguish primary forests from second-
ary forests, closed forests from open forests
and grasslands, and dominant types of trees
(e.g., broadleaved, coniferous, mangroves).

forest cover over time. Hence, only a few of
the estimated deforestation rates given in the
FAO/UNEP study, presented later in this chap-
ter, are based on remote sensing data. The rest
are mainly subjective estimates. In addition,
since expertise and computers to analyze Land-
sat data are not available in some tropical na-
tions, many analyses have relied on visual in-
terpretation of images. This method is more
subjective and less sensitive to small-scale
changes in forest area boundaries. In some
cases, images cannot be used because of cloud

Unfortunately, Landsat data have not been
collected long enough to reveal trends in the


Closed Forest
Tropical nations contained some 1.2 billion
hectares (ha) of closed forest at the end of 1980.
Tropical America has 57 percent of the world's
closed tropical forests, while Asia has 25 per-
cent, and Africa has 18 percent (fig. 13). These
forests are unevenly distributed among the
tropical nations. Brazil alone has nearly two-
fifths of the world's total closed tropical forests
and Indonesia and Zaire each account for near-
ly another tenth (table A-1 in app. A).
The condition of closed tropical forests may
be divided into several categories: undisturbed,
logged, managed, physically unproductive, and
protected areas. Table A-2 in appendix A
shows the percent of forest in each category
for each of the 76 nations.
Over half (56 percent) of the total tropical
closed forest is classified as undisturbed forest.
This forest has commercial potential, but most
of it is relatively inaccessible to human popula-
tions. When Brazil and Zaire with their enor-
mous remote forests are excluded, the remain-
ing tropical nations have two-fifths (41 percent)
of their closed forest in the undisturbed cate-

Another 14 percent of the total closed forest
is productive forest that has been logged but
is not under active forestry management. Ivory
Coast, Togo, Benin, Sri Lanka, and Belize all
have at least 60 percent of their closed forest
in this condition. Some other countries have
had extensive logging but register little forest
in the logged condition because farmers quick-
ly convert the logged forest to temporary or
permanent cropland. A prime example is Thai-
land, which has had extensive logging but
shows no forest in the logged condition.

Only about 3 percent of the total closed trop-
ical forest is classified as managed. Much of
this is in logged-over condition, but significant
investments are being made to manage natural
regeneration. India classifies 63 percent of its
closed forest as managed; Burma and Malaysia
each classify about 12 percent as managed. Ex-
cluding these three countries, only 0.3 percent
of the rest of the tropical closed forest is
classified as managed. Most of that is in Ghana,
Uganda, Kenya, Sudan, and Zambia.

Another one-quarter (23 percent) of the
closed forest is unproductive for physical
reasons. Much of this has not been disturbed

Ch. 3-Status of Tropical Forests 65

Definitions of Forest Categories
To discuss the status of the world's tropical forest resources, the FAO/UNEP study divides
forests into a number of categories (fig. 12). Those used in this report are:
Closed forest includes land where trees shade so much of the ground that a continuous layer
of grass cannot grow. The tree cover is often multi-storied. Trees may be evergreen, semi-
deciduous, or deciduous. Closed forests grow where the climate is relatively moist. The data
on closed forest areas do not include the land which is forest fallow, which is accounted
for separately. Forest plantations are also separate.
Broadleaf forest is a subset of closed forest, where broadleaf species (dicotyledons or mono-
cotyledons) predominate. The broadleaf trees (especially the dicotyledons) are often referred
to as "hardwoods." The FAO/UNEP study makes a separate category for bamboo-dominated
forests, but these are included with the broadleaf forests in this report.
Conifer forest is another subset of closed forest. It includes only areas where conifer species
(gymnosperms) predominate. These trees are often referred to as "softwoods."
Open forest has trees that cover at least 10 percent of the ground but still allow enough light
to reach the forest floor so that a dense, continuous cover of grass can grow. The grass cover
increases the likelihood of grazing by livestock and the spread of fires. Open forests general-
ly occur where the climate is relatively dry. The data on open forest areas do include the
land which is forest fallow. For tropical Africa, data are also available to separate the open
forest fallow from the total open forest.
Productive forest is a term used to describe subsets of both closed and open forests. In pro-
ductive forest, the characteristics of the trees, terrain, and forest regulations potentially allow
the production of wood for industrial purposes (e.g., sawlogs, veneerlogs, pulpwood, and
industrial poles). The distance to consumption or export centers is not taken into account,
so the category includes some forests that are not now economically accessible.
Undisturbed forest is productive forest that has not been logged or cleared in the last 60
to 80 years. The category includes both primary forests and old growth secondary forests.
It is not applied to open forests because nearly all open forests have been subject to cutting,
burning, and grazing.
Logged-over forest is productive forest area that has been logged or cleared at least once
in the last 60 to 80 years but does not fit the criteria for managed forest. This category is
not applied to open forests.
Managed forest is productive forest where harvesting regulations are enforced, silvicultural
treatments are carried out, and trees are protected from fires and diseases.
Unproductive forest for physical reasons is not suitable for industrial wood production
due to rough or inundated terrain or poor growth characteristics of the trees (stunted or
Legally protected forest is the category for forest where logging is prohibited by law. It in-
cludes a variety of parks and protected areas. Illegal logging does occur in some of these areas.
Forest fallow is land that has been cleared for cultivation and subsequently abandoned so
that it may again have some woody vegetation. This category also includes patches of land
that are being used to grow crops and some patches where forest has not been cleared but
are too small to account for separately. The category is not supposed to include land where
erosion or leaching have so degraded the site that only shrubs or grasses grow after the land
is abandoned. Land in the forest fallow category is excluded from the definition of closed
forest but included in the definition of open forest.
Plantations are tree stands that have been established by human activity. The term includes
reforestation (reestablishment of a tree cover on deforested or degraded forest lands) and
replacement of natural forest by a different tree crop.
Industrial plantations are sites where trees are planted to produce sawlogs, veneer logs,
pulpwood, and pitprops. This category excludes plantations that produce fuelwood for indus-
trial use.

66 Technologies to Sustain Tropical Forest Resources

-tW- n VI=v nBmanta pflatats aswdi _asil .for s ,ihid water protection or to pro-
S. e fuelwoodand charcoal, polewood o castrucfon woo tor local use, or nonwood prod-
!Z6- h u- gum arabes. The diqt etatis i or nonawood commodities such
I"as rul r, palm oil, coconuts, cloVes, coffee, and cocoa. It also excludes trees planted to
Shade igriultural crops.
e Sublmaid.has woody vegetation covering at least 10 percent of the ground, but the main
woody plants are bushy species With a height at maturity of.0.5 to 7 meters. Shrubland may
be the natural vegetation under dry or otherwise stressful conditions, or it may result from
severe degradation of open or closed forest land. The data on shrubland areas include some
fallow agricultural land. *

Figure 12.-Classification of Woody Vegetation

Closed Open
forest forest

Forest Forest
fallow fallow

Un- Un- Social
Productive productive Productive productive: Industrial and

Without With For For
intensive intensive physical legal
management management reasons reasons

Un- Logged-
disturbed over

SOURCE: Adapted from Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources, Forestry Paper No. 30(Rome: FAO, 1982).

by cutting; it is either too steep or too wet for misleading, since much of this forest can be
logging or farming. However, this category also productive for fuelwood and other nonin-
includes forest where the trees have no poten- dustrial products and for essential environmen-
tial for industrial wood production, in some tal services such as watershed protection.
cases due to excessive cutting and consequent
resource degradation. Brazil, Indonesia, Peru, Finally, about 3 percent of the closed tropical
Mexico, New Guinea, and Zaire each have at forest has been given park or other legal pro-
least 20 million ha of forest unproductive for tection status. Again, the percentage of the
physical reasons. The name of this category is total hides an unequal distribution. Over half

Ch. 3-Status of Tropical Forests 67

Figure 13.-Areas of Woody Vegetationa in 76 Tropical Nations by Region
(thousands of hectares, 1980 estimates)
Tropical America

Open woodland

Tropical Africa

Closed forest

Open woodlands

Tropical Asia

Closed forest

Open woodland
Closed forest

Shrublands T Open woodlands
35,503 \ 30,948


Open woodland

aClosed forest has dense canopies and no continuous grass cover. Open forest has scattered trees and continuous grass cover. Forest fallow is land used
or abandoned from agriculture. Shrubland has wood vegetation under 7 meters tall.
SOURCE: Adapted from Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources Forestry Paper No. 30 (Rome:
FAO, 1982).

(55 percent) of the protected forests are located
in just four countries-India, Zaire, Indonesia,
and Brazil. Despite the legal status of park
lands on paper, many of these forests in fact
do not receive much protection (3).

Open Forests and Shrublands

Tropical nations contain some 746 million
ha of open forest and 624 million ha of shrub-
land. Whether the natural vegetation of a trop-
ical area is closed forest, open forest, shrub-

land, grassland, or desert primarily depends on
how dry the climate is and on the moisture-
holding capacity of the soil. To an increasing
extent, however, it also depends on human-
caused factors (11).

Generally, closed forests grow where average
annual rainfall is above 1,600 millimeters (mm).
Open forests are found where rain is from 900
to 1,200 mm. In areas with 1,200 to 1,600 mm
of rain, the natural cover may be either open
or closed forest, depending on fire history, soil,
frequency of drought, and other environmen-

68 Technologies to Sustain Tropical Forest Resources

tal factors. Shrublands grow where rain is
below 900 mm. In transitional areas, fires and
livestock grazing can convert closed forest to
open forest and open forest to shrubland. Con-
versely, closed or open forests can be reestab-
lished in some places when fire and other pres-
sures are eliminated (4,11).
Open forest and shrubland areas are uneven-
ly distributed among tropical nations. The data
describing these types of forests are much less
accurate than for closed forests. This is partly
because boundaries between open forest,
shrubland, grassland, and fallow agricultural
land are difficult to determine. It is also be-
cause there has been less interest in measur-
ing or monitoring open forests and shrubland.
Table A-3 in appendix A shows estimates for
areas of open forest and shrubland in each of
the 76 nations. Together, the African nations
have most (65 percent) of the tropical open for-
ests, but Brazil again dominates with 157 mil-
lion ha. Zaire has 71 million ha; Angola has 51
million ha.
Shrublands also are mainly (71 percent)
found in Africa. Sudan has 87 million ha of
shrubland, and other African nations with
large expanses of shrubland include Tanzania,
Central African Republic, Zambia, and
Ethiopia. In tropical America, Brazil has 61
million ha; Paraguay, Bolivia, and Mexico also
have extensive shrublands. Among the tropical
Asian nations, Thailand, Kampuchea, Laos,
and Indonesia all have substantial shrubland
Since open tropical forests are more easily
penetrable than closed forests, nearly all of
them have been cut, burned, or grazed by
livestock. Hence, no open forests are classified
as undisturbed. Two-thirds of tropical
America's open forest is classified as
productive-having potential to produce wood
for industry. In Africa, where these forests are
generally drier, only one-third is classified as
productive; just over one-fourth is classified
productive in tropical Asia.
Although few open forests fit the FAO/UNEP
definition for "productive," these woodlands

are important for nonindustrial products and
services. Much, perhaps most, of the open
forest is used for livestock grazing and
fuelwood collecting. These forests protect soils
and watersheds in the semiarid regions and
their wildlife is important as food. Further,
many of the trees are legumes capable of con-
verting atmospheric nitrogen to fertilizer, and
so they are important for restoring the fertili-
ty of abandoned croplands.
Parks and protected areas account for 9 per-
cent of the African tropical nations' open for-
ests. Tropical America has given protected area
status to just 1 percent, and tropical Asia has
designated 2 percent for protection.

Forest Fallow
The closed tropical forest regions include
some 240 million ha of land in forest fallow.
Overall about 1 in 6 ha in the closed forests are
being used for shifting agriculture. But in many
nations, shifting agriculture has claimed a larg-
er part of the closed forest. Sierra Leone has
five times as much forest fallow as closed for-
est. Five other nations in tropical Africa, four
in tropical Asia, and four in tropical America
have from 50 to 100 percent as much forest fal-
low as closed forest. Table A-4 in appendix A
shows the ratio of forest fallow to forest for
each of the 76 nations. It is likely that much
of this fallow land will not be returned to forest
uses. Under unfavorable site conditions and
short fallow periods, much of this land may
eventually become unproductive for agricul-
ture as well.
Estimates of forest fallow areas are not ac-
curate. However, shifting agriculture is by no
means limited to moist areas. In dry regions,
fallow serves to restore moisture as well as
organic matter and plant nutrients to the soil.
The FAO/UNEP report estimates that about
one-fifth of the land reported to be open forest
is in fact forest fallow. Livestock graze on both
the forest fallow and the open forest that has
not yet been used for crops.
Figure 14 shows relative areas of each vegeta-
tion type for the 76 nations as a whole.

Ch. 3-Status of Tropical Forests 69

Figure 14.-Overall Area of Tropical
Woody Vegetation
Land surface of the Earth

forests Plantations
SOURCE: Food and Agriculture Organization/United Nations Environment
Programme, Tropical Forest Resources Assessment Project (GEMS):
TropicalAfrica, Tropical Asia, Tropical America, 4 vols. (Rome: FAO,


Forest Legislation and Policy

Forest legislation and policy are evolving in
tropical countries to reflect a growing aware-
ness of the social and environmental implica-
tions of forestry decisions. Many tropical na-
tions substantially revised their forestry laws
during the 1960's and 1970's. In many cases,
however, the laws look good on paper, but are
not well-enforced (7).
Some issues have become more prominent
in the last 5 to 10 years. For example, many
countries have revised their logging laws and
policies to be more restrictive regarding timber
allocation from public land, lease terms, con-
cession fees and taxes, annual allowable cut
limits, regeneration methods, and export of un-
processed logs.

Other prominent policy issues include accel-
erating reforestation on degraded lands, pro-
tecting watersheds, increasing incentives for
industrial plantations and farm forestry, and
legislative support for reforesting communal
land. Social issues, too, increasingly are being
recognized (e.g., the needs of slash-and-burn
cultivators and nomadic grazers, domestic fuel-
wood requirements, and release of forest lands
to settled agriculture). Many tropical countries
now view conservation as important to eco-
nomic development and, thus, are more aware
of the need to sustain multiple-use of forests,
preserve biological diversity, maintain parks
and protected areas, and guard against the loss
of mangroves.
Some gaps, however, still need to be ad-
dressed. There is a need to evaluate tropical

70 Technologies to Sustain Tropical Forest Resources

forest resource policy, but no organization has
such a program. The connection between
forests and policies in other sectors such as
land tenure and agrarian reform also needs to
be assessed.

Forest Ownership
In order to understand the use and loss of
forest resources and to devise effective policies
for managing forests, it is important to know
the legal and de facto ownership of forest lands
and trees. The legal status of land may not in-
dicate who has practical control of land use.
For example, owners of large properties may
appropriate adjoining public lands. Also, slash-
and-burn cultivators and other landless poor
may occupy communal forests. In fact, tree ten-
ure may differ from land tenure.
The FAO/UNEP report (3) summarizes forest
ownership by regions and provides some de-
tails at the national level. In tropical America,
forest ownerships may be public, private, or
communal. Most conifer forests in Brazil and
in Central American nations are privately
owned. The much larger broadleaved forests
are public property, but national laws regard-
ing forest ownership often are contradicted by
local practice.
The situation is more complex in tropical Af-
rica where private ownership of forests is rare.
Traditional use rights in most forest areas are rec-
ognized for hunting, gathering nonwood prod-
ucts, acquisition of fuelwood and construction
wood, and shifting cultivation or grazing. Peo-
ple may have exclusive rights over trees that
they plant on communal lands. Local com-
munity ownership of forest lands in many for-
mer British colonies is recognized in national
forestry laws. In former French colonies, local
rights are not recognized at the national level
and all forests are considered state property.
In tropical Asia, 80 to 90 percent of the forest
land is state-owned and under the legal con-
trol of the forest departments. However, a large
part of this land is illegally occupied by forest
farmers, both those who practice traditional
shifting agriculture and those who try to use

the forest land for continuous cropping and
grazing. State control over forest lands has
been a gradual process, taking place mainly
over the past 30 years. The central government
in Nepal and some states in India such as West
Bengal took control of all forested land from
the villages in the 1950's. Papua New Guinea
and most of the Pacific Islands are exceptions
to this general rule. There, forests are owned
by clans and tribes and the government has to
negotiate with them for the right to use forest

Wood Production
The 76 nations covered by the FAO/UNEP
study of tropical forests produce 1.4 billion
cubic meters of wood annually (measured as
round logs extracted from the forest). As fig-
ure 15 indicates, this is about half of all the
wood production in the world, and most (86
percent) of it is used for firewood or charcoal.
The rest is "industrial wood" used for domestic
and export production of sawlogs, veneer logs,
lumber, poles, pulpwood, wood panels, and
other processed products. Figure 16 indicates
changes in wood production for each of the
tropical regions over a 12-year period.
The production of industrial wood varies
with economic conditions. Generally economic
development during the 1970's, resulted in in-
creasing demand for industrial wood in all the
tropical regions. Industrial wood production
increased most rapidly in tropical Asia and in
West Africa with the growth of markets for
sawlogs and veneer logs from those regions.
More recently, slowing economies have con-
strained the growth in production. If rapid
economic growth resumes, tropical America
may experience substantial industrial wood
production increases.
Significant investments were made in mills
and infrastructure during the 1970's, but these
have operated below capacity because of weak
markets. In Asia and West Africa, depletion of
resources is likely to constrain sawlog and
veneer log production, but resurgence of
economic growth should create domestic

Ch. 3-Status of Tropical Forests 71

Figure 15.-Comparative Production of Wood, 1980

25% Tropical Africa
Other Tropical America
64% 5%
Tropical Asia

Fuelwood Industrial roundwood


Total roundwood
SOURCE: Adapted from Food and Agriculture OrganizationlUnited Nations Environment Programme, Tropical Forest Resources, Forestry Paper No.
30 (Rome: FAO, 1982)

markets for wood chips to produce pulp and
other wood products made from a wider varie-
ty of trees.

The increase in total wood production is
driven by a steady increase in fuelwood pro-
duction. However, the data on fuelwood appar-
ently are obtained by multiplying unchanging
estimates of per capital consumption by each
country's population. Thus, the growth in pro-
duction is probably not so steady as figure 16
suggests. Nevertheless, fuel is certainly the
dominant use for wood in the Tropics and that

dominance will become greater where eco-
nomic growth continues to be slow.
Looking at figure 16, one might expect that
tropical forestry efforts would be concentrated
mainly on fuelwood production. However, un-
til recently forestry departments in tropical
countries, international assistance agencies,
and multilateral development banks have con-
centrated most of their efforts on industrial
wood production. Industrial production at-
tracts investment in the forestry sector because
it can earn foreign exchange and concession
fees, and it can be taxed. Thus, industrial wood

72 Technologies to Sustain Tropical Forest Resources

Figure 16A.-Wood Production in Tropical Africa, 1969-80

1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
SOURCE: Adapted from Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources, Forestry Paper No.
30 (Rome: FAO, 1982)

Figure 16B.-Wood Production in Tropical America, 1969-80
A Rn nnn



S 300,000

0 200,000




1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
SOURCE: Adapted from Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources, Forestry Paper No.
30 (Rome: FAO, 1982)

Fuelwood Sawlogs and Other industrial
veneer logs roundwood
*I i


Ch. 3-Status of Tropical Forests 73

Figure 16C.-Wood Production in Tropical Asia, 1969-80
700n00 no


500,000 -

400,000 -

300,000 -

200,000 -

100,000 -

1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
SOURCE: Adapted from Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources Forestry Paper No.
30 (Rome: FAO, 1982).

production probably will continue to dominate
tropical forestry activities.
The problem of ensuring an adequate indus-
trial wood supply for international trade* is
more tractable than problems associated with
fuelwood supply, impacts of deforestation on
soil and water resources, or maintenance of
biological diversity. First, nearly 75 percent of
the world's industrial wood is now produced
in the temperate zone. Second, industrial wood
supplies have grown at reasonably stable rates
for 30 years (9). And third, a large proportion
of the world's future consumption of industrial
wood can come from plantations. One recent
estimate is that 140 million ha of well-managed
plantations could, theoretically, supply all the
industrial wood consumed in the world in the
year 2000 (8). That would be an area equal to
5 percent of the present forested area in the
*See the OTA assessment Wood Use: U.S. Competitiveness
and Technology, OTA-ITE-210, August 1983, for an analysis of
world markets for industrial woods.

Much more wood is consumed in tropical
countries for fuelwood, however. Serious short-
ages of fuelwood, lumber, poles, paper, and
other forest products within nations are not be-
ing met through international trade because of
high transportation costs and persistent pover-
ty. Furthermore, conflicts between forest and
agricultural land uses are critical in many

Natural Forest Management

Only small areas of tropical forests are under
intensive management (3). In tropical America,
management is increasing. For example, Mex-
ico is managing watershed forests through con-
trolled logging. Belize, Brazil, Guatemala, and
Paraguay are designing management plans for
natural resources. Silvicultural trials and
research efforts to develop suitable technolo-
gies for managing natural forests are under
way in Brazil, Costa Rica, French Guyana,
Mexico, Peru, and Venezuela.

25-287 0 84 6

Fuelwood Sawlogs and Other industrial
veneer logs roundwood

74 Technologies to Sustain Tropical Forest Resources

Some African nations, when they were Brit-
ish and Belgian colonies, had developed har-
vesting regulations and working plans for man-
aging natural forests, but these have been aban-
doned over the past two decades. Nigeria,
Zaire, and Tanzania previously managed large
areas of natural forest, but no longer do so.
Uganda reports a large managed area, although
it is doubtful that the management plans have
been implemented. The Congo also is prepar-
ing plans that set the allowable cut for natural
forests and indicate appropriate silvicultural

The deciduous and conifer forests of South
Asia-Burma, Bangladesh, India, and Paki-
stan-have a long history of intensive forest
management. India alone contains 60 percent
of all the managed forest in the 76 tropical na-
tions. However, the remaining tropical forests
of South Asia and the forests of Southeast Asia
are not intensively managed for a number of
reasons. Informationon forest ecology and dy-
namics is scarce. Forestry departments lack
trained personnel to manage the forests. The
emphasis in forestry has been on commercial
exploitation so that little attention has been
given to silvicultural treatments (3).

About 11.5 million ha of tree plantations had
been established in the 76 nations by the end
of 1980 (table A-5 in app. A). Most (68 percent)
of these are in just three countries: Brazil, In-
dia, and Indonesia. About 7 million ha are in-
tended to produce sawlogs, veneerlogs, pulp-
wood, or industrial poles. Only 4.4 million ha
have been planted for fuelwood and charcoal,
for environmental protection, and for nonwood
products such as gum arabic.

The estimated rate of planting in the tropical
nations is about 1.1 million ha/yr (4). Current
planting is intended mainly (53 percent) for
lumber, paper, and industrial poles, but a grad-
ual shift to fast-growing trees to produce fuel-
wood and charcoal is occurring as a result of
changing objectives in tropical forestry.

Forestry plantations are usually monocul-
tures, often of exotic species, planted not where
forest cutting is occurring, but rather on land
that has been cleared for some time, such as
abandoned farmland (5). Most industrial wood
plantations in East Africa are softwoods (pines
and cypress), while in West Africa hardwoods
(principally teak) are planted. In tropical
America, pines are usually grown for saw tim-
ber, while eucalyptus and gmelina are planted
for pulpwood. Eucalyptus frequently is grown
for pulpwood in India, while teak is grown for
timber in India and Indonesia.
Two-thirds of nonindustrial plantations in
Africa are for fuelwood; the rest are mainly for
gum arabic production or watershed protec-
tion. In tropical America, three-quarters of the
plantations classified as nonindustrial are euca-
lyptus trees planted to supply charcoal to the
iron and steel industry in the Brazilian State
of Minas Gerais. Most of the rest is for produc-
tion of forest fruit, such as "palmito." Only
about 100,000 ha of plantations in tropical
America are intended primarily for soil and
watershed protection; Mexico has most of
these. In Asia, most nonindustrial plantations
are intended to produce locally consumed fire-
wood and these are being planted at a rate of
about 1 million ha/yr.
The rate of forest plantation establishment
is much too low to replace the amount of forest
being cleared. In tropical America, the ratio of
area planted to area deforested annually is
about 1 to 10.5; in tropical Africa it is 1 to 29;
and in tropical Asia it is 1 to 4.5 (4). Further-
more, most reforestation programs are not car-
ried out where deforestation takes place. In
Brazil, for example, plantations are concen-
trated in the South, whereas forest clearing oc-
curs mainly in the North.
The greatest discrepancy between reforesta-
tion rates and the demand for wood and other
forest products is in Africa. In Asia, reforesta-
tion is closer to deforestation because
deforestation rates level off as the remaining
forest is left only in inaccessible areas and
because severe wood shortages in heavily
populated areas are leading to greater planting
efforts (4).

Ch. 3-Status of Tropical Forests 75


Distinguishing between deforestation (also
called "clearing" in this report) and degrada-
tion of forest resources is important. The FAO/
UNEP study estimates deforestation rates for
1976-80 and projects rate estimates for 1981-85.
It does not, however, estimate degradation
rates. Unlike deforestation, degradation is not
easy to identify through time-series Landsat or
other remote-sensing analyses.

Each year about 0.5 percent of the remain-
ing closed tropical forests and 0.6 percent of
the remaining open tropical forests are con-
verted to nonforest land uses or to wasteland.
This is an aggregation of estimated deforesta-
tion rates from the 76 countries covered by the
FAO/UNEP report. In some countries, the de-
forestation rate has been estimated by compar-
ing Landsat or other remote-sensing data from
two time periods; for some, information on
population growth, farming, and animal hus-

.: i restatt and Depradation
o, .i ftheconfuston ever rates of change
i,'* i *Baes sterns from the failure to dis-
ei, aweean deforestation and degrade'
St dffinedahre.and.ti the, PAQOUNEP

bandry practices were considered as well.
Table A-6 in appendix A shows estimated areas
of closed forest converted to nonforest annu-
ally for each of the 76 countries.
The overall tropical deforestation rate is
strongly affected by the status of the forests in
a few tropical nations that have very large for-
est areas relative to their population. Thus, the
0.5 and 0.6 percent/yr figures obscure both sub-
stantial differences among nations and the
overall severity of tropical deforestation.
Closed forest area per capital is already less
than 0.05 ha in 17 of the 76 nations. Over half
the rest have deforestation rates between 1 and
6.5 percent/yr. Table 3 indicates forest areas
per capital and deforestation rate estimates for
each country.
Table 4 shows the 76 nations divided into
nine categories of closed forest area and popu-
lation size. Several countries, including Gabon,
Congo, French Guiana, Surinam, and Guyana,
have such large forests and so few people that
their deforestation rates are very low. Clearly,
closed tropical forests will exist in these na-
tions for many decades, although even a
relatively small population can cause resource
degradation over large areas. Other nations,
such as Liberia and Honduras, have large
amounts of forest but also have high deforesta-
tion rates. If current rates of deforestation and
population growth were to continue, these two
nations would, in just 15 years, reduce their
forest area per capital to half what it is. In some
nations, deforestation can be expected to slow
as the forests are reduced to inaccessible areas
that are unattractive to farmers. However, ex-
perience in nations such as Haiti, El Salvador,
Jamaica, Costa Rica, Nepal, Sri Lanka, Angola,
and Ghana indicate that deforestation can con-
tinue rapidly even when only limited forests
In tropical Africa, deforestation rates are
highest in the West African nations. Nigeria
and Ivory Coast together incur almost half (45
percent) of the continent's total annual defor-
estation of closed forests. About 4 percent of
the closed forests of the West African nations

76 Technologies to Sustain Tropical Forest Resources

Table 3.-Estimates of Per Capita Closed Forest Areas and Deforestation Rates
in Tropical Africa, America, and Asia

Closed forest Closed forest Percent Closed forest Closed forest Percent
area area (ha) deforested area area (ha) deforested
Country (1,000 ha) per capital per yeara Country (1,000 ha) per capital per yeara
Tropical Africa: El Salvador .......... 141 3.2
Ivory Coast .......... 4,458 0.5 6.5 Jamaica ............. 67 b 3.0
Nigeria............. 5,950 0.7 5.0Nicaragua 4,496 1. 2.7
Rwanda............. 120 b 2.7 Nicaragua........... 4,496 1.6 2.7
Burundi ............. 26 b 2.7 Ecuador.............. 14,250 1.6 2.4
Benin ............... 47 b 2.6 Honduras ........... 3,797 0.9 2.4
Guinea-Bissau ....... 660 0.8 2.6 Guatemala ........... 4,442 0.6 2.0
Liberia .............. 2,000 1.0 2.3 Colombia............ 46,400 1.7 1.8
Guinea.............. 2,050 0.4 1.8 Mexico.............. 46,250 0.6 1.3
Kenya. ............. 1,105 0.1 1.7 Panama ............. 4,165 2.0 0.9
Madagascar ......... 10,300 1.1 1.5 Belize............... 1,354 5.0 0.7
Angola .............. 2,900 0.4 1.5 Dominican Republic 629 0.1 0.6
Uganda ............. 765 0.1 1.3 Dominican Republic' 629 01 06
Zambia.............. 3,010 0.5 1.3 Trinidad and Tobago.. 208 0.2 0.4
Ghana .............. 1,718 0.1 1.3 Peru ................ 69,680 3.6 0.4
Mozambique......... 935 0.1 1.1 Brazil ......... .... 357,480 2.7 0.4
Sierra Leone......... 740 0.2 0.8 Venezuela ........... 31,870 1.8 0.4
Tanzania ............ 1,440 0.1 0.7 Bolivia .............. 44,010 7.5 0.2
Togo ................ 304 0.1 0.7 Cuba ............... 1,455 0.1 0.1
Sudan .............. 650 b 0.6 French Guiana....... 8,900 129.1 c
Chad ............... 500 0.1 0.4 Surinam 14,830 37.1 c
Cameroon ........... 17,920 2.0 0.4 Surinam ............. 14,830 37.1
Ethiopia............. 4,350 0.1 0.2 Guyana ............. 18,475 23.1 c
Somalia ............. 1,540 0.3 0.2 Totals............. 678,655 2.1 0.6
Equatorial Guinea .... 1,295 4.3 0.2
Zaire ................ 105,750 3.4 0.2 Tropical Asia:
Central African Nepal ............... 1,941 0.1 4.3
Republic .......... 3,590 1.4 0.1 Sri Lanka............ 1,659 0.1 3.5
Gabon .............. 20,500 29.3 0.1 Thailand ............ 9,235 0.2 2.7
Congo .............. 21,340 12.6 0.1 Brunei .............. 323 1.2 1.5
Zimbabwe ........... 200 b c
Namibia ............. c b c Malaysia ............ 20,995 1.4 1.2
Botswana ........... c b c Laos................ 8,410 2.3 1.2
Mali ................ c b c Philippines .......... 9,510 0.2 1.0
Upper Volta.......... c b c Bangladesh.......... 927 b 0.9
Niger ............... c b c Viet Nam ............ 8,770 0.2 0.7
Senegal ............. 220 b c Indonesia ........... 113,895 0.7 0.5
Malawi .............. 186 b c Pakistan ............ 2,185 b 0.3
Gambia 65 0.1 c Burma .............. 31,941 0.8 0.3
Totals.............. 216,634 0.6 0.61 Kampuchea.......... 7,548 1.3 0.3
Tropical America: India................. 51,841 0.1 0.3
Paraguay ............ 4,070 1.2 4.7 Bhutan.............. 2,100 1.5 0.1
Costa Rica .......... 1,638 0.7 4.0 Papua New Guinea ... 34,230 11.0 0.1
Haiti ................ 48 b 3.8 Totals............. 305,510 0.2 0.6
aFrom 1981-85.
bLess than 0.05 forest hectares per capital.
CNo data; in most cases this is where the areas are very small.
SOURCES: Population Reference Bureau, 1983 World Population Data Sheet, Washington, D.C.; Food and Agriculture Organization/United Nations Environment Programme,
Tropical Forest Resources Assessment Project (GEMS): Tropical Africa, Tropical Asia, Tropical America, 4 vols. (Rome: FAO, 1981).

are deforested each year. Other African regions Five nations in tropical America (Paraguay,
with high deforestation rates include East Afri- Costa Rica, Haiti, El Salvador, and Jamaica)
ca, where 1.4 percent of the closed forest ca- have deforestation rates of at least 3 percent/yr,
pable of producing industrial wood is cleared while another six (Nicaragua, Ecuador, Hon-
each year, and the nations of Burundi and duras, Guatemala, Columbia, and Mexico) con-
Rwanda, where the rate is 2.7 percent/yr. Large vert at least 1 percent/yr of their closed forest
areas of closed forest in Zaire and Cameroon to other uses or to unforested wasteland. Al-
are cleared-262,000 ha/yr together-but like though deforestation in Brazil is low when ex-
Brazil these countries are forest-rich so the pressed as a percent of the remaining forest (0.4
rates do not seem so alarming as in the other percent), it affects a large area-about 1.5 mil-
African nations. lion ha/yr. That is one-third of all the closed

Ch. 3-Status of Tropical Forests 77

Table 4.-Comparison of Tropical Countries' Closed Forest Sizes, Population Sizes, and Deforestation Rates
Closed forest Population Deforestation Closed forest Population Deforestation
Region/country sizea sizeb rate Region/country size sizeb ratec

Tropical Africa:
Uganda ..............
Ghana ...............
Mozambique ..........
Tanzania .............
Sudan ...............
Burundi ..............
Rwanda ..............
Benin ................
Sierra Leone ..........
Chad ..............
Upper Volta...........
Zimbabwe ............
Mali .................
Niger ................
Senegal ..............
Malawi ...............
Guinea-Bissau ........
Togo. ................
Equatorial Guinea .....
Botswana ............
Gambia ..............
Namibia .............

Ivory Coast ...........
Nigeria ...............
Ethiopia. .............
Guinea ..............
Zambia ..............
Somalia ..............
Liberia ...............
Central African Republic.

Madagascar ..........
Cameroon ............
Zaire ................
Gabon ...............
Congo ...............
Tropical America:
C uba ................
H aiti .................
El Salvador ...........
Dominican Republic ...












Costa Rica ...........
Jamaica ..............
Belize ................
Trinidad and Tobago...

Guatemala ............
Paraguay .............
Honduras ............
Nicaragua ............
Panama ..............

Ecuador. .............
Colombia ............
M exico ...............
Venezuela ............
Peru .................
Brazil ................
Bolivia ...............
Surinam ..............
Guyana ..............
French Guiana ........
Tropical Asia:
Sri Lanka ............
Brunei ...............
Bangladesh ............
Pakistan .............
Bhutan .............
Laos .................
Papua New Guinea ....
Thailand .............
M alaysia .............
Philippines ...........
Viet Nam .............
Indonesia ............
Burm a ...............















aClosed forest size classes for this table are: large-more than 6 million hectares; medium-2 to 6 million hectares; small-less than 2 million hectares.
population size classes for this table are: large-more than 7.5 million people; medium-3 to 7.5 million people; small-less than 3 million people.
CDeforestation rate is the percent of the 1980 closed forest area that is being cleared each year during 1981 to 1985.
indicates the annual deforestation rate is less than 0.05 percent.
SOURCES: Population Reference Bureau, 1983 World Population Data Sheet. Food and Agriculture Organization/United Nations Environmental Programme, Tropical
Forests Resources Assessment Project (GEMS): Tropical Asia, Tropical America, Tropical Africa, 4 vols. (Rome: FAO, 1981).



78 Technologies to Sustain Tropical Forest Resources

forest clearing each year in tropical America.
Colombia and Mexico together account for
another third.
Three-fifths of the closed forest cleared in
tropical Asia each year is logged-over produc-
tive forest and about one-quarter is previously
undisturbed forests. The highest deforestation
rate in Asia is 4.3 percent/yr in Nepal, and a
significant portion of this cutting occurs in
temperate forests on mountain watersheds. In
Sri Lanka, deforestation is 3.5 percent/yr, and
in Thailand it is 2.7 percent. Brunei, the Philip-
pines, and Bangladesh also have very high
deforestation rates.
Rates of deforestation are calculated as the
estimated area deforested per year divided by
the estimated 1980 forest area. Thus, these
rates should not be confused with geometric
rates of change, such as population growth
rates. Acceleration or deceleration of deforesta-
tion rates are influenced not only by popula-
tion growth but also by many other factors such
as rural to urban migration rates, land tenure
changes, and especially road-building activi-
ties. Much too little is known about how these
factors interact to predict how deforestation
rates will change over any long period.
The FAO/UNEP study does draw some infer-
ences about changes in the accessibility of the
remaining forests. The area of closed tropical
forest cleared each year may be decreasing
slightly for tropical Africa as a whole during
the first half of the 1980's, since during the
previous decade the closed forests in heavily
populated countries of West Africa generally
were reduced to sites that are unattractive to
farmers. However, the rate probably is ac-
celerating in some nations. Deforestation in
Latin America, on the other hand, probably is
increasing because additional forested areas
are becoming accessible as new roads and
bridges are built. In tropical Asia, deforesta-
tion is also thought to be increasing, but the
rate probably will level off in the 1990's as the
forests are reduced to inaccessible areas or
sites where agricultural clearing is not worth-

Based on current and planned rates of tree
plantation establishment, the areas reforested
in the Tropics as a whole are about one-tenth
of the areas deforested.
Deforestation also occurs in open tropical
forests. Trees are cut and burned both by tradi-
tional shifting agriculturists and by farmers in-
tending to establish permanent croplands. Ex-
tracting wood for fuel or industrial use, fires,
and excessive grazing all cause deforestation
by reducing tree cover to less than 10 percent.
The open forest area data are poor, however,
and the estimates of deforestation rates are
even less precise. Deforestation in the dry open
forests is typically a gradual process and thus
is more difficult to see than in moist areas
where the tree canopies are more dense. Fur-
ther, the open forest lands are often under the
jurisdiction of agencies that consider grazing
to be the main use of this land. Thus, the land
is likely to be classified by its herbaceous cover
rather than its tree cover.
The FAO/UNEP study does not list country-
specific deforestation rates for open forests, but
it does provide overall estimates of open forest
clearing for tropical Africa, America, and Asia.
These are shown in table 5. As a rough indi-
cator of the pressure on open forest resources,
table A-7 in appendix A indicates open forest
area per capital for each of the 76 nations.

Resource Degradation
Resource degradation, the long-term loss of
productive potential, is much more difficult to
measure than deforestation. Reduction of soil
quality and loss of superior genetic types of
trees have been documented for specific forest
locations (6). But so little is known about the
ecology of the tropical forests or the economic
potential of the many tropical forest species that
degradation can be a highly subjective term.
Forest resource degradation is undoubtedly oc-
curring (3,6) and, especially in the drier open
forests where recovery is slower, it may be a
more important change than deforestation (12).

Ch. 3-Status of Tropical Forests 79

Table 5.-Annual Deforestation, 1981-85

Closed forests Open Total open and reforested
Undisturbed Productive, logged Unproductive forests closed forests annually
(1,000 ha) (%) (1,000 ha) (%) (1,000 ha) (%) (1,000 ha) (%) (1,000 ha) (%) (1,000 ha)
Tropical America 1,299 0.29 1,867 2.78 1,173 0.74 1,272 0.59 5,611 0.63 535
Tropical Africa ... 226 0.19 1,032 2.31 73 0.14 2,345 0.98 3,676 0.52 126
Tropical Asia..... 395 0.39 1,278 1.28 153 0.15 190 0.61 2,016 0.60 438
Total .......... 1,920 0.28 4,177 1.98 1,399 0.45 3,807 0.52 11,303 0.58 1,099
SOURCE: Calculated from: Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources, Forestry Paper No. 30 (Rome: FAO, 1982).

Forest resource degradation has multiple
causes. Logging practices can cause degrada-
tion by damaging residual trees, damaging soil,
or failing to create an environment where nat-
ural regeneration of valuable forest species can
occur. Forests in tropical America and Africa
typically contain a large number of tree species
per hectare, but just a few are commercially
valuable for timber. Logging in these areas usu-
ally means felling and extracting only the best-
shaped, large individuals of selected species.
Yet, substantial and lasting damage is often
done to the residual trees as a result of mech-
anized logging and skidding operations (10). As
much as one-half of the residual stand may be
damaged (e.g., broken stems and branches or
disturbed roots) and one-third of the logged
area may undergo soil damage (2).
Some tropical forests, such as the Diptero-
carp forests of South and Southeast Asia, have
a large number of commercially valuable spe-
cies per hectare and are clearcut. This can
cause soil erosion that reduces the potential for
natural regeneration. In tropical moist forests
a large proportion of the ecosystem's nutrients
are tied up within the biomass of trees rather
than the soils (fig. 17). Thus, a large share of
the nutrients may be exported from the forest

with the logs. Machinery is available to harvest
whole trees and to use multiple species to pro-
duce pulpwood. Although these technologies
are not yet widely used in the Tropics, they
could accelerate the loss of soil fertility (2). Fur-
thermore, many tropical tree species seed irreg-
ularly or at long intervals (once in 5 to 7 years).
If clearcutting is practiced, natural regenera-
tion of these species may not occur. Clearcut-
ting also reduces regeneration of trees, such
as Dipterocarps, whose seedlings need to grow
in partial shade (1).
Conifer and mangrove forests in all three
tropical regions and certain other forests in
tropical America (e.g., "cativo" and "sanjo"
forests of Panama and Colombia) also have a
low diversity and often are clearcut or cutover
so severely that soil conditions are unable to
support natural regeneration.
Even where clearcutting is not practiced, log-
ging roads can lead to degradation. For exam-
ple, in Sabah and the Philippines, approximate-
ly 14 percent of forest concession areas are
cleared for logging roads (3). Poorly designed
or constructed roads cause erosion and water
drainage problems and may increase the sever-
ity of landslides.


The FAO/UNEP study provides some
estimates of rates at which forests are being
changed from one category to another during
the period 1980-85, although quantitative data
on natural resource degradation in areas that
remain classified as forest are not available. A

straight-line projection of the FAO/UNEP esti-
mates, while not a forecast, can provide an
understandable way to describe the magnitude
of resource changes that may occur. Table 6
shows the projected forest areas for each of the
three tropical regions.

80 Technologies to Sustain Tropical Forest Resources

Figure 17.-Plant Nutrient Loss Caused by Logging in Tropical v. Temperate Forests

Tropical Temperate







Total ecosystem nutrients (numbers in circle) and the fraction lost through harvest in sample temperate and tropical
forests. Values are kilograms per hectare. Shaded area indicates the amount removed when trees are harvested (boles only),
assuming that all roots, branches, and leaves remain in the forest.
Temperate data are a mean of four kinds of vegetation from Ovington (1962): Pinus sylvestris, Pseudotsuga taxifolia, Betula
verrucosa, and Quercus robur. Tropical data are a mean of data from Kade, Nigeria and Yangambi, Zaire (summarized in Nye
and Greenland,1960) plus Puerto Rico (Odum and Pigeon,1970).
SOURCE: J. Ewel and E. Conde, "Environmental Implications of Any-Species Utilization in Moist Tropics," paper for
Conference on Improved Utilization of Tropical Forests, Madison, Wis., 1978, pp. 63-82.

Ch. 3-Status of Tropical Forests 81

Table 6.-Forest Area Projections (1,000 ha)

Tropical Africa Tropical America Tropical Asia
Change Change Change
over 20 over 20 over 20
b b a a b

Forest Category 1980a 1985" 2000" years (%) 1980a 1985 2000" years (%) 198o" 19ia" 2UUU years (
Closed forests:
Undisturbed, productive ...... 118,450 114,134 101,186 -15 454,507 438,119 388,995 -14 101,352 89,087 52,292 -48
Logged, productive .......... 42,848 40,911 35,100 -18 66,622 67,281 69,258 +4 59,847 60,424 62,155 +4
Managed, productive ......... 1,735 1,689 1,551 -11 522 522 522 0 39,790 40,032 40,758 +2
Fallow in closed forests ...... 61,646 66,705 81,882 +33 108,612 116,303 139,376 +28 69,225 73,729 87,241 +26
Physically unproductive or
parks and protected areas .. 53,601 53,236 52,141 -3 157,004 151,140 133,548 -15 104,521 106,836 113,781 +9
Open forests:
Productive .................. 169,218 159,555 130,566 -23 142,887 136,787 118,487 -17 8,530 8,075 6,710 -21
Unproductive ................ 317,227 315,167 308,987 -3 74,110 73,850 73,070 -1 22,418 21,923 20,438 -9
Fallow in open forests........ 104,335 111,520 133,075 +28 61,650 62,950 66,850 +8 3,990 4,100 4,430 +11
aSOURCE: Food and Agriculture Organization/United Nations Environment Programme, Tropical Forest Resources, Forestry Paper No. 30 (Rome: FAO, 1982).
bExtrapolated from current rates of change, excludes plantations.


This 20-year projection suggests that at cur-
rent rates of logging and deforestation in trop-
ical Africa, the area of undisturbed forest
would decline 15 percent by the year 2000.
Some of this is because timber harvest will con-
vert undisturbed forest to logged forest. The
logged forest category also includes secondary
forest on land that is recovering from use for
shifting agriculture. However, in spite of these
additions, the logged forest area is decreasing
because this category incurs most of the defor-
estation for agriculture. Since the land does not
sustain continuous cropping, the forest fallow
area is expected to increase over the 20-year
period by one-third. Changes in the open for-
ests of Africa would be even greater. The open
forest fallow is already larger than the fallow
area in Africa's closed tropical forests. It would
increase by another 28 million ha as produc-
tive open forest is degraded to the unpro-
ductive category and both are cleared for shift-
ing agriculture.
The projection shows a 14-percent reduction
in the area of productive undisturbed forest in
tropical America. It also shows a 4 percent in-
crease in the area of logged forest, which sug-
gests that logging of undisturbed forest out-
paces clearing of logged forest only slightly.
Meanwhile, the forest fallow area in tropical
America would increase by only about half as
many hectares as are lost from the forest cate-
gories, implying that large areas are being con-
verted to nonforest uses other than shifting ag-
riculture. The main reason for converting for-

est land in tropical America in recent years has
been to make cattle pasture, although this use
generally is not sustainable in moist forest
areas. The area of closed forest that is unpro-
ductive for physical or legal reasons is also de-
clining significantly, suggesting that this land
is not so inaccessible as its definition implies.

The change rates for tropical America's open
forests imply degradation of forest from the
productive category, simultaneous clearing of
the unproductive forest, and a net increase in
open forest fallow that can account for only a
fraction of the reduction in the forest catego-
ries. Again, this means a net conversion of
open forest into cropland, grazing land, and
degraded land where forests do not regenerate
naturally, and it means a substantial decline
in the quality of the remaining open forest.

Tropical Asia shows the highest reduction
(21 percent) in undisturbed productive forest,
although such forest has already been reduc-
ed to an area much smaller than in tropical
Africa and America. The logged-over area is
increasing slightly, probably because forestry
departments in several Asian nations have
some control over the spontaneous clearing for
cropland that follows logging operations. The
area of forests unproductive for physical or
legal reasons is increasing in tropical Asia,
though whether this is a result of more parks
being established or of severe degradation of
the logged-over forests is not clear. Open for-
ests in tropical Asia are not so extensive as in

82 Technologies to Sustain Tropical Forest Resources

the other regions, but the pattern of degrada-
tion and deforestation is similar.
Reviewing the FAO/UNEP study's findings
on deforestation and resource degradation,
Westoby (12) declares that the situation is most
alarming in the drier areas, where the data are
least precise:
Among the one and a half thousand million
or so hectares of open forest and shrub land,
there is an infinite gradation of forest and
shrub, ranging from less dry and reasonably
wooded forests at one end to extremely arid
shrub formations at the other, with the bor-
derline between what can still be regarded as
forest and what is irretrievably lost, vague, dif-

ficult to identify from aerial photography or
satellite imagery, and by no means easy to be
sure about when one is actually there standing
in it. What is happening to these forests to-
day, under the impact of a variety of pres-
sures, can best be visualized as a steady push-
ing along the spectrum, a general downgrad-
ing, with the result that very substantial areas
every year slide out of sight and can no longer
be considered as forest on even the most gen-
erous definition. But what should be giving
concern is not so much the 4 million or so hec-
tares that are sliding off the visible spectrum
as the general degradation which is sapping
away at the drier tropical forests through the
whole spectrum.


1. Abraham, F., "Practices and Experience of
NASIPIT Lumber Co., Inc., and Affiliates in Its
Natural and Artificial Regeneration of Forests
and Plantations," Proceedings of a Conference
on Improved Utilization of Tropical Forests
(Madison, Wis: U.S. Forest Service Forest Prod-
ucts Laboratory, 1978).
2. Ewel, J., "Environmental Implications of Trop-
ical Forest Utilization," International Sympo-
sium on Tropical Forests Utilization and Con-
servation, F. Mergen (ed.) (New Haven, Conn.:
Yale University Press, 1981), pp. 156-167.
3. Food and Agriculture Organization/United Na-
tions Environment Programme, Tropical Forest
Resources Assessment Project (GEMS): Tropi-
cal Africa, Tropical Asia, Tropical America (4
vols.) (Rome: FAO, 1981).
4. Food and Agriculture Organization/United Na-
tions Environment Programme, Tropical Forest
Resources, Forestry Paper No. 30 (Rome: FAO,
5. Gallegos, C., et al., "Technologies for Reforesta-
tion of Degraded Lands in the Tropics," OTA
commissioned paper, 1982.

6. Myers, N., Conversion of Tropical Moist For-
ests (Washington, D.C.: National Academy of
Sciences, 1980).
7. Schmithusen, F., "Recent Trends of Forest
Legislation in Developing Countries," Pro-
ceedings: XVII IUFRO World Congress, Divi-
sion 4 (Vienna: International Union of Forest
Research Organizations, 1981).
8. Sedjo, R., and Clawson, M., Global Forests
(Washington, D.C.: Resources for the Future,
9. Spears, J., Tropical Reforestation: An Achievable
Goal? (Washington, D.C.: World Bank, 1983).
10. United Nations Economic, Social, and Cultural
Organization, Tropical Forest Ecosystems (Par-
is: UNESCO/UNEP/FAO, 1978).
11. Weber, F., "Combating Desertification With
Trees," OTA commissioned paper, 1982.
12. Westoby, J., "Halting Tropical Deforestation:
The Role of Technology," OTA commissioned
paper, 1982.

Chapter 4
Causes of Deforestation and
Forest Resource Degradation


Highlights ............................................................ 85
Historical Context .................................................... 85
Soil: Its Relationship to Deforestation and Land Degradation .................. 87
Visible Agents of Forest Change .......................................... 89
Subsistence ... ............................. .......................... 89
Shifting Cultivators ....................................... ............ 89
Livestock Raisers .................... .............................. 90
Fuelwood Gatherers ............................................ .... 91
Fires ......................................... ...................... 93
Warfare ................. ........................................... 94
Commercial Resource Use .............................................. 95
Commercial Agriculturalists and Cattle Ranchers ........................ 95
Loggers ...... ...................................... ............... 97
Underlying Causes of Forest Degradation ............... .. ................ 98
Property Rights and Control of Forest Resources ........................... 98
Transformation of Forestry Administrations ..................... .......... 99
Chapter 4 References ................................................. 100

Table No. Page
7. The Main Soil Constraints in the Amazon Basin Under Native Vegetation ..... 88

Chapter 4

Causes of Deforestation and

Forest Resource Degradation


* Tropical deforestation and forest resource
degradation are caused by subsistence
agriculturalists, livestock raisers, firewood
collectors, and loggers.

* The agents of tropical forest loss vary in
prominence among the three major tropical
forest regions (American, Africa, and Asia).
Many times, the combination of these activ-
ities exacerbates forest resource problems.

* In many tropical areas, political, economic,
and social forces lead to overexploitation
and underinvestment in management of
tropical forest resources.
* Regardless of what activities are responsi-
ble for forest removal from tropical lands,
the soil plays a large role in determining
whether agriculture, new forest growth, or
barren wastelands will replace the forest in
the long run.


Deforestation of tropical lands is not solely
a recent phenomenon. In fact, the main loss
of forests in some places occurred in the 19th
century, when forests were cleared to estab-
lish plantations of export crops such as sugar,
abaca, coffee, indigo, and tobacco (36).
Sugar plantations swept away the Caribbean
forests in turn: first Barbados, then the Lee-
ward Islands, Jamaica, and Haiti. The slave re-
bellion in Haiti left the country in ruins and
made possible the sugar boom in Cuba.
Cuba's story is typical and better docu-
mented than that of other parts of the Carib-
bean (7). Upon reaching the northeast coast of
Cuba in 1492, Christopher Columbus was im-
pressed by the island's rich forests. A few years
later, priest Fray Bartolome wrote that it was
possible to walk from one end of the island to
the other without leaving the shade of trees.
In 1812, forests still covered 89 percent of
Cuba. But thereafter, fields of sugar cane began

to replace the forests. Fire and axe were used
to clear forests for ranching as well. Forest
cover had shrunk to 53 percent by 1900. With
the declaration of the Republic in 1902, and the
subsequent heavy influx of foreign capital into
the Cuban economy, forests continued to shrink.
Small farms were swallowed up by large plan-
tations. The farmers were driven to eke out a
living in the hills where their struggle for sur-
vival, together with the insatiable fuel demands
of the sugar mills, took a heavy toll on the up-
land forests. By 1946, forest cover was down
to 11 percent of the land area. The average
yearly deforestation had been 1.7 percent of the
forest area that existed in 1900.
The history of Brazil, which was the world's
largest sugar producer until the middle of the
17th century, illustrates the severe damage that
deforestation can inflict. The northeastern re-
gion of the country is notorious for its pover-
ty. The densely populated coastal region re-
ceives substantial rainfall and when the area

86 Technologies to Sustain Tropical Forest Resources

was forest-covered, its soils were described as
fertile and rich in humus. But the forests were
cleared for sugar plantations, which were aban-
doned as the soils wore out. Now the infertile,
eroded soils only support savanna. Rainfall is
rapidly shed as runoff so that streams and stor-
ages dry up during protracted droughts. As a
consequence, the region frequently gives rise
to mass emigrations (50).
Similarly, little of South China's tropical for-
ests remain except in the extreme southwest
and in the interior of Hainan Island. Fire and
cultivation took a heavy toll as these forests
came under increased human pressure about
1,000 years ago (45). Fire was used widely to
clear forests for grazing lands and croplands.
Overgrazing and poor agricultural practices
further reduced the likelihood that forests
would ever reestablish naturally. Timber was
used to build houses, temples, and ships, and
wood was cut to supply fuel for cooking and
heating. Forests probably were eliminated in
part to destroy the habitat of dangerous wild
animals or to minimize the hiding places for
bandits. Today's partly grass covered, eroded,

and depopulated hills and mountains in South
China attest to the severity of past land-use
practices and the inability of the forest to
regenerate naturally (46).

In the African Sahel, resource degradation
of dry forests has for centuries been caused by
a combination of processes including dry and
erratic climate, brush fires, trans-Saharan
trade, gum arabic trade, agricultural expan-
sion, and cattle. Herodotus and others, writing
around 450 B.C., described an active trans-
Saharan trade based on precious stones called
"carbuncles," gold dust, and slaves. This trade
had great adverse impacts on the land. For in-
stance, large areas were cleared of Acacia rad-
diana to produce charcoal. In the late 18th cen-
tury, huge caravans of 4,000 camels and 1,000
men would stop at the desert margin and cut
wood for charcoal to cook and trade. The char-
coal even was used as emergency rations for
the camels (34).
The resulting encroachment of the desert
margin encouraged a southward shift of
drysteppe vegetation. This, in turn, altered eco-

Photo credit: OTA staff
Even in areas with abundant rainfall, deforestation can be permanent. Barren landscapes on islands along the south
coast of China were deforested hundreds of years ago

Ch. 4-Causes of Deforestation and Forest Resource Degradation 87

logical relationships and amplified the impact
of hazards such as drought (27). Even though
the human populations in the Sahel had suf-
fered periodic droughts for centuries, far
greater harm was caused during the 1970's
when drought was coupled with a seriously de-
graded natural resource base. This is the ex-
pected response of a resource system where
there is self-perpetuating degradation. The
problem increases gradually for a long time,
but it is typically a logarithmic progression and
can lead to catastrophe (11).

For centuries, tropical deforestation has been
associated with poverty (17). People displaced
by development processes are often the direct
agent of deforestation. While peasant cultiva-
tors and herders have done the actual tree cut-
ting and burning, the causes lie in a chain of
events that have left these people few options
but to destroy the forest or starve.


Soils, by themselves, are not a direct cause
of tropical deforestation. They do, however, set
the stage in many tropical regions for the prac-
tice of shifting cultivation, which causes defor-
estation. When it is cleared, forest land com-
monly loses its fertility, produces declining
crop yields, and ultimately is abandoned. If
forest soils could sustain agriculture, continual
relocation of farm fields would be less likely
to occur and fewer forests would be cut down.
But few tropical forest soils can sustain pro-
ductive agriculture over the long term. The
presence of large areas of either heavily
leached soils of low fertility, thin erosion-prone
soils, or dry soils makes the establishment of
permanent farming sites extremely difficult.
Therefore, regardless of what activities are re-
sponsible for cutting tropical forests, the under-
lying soil materials play a large role in de-
termining whether agriculture, new forest
growth, or barren wastelands will be the long-
term results.
A simple but useful way of discussing tropi-
cal forest soil is to divide the forest lands into
three categories:
1. hot, wetlands;
2. arid/semiarid lands; and
3. mountainous lands.

Although the soils on certain deltas, young
volcanic materials, and flood plains may be fer-
tile, most soils in hot, wetlands have signifi-
cant fertility problems. These soils are formed
by chemical weathering of rocks. High
temperatures and high rainfall combine to ac-
celerate leaching of nutrients from the rock and
soil mineral particles. The residual minerals
tend to be composed mostly of aluminum, sili-
con, iron, oxygen, and water, a chemical com-
position so restricted that many food or tree
crops planted on such soils will have stunted
growth or will not survive. In some of the soils,
silicon and iron concentrations are so low, and
aluminum so high, that the soil may approach
or reach the composition of bauxite, an alumi-
num ore.*
These soils have other problems when fer-
tilized with certain essential plant nutrients.
Phosphorus becomes so tightly held by certain
clay minerals, aluminum, iron, and manganese
oxides that plants cannot extract enough for
their own benefit (4,13). In the Amazon Basin,

*See Van Wambeke (47) and Fripiat and Herbillon (12) for more
detailed information. These are good references on soils of the
hot, wet tropics that not only contain the commonly cited infor-
mation on agriculture, soil names, etc., but also provide discus-
sions of mineralogical and chemical processes.

88 Technologies to Sustain Tropical Forest Resources

for example, 16 percent of the soils suffer this
problem. Overall, 90 percent of the Basin's soils
(table 7) have a phosphorus deficiency (37).
Some 15 percent of the Amazon Basin soils
have a poor ability to hold potassium and other
common plant nutrients (low cation exchange
capacity). If such nutrients are added to the soil
as fertilizer, they can be expected to be leached
away rapidly (4,13).
In addition, an estimated 2 percent of these
soils will harden irreversibly upon drying (47),
severely limiting reestablishment of vegetation
(21). In some cases, soil hardening is so com-
plete that the hardened material can be crushed
and used as gravel for road building (24).
Undisturbed tropical forests have an efficient
nutrient recycling system. As long as the forest
is undisturbed, the nutrient supply remains
stable. Soil shaded by the closed forest canopy
is cool enough for the abundant organic mate-
rial to decay gradually. Thus, the forest soils
typically have a substantial humus content and
can hold the nutrients released by micro-
organisms until they are absorbed back into the
web of tree roots to be recycled again. Slash-
and-burn agriculture takes advantage of the
humus and of the rapid release of nutrients
that occurs when the vegetation is burned. But
as soil temperatures rise, the humus is oxidized
rapidly, and as the forest is removed, the or-
ganic inputs are reduced. Soil with less humus
is less able to hold nutrients, and when rain
falls the soil fertility fades. If the land is re-
turned to forest fallow soon enough, a new
growth of trees can reestablish the soil's hu-

mus, the web of roots, and the recycling sys-
In hot, dry lands physical breakdown of
rocks and soil minerals plays a larger role in
soil formation. In this process, the particles be-
come smaller, but the chemical composition re-
mains nearly the same and leaching of soil nu-
trients is low. Physical disintegration can oc-
cur in a number of ways; for instance, day and
night temperature variations cause rocks and
minerals to expand and contract and, in time,
crack. Salts and other substances collect in
cracks, expanding when wet and contracting
when dry, further breaking the grains (3).
Another mechanical way particles become
smaller is through impact of other windblown
grains. And, of course, the growth of plant
roots is a powerful agent in breaking up and
holding rock and soil particles.
In arid/semiarid areas, nutrients needed by
many plants commonly are in the soil but be-
come available to the plants only if sufficient
water is available (6). If most of the water evap-
orates from the soil surface rather than perco-
lating down into the soil, dissolved solids or
salts can accumulate as crusts at or near the
land surface in concentrations that few plants
can tolerate (16).
Mountainous lands, though generally cooler
than the other two categories, exist in both wet
and dry climates and, thus, either chemical
or physical processes may dominate. Rather
than percolating into the ground to form thick
soils through chemical weathering, much of the

Table 7.-The Main Soil Constraints in the Amazon Basin Under Native Vegetation
Millions of Percentage of
Soil constraint hectares Amazon Basin
Phosphorus deficiency .............................. 436 90
Alum inum toxicity ................................... 315 73
Low potassium reserves .............................. 242 56
Poor drainage and flooding hazard ..................... 116 24
High phosphorus fixation ............................. 77 16
Low cation exchange capacity ................. ....... 64 15
High erodibility ............. ......... ............. 39 8
No major limitations ....................... ........ 32 6
Steep slopes (>30 percent) ........................... 30 6
Laterite hazard if subsoil exposed ..................... 21 4
SOURCE: P. A. Sanchez, D. E. Bandy, J. H. Villachica, and J. J. Nicholaides, "Amazon Basin Soils: Management for Continuous
Crop Production," Science 216:821-827, 1982.

Ch. 4-Causes of Deforestation and Forest Resource Degradation 89

rainfall runs off the land surface to streams.
The soils that do form are easily eroded. Con-
sequently, soils in mountainous lands, in gen-
eral, are likely to be rocky and thin, except per-
haps on the lower slopes (6). Deforestation in
mountainous regions is one of today's most
acute and serious ecological problems (10).
The presence of organic matter is an impor-
tant factor in the soil's productivity because it:
contributes to the development of soil ag-
gregates, which enhance root development
and reduce the energy needed to work the
increases the air- and water-holding ca-
pacity of the soil, which is necessary for

plant growth as well as helping to reduce
releases essential nutrients as it decays;
holds nutrients from fertilizer in storage
until the plants need them; and
enhances the abundance and distribution
of vital biota (31).
Therefore, deforestation, by reducing organic
matter, lowers the potential productivity of
tropical lands. Thus, when tropical land is
abandoned, natural regeneration of the forest
may not occur, and replanting the forest may
be difficult.


Shifting Cultivators
Shifting cultivation is common in the Trop-
ics. The techniques are basically similar every-
where: farmers fell and burn the woody vegeta-
tion; then cultivate the cleared ground for 1,
2, or 3 years; and then abandon the site for a
long period to forest or brush cover (forest fal-
low). There are four reasons for shifting to new
fields: decreasing soil fertility, reduced soil
moisture, pest outbreaks, or excessive weeds
that raise labor requirements. Long fallow pe-
riods generally allow the land to recuperate
and become productive once more.
Shifting cultivators fall into two broad classes:
indigenous groups and recent occupants. In-
digenous groups have long experience with the
local environment and use farming practices
that tend to be resource conserving. These
farmers traditionally have practiced shifting
cultivation using methods particular to them
and woven into their family and tribal customs,
and sometimes into their religion. Usually the
choice of land to be cleared is based on knowl-
edge of nature and soils. The timing of various
agricultural activities is determined by specific
indications of nature, such as the blossoming
of wild plants, the emergence of particular in-
sects, and so on.

In contrast, recent occupants generally are
less knowledgeable about local environments
and apply farming systems that are more de-
structive of resources (23). These people also
cut and burn part of the forest. But unlike
native populations, they may farm the same
plot until the fertility of the soil is exhausted
or shorten the fallow period so that the vegeta-
tion cannot recover. This type of cultivator is
often a "colonist" who comes to the forests for
land because ownership there is ill-defined or
badly protected.
Generally, the new lands are only marginal-
ly productive for agriculture. In addition, re-
cent occupants bring with them dietary pref-
erences and agricultural technologies that are
suited to intensive culture of the more fertile
lowlands. By applying inappropriate farming
systems on fragile soils, they often destroy the
land's productivity.
A large part* of the agricultural population
of Latin America farms on steep slopes. Pop-
ulation growth often leads to increased clear-
ance of forested watersheds and forces many
farmers to migrate down the slopes, clearing
*In most of the tropical countries of Latin America, over 30
percent of the agricultural population is on steep slopes, includ-
ing 50 percent in Peru and Colombia, 40 percent in Ecuador,
65 percent in Guatemala and Haiti, and 45 percent in Mexico

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