Technologies to sustain tropical forest resources

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Technologies to sustain tropical forest resources
United States -- Congress. -- Office of Technology Assessment
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Rain forests ( lcsh )
Reforestation -- Tropics ( lcsh )
Forest conservation -- Tropics ( lcsh )
bibliography ( marcgt )
federal government publication ( marcgt )
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Includes bibliographical references and index.
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"OTA-F-214"--P. [4] of cover.
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Office of Technology Assessment
W g DC 20510

Office of Technology Assessment

Congressional Board of the 98th Congress

MORRIS K. UDALL, Arizona, Chairman TED STEVENS, Alaska, Vice Chairman

Senate House
Utah California
Maryland Michigan
Massachusetts Kansas
South Carolina Ohio
Rhode Island Iowa

Advisory Council

Midwest Research Institute University of Pittsburgh University of Wisconsin
University of Alaska Tennessee Valley Authority Hambrecht & Quist
General Accounting Office Congressional Research Service General Motors Corp.
California Land Commission University of Arizona 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.




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.

o Office of Technology Assessment
4' Washington, D. C. 20510

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 potentially 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 longterm 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, Subcommittee on International Organizations, held hearings on tropical deforestation. The committee then requested the Office of Technology Assessment (OTA) to conduct a more thorough assessment of the problem, the technologies that could help sustain tropical forest resources, and possible options for Congress. The Subcommittee 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 International Institutions) identify and discuss in-depth some of the constraints and opportunities 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 Government 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 Jan Laarman
Conservationist Department of Forestry
Hugh Bollinger North Carolina State University
Vice President Charles Lankester
Native Plants, Inc. U.N. Development Programme
Robert Cassagnol Robert Owen
Technical Committee Chief Conservationist (retired)
CONAELE Trust Territory of the Pacific Islands
Robert Cramer Christine Padoch
Former President Institute of Environmental Studies
Virgin Islands Corp. University of Wisconsin
Gary Eilerts Allen Putney
Appropriate Technology International ENCAMP
John Ewel West Indies Lab
Department of Botany Jeff Romm
University of Florida Department of Forestry
Robert Hart University of California
Winrock International John Terborgh
Susanna Hecht Department of Biology
Department of Geography Princeton University
University of California Henry Tschinkel
Marilyn Hoskins Regional Office for Central American Programs
Department of Sociology Agency for International Development
Virginia Polytechnic Institute U.S. Department of State
John Hunter*
Michigan State University
Norman Johnson
Vice President, North Carolina Region Weyerhaeuser Co.

*Resigned in July 1982.


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 Gerald Murray
Centre for Science and Environment Pan American Development Foundation
New Delhi, India Haiti
Jose Roberto Castillio Gunnar Poulsen
Farmer/Businessman Tropical Forestry Consultant
Mexico Denmark
Merrill Conitz David Richards
Agency for International Development Appropriate Technology International
Nairobi, Kenya Washington, D.C.
Robert Fishwick Skip Stiles
World Bank Office of Congressman George E. Brown, Jr.
Washington, D.C. Washington, D.C.
Marilyn Hoskins
Virginia Polytechnic Institute
Blacksburg, Va.

Systems Analysis Workshop

Donella H. Meadows, Chairwoman Resource Policy Center, Dartmouth College
Jeffrey Gritzner 'John Terborgh
Board on Science and Technology Department of Biology
for International Development Princeton University
National Academy of Sciences Frank Wadsworth
Jeff Romm Institute of Tropical Forestry
Department of Forestry Puerto Rico
University of California



Chapter Page
Introduction 3 1. Sum m ary 9 2. Importance of Tropical Forests 37 3. Status of Tropical Forests. 63 4. Causes of Deforestation and Forest Resource Degradation 85 5. Organizations Dealing With Tropical Forest Resources 105 6. U.S. Tropical Forests: Caribbean and Western Pacific 127 7. Technologies for Undisturbed Forests 159 8. Technologies to Reduce Overcutting. 177 9. Forestry Technologies for Disturbed Forests 195 10. Forestry Technologies to Support Tropical Agriculture 219 11. Resource Development Planning 243 12. Education, Research, and Technology Transfer 257 13. Forestry Technologies for U.S. Tropical Territories 275 14. Options for Congress. 301 Appendix Page
A. Status of Tropical Forests: Tables 323 B. Glossary . 332 C. Commissioned Papers 336 Index 341




Each year, 11.3 million hectares of the Depending on the methods of management,
Earth's remaining tropical forests (an area these natural resources may be sustained or unroughly the size of Pennsylvania) are cleared sustained. Sustained resources are those in
and converted to other land uses or to unpro- which the inherent productivity is not diminductive land. Where the land can support sus- wished over time. Conversely, unsustained retainable agriculture, deforestation may be ben- sources suffer declining or degraded produceficial. But most of the Tropics' remaining for- tivity. Productivity of almost any land can be
est land cannot sustain continuous farming or sustained by applying substantial inputs (e.g.,
grazing using current practices and so is soon fertilizer, water), but this is not the general
abandoned. The abandoned land has lost much practice on tropical lands.
of its inherent productivity-a loss the tropical Undisturbed forest is the only productive
nations and the world can ill afford. The form that maintains itself without human manUnited States, however, can contribute expertise to develop and disseminate technologies gazn land y esrnd ande
that could reduce the need to convert forests frest-potntl ar intec ane abe
to unsustainable land uses.ample, cropland can be followed into grazing
Forest land and former forest land in tropical land, which can be planted with trees. In some
areas can be classified as undisturbed forest, cases, several land uses can be realized simuldisturbed forest (secondary forest and man- taneously-e.g., agroforestry can combine
made forest), converted land (cropland and agriculture, forestry, and grazing. Little, if any,
grazing land), and unproductive land.* The land changes back into undisturbed forest or
products from these lands differ, with the most out of unproductive land, although in theory
actively managed lands-cropland and man- undisturbed forest might be regenerated from
made forest-generally yielding the highest other land types or unproductive land might
economic value. Secondary forest is often per- be made productive if given enough investment
ceived as relatively unproductive. Yet all for- or time to recuperate (fig. 1).
ested land provides important services includ- Because this process moves tropical land
ing climate and runoff regulation, water reten- from forest to unproductive land rapidly and
tion, and maintenance of an enormous, still-un- from unproductive land back to forest more
cataloged stock of species. slowly, the area of unproductive land is grow*Undisturbed forest-natural tropical forest with at most a ing steadily. Thus, serious land degradation is few small areas cleared by natural or human-induced events, taking place, but the change may not be felt imregenerating by natural stages of succession. mediately in terms of price or availability of
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. levels of land use are being maintained by conUsually it is sufficiently degraded or harvested so often that tinually clearing undisturbed forest to replace it does not return to its original state. Trees may be managed land that becomes unproductive. Figure 2 deor left to natural succession, and
Manmade forest planted and maintained in trees, often in ex- picts the trend of land-use changes over time otic species, often a tree monoculture and sometimes also typical of tropical areas.*
with a useful understory.
Converted Land-includes:
Cropland planted annually or every few years with food or *Thi discussion does not present documented trends in land fiber crops, and class but provides a general discussion of concepts. The interGrazing land covered permanently with grasses, legumes, and/ actions implied by the diagrams are derived from the principles or herbaceous species, harvested by grazing animals. and experience of members of the Advisory Panel and of a Unproductive land-land that has been so degraded that it pro- workshop attended by Dr. Donella Meadows, Dr. Jeff Gritzner,
duces few useful products and provides minimal environ- Dr. Frank Wadsworth, Dr. Jeff Romm, Dr. John Terborgh, and mental services (e.g., erosion and flood control). It usually the OTA project staff. Thus, figures 2 and 3 present no scales, supports very little growth of useful species and does not nor are specific countries or regions classified by position on
return naturally to any of the previous categories, the curves.


4 Technologies to Sustain Tropical Forest Resources

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

Undisturbed Sustained Unsustained Sustained Unsustained Unproductive
disturbed disturbed cropland and cropland and land
forest forest forest grazing land grazing land

SOURCE: Office of Technology Assessment.

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


grazing land
a) manmade forest,
SU disturbed forest
& Undisturbed

SOURCE: Office of Technology Assessment.

If nothing were done to change the system, of production. The actual equilibrium may be
the point at which the amount of undisturbed delayed until even more undisturbed forest is
forest land and unproductive land stabilize for cleared because costs and benefits accrue to a given region would be, in theory, where the different groups of people, skewing both mocost of clearing the next acre of undisturbed tivations to invest and to exploit.
forest equals the cost of reclaiming an acre of unproductive land. Since that cost is high for Many technologies exist but are not fully
known technologies, this equilibrium implies used to prevent conversion of productive land
little accessible undisturbed forest, a great deal to unproductive land, to increase yields on inof unproductive land, and extremely low levels termediate lands, or to harvest from undis-

Introduction 5

turbed forest without converting it to a less clouding most of the land capable of sussustainable land type. There are also social taming continuous agriculture. Further
changes both possible and desirable to re- clearing is occurring and technologies to
duce the driving forces behind conversion to sustain productivity on these lands genunsustainable uses. rally are not applied.
Because different countries or regions of Countries where emergency measures are
countries fall at different points along the required-the ratio of unproductive land
curves in figure 2, the actions needed to halt increasing, sevre ores of locap this degradation would be most effective if de- ducked forest products are occurring, and signed for the urgency of the situation in each
country. For example, regions with low rain- tecamont of iermetecldtes is
fall and/or dense populations probably follow dei apily becaustcnologe re
this process more rapidly than countries with notadqty u
moist forest and large areas of currently inaccessible land. Categorization of countries or An improved division of countries into catemajor regions to indicate the urgency for ac- glories might account separately for urgency of tions to address loss of tropical forest resources human needs (e.g., food, fuelwood, materials and degradation of land productivity might for shelter, fodder, etc.) and urgency of ecologtake the form indicated in figure 3: ical need (e.g., loss of genetic diversity). The
Countries where the problem is latent but Food and Agriculture Organization has catenot compelling: A considerable amount gorized countries by need for action to ameof original forest land remains, but with- liorate fuelwood deficiencies, but scales to
out pproriae mesure, ppulaion measure other dimensions of forest resource
out appropriate measures, population pressures and development needs can be
expected eventually to propel these coun- The loss of tropical forest resources is not tries into the next categories. new, and its effects are not restricted to those
Countries where the problem is critical: who live within the forests. Part I of this report
Much original forest land has been con- describes the Background of tropical forest averted into the four intermediate uses, in- resource changes, including who is affected,

Figure 3.-Conceptual Diagram Indicating Possible Categorization of Countries or Regions by Urgency of Land Degradation Probiems
Latent condition Critical condition Emergency condition

r r Unproductive
to i uland
a) Cropland,
inreasing seeeahrtgsnfloalypo

forest disturbed forest

SOURCE: Office r i Technology Assessment.

6 Technologies to Sustain Tropical Forest Resources

the current status, the visible agents and un- reduce degradation of the resource base, derlying causes of change, and the organiza- e reduce demand on the ecosystems, tions-United States, national, and internation- o provide more timely and accurate inforal-involved. This section also describes the nation to decisionmakers or reduce the
tropical lands of most direct concern to the time necessary to implement decisions.
U.S. Congress: the U.S. tropical territories. A final chapter in this section discusses appliPart II of this report, Technology Assess- cation of the various kinds of technologies to ment, discusses various technologies for re- the U.S. tropical forests. source-sustaining development of tropical for- Part III describes Issues and Options for est lands. The technologies considered cover Congress to promote development and use of a broad range. Some are techniques to manage technologies that can sustain tropical forest rethe forests-undisturbed and disturbed-and
the oress-udistrbedanddistrbedand sources globally and within U.S. tropical tersome are technologies to use forests to protect r y
related resources such as agriculture and wa- roress The oganiat of optin for ter. Others are techniques to prepare people for Conge oe not idate th late ipthe various tasks involved in sustaining tropical tons are not taken to build institutions conforest resources, such as resource development corned with the sustainable use of tropical forplanning, education, research, and technology tests, short-term actions will be overwhelmed. transfer.
tranfer.And conversely, if short-term measures are not Within each technology discussion, actions taken, development of institutions to manage are suggested to promote development of sus- the forest resources in the long term may be tainable tropical forest use. In general, actions pointless. can enhance the stability and productivity of
tropical lands if they:

Chapter 1 Summary


Introduction 9
Importance of Tropical Forest Resources. 10
Status of Tropical Forests. 10
Technology A ssessm ent. 14 Technologies for Undisturbed Forests. 14 M aintaining Sample Ecosystems. 14 Making Undisturbed Forests More Valuable 14 Technologies to Reduce Overcutting 15 Industrial W ood 15 F uelw ood 16 Technologies for Disturbed Forests 17 M anagement 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 du cation 20 R esearch 2 1 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. T ropical 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 To avoid even more acute problems, they need the tropical nations' land (fig. 4). To support a to restore resource productivity. Other nations, population of 2 billion, these nations must use even those with adequate forests, need to susthe natural resources found in these forests: tai their forest resources to avoid future probsoil, water, plants, and animals. The produc- lems. In just 30 years, the population of tropical tivity of these resources can be renewable, but nations is expected to double to 4 billion peoonly if tropical people use resource-sustaining ple. Thus, the importance of tropical forest protechnologies. ductivity is increasing as more and more peoSome tropical nations are experiencing se- ple depend on forest products and services for Soe otgopal rdut adsrvcs basic needs such as fuel, materials for shelter,
vere shortages of forest products and services reliable water supply.

Figure 4.-Global Areas of Tropical Woody Substantial institutional activity is occurring
Vegetation worldwide that directly or indirectly benefits
Land surface of the Earth tropical forest resources. The U.S. Agency for
International Development (AID), the United Nations agencies, the multilateral development banks, and others have increased their attention to forestry in recent years. Private corporations and nonprofit organizations also have Land surface of the 76 countries studied been involved in the search for solutions to tropical forest problems. Most importantly, tropical nations' governments have come to Land surface of recognize that deforestation and forest rewoody vegetation source degradation constrain their economies
and their development options.
~ fallow The large number of organizations that have
Closedsome responsibilities in forestry might imply
broad-leaved that an adequate level of activity is under way.
forests Open
forests But the total amount of expertise and funding
available to forestry still remains small relative Shrubandsto the scope of the problem. International deShrublandsvelopment assistance organizations cannot fund enough forest conservation to offset deConiferforestation because the underlying institutional forests Plantations causes can only be resolved by the tropical
SOURCE: M. Hadley and J. P. Lanley, "Tropical Forest Ecosystems: Identifying countries themselves.
Differences, Seeking Similarities," Nature and Resources UNESCO,
19 1):2-19,a1983.


25-287 0 84 2

10 Technologies to Sustain Tropical Forest Resources


For tropical nations, forests and shrublands meant or the U.S. private sector are being underprovide wood for lumber and paper, building cut by flooding, siltation of reservoirs, pest outmaterials, and fuel, and are an important breaks, and other problems associated with desource of foreign exchange. Forests help main- forestation. Food and jobs, both critical for potain soil quality, limit erosion, stabilize hill- political stability in developing nations, can be sides, modulate seasonal flooding, and protect reduced by the consequences of deforestation. waterways and marine resources from accel- The highly diverse tropical forests contain erated siltation. In addition, many millions of plants, animals, genetic material, and chemipeople living in and near the forests depend calls that have great potential value for medidirectly on them for food, medicines, and other cine, agriculture, and other industries. The basic needs.
basic eeds.Tropics are thought to contain two-thirds of the
The benefits from tropical forests are not lim- world's approximately 4.5 million plant and anited to tropical nations. World trade in tropical imal species. An estimated 2.5 million of the wood is significant to the economies of both tropical species are yet unknown to science. the producing and consuming nations. The Considering the value to society that has come United States is the second largest importer of from those tropical species that have been studtropical wood products, and U.S. demand for ied (e.g., many major agricultural crops, antitropical wood has been growing at rates well cancer drugs, insects used in integrated pest above our population and gross national prod- management), it is very likely that some of the uct growth rates. Tropical forests also provide r an ustudied pecs or ptn a broad array of nonwood products such as impant reouce, particularlyefr p noils, spices, and rattan that are valuable for tr plateeng, g iclegineering ad both subsistence and commerce. The annual othe technqges Bologissa a d
world trade in rattan, for example, is estimated
to be $1.2 billion. Thus, industrial wood and micro-organisms to screen for their production other forest product exports earn substantial of useful chemicals. foreign exchange for nations that trade with Tropical forests also provide habitats for the United States. many of the world's migratory birds and various endangered species. About two-thirds of
The productivity of renewable resources in the birds that breed in North America migrate the Tropics affects both the economic viabili- to Latin America or the Caribbean for winter. ty of U.S. investments overseas and political Some of these migratory birds play an imporstability in the tropical nations. Many devel- tant role in controlling agricultural pests in the opment projects funded by the U.S. Govern- United States.

Some 76 nations located entirely or largely areas where soils are dry or have low fertility. within the tropical latitudes contain about half Commercial agriculture, on the other hand, the world's population (approximately 2 bil- generally is sited on the more fertile and often lion). These nations are characterized by rapid- irrigated alluvial plains of major river valleys. ly growing populations, low per capital in- Both types of agriculture are strongly affected comes, and predominantly agrarian econo- by the 1.2 billion hectares* of moist tropical miles. Near forest lands, much of the agricul r c e ture is subsistence farming, often in upland *One hectare equals 2.47 acres.

Ch. 1-Summary 11

forest and 800 million hectares of drier open forest types are unequally distributed among
woodlands. countries.

The type and distribution of forests vary con- Data on the extent and condition of tropical
siderably across regions in the Tropics (fig. 5). forests are widely scattered and often iacTwo-thirds of the closed forests* are found in curate. Overall figures for deforestation* mask
tropical America, while Africa has two-thirds of the open forests.** Even within regions, *Deforestation is the conversion of closed or open forest to
___________nonforest. A distinction should be made between deforestation
*Closed forest means that trees shade so much of the ground and degradation; the letter refers to biological, physical, and that a continuous layer of grass cannot grow. chemical processes that result in loss of the productive poten**Open forest has trees that cover at least 10 percent of the trial of natural resources in areas that remain classified as forest. ground but still allow enough light to reach the forest floor so This distinction explains some of the confusion in estimates of that a dense, continuous cover of grass can grow. change in forest resources.

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

Closed forest

fo rests
4,620 Closed forest
Open woodland10,2

61,650 Open woodlands
Tropical Africa

Tropical Asia

CClosed forest 1305,510

Closed forest

Shrublands Open woodland
Shrublands Open woodlands
Closed forest fallowfallow

Plantation Open woodland
Plantation forests fallow
forests 5,111 3,990
aClosed forest has aense 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 able access to farmland. People displaced by which individual countries are using and alter- development in the lowlands often have been ing their forest resources (table 1). If present the direct agents of deforestation because they trends were to continue, nine tropical coun- have little choice if they are to survive. tries would eliminate practically all of their
closed forests within the next 30 years and The main agents of tropical deforestation and another 13 countries would exhaust theirs forest resource degradation continue to be subwithin 55 years. sistence agriculturalists, livestock raisers, fuelwood collectors, and people who set fires to
Estimates of overall deforestation rates also facilitate clearing or gathering activities. Coiconceal significant differences in the types of mercial agriculture plays a smaller role in detropical forest affected. The loss of species is forestation today than it has in the past, alprobably greatest in the broad-leaved humid though in some areas (e.g., Central America lowland forests as these are biologically the and Brazil) clearing tropical forests for cattle most complex and diverse. But the tropical ranching causes a large part of the forest reconifer forests cover much smaller areas and source loss. Commercial logging is also an imhave been severely degraded by logging and ag- portent cause of forest degradation. riculture. Direct impacts on people are greatest
in dry regions where degradation of open for- Both subsistence and commercial use of forests leads to severe shortages of wood for fuel. est lands can cause deforestation. Combined, But the loss of mountain watershed forest may they form particularly pernicious relationships. affect even more people by making river flows For example, loggers build roads through unmore erratic. disturbed forests to remove timber. Slash-andEach year approximately 11.3 million hec- burn cultivators use the roads to gain access tares of the Earth's remaining tropical forests to the forests and clear patches for temporary
-an area roughly the size of Pennsylvania- agriculture. Ranching or commercial agriculare cleared and converted to other uses. Whereland's cleared land is developed for sustainable agri remaining productivity, then move on into new culture, deforestation can be beneficial. But ar Te agents o tropical o estca most land being cleared cannot sustain farm- va in o i am ing or grazing with available technologies. So
it is abandoned after a few years. Often, com- Alternative techniques exist that could be mercially valuable trees do not grow back substituted for these destructive practices. quickly because of highly weathered soils, However, sustainable forestry and agriculture harsh climates, and recurring fires. Thus, productive but underused forest resources are giv- p ie gen ly no be devel ing way to low productivity grasslands and adapid h neligcue fti al
deserts. ure lie in political, economic, and social forces
deserts.(e.g., undefined property rights) that cause peoDeforestation and degradation of tropical ple to use forests in ways that are inappropriate lands are not new. Losses of forest resources to ecological conditions. Deterioration of the have been reported as early as 450 B.C. in the forest resources seems likely to continue until African Sahel and 1000 A.D. in South China. combinations of improved technologies and enFor centuries, tropical deforestation has been forced resource development policies make associated with poverty and with patterns of sustaining the forests more profitable than deeconomic development that result in inequit- straying them.

Ch.1-Summary 13

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

Closed forest Percent Closed forest Percent
area deforested area deforested
Country (1,000 ha) per year (1,000 ha) per year'
Tropical Africa: Haiti 48 3.8
Ivory Coast. 4,458 6.5 El Salvador. 141 3.2
Nigeria 5,950 5.0 Jamaica 67 3.0
Rwanda. 120 2.7 Nicaragua. 4,496 2.7
Burundi. 26 2.7 Ecuador 14,250 2.4
Benin 47 2.6 Honduras 3,797 2.4
Guinea-Bissau. 660 2.6 Guatemala. 4,442 2.0
Liberia. 2,000 2.3 Colombia 46,400 1.8
Guinea 2,050 1.8 Mexico 46,250 1.3
Kenya 1,105 1.7 Panama. 4,165 0.9
Madagascar 10,300 1.5 Belize 1,354 0.7
Angola 2,900 1.5 Dominican Republic. 629 0.6
Uganda. 765 1.3 Trinidad and Tobago 208 0.4
Zam bia 3,010 1.3 Peru. 69,680 0.4
Ghana. 1,718 1.3 Brazil. 357,480 0.4
Mozambique 935 1.1 Venezuela. 31,870 0.4
Sierra Leone 740 0.8 Bolivia. 44,010 0.2
Tanzania. 1,440 0.7 Cuba. 1,455 0.1
Togo 304 0.7 French Guiana. 8,900 b
Sudan 650 0.6 Surinam 14,830 b
Chad. 500 0.4 Guyana. 18,475 b
Cameroon. 17,920 0.4 Totals 678,655 0.6
Ethiopia 4,350 0.2
Somalia 1,540 0.2 Tropical Asia:
Equatorial Guinea. 1,295 0.2 Nepal 1,941 4.3
Zaire 105,750 0.2 Sri Lanka 1,659 3.5
Central African Republic. 3,590 0.1 Thailand 9,235 2.7
Gabon. 20,500 0.1 Brunei. 323 1.5
Congo. 21,340 0.1 Malaysia. 20,995 1.2
Zimbabwe. 200 b Laos 8,410 1.2
Nam ibia b b Philippines. 9,510 1.0
Botswana. b b Bangladesh 927 0.9
M ali. b b Viet Nam 8,770 0.7
Upper Volta b b Indonesia 113,895 0.5
Niger. b b Pakistan 2,185 0.3
Senegal 220 b Burma. 31,941 0.3
Malawi 186 b Kampuchea 7,548 0.3
Gam bia. 65 b India 51,841 0.3
Totls.1663 061 Bhutan. 2,100 0.1
Totals 216,634 0.61 New Gunea 34,230 0.1
Tropical America: Totals 305,510 0.6
Paraguay 4,070 4.7
Costa Rica. 1,638 4.0
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, Tropical
Asia, Tropical America, 4 vols., Rome, 1981.

14 Technologies to Sustain Tropical Forest Resources


This report discusses various technologies to Strict preservation with total exclusion of develop tropical forest resources. Some are economic activity is not practical for many techniques to manage forests-undisturbed and sites where protection of undisturbed forests disturbed-and some are technologies to use is important. Recognizing the growing deforests to protect related resources such as ag- mands to develop rural land, protected area riculture and water. Others are techniques to planners and managers have begun to pay prepare people for the various tasks involved more attention to socioeconomic and instituin developing and implementing technologies tonal factors. They seek participation from to sustain the resources. both the people who will affect or be affected
by forest resources and the people and agenTechnologies for cies that must support management programs.
Undisturbed Forests Some innovative plans that include the surUndisturbed forests produce many valuable rounding biophysical and socioeconomic setproducts and services, usually with little or no ting have been developed for protected areas. human management. One way to reduce the One such activity is the UNESCO Man and the
rate at which undisturbed forests are converted Biosphere (MAB) program's worldwide netto other, nonsustainable uses is through sys- work of biosphere reserves (fig. 6). The mantematic preservation of sample ecosystems in agement of these reserves considers the needs parks and protected areas. Another approach of local populations and seeks ways to make is to enhance the value of the forest by develop- benefits available to local people. More field ing its resources other than timber-the non- experience and monitoring are needed to evalwood products and forest food sources. For uate the successes of existing biosphere reeither approach to succeed, willing involve- serves. However, the MAB effort is constrained ment of local people and political commitment by a lack of strong, consistent commitments from government decisionmakers are essential. from U.S. and other governments.

Maintaining Sample Ecosystems Making Undisturbed Forests
Parks and protected areas can be managed More Valuable for direct income (e.g., tourism) and for indirect
benefits, such as preventing siltation of reser- Few de t attemts he ben made to voirs. Some of these benefits can be estimated foressproducts ortanier and for resource allocation decisions. Other major fenwoo in tainable orie wyln benefits provided by protected areas-e.g., cete to mtain undogg ed t uld
preservation of biological diversity-cannot be be rete th er e oe tuse measured in dollars. Thus, in the past, the loca- etresourcoterthn timbero uly tions of protected areas have been determined er by scoring new, a e procs more for watershed protection or tourist poten- or enou co nc
tial than for conserving of biological diversity.
A marked disparity exists in the worldwide Products obtained from animals and from distribution of parks and protected areas, with wood, bark, leaves, or roots of trees and other some types of ecosystems well represented and forest vegetation offer significant opportunities others not represented at all. Many legally pro- for tropical countries to develop cottage industected areas lack firm commitments from local, tries. Employment and incomes for people livnational, and international agencies. Conse- ing in or near forests could be improved while quently, they receive little actual protection or encouraging maintenance of the natural ecoare inadequately managed. systems. Improved assessment of the role of

Ch.1-Summary 15

Figure 6.-A Typical Biosphere Reserve forests by cutting more wood than grows each
-~ -~year. Development of improved wood processing technologies and markets for more of the / X many tree species and sizes growing in the
r closed forests would reduce the area that must
/ be logged to satisfy timber demand. Where too
fmuch wood is being cut, it may be necessary to reduce demand by increasing the efficiensvicy of woodstoves and charcoal kilns or by subforeststituting alternative energy sources.

X Industrial Wood

l e Intensive forest harvesting could give inScreased output per unit area, thus reducing defmand to cut elsewhere. But this approach can X have both positive and negative impacts. It can
Semake reforestation planting more feasible. On Sthe other hand, it increases the potential for Fewdamage to the site from poor road engineerting, inadequate site protection, and tardy restoration of forest stands. Intensive harvesting
CrCore area Research station would require strict enforcement of regulations
Buffer zone 1 Tourism to prevent adverse impacts on the land's longope term productivity.
W Buffer zone 2 X X X Human settlement s Inesvhaetigdpdsote ala
A t iosphere reserve considers the needs of the local people by incorporating biophysical and socioeconomic factors into its management plan ability of profitable technologies to extract, procSOURCE: M. eatisse, "The Bliosphere Reserve: A Tool for Environmental Con- ess, and market a wider range of tree species
servaMion and Management," Environmenta Conservation, ol. 9, summer 1982. and Grouping according
uses (e.g., construction material) is an approach forest products in subsistence economies and that has been successful in Africa. However, development of markets for nonwood products many unused species have sizes, shapes, or could help decisionmakers recognize the value wood characteristics that make them difficult of undisturbed forests. U.S. scientific and to harvest and process and that limit their usemanagerial expertise could be applied to this fulness. problem, especially from the fields of ecology, botany, business, and forest management. The use of smaller trees would require costtly replacement of existing equipment, which ewctechrenowloie eistods tt can trca has been designed for large logs. Portable sawfoeseeted renele reorest far a tica mills and small units that could be carried easifoestowile eaving b te foreg narly ntat ly and set up to mill logs at the stump could Crclethat ad butterflypfarmingeareTtdex- make logging much more efficient. Such techopmest oothr being imlemuce-ne g nologies might minimize adverse environmenttpmens of ohershror-ne al effects from hauling logs but might encourage logging of currently inaccessible areas.

Technologies to Reduce Overcutlng .The greatest progress toward making intensive harvest profitable has occurred where mulMuch resource degradation is caused in tispecies wood chips are produced for wood
closed tropical forests by inappropriate wood pulp or fuel. The "press-dry paper process" harvesting methods and in mountain and dry 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 forests 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 susceptible to attack by termites, other insects, or fungi under tropical conditions. Although wood preservatives are available, they generally are costly. Some less expensive techniques exist but their effectiveness has not been proven.

Approximately 80 percent of the estimated 1 billion cubic meters of wood removed annually from tropical forests is used for fuel. The effects of excessive fuelwood cutting are seen first near cities and towns where fuel demand is concentrated. But overcutting does not Photo credit: OTA staff
always remain a local problem. Mangrove Since most wood fuel in tropical nations is used in
forests of Thailand and dry forests of Kenya, homes for cooking, disseminating more efficient and for example, are overcut to produce charcoal low-cost stoves should significantly
that is transported by ship to other nations. reduce fuelwood demand
Most wood fuel is used in homes for cooking, though tobacco drying and other rural industries also consume substantial quantities. mandtrire eallcrupn g
Common domestic stoves waste much of the wood energy, as do traditional methods of mak- Nonwood fuels such as kerosene can someing charcoal. Therefore, it should be possible times be used to reduce wood demand tempoto reduce fuelwood demand significantly and rarely while fuelwood plantations are estabconsequent overcutting by disseminating more listed and while natural forests recover from efficient stoves and charcoal kilns. exploitation. But the costs of obtaining and
Attempts to introduce such technologies in distributing nonwood fuel substitutes are often tmpiclntis haehdmxdscs.I- prohibitive, especially to the rural poor. Smalltropical nations have had mixed success. Im- sae eeal nrytcnlge uha
proved stoves are not quickly and widely ac- solr ryeave more tenolog-term cepted. Though cheap by U.S. standards, they se, but he aoposnhibt by inoften cost too much. Some reduce the range u 1 and a of fuels that can be used. Further, improved cia nagerial constraints.
charcoal production sometimes does not lead Substituting plantation-grown wood for nato less wood cutting because charcoal makers tural forest wood clearly is an important opmay use the time or profits they gain to make tion in many tropical regions. Investment in even more charcoal. Techniques to reduce de- plantations is constrained, however, where ac-

Ch.1-Summary 17

cess to "free-for-the-taking" forest wood is not production exist, but for most of these the time restricted. Thus, regulatory controls on fuel- lag before payback begins is too long and rewood gathering from the natural forest must turn on the investments is too low to attract be enforced if the fuelwood plantation option adequate private and public capital. Opportuis to be used before all the accessible natural cities to improve this situation include: forests are destroyed. Where fuelwood has resolution of land tenure issues
commercial value above the cost of cutting and
transportation, thereand development to make sustainable secers and business will invest in planting trees. ondary forest management more profitSecuring future wood supplies is a social, able,
political, and economic problem. Investments e increased technology transfer of profitable of land, labor, and capital in tree growing are resource-sustaining forest management constrained by problems with land ownership, methods, and
laws, and social organization. Until these are & implementation of resource use regularesolved and woodfuel supplies are being effec- tons, tax laws, or subsidies to make intively replenished, measures to reduce demand vestments in secondary forest managewill fail to reach the root of the problem. De- meant more profitable. mand reduction creates no incentives for in- Simply reducing logging damage by using apcreased supply; it may achieve the reverse.
propriate or improved harvesting equipment
Technologiescan increase the number of trees available for Teihololes or istrbedForsts a future crop as well as increase natural regenAn estimated 400 million hectares of poten- ration and facilitate enrichment planting. But tially productive secondary forest* exist in to ensure that this occurs, regulations to conclosed tropical forest areas. Approximately 2 trol logging practices must be enforced. billion hectares of tropical lands are in various
stages of degradation. Investment in the im- efrsttion of Degraded Lands provement of secondary forests and reforesta- Technologies are available to reforest certain tion of degraded lands offers opportunities to degraded lands. But tree planting sometimes meet needs for materials, substitute domestic does not compete well, in economic terms, production for imports, and provide new with other land uses. The solutions to this disources of employment in wood production lemma include reducing reforestation costs, reand processing. during plantation failure rates by enlisting support of local people, increasing plantation
Management of Secondary Forests yields, and developing methods to quantify the
Many tropical countries could sustain pro- indirect benefits of reforestation.
duction of all the wood they will need for dec- Reforestation costs can be reduced if land ades if adequate investments were made to de- preparation is used to reduce weed invasion velop and manage cutover secondary forests. and ensure a favorable environment for seedlHowever, such investments are seldom made. ing growth. Plantation yields can be increased Land tenure can be a constraint, but even by selecting high-yielding, fast-growing, soilwhere the forests are clearly owned and con- enriching, and stress-tolerant tree species. trolled by government forestry agencies or Developing and implementing tree breeding private landowners, investments are usually in- and improvement programs can produce vanadequate. Technologies for sustained forest ties with high yields and other desired characteristics. Careful provenance testing-match*Secondary forest includes both residual forest that has been ing the appropriate variety to a particular cut once or several times during the past 60 to 80 years and sec- site-should improve species performance and ond growth forests that invade after periodic cultivation, reduce mortality.

18 Technologies to Sustain Tropical Forest Resources

To achieve successful reforestation, several Forestry Technologies to Support constraints must be overcome: Tropicl Agriculture
shortage of planting stock and lack of qual- Medium- and long-term maintenance of tropity control in seed and clone production, ical forest resources may depend more on sus* inadequate knowledge of tropical site con- taming the land already under cultivation than
ditions, and on refining use of the remaining forest. Intro* lack of information dissemination. during woody perennials into farming and pasThe coordination of collection, certification, toral land (agroforestry) and improving farmand international distribution of high-quality ing techniques for upland watershed areas seeds in commercial quantities needs to be im- could help sustain the productivity of lands proved. Information on proven silvicultural under cultivation and so reduce the need to techniques must be disseminated to the local clear additional forest lands. people.
These technical problems can be solved A
given adequate funding and time. A more subtle problem is to get local people to maintain Agroforestry encompasses many well-known tree plantations. First of all, they must clearly and long-practiced land-use methods. The aim understand the reasons for planting trees. The is to create productive farming systems able to trees should produce products local people supply a higher and more sustainable output
want, and the people must be convinced that of basic needs and saleable products than ocsubstantial benefits from the trees will accrue curs without trees. Agroforestry is most impordirectly to them. Often this means using spe- tant on lands with serious soil fertility probcies selected by local people rather than species lems and lands where inadequate rural infraselected by foresters. 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 disciplines, its research and development requires an interdisciplinary approach. Because of fragmented 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 (systematic 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 requirePhoto credit: J. fauer ments.
Mahogany seed. Shortage of planting stock and lack of The potential for farmers and pastoralists acquality control in seed production are constraints to tually to adopt agroforestry system improvereforestation. Systematic collection, certification, and distribution of seeds in commercial quantity ments is more difficult to assess. Peasant farmcould facilitate tree planting ers can ill afford the risks of innovation. Large-

Ch.1-Summary *19


Photo credit: H. Bollinger
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 until farmers and herders in upland areas have
would require creating incentives for people incentives to stop destructive land-use practo implement new practices in spite of the ini- ties. To provide upland farmers with nondestial risks and delayed returns. tructive land-use alternatives necessitates:

Watershed Management developing methods of land use that are
more profitable to the local community
The greatest problems in tropical watersheds and at the same time improve control of
occur where subsistence farmers and their live- water flows;. stock move onto steep uplands. Excluding developing improved techniques to measfarmers and livestock from such areas can al- ure and predict tradeoffs of different manlow vegetation time to recover, but enforcing agement actions; and
such policies is difficult. Mechanical structures 0 testing new technologies and getting the and replanting methods can restore water flow useful ones adopted by the local communistability from some deforested slopes. Further, ty. Subsidies from downstream beneficiconservation practices exist that allow farm- arises of the watershed protection may be
ing and grazing on many moderate watershed necessary. Sociological studies could help
slopes. However, the watershed management define the type of incentives needed to obtechniques are unlikely to become widespread taTo farmers' cooperation.

20 Technologies to Sustain Tropical Forest Resources

Resource Development Planning Finally; even well-planned development may
Most conversions of tropical forests to other pleentainbei planning is doe beland uses take place without adequate consid- prjets begin when lat is on bu eration of whether the natural and human re- bopysica in h n resucs atotheasit sources available can sustain the new land use. Cio s pannigmnitorng an eaitaSometimes, destructive forest conversions are tion are necessary during and after the project. an unplanned result of some other, narrowly The major development assistance organizaplanned development. For instance, poorly tons have begun to institute such procedures sited logging roads can open highly erodible but have not yet determined how to use the reforest land to unplanned clearing for slash-and- sults. burn agriculture.
burnagrcultre.Opportunities to enhance the use of resource
This problem can be ameliorated through the development planning include improving data use of resource development planning tech- availability, more demonstration of the techniques that match land development activities niques' potentials, better communication of to the natural and human capabilities of specif- planning successes, increasing the number of ic sites. These techniques can identify which trained planners, improving techniques for sites can sustain crop production, grazing, res- economic and social analysis, and assuring that ervoirs, new settlements, intensive forestry or projects remain open to redirection after impleagroforestry, and which will be most produc- mentation begins. tive if retained as natural forest.
Ideally, resource development planning includes four components: biophysical assessment, financial (investor's viewpoint) and eco- Technology Transfer
nomic (society's viewpoint) assessment, social Forest resource development is constrained assessment, and project monitoring and eval- in most tropical nations uation. Biophysical assessment is used more fessional and technical personnel who know often than the others, although it still is under- about appropriate technologies and who also used. Furthermore, the techniques commonly understand the institutional, economic, and are used to find the best site for a particular cultural aspects of forest resource systems. In development purpose rather than to develop the near term, expatriates, including U.S. proa comprehensive strategy for all sites in a fessionals, can provide some expertise. But this region. is not likely to be sufficient because the scope
Use of each of the four planning components of tropical forest resource problems is so large is constrained by a lack of information on and the number of expatriate experts is few. cause-and-effect relationships. Economic as- Further, expatriates lack the political and culcauseand-efecttural ties necessary to influence policy. Sustainsessment encounters difficulty measuring nonmarket values. Further, the analyses may con- in o forestgesou re ires o
sider the forest values only of a small site, resource development. Education, research, disregarding the interrelationships between and technology transfer are the means to dethat site and the surrounding area. For example, loss of the genetic resources in a small vetopiexpertion ta patch of a large forest may seem unimportant
because nearby forested areas contain the same Education biological diversity. Consequently, individual
economic analyses may justify clearing the for- U.S. universities can act to sustain tropical ested region piece by piece without accounting forests in two ways: educating professionals for the overall genetic loss incurred, who will work in tropical forestry related fields

Ch.1-Summary 21

and strengthening tropical nations' universi- who make decisions about the use of natural ies. However, tropical forestry is peripheral to resources. Environmental education aims to the interests of most U.S. forestry schools and change people's attitudes and behavior by prothe experts are scattered widely among institu- hiding them with the motivation and the knowltions. Consequently, efficient mechanisms edge necessary to make decisions and take acmust be developed to bring together multidis- tons that will sustain natural resource prociplinary teams of researchers and educators ductivity. and connect them with students, foreign universities, and others seeking to develop tropical Environmental education efforts can be diforest expertise. reacted at the general public using mass media
Twinning, which creates associations be- or programs in primary and secondary schools. tween tropical nation institutions and individ- Or the efforts can be directed more narrowly ual developed nation institutions, has worked at higher level decision makers. Unfortunatewith a few university forestry schools. Consor- ly, the behavioral science basis for environmentia of U.S. universities can provide tropical in- tal education is not well established, so the stitutions access to a wider range of expertise techniques must be developed by unscientific and experience than twinning arrangements. trial and error. This development could be acHowever, this approach still does not resolve celebrated if significant investments were made several of the fundamental deficiencies that re- to evaluate, document, and communicate the duce the effectiveness of U.S. institutions. U.S. environmental education efforts that are under forestry schools lack a tropical setting for way. Having neither a strong scientific founteaching and research. Further, their curricula nation nor substantial documentation of the do not prepare students to solve the social and causes of program success and failure, enviinstitutional problems that confront tropical ronmental education projects have a difficult forest resource development. time competing with other projects for funds
The development of one or more U.S. centers of excellence in tropical forestry might
resolve these deficiencies. For example, a
center of excellence in Puerto Rico could focus Reserch on Latin American forest development needs,
providing the necessary tropical setting as well Technologies intended to develop renewable as benefiting the U.S. tropical forests. resources are likely to fail if they are based on inadequate knowledge. Thus, both fundamenA major objective of U.S. efforts to enhance tal and applied research are necessary compotropical forest education could be to strengthen nets of any strategy to sustain tropical forest schools in the Tropics. Some 138 universities resources. Fundamental research is the founand 220 technical schools in tropical nations nation for applied research, while applied reprovide forestry education and training. Near- search is needed to improve existing forestry ly all these schools are new. Most are small and technologies and develop new ones. produce few graduates each year. Thus, substantial support is needed to provide in-service
faculty training, to produce locally relevant an exts o t s stining ropcourse materials, and to modernize basic education facilities such as herbariums, library col- is al needdto detemi Thesinterclections, and computers. i seilynee odtrieteitrc
lectonsand ompuers.tions between the social and biophysical facResource development professionals, the sci- tors of tropical forest systems. Some knowledge entists who develop technologies, and the tech- about social and institutional factors is being nicians who implement them are ineffective used in resource development projects supwithout strong support from the many people ported by U.S. agencies. However, this knowl-

22 Technologies to Sustain Tropical Forest Resources

edge usually is based on personal experience, tinually repeated, and potentially successful not on careful research. A substantial increase technologies spread slowly, if at all. in truly interdisciplinary research could enhance the likelihood that institutional changes
would result in sustainable forest resource The experience of U.S. forestry organizations development. shows that many potentially profitable techThe techniques used to manage tropical for- niques languish for lack of effective technology est resources are generally based on trial-and- transfer among scientists, between scientists error experience gained in past centuries. They and technology users, and among technology have benefited little from the rapid advances users. Thus, it is appropriate that international in fundamental and applied biology that have development assistance organizations focus occurred recently. For most tropical forest their efforts not on promoting particular techtypes, techniques have not been developed nologies but rather on building local instituthatcan:tions' capacities to choose, receive, adapt, and thatdeliver technologies appropriate to local cir* produce the products, environmental serv- cumstances.
ices, and employment opportunities that An important constraint on development aslocal people need, and distance effectiveness in forestry is the lack of
sustain the productivity of the resource coordination among many bilateral and multibase, and
be profitable enough to motivate people to ltera projects Coriationco resordriskutes the appropriate actions at the appropriate Applied research to improve existing technol- time to accomplish long-range plans should be ogies probably will not suffice to meet these the responsibility of tropical governments. But goals. Innovations based on new fundamental donor agencies usually fund the projects they research will also be necessary. identify rather than projects identified in some
Low levels and short periods of funding are longer term planning process. One approach major constraints on fundamental research in p p g
tropical areas, but these are not the only rea- nology transfer is the use of ad hoc internasons why basic knowledge is inadequate to sustain tropical forests. Most fundamental re- policies and problems of individual governsearch in tropical biology has been designeddevelopment assistance orto develop evolutionary theory, and relatively gaiz nations. Cm t e atene inlittle work has been done or is being done on situd Corinatin foveloment in Afecologicalveloping long-range plans and in identifying Another problem is poor communication and recommending projects for the various inamong researchers and between researchers international organizations. and technology users. Most forestry and biol- The OTA assessment identified a number of ogy research organizations reward scientists,
including those working on applied research, na ns for ucces tehnology
for publishing in journals that technology users trase orost togestackiof seldom read. In fact, few journals exist that are the edition sem t ons designed to communicate research results to
resource developers. The U.S. Forest Service Technology is transferred most effectiveperiodical The Caribbean Forester once served ly by direct people-to-people actions. Peothis purpose but has been discontinued. As a ple who are to adapt and apply the techresult of poor communication, the pace of inresut o por cmmuicatonthepac ofin- *These conditions were a result of discussions among OTA novation is slower than it needs to be, tech- staff; Roger Moeller, AID; and Gary Eierts, Appropriate niques are reinvented, some mistakes are con- Technology International.

Ch.1-Summary 23

nology need to learn it directly from peo- agents, facilitator, and end users-must ple who have experience applying it. feel that they are winners and must, in
The technology needs to be adapted at the fact, be winners. Each actor's self interests
users' end to local biophysical and socio- should be identified at the start of the techeconomic conditions. nology transfer process so that they can
Well-qualified people with knowledge be addressed.
about the technology are needed on the Each participant must be aware of subsesource end of the transfer, and receptive, quent steps in the transfer process so his capable people are needed on the receiv- or her actions are appropriate to the later ing end. These people may be local trans- steps. This requires early definition of
fer agents or they may be the end users. roles for each person involved.
Another type of actor, the "facilitator," is The environment for technology demonalso necessary. Facilitators understand the stations should be similar to the environtechnology transfer process, including the meant that will exist during subsequent market for the technology and its products steps of the transfer process. Pilot transfer and the political, social, and economic projects should not be unrealistically easy.
constraints and opportunities that affect 0 The initial commitment of resources to the all the other actors. process should be sufficient to carry the
Users and transfer agents should be in- technology transfer until it is self-supportvolved in choosing the technologies and ing.
in planning and implementing the transfer 0 The transfer process must include mechprocess so that the technology and the anisms through which all participants can
transfer meet actual needs and are appro- contribute effectively to interim evaluapriate for the local situation. tons and improvements.
a All parties involved-source, transfer

Tropical forest resources represent a great of the tropical nations. However, the United opportunity for sustained development because States can help stimulate such reforms. Some they are fundamentally renewable. However, U.S. technologies, such as Landsat imagery, altoo little such development is occurring. In- ready supply vital information to improve restead, the productivity of the forests continues source development decisions. U.S. diplomato be diminished. The U.S. Congress has al- cy-for example, supporting the United Naready helped to sustain tropical forests by tions Environment Program and UNESCO's directing AID and the U.S. representatives to MAB program-also can help to foster underinternational organizations to give forest re- standing of resource problems and coordinate source development higher priority in devel- international efforts to resolve them. opment assistance programs. To expand this
progress, Congress could take actions thatot t
more directly. U.S. and international organizato plan and coordinate resource development tons that Congress can influence have the caprojects. ability to: 1) develop technologies to produce

The underlying causes of forest resource de- goods and services for local people while conterioration are institutional, social, and eco- serving forest productivity, and 2) assist tropnomic. Consequently, the reforms needed to ical organizations and individuals in developsupport sustainable resource development can ing, adapting, and implementing such technolonly come from the governments and people ogies. U.S. agencies that are applying this type

24 Technologies to Sustain Tropical Forest Resources

of expertise include AID, the Forest Service, recent years for forest related projects. Howthe National Academy of Sciences, the Nation- ever, many opportunities for use of developal Park Service, the Fish and Wildlife Service, meant assistance to sustain tropical forest reand the Soil Conservation Service. Some com- sources are not being pursued adequately. Exmercial firms, private voluntary organizations, samples of such opportunities are: and U.S. universities also have expertise rele- a emphasize agroforestry, innovative crops, vant to sustaining tropical forest resources. and other techniques to sustain permanent
Congress has ways to influence multilateral agriculture on relatively poor soils; banks and U.N. agencies, some obvious (e.g., promote reforestation and management of through allocation of funds) and some subtle natural forests to sustain environmental (e.g., using the prestige of Congress to give services and produce fuelwood, construccredibility to a new idea). The final chapter de- tion wood, polewood, and nonwood prodscribes opportunities for congressional action ucts; to: stress institution-building to enable tropi* expand and coordinate development cal governments to exercise improved conassistance, trol over timber concession operators; and
encourage resource development plan- support livestock projects that do not reni roiclgors reercande sult in deforestation or forest degradation.
improve tropical forest .research and de- Oto
velopment efforts,
protect biological diversity, and To encourage expanded support for forestry
expand U.S. expertise in tropical forest re- projects, committees of Congress could continsources. ue oversight hearings requesting AID officials
The U.S. tropical forests are discussed sepa- and U.S. representatives to multilateral develrately in this summary. opment assistance organizations to testify on
the extent to which assistance practices accomExpad ad Cordiateplish the objectives set forth in section 118 of
Exp d and Coordinatthe Foreign Assistance Act.
Development Assistance
issue (Cordination)
Issue (Projects) Development assistance agencies generalDevelopment assistance progress is slow ly do not coordinate their projects effectiveand the gains are insufficient to sustain trop- ly at the country or regional level. To improve ical forest resources. Many opportunities ex- their effectiveness, projects could be orgaist to enhance gains already made, but con- nized as steps in comprehensive strategies degressional vigilance is necessary to ensure signed to develop sustainable forest resource that forestry projects receive an appropriate use systems. Individual development assistshare of U.S. development assistance funds dance agencies have neither developed nor coand that other types of projects complement ordinated such strategies. the forest ry efforts.
the oretry ffots.The reasons why host governments and inThe Foreign Assistance Act directs develop- international assistance organizations do not ment assistance organizations in which the coordinate activities more effectively are comUnited States participates to give higher priori- plex. But coordination could play a key role in ty to protecting against the loss and degrada- improving the cost effectiveness of U.S. assistion of tropical forests. Accordingly, AID, the tance. If the Congress decides that improving World Bank, the U.N. Food and Agriculture cost effectiveness is worth relinquishing some Organization (FAO), and some other multilat- degree of U.S. control over what projects are eral organizations have increased funding in funded, it could mandate increased U.S. effort

Ch.1-Summary 25

to enhance the tropical nations' abilities to meant banks to promote environmental assesscoordinate the work of development assistance ments at an early stage of project planning. organizations. This request could be followed up with hearings to determine whether the banks are using
Options environmental assessment procedures effecOne way to begin such a fundamental shift timely. 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 and Market Development plans for sustained forest resource development. Another mechanism is to create ad hoc Issue (Research) committees of experts from donor nations and Fundamental research, applied research, tropical nations to work together to identify and technology implementation related to problems and plan regional forest development tropical forests are not well coordinated. strategies. Moreover, interactions among factors that

Encourageconstrain forest resource development are
Encorag Resurc Devlopent poorly understood. Consequently, resource
Planning development projects often fail and technolissue ogies that seem to succeed in trials fail to
Although resource development planning spread beyond demonstration areas. Retechnologies can improve the sustainability search on tropical forest resources needs to of tropical forest development, they are sel- be more interdisciplinary and more closely dom applied to their full potential. related to technology implementation.
Resource development planning techniques Much work remains to develop profitable can be used to identify development activities technologies that can supply local people's that match the available human and natural resources. The techniques can give decisionmak- productivity. New techniques need to be based ers a clearer picture of the social, economic, on improved understanding of the biological, and environmental implications of a particularaffecting forest type oevloment onmpliaticularfsite.tAlso, resources. This calls for interdisciplinary retype of development on a particular site. Also, sac ae na dqaeudrtnigo they can be used to determine the best locations
for protection of natural areas to maintain bio- the needs of technology implementors. logical diversity while providing tangible ben- Options efits. But the application of planning is hampered by shortages of information on how bio- Initially, Congress could conduct hearings to physical, social, and economic factors interact. determine whether the research organizations that receive U.S. funds give adequate priority
Options to interdisciplinary tropical forestry that links
To encourage the use of resource develop- research and development. Special attention ment planning, Congress could maintain the should be paid to disseminating research reavailability of low-cost Landsat images to trop- sults. Congress could increase support for ical governments. Congress also could direct agencies where such research and developAID to expand its Environmental Profiles to meant is stressed. include macro-level land classification and col- The other approaches would be for Congress lection of information for social and institu- to appropriate funds specifically to support tional analyses. Further, Congress could direct UNESCO's MAB program or to amend the ForU.S. representatives to multilateral develop- 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- Protect Biological Diversity
terdisciplinary research. Additionally, Congress could amend the existing legislation that I allocates funds for tropical agriculture to include tropical forestry and agroforestry explic- Benefits from preserving the biological diitly. Congress also could determine the feas- varsity of tropical forests accrue to society as ibility of establishing a forestry research pro- a whole, including future generations in the gram at existing Consultative Group on Inter- U.S. and elsewhere, yet the costs are borne national Agricultural Research (CGIAR) institu- by the people of the tropical countries. tions. Congress could establish a trust fund for Developing new markets and ways of harthe Forestry Department of FAO of the United vesting and using tropical forest species evenNations specifically to support improved com- tally may make it possible to manage natural munication among researchers and technology forests profitably and sustainable. But until the implementors. markets and technologies are developed, it is
necessary to protect and maintain undisturbed
Issue (Market Development) portions of these biologically diverse ecosysIn many areas sustaining tropical forest resources will depend on local markets for for- Options est products. People seldom attempt to sustain the productivity of natural resources
used for subsistence products because these maintain biological diversity. First, it could appear to be "free." Government agencies conduct hearings on its recent amendment to typically are not aware of the natural forest's the Foreign Assistance Act which directs AID, potential to support rural communities. in concert with other appropriate agencies, to
develop a comprehensive U.S. strategy to mainTropical forest ecosystems house complex tam biological diversity. associations of vegetation, wildlife, and other
potential resources that could be developed. adi tonal uld supotite
Development of markets, along with research cretonofhnnternatna n to iiz on ways to manage the unused resources for the ablishment a eane o tropia sustained yields, could help motivate local peo- park and pec ted y forisuchoa ple and local resource agencies to manage the f ou ld trbute by avitno
forests effectively. It could be possible in some
places to maintain biological diversity and si- assistance agencies (e.g., AID, multilateral multaneously support profitable rural develop- development banks, and U.N. agencies), inment. However, such market development is creased export taxes and import duties on troplikely to reduce subsistence opportunities for ical forest products, and donations from prilandless poor people. vate foundations and multinational corporations.
Options Expand U.S. Expertise in Tropical
Congress could direct and fund the U.S. For- Forest Resources
est Products Laboratory to develop new products and market information to use tropical Issue tree species and increase its efforts to transfer technologies. Similarly, AID could be di- U.S. tcalsre soure epetiei
rected to expand its support for synthesis and widectend dissemination of information on underused
tropical forest resources and to assist in devel- The United States has recognized expertise oping markets for those products that can be (both individuals and organizations) in many produced on a sustainable basis. resource fields, including reforestation, water-

Ch.1-Summary 27

shed management, commercial forestry, re- to the unplanned or unmanaged conversion or source inventory and mapping, resource devel- degradation of tropical forests. Further, Conopment planning, and information collection, gress could direct Federal agencies to encourprocessing, and dissemination. But only a few age employees to participate in international of these experts or organizations have the ex- assistance efforts under existing laws or it perience or training to apply their skills directly could amend legislation to encourage such into the increasingly important field of tropical terchange. Congress could encourage particiforest resources. pation of the U.S. private sector to develop and
implement technologies to sustain tropical forosest resources. Congress could contribute to the OptionsUnited Nations Associate Experts Program
Congress could modify the organic legisla- whereby young U.S. professionals can gain tion of those U.S. agencies whose actions af- field experience in tropical forestry. Congress fect the tropical nations or the U.S. tropical ter- also could designate U.S. centers of excellence ritories to say that tropical forests are valuable in tropical forest resources to develop and renewable resources and to direct each agen- make available U.S. expertise in tropical recy to conduct its activities without contributing source issues.


Introduction Only in Hawaii has forestry been made an
integral part of the region's economic developLess than 1 percent of the world's tropical meant. To protect watershed values, most forforests fall under U.S. jurisdiction. These for- tested land in Hawaii is classified under conests are located primarily in Puerto Rico, the servation zoning which restricts or prohibits U.S. Virgin Islands, Hawaii, and the U.S. west- conversion to land uses other than forest. Nearern Pacific territories of American Samoa and ly half of Hawaii's designated "commercial forMicronesia (which includes Guam, the Coin- est land" is owned by the State. Since 1962, the monwealth of the Northern Mariana Islands, Hawaii Department of Land and Natural Reand the Trust Territory of the Pacific Islands). sources has followed multiple-use programs for As Congress becomes more involved in efforts managing water, timber, livestock forage, recto sustain tropical forest resources worldwide, reaction, and wildlife habitat on these lands. In it has reason to pay particular attention to the addition, two of the three programs of the U.S. tropical forests in territories under its care. Forest Service Institute of Pacific Islands Forelstry are dedicated to research on Hawaiian
tropical forests are important resources to local
people and economies: they supply food, fod- Even though forestry problems still exist in der, fuel, and employment; reduce erosion; and the Hawaiian islands (e.g., the recent dieback protect ocean fisheries. Most wood products, of native forests, endangered status of numerhowever, are imported to these areas. For ex- ous native plants and animals) considerable efample, Puerto Rico imported $400 million fort has been made to mitigate these problems.
worth of wood products in 1981. Perhaps the A number of organizations working to sustain most important value of forests on these trop- tropical forest resources are based in Hawaii, ical islands is regulation of water regimes. For including the Nitrogen-Fixing Tree Associainstance, because of deforestation the U.S. Vir- tion, the Bioenergy Development Corp., the gin Islands no longer has permanent streams. EastWest Center, and the College of Tropical Most other islands also have experienced prob- Agriculture and Human Resources at the Unilems with water quality and quantity. varsity of Hawaii. These are among the sources

28 Technologies to Sustain Tropical Forest Resources

of expertise housed in Hawaii that can be ap- that can be owned by an individual or corporaplied to the U.S. tropical territories and to the tion. world's tropical forest resources. Opportunities exist to develop small-scale
Forest resources in the U.S. Caribbean and forest industries to serve domestic markets Pacific tropical territories are not receiving a using technologies that require comparativesimilar level of attention. The forests have suf- ly low capital outlay, such as the portable fered degradation in the past as a result of poor sawmills now used in Puerto Rican Commonland-use practices. More recently, incentives wealth forests. The sawmills are one compofor local people to undertake and improve agri- nent of a Puerto Rico Department of Natural cultural or forestry activities have been re- Resources program to bring private landholdduced by dependence on U.S. Federal income ers into commercial forestry. This program supports and by economic development focus- relies heavily on U.S. Federal cost-sharing proing on industrial growth. This has resulted in grams and on funding from the U.S. Forest a movement away from agriculture and cor- Service's State and Private Forestry grants. Inresponding increases in abandoned agricultur- creased support for these activities could enal land and unmanaged secondary forests. In courage plantation forestry and increase Puermany places, runoff and erosion resulting from to Rican self-sufficiency in forest products. past forest loss threaten water supplies and The U.S. Virgin Islands have little remaincoastal marine resources. With forest resource
development technologies, much of the pro- insioet and no forest s b ae
ductivity of this degraded and abandoned land eensivelyafrouism lackof fore managecould be restored to support economic growth. gn and a ig p opul inte U.S.mVir Although current overexploitation of forest Thus, water must be shipped from Puerto Rico resources is not a problem in most of the ter- or desalinized from sea water at great expense. ritories, the remaining forests are vulnerable Reforestation and management of island wateras populations and expectations rise. Future sheds could reduce runoff rates, decrease eroproblems could be averted, however, if sustain- sion, and enhance aquifer recharge. able forest use techniques could be integrated The main constraints to sustaining tropical into strategies for regional economic develop- forest resources in the U.S. Caribbean are lack ment. of support for existing forest resource developThement institutions and lack of a skilled cadre of
The aribea Teritoies Pueto ico local resource managers. The U.S. Forest Servand the U.S. Virgin Islands ice maintains a forestry research station, the
The Commonwealth of Puerto Rico is the Institute of Tropical Forestry (ITF). It also
largest contiguous tropical area under U.S. manages the Caribbean National Forest and jurisdiction (see fig. 7). At least one-third of its supports a State and Private Forestry cooperland area is under forest cover-mostly second- active program with the Puerto Rico Departgrowth trees, fruit tree plantations, and shade meant of Natural Resources and the Virgin trees in coffee-growing regions. Because Puerto Islands Department of Agriculture. At a time Rico has a relatively large forest area, a relative- when U.S. Forest Service research needs to be ly well-developed road system, and secure land expanded to include agroforestry, watershed tenure, it has significant potential for commer- protection, and other areas of importance to cial forestry to supply its domestic economy. landholders and the public, its research funds About 200,000 acres in Puerto Rico have been and staff size have been reduced, identified as suitable for commercial forestry. In the short term, people with general tropiHowever, large-scale forestry is hindered by cal forestry expertise can be attracted to work high land prices and a law limiting the acreage 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

United States


% Puerto U.S. Virgin
Puro Islands
*.-! Haiti Rc
Mexico 0

Jamaica Republic

El Salvador

Costa Rica Panama

SOURCE: Office of Technology Assessment.

established method to train people to manage ies with the nature of each island. Few truly tropical natural resources specific to that re- undisturbed forests exist, but considerable gion is needed. Increased environmental edu- areas of secondary forest have regenerated. Litcation, scholarships, and creation of a natural tle of this is managed to provide forest prodresource management curriculum at the Uni- ucts. Fuelwood and some nonwood forest
versity of Puerto Rico could help train the nec- products are harvested for local use, but most essary resource managers. In the meantime, wood products are imported.
adequate Federal support of Puerto Rico and As in the U.S. Caribbean, the major value of
U.S. Virgin Islands forestry programs through forest resources in the U.S. western Pacific is the State Forestry Grants of the State and Private Forestry Division of the U.S. Forest Serv- not timber but regulation of water regimes and ice are needed to stimulate development, dem- tecIon o iogi rioa ecosysonstration,c. ily for both subsistence and trade on marine
estryorganisms that feed and spawn in mangrove habitats, lagoons, and coral reefs. Unplanned The Western Pacific: Micronesia exploitation of upland forests can substantially reduce the productivity of these coastal and American Samoa areas. This already is occurring on some isU.S. tropical forests exist on some 2,000 lands. islands spread over 3 million square miles in Transportation costs, limited land areas, and the western Pacific (see fig. 8). Forest cover var- insecure or communal land tenure limit the re-

30 Technologies to Sustain Tropical Forest Resources

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


Trust territory of the Northern Pacific Islands ',M ariana T u tt r t
Marshall Philippines islands
00Guam .'

ap.* -*

.,Truk** Ponape \ Pa la u

\ I Kosrae Equator

Papua New
G ~ uinea

Australia C Samoa

gion's industrial forestry opportunities. How- pie, improved small-scale charcoal production, ever, small-scale management, harvesting, and if developed and promoted wisely, could inprocessing technologies could be applied to the crease the importance of wood as a sustainable secondary forests and abandoned coconut energy source in the U.S. Pacific. Production
plantations to increase their provision of food, from existing agroforestry lands could be enfuel, employment, and other goods. For exam- hanced with new techniques. Coconut shell

Ch.1-Summary 31

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
rith local customs could be a joint undertaking of U.S. and local western Pacific organizations.

Issues and Options for Congress
The primary requirement for sustaining tropical forest resources in the U.S. tropical territories is the development of indigenous orgada nizations capable of managing the islands' rePhoto credit: C.Whitesell sources. Because the territories' governments Opportunities exist for small-scale forestry operations still depend on U.S. support and their natural oriented toward domestic markets. This small sawmill resource agencies are generally new, small, operates on Ponape, Federated State of Micronesia and undersupported, the U.S. retains a substantial role in both the development of the
charcoal can be used as a filter in various in- data imlmntation of forest-sstaiing t dustrial and pharmaceutical uses and could be snesi.e exported from these islands. planAny forest development in the U.S. western Option Pacific territories, however, will require careful Congress could direct the U.S. Forest Servplanning and management to avoid further ice to 1) expand the scope of research and
degradation of the resources and to ensure the technology development in its research instisustainable production of both goods and serv- tutions with jurisdiction in the U.S. tropical ices provided by the forests. This requires up- territories and 2) increase cooperative efforts to-date and comprehensive data bases on trop- with local governments. ical forest resources, their uses, and the poten- Development of forestry management plans, trials for their development. U.S. Federal agen- in the short run, will require technical assistcies can play a major role in creating these data

baes.uc amanagementd byrrS.cexprtise.tSmilarly adaptation of technologies to conditions in the
Integrating forestry into development plan- U.S. tropical territories requires Federal assistning in the U.S. western Pacific will require ance. In the long run Federal aid could be repersonnel with substantial knowledge in trop- placed when more people are trained in natuical resource management and strong local in- ral resource management at local institutions. stitutions through which they can work. Yet, Development of programs to encourage private no natural resource management education forestry appropriate for each island probably
programs exist in the U.S. western Pacific ter- also will require Federal assistance. The Fedritories, and few of the students who receive eral organizations responsible for assisting training at U.S. or other institutions return to forestry development in the U.S. tropical terwork in their own regions. Actions to help sup- ritories are too small and their focus is too limply needed expertise include creating a natural ited to give the impetus needed for local deresource management curriculum at the Uni- development. More research, more forestry techversity of Guam and increasing scholarships nology transfer, and greater response to the for potential resource managers. changing needs of the territories are required.

32 Technologies to Sustain Tropical Forest Resources

Option to forest owners. Replacing these subsidies
Congress could support natural resource with a program of grants administered by the agencies in U.S. territories by increasing territorial governments would provide the flexfunding for the cooperative State and Private ability needed to respond to each island terrForestry programs of the U.S. Forest Service story's unique cultural, economic, and ecologiinstitutes in Puerto Rico and Hawaii. Con- cal characteristics. Furthermore, it would engress could also create a program of grants courage the development of a constituency to territorial governments to encourage in- concerned with sustaining the forest resources. vestment in privately owned forests.
The Federal Government subsidizes private
forestry with cost-sharing and direct payments

PART I Background

Chapter 2
Importance of Tropical Forests


Highlights 37
Social and Economic Context 37
Water and Climate 40
Hydrology in Tropical Regions 40 Local Climate 42
Tropical Agriculture 42
Basic Human Needs. 44 Wood for Fuel 44 Other Basic Human Needs 45 Employment 47
Commercial Forest Products 48 W ood 48 Products for M edicine 50 Other Forest Products 51
Environment 52 Endangered Species 52 M igratory A nim als 52 C lim ate 52 Political Implications 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 earn substantial foreign exchange for tropitropical forests will become increasingly im- cal nations that trade with the United States.
portant over the next 30 years as the tropical Tropical forest resources provide food, fuel, nations' population grows from 2 billion to medicines, and other basic human needs for 4 billion people. millions of people who live in and near them.
* Tropical forests support economic develop- Where fuel wood is not available, agriculturment. They sustain production on land that al lands are damaged as people have to burn rapidly loses productivity if they are re- crop residues and manure that would othermoved and they can restore the productivity wise be used as fertilizer.
of degraded land.
* Economic development in tropical nations The highly diverse tropical forests contain
is important to the people of the United plants and animals that have great potential States for humanitarian reasons and because indue Tese wilmre valuable of our economic ties with these nations. industries come to re more onubeche Industrial wood and other forest products nology.

Tropical nations face a dilemma. Forests Because the population structure in tropical must be cut and cleared to increase production countries is dominated by young people, food in the near term, but the loss of forests can and other needs are growing faster than popureduce productivity in the long term. lation (fig. 10). For example, food production
About 76 nations, containing about half the in developing nations needs to increase by world's population (2 billion), are located en- about 4 percent per year, while population is tirely or largely within the tropical latitudes growing at about 2 percent. The age structure characterized by fast- also means that population growth has a built(fig 9).Thee naionareinromesiues tand willrevn th woumboter

growing populations, low per capital incomes, fromentum sabistil wll int the nere and agrarian economies- Some of their agricul- trytrol fo eent c(n ture is subsistence farming in upland areaspo where soils have low fertility or are dry. Some Part of the needed gains in agricultural prois commercial agriculture on the more fertile duction can come from improved irrigation, and generally irrigated alluvial plains of major crop breeding, and technical inputs that enriver valleys. The success of both types of agri- chance agricultural yields. But average yields culture is linked to the status of 1.2 billion hec- probably cannot increase every year by 4 pertares (ha) of moist tropical forest and 800 mil- cent. Two percent gains may be possible, but lion ha* of drier open woodlands. to sustain even that rate over several decades
otwill be very difficult. Consequently, the amount worls poreesuland are blin) care h) n ctae oflnen-d n rzdwilhv ob

equals 2.47 acres. One square kilometer equals 100 ha. One
square mile equals 259 ha. Thus 1.2 billion ha of moist tropical expanded and people will continue to clear forforest is 3 billion acres or 4.6 million square miles. 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 23.50 S, and at Other Frost-Free Localities

tw~Nowa nlan-Tukl

Un ond orf Soie ocais Rpblc

*A c., manLy.cenmvn

-Trrance ou Rumana

Italy Nath Japn

Ag ri Lea, at tel ra


T ro0 c o f C a riM eo rc S au a" E na.i d a u m
au Pna-n
Pegnem Peru BraPeeMalaw000im AngoaZam0
Bol___aNambaZmba we

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

Age More developed regions Age
Male Female
75+ 75+

70 70

60 60

50 50

40 40

Less developed regions 30 30

Age Male Female Age
75+ 20 20 75+

70 70

10 10

60 60
0 1 I1 0
100 60 20 0 20 60 100 50
40 40

30 30

20 0- 0

10 10

300 260 220 180 140 100 60 20 0 20 60 100 140 180 220 260 300 0
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 One approach to accommodate the conflictyoung people in tropical populations also result ing needs of tropical people is to accelerate ecoin a rapidly growing labor force. But in most nomic development of resources outside the tropical nations, it does not seem likely that forest to provide food, goods, jobs, and foreign industry and commercial agriculture will be exchange. This would reduce the need to exable to sustain growth of over 2 percent per plot and clear tropical forests. While this may year in job opportunities. Thus, substantial have the greatest effect in the long run, these numbers of people will turn to the forests- types of technologies (e.g., improving tropical either clearing them for conventional farming agriculture) are outside the scope of this and grazing, or managing them for forestry and assessment. agroforestry production. A second approach is to direct the use of forThe need for food and jobs is direct and com- est resources so that both sets of needs-propelling, while the environmental services pro- vision of food, jobs, and national income and vided by tropical forest resources affect tropi- maintenance of the forests' environmental cal people indirectly and forest loss becomes services-are fulfilled. apparent slowly. In the long term, tropical people need the watershed protection, preservation of habitat and genetic diversity provided
by the forests (fig. 11).

Hydrology IO Tropical Regions ary water storage. In addition, organic litter on
the soil surface and the porous topsoil store
Most rainfall in the Tropics occurs where the water. The organic litter in closed tropical fornortheast and southwest trade winds converge. tests is typically 10 to 30 centimeters thick and This Inter-Tropical Convergence Zone is intrin- the topsoil has a high organic material content sically unstable, oscillating to the north and (49,61). These mechanisms minimize the imsouth of the Equator, causing an erratic rain- pacts of intense rainstorms, reduce peak stormfall pattern with sharp seasonal contrasts (49). flows, and help mitigate flooding. When tropical rains do fall, storms are moresefo violent than those in temperate areas. More he sefeces so fret t covsets ofreansIo
watr fllsperstom, uiclyatuatigte hveion fodjosure ind tioal a

aater ltrm, p rting the moist montane forest in Kenya, fvr example, soil. Consequently, a agrpooto fte water measurements were taken on two adjarainfall runs off the soil surface. Furthermore, cent 600 ha valleys for over 25 years. When one in tropical storms raindrops are larger, thus valley was cleared for a tea plantation-leaving having great kinetic energy and high erosie the steeper slopes and riverbanks under forest power (1,59). For example, in areas of the -t he immediate effect was a fourfold increase Amazon Basin where annual rainfall averages in peak stormflow. Even after installing con2,100 millimeters per year and land slope is servation practices (e.g., contour planting, cutabout 15 percent, erosion removes only about off drains, cover crops), stormnflows remained 360 kilograms of soil per hectare per year from double that measured in the undisturbed forest, forested land. But after the forest is although the total flows were small (49). Simierosion increases 100 times (43). larly, an experiment was conducted in India
Tropical forests protect soil and modulate on a forest which had been reduced to wastewater flows in several ways. The canopy of land by fuelwod cutting and overgrazing. leaves intercepts rainfall and provides tempor- When the severely eroded Siwalik hills of

Ch. 2-Importance of Tropical Forests 41

Figure 11.-The Role of Forests

Catchmednd Controlled runoff, water
Cp tchcon supplies, irrigation, soil
pr otctionfertility, oxygen

Recreation, tourism,
Ecology and wild- national parks, protection
Ecological effects lfcosrainof endangered species of
flora and fauna

Windbreaks, shelter belts, Soil erosion dune fixation, reclamation
control of eroded lands

Fuelwood and Cooking, heating, and
charcoal household uses

Shifting cultivation, forest
Agiculuralusesgrazing, nitrogen fixation, mulches, fruits and nuts

Housing, buildings
Seruiltue pul construction, fencing,

Indigenous consumption C sawiig and r e uritnune, con

sad lln ashescical, amakilings Ropes and string,
PWvin matebaskets, furniture, furnishings

Ser iutre, apicul- I S lk, honey, wax, lac

Special woods Carving, incense,
and ashes chemicals, glassmakIng

Naval stores, tannin,
Gums, resins, turpentine, distillates,
and oils resin, essential o rd,

wtRed on aen for steel S Charcoal m makng, chem alsk poly
inyl chloride (PVC), dry cells

Transmission pols
-Poles Pitprops

Lumber, joiner,, furniture, Indstialuss awlogs packng, shpbuilig
mining cosrucin, seprs

Veneerlogsood, veneertfurnitture,

Newsprint, paperboard,
printing and writing paper,
Pulpood containers, packaging,
dissolving pulp, distillates, textiles and clothing

ResiuesParticle board, fibebord wastepaper

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

25-287 O 84 4

42 Technologies to Sustain Tropical Forest Resources

Chandigah were reforested, the peak rate of rence and persistence of mists. Thus, the heat flow from the watershed was reduced 73 per- flux from a closed tropical forest in the dry seacent and total flow was reduced 28 percent (73). son is only half that from similar land covered
In dry environments where tree canopies are(49). open, forests are less effective in protecting the
soil and modulating water flows, but their in- ly to enjoy greater soil moisture content than fluence is still beneficial. Open forests provide those on cleared land, provided that they are shade and act as windbreaks. They reduce soil planted beyond the root-spread of the trees. surface temperatures and wind erosion and sta- Similarly, windbreaks and shade trees can imbilize streambanks. They can anchor shifting prove microclimate for crops in dry areas. sand dunes that can otherwise destroy crop- Some mountain forests in low rainfall areas lands and irrigation systems. In coastal plains, collect useful amounts of water by condensation trees can prevent the rise of saline ground wa- from mists and release the water as "drip-fall," ter. Trees in arid areas, however, may through sometimes giving rise to perennial streams (49). evapotranspiration leave less water available However, the belief that forests actually cause for human uses (49). rain is questionable. (One recent study in the
Amazon reports that a significant part of the
rain falling there is water evaporated from the
Local Climate forest, but the results have not been verified
by other studies.) The dessication that is so freTropical forests also can affect local climate. quently a consequence of large-scale forest desIn moist forests with closed canopies, tran- traction is due to the hydrological damage spiration of water extracted from the soil and caused by loss of infiltration and underground the direct evaporation of intercepted rainfall storage. In general, forests thus have a critically cool the surrounding air. The resulting cool- important influence on the reception of raining effect is pronounced, increasing the occur- fall, but not on its generation (49).

The populations of tropical nations generally celebrated siltation that accompanies abnormal are concentrated on the coastal plains and in floods can fill reservoirs, canals, and stream the valleys of the great rivers. Most forests in channels, reducing the precision of water conthese areas already have been cleared for crop- trol in subsequent years. Thus, the Green Revlands. Much of this land is irrigated by old solution not only increased production from the systems that control the drainage of seasonal best tropical croplands but also increased susfloodwaters. Land that is irrigated with newer ceptibility to damage by floods and siltation. systems uses large dams to store excess flood- This makes watershed protection provided by water and can produce more than one crop per tropical forests even more important.
is Unfortunately, recent decades have been a
The most productive tropical agriculture is time of rapid deforestation in many tropical nabased on annual flooding, but it fails when the tions. Consequently, river flows have become floods are severe. New high-yielding crop vari- more erratic, flood damage to crops and struceties of the Green Revolution are short- tures has been severe, and siltation of waterstemmed and so require precise control of ways and reservoirs has increased (49).
water levels. Excessive flooding also can result
in shortages of reservoir water for irrigation The modulating effect of forests on streamin the following dry season. Further, the ac- 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 thsrervisaeflngwhsdmntt been destroyed. In Pakistan, for example, some tieteepce ae(9.Smlry itto
70 million people depend on 14 million ha of isepcdtoruethlftmefteHra irrigated land in the Indus Basin for food. The kurerviinIdafo 10yasto3
irrigation depends on river flow, but deforesta- yer(5) tion on the Indus' headlands has resulted in increased peak flows during the monsoons, fol- I niteae farclua addm
lowed by water shortages during the dry sea- ae ahya yfod otne oices son. With World Bank funding, two dams, the asdfrttinocs.TeraofmstoMangla and the Tarbella, were constructed for escladechyrisbot1700a(2) hydropower, flood control, and irrigation. Careful studies of sedimentation rates had teps 0yas rm2 ilo o2 ilo
indicated that these dams would repay con- ha(2.Cernofoessvrtepst0 struction costs by providing benefits for many yerinndahscudfloadeoin decades. However, parts of both watersheds dmg siae tUS$6blini 92
havesufere uncntrlle deoresatin ad Tis estiate incldesth lssi of til lossaku eevi i.niYrm11 er o3

est~Pot claeecerdiot 147,000 bPetnhan(29) Ghaa as nvstd havly n heVola ive pojct.Th nthe area loodedhavstmn friend 18 peren longver of he ,25 ml rsevoi, wic intur dpens o w trhed pastetio 0yaffr, fo es22 milin to26millio

mostevientwhentheproectvefresshve has (72.sCering ofe forests ovetheipast 20

irrgatd andin heInds Bsi fo fod.The kdryear i in Indiacue food and person
tiodmag esimte ate U.S.$36 billiond ins 1982.dinin

haversuffered unodcontrol defortation. and th eat ldehs lossn of tpsoilt loseo

44 Technologies to Sustain Tropical Forest Resources

nutrients, loss of property to floods, and short- in the tropical forests. For example, a recent ened reservoir lifetimes (57). improvement in resistance of peanuts to leafFlood control and irrigation also are impor- spot was derived from breeding crop varieties tant in Central America. By the year 2000, with wild forms from the Amazon region. The
Cost Ria ad Paamapla to xpad teir estimated benefit from this one improvement Costa Rica and Panama plan to expand their i 50mlinprya 4)
irrigated areas by 180 percent and 340 percent,
respectively (45). Yet, in these countries defor- The peanut is just one of many crops with estation is rapid and uncontrolled. In many
Central American locations, water needs for ancesorsei tropical fors area ther irrigation, consumption, industry, and naviga- cate troical platane ptans, tion are reaching the limits of low-season flows. yas Tr cs sugar poatoes and Half of the region's forests have been cleared in cewpes Treeacrops ith opical rea the past 25 years and water flows are becoming cestors and i n ilpam ruber more erratic as deforestation continues (26,45, cfee coca, an an iortat f 77). Similarly, in Africa along a broad belt bor- the cal co un for t leas during the equatorial humid tropical forest ng (47), as well as many commodities important along the Gulf of Guinea, the forests are being t h .eooy uuegisi rdc
destroyed. Consequently, several nations in the toth U om utue gan iprducregion are expected to suffer agricultural water tural crops may depend on the genes in their shortages before the end of the century (77). wild progenitors and, thus, on the continued
In addition to watershed protection for the existence of tropical forests and associated natcurrent year's crops, forests have longer term rural areas. values for agriculture. Farmers throughout the
world are using more high-yielding crop vari- For the people of the Tropics, damage from eties. In fact, about half the increase in agri- increased flooding and siltation and the potencultural production in recent decades can be trial loss of crop breeding opportunities mean attributed to plant breeding (81). The reliance poorer nutrition, slower economic progress, on high-yielding varieties has reduced the ge- and less prospect of achieving prosperous, netic diversity of agricultural systems and so stable economies. For the United States, this increased the risk of catastrophic damage from means the affected nations are less able to trade diseases, pests, and other stresses. Yet, no great internationally. The developing nations already increase in crop failures has occurred. This is are a major market-and the fastest growing due to new methods of crop protection and the market-for U.S. exports. Their purchases ability of crop breeders to respond to threats from the United States in 1982 were valued at quickly by breeding new traits into the crops- $82.7 billion, over one-third of all U.S. exports traits sometimes obtained from wild relatives (82).

Wood for Fuel wood and charcoal. Another billion people
Wood is the most important source of fuel meet at least 50 percent of their energy needs in most tropical nations (two exceptions are this way (25). Brazil and Mexico, where oil and gas provide Fuelwood, however, is becoming harder and a greater share of total fuel than wood). One harder to find. Some 100 million people already and one-half billion people in developing coun- are experiencing acute fuelwood scarcity and tries meet 90 percent of their energy needs with another billion are affected by lesser shortages

Ch. 2-Importance of Tropical Forests 45

other Bascd Human Needs
The exact number of people living in and near tropical forests, relying on the productivity of forests to supply their basic needs, is not known. The U.N. estimates that about 28 million people practice shifting cultivation in the closed tropical forests of Asia, 20 million in Africa, and 40 million in Latin America-totaling some 88 million people (31). This means some 3 to 4 percent of the total agricultural population in Asia, about 10 percent in Africa, and 35 percent in Latin America, work inside the closed forests. These estimates include ethnic populations practicing shifting cultivation

as a traditional way of life. They do not include

agiulua wastesltra withl advrs impct oneyhutr
lad and gatherers, nor people who recently moved
into forests. This can be significant, since in tropical Asia, at least, squatters probably outnumber shifting cultivators. e Many millions of additional people live in drier, mixed tree and grassland environments t off(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 enPradesh, 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 person-days of work to satisfy one household's annual fuelwood needs-forcing some dramatic changes in lifestyle. For example, many fameilies in Upper Volta eat only one cooked meal 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 n
numbers of people to burn animal dung and Mo
agricultural wastes, with adverse impacts on land productivity. It has been estimated that w
if the cow dung burned for fuel in Asia, Africa,a and the Near East were used for fertilizer, grain Photo credit: U.S. Agency for Wtemational 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 1904 erosion resulting from deforestation was grasses provide poor fodder. People living in responsible for clogging the once-navigable Rio open woodlands use wood for cooking, boiling das Velhas in Brazil to such an extent that even water, heating, drying crops, and as fuel for canoes ran aground (87). Today, deforestation small industries. Open woodland dwellers, like is much more widespread in Brazil, and other the people of the closed forests, use trees and navigable rivers such as the Cuiaba and S-o wild plants for medicines, soaps, and many Francisco have large parts filled with silt from other basic needs (86). eroded forest soils (3,8). Inland waterway transFood from the forests-both closed and portation is further damaged by the seasonal
open-meets a significant part of the world's drying up of local streams that can be a connutritional needs. Meat from wild animals, sequence of deforestation (18,88). fruits, nuts, honey, insects, fungi, and foliage Increased erosion caused by deforestation are all important forest food sources. At least has accelerated siltation of the Panama Canal's 500 species of edible leaves are used in Africa system of reservoirs at the same time that accelalone (42). "Bush meat," including rodents and rated runoff has diminished water storage in reptiles as well as wild ungulates and other the Canal's watershed. During a 1977 drought, mammals and birds, supply as much as 75 per- the canal was closed to large vessels because cent of the animal protein consumed in some of low water, a situation that experts believe tropical regions (20). may occur with increasing frequency unless
Forest trees and vegetation are the main ma- watershed forest cover is restored (85).
terials used in the Tropics to build homes and Another impact of deforestation on tropical buildings. In many rural societies, wood fre- waterways relates to the release of nutrients quently is preferred even when other materials from the forest biomass and soil. Organic matare available (91). Local wood also serves as ter production is sharply reduced under nonpoles, fences, stakes, furniture, tools, and uten- forest conditions. Further, the soluble nutrients sils. Substitutes for these products are rarely from the ash of burned forests and from rapidly available in subsistence cultures. Various fibers decomposing soil organic matter are easily derived from forest vegetation are also impor- leached from soil by heavy rainfall. The resulttant, especially for household use. Rattans, for ing increased nutrient content of runoff can example, are climbing palms used for cane fur- accelerate the growth of noxious plants and niture, baskets, mats, and similar uses. algae in nearby lakes, canals, and rivers. AquatIn the northwestern Amazon forest alone, at ic weeds block canals and pumps in irrigation least 1,300 plant species have been used by projects. Also, they interfere with hydroelectric native people as medicines and drugs (62). Tra- production, waste water through evapotranditional healers in Southeast Asia use some aspiration, hinder boat traffic, increase water6,500 plants as treatments for malaria, stomach borne disease, interfere with fishing and fish ulcers, syphilis, and other disorders, and also culture, and clog rivers and canals so that as sedatives and emetics (50). A number of drainage is severely retarded and floods result. these plants identified and tested by native peo- In India, for example, plants reduce water ple through generations of trial and error yield flow in some large irrigation projects by as exceptionally promising compounds when much as four-fifths. Rafts of water hyacinth
screened in modern laboratories (21,24). weighing as much as 300 tons float over rice
Forests also protect both inland and coastal paddies in Bangladesh during floods. When the waters, providing another important benefit to water recedes, the weeds settle and kill the gerpeople. After deforestation, increased runoff minting rice. Maintaining forested wateraccelerates erosion and carries excessive sheds would reduce erosion and runoff, reduce
amounts of sediment to nearby lakes, reser- populations of aquatic weeds, and reduce the voirs, and streams. For example, as early as cost of maintaining waterways.

Ch. 2-Importance of Tropical Forests 47

Forests also act as a buffer against the force labor because site preparation usually involves of typhoons and other violent storms in coastal more cutting and tree removal than does harzones. Tropical Asia, for example, suffers an vest (63). Table 2 is a summary of estimated average of 57 typhoons each year, causing annual person-day requirements for various
storm damage that averages $2.8 billion (92). forest plantation operations in World Bank Forests reduce the destructive energy of these projects. storms by deflecting wind and reducing the Some tropical governments view tree plantoccurrence of landslides and other environ- ing as a way to reduce unemployment (33). For mental damage. example, planting programs are planned with
Tropical storms are most violent in coastal employment as a major benefit in various areas areas, typically the areas that are most popu- of Brazil. In the states of Minas Gerais and lated. Yet coastal forests are being eliminated Espirito Santo, a large work force plants more rapidly than most other types of tropical 100,000 ha/yr by hand, and in the Amazon reforests, with sometimes devastating effects (45). gion two large companies only do hand-plantFor example, Bangladesh has a coastal zone of ing. Similarly, large-scale, labor-intensive pro20,000 square kilometers that supports 20 mil- grams have been developed in Colombia, Venelion people. This nation's coastal areas were zuela, the Philippines, the Republic of Congo, extensively cleared in the 1960's, leaving little and other Asian and African countries, and protective forest. When a severe typhoon smaller programs are under way in Guatemala
struck in 1970, 150,000 Bangladeshis drowned and Honduras (89). (35,65). Each year, typhoons and floods to- Forestry and agroforestry require protection
gether claim the lives of 200,000 people and and management and so provide even more destroy many hundred thousand hectares of employment opportunities. Using agroforestry
crops (92). A portion of these lives and crops systems including cultivated crops, several tree could be saved if forest cover were maintained crops, and livestock on a 100-ha farm in India, and enhanced (45). employment is estimated to rise from 20 to 50
About 15.5 million ha of mangrove forests people at the final, sustained yield stage. Thus, grow along coastlines and in estuaries in trop- agroforestry systems to reclaim 5 million ha of ical America, Asia, and Africa (31). These for- India's degraded lands might employ 2 million ests have several important functions aside people (57). Furthermore, forest products could from acting as a coastal buffer against storms, serve as the basis for cottage industries, providseawash, and floods. They also process sewage, ing more employment and producing goods for absorb nutrients and heavy metals, and precip- domestic use and export. 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 Table 2.-Estimated Annual Person-day Requirements young move into mangroves where they seek for Various Forestry Operations
food and protection. Mangroves also provide panin design nurseries for such commercially important (more for energy plantations)
fishes as mullet, grunts, and milkfish (66). Task Person-days
Nursery work/i ,000 plants. 7-13
EmploymentLand clearing and burning/haa.10-50 EmlyetPitting for planting/ha. 315 Forest management and forest products in-.6-36 Fores mangemet an foret prduct in- Pruning/ha 5.15 dustries can be a major source of employment Thinning.8-11 in tropical countries. Industrial wood harvest aThese measures vary greatly according to site conditions. in tropical forests takes about 60 person-days SOURCE: P.J. Wood, J. Burley, and A. Granger, "Technologies and Technology systems for Reforestation of Degraded Tropical Lands," OTA comper hectare. Planting trees takes even more missioned paper, 1982.

48 Technologies to Sustain Tropical Forest Resources

Mangrove forests are important-economically and ecologically. However, mangrove ecosystems can be damaged by human activity. Deforestation of watershed areas can accelerate deposition of sand, silt, and clay in alluvial areas; changes in the pattern and volume of freshwater runoff can be attributed to irrigation, roadbuilding, and other such projects; coastal engineering practices may bring about a change in tidal flushing regimes. Other major stresses include pollutants such as pesticides and insecticides used in large agricultural projects and recurring oil spills due
to the exploitation and transportation of offshore oil.
Several mangrove species are highly valued as firewood because they burn evenly with little
smoke, and as charcoal because they have high caloric value. Charcoal for commercial sale is the main mangrove product in several Asian countries. Mangrove poles are used extensively for rural houses, foundations, and scaffolding of urban construction because the wood of many mangrove species is durable and resistant to termites (14). In recent years, mangrove has been harvested for woodchips to be used in chipboard manufacture, newspaper, and as a source of cellulose for rayon (71). The conversion of mangrove land to aquaculture ponds also is increasing, which could have potential to increase fish production. However, improper site selection and poor design could have
substantial negative impacts.
Management of mangrove forests can be complicated. In clearcut mangrove areas, increased
temperatures and evaporation can raise soil salinity so that mangroves are unable to regrow. Hand planting of seedlings is possible but costly. Selective felling systems that retain trees below certain diameters often involve rather complicated regulations that may be difficult to administer. Natural regeneration can be enhanced by clearcutting narrow strips so that nearby trees can provide seeds.
The pressure to clear additional mangrove forest areas for agricultural, industrial, and aquacultural purposes will continue and the demand for fuelwood and poles will increase. Short- and long-term socioeconomic impacts of all alternative uses of mangrove forest areas must be evaluated to determine the optimum uses. It is only partly known, for instance, to what extent marine species are affected by removal of mangrove forests. Improved understanding of this important
interaction could have significant forest management payoffs.


Wood Value estimates exist for the 6 percent of the
commercial tropical wood harvest that is exThe principal commercial products of trop- ported. The total value of wood and wood prodical forests are timber and fuelwood. Tropical uct exports from the tropical nations has inhardwoods are used to produce lumber for con- creased by about 500 percent in the past 10 struction, poles, pilings, railway ties, props in years (32). Indonesia's wood exports in 1980 mines, and panel products such as plywood, earned some $1.9 billion. The value of wood
veneer, fiberboard, and particle board. Hard- exports for Malaysia was $2 billion in 1980; for wood is also important for finished goods such the Philippines, $415 million; for Brazil, $816 as furniture and paper products. In addition, million; for the Ivory Coast, $415 million (32). some softwoods from tropical forests are used World trade in tropical wood is significant
for lumber and pulp. to the economies of both the producing and
Most tropical forest wood is used within the consuming nations. The largest single importer country of origin and the economic value of is Japan. Several other large importers-e.g.,
this domestic consumption is difficult to assess. Singapore, Hong Kong, and South Korea-

Ch. 2-Importance of Tropical Forests 49

reexport most of the wood to industrialized na- housing industry, so industrial demand for tions after partial or complete processing. tropical wood has grown at a rate that generally follows housing starts. The paper industry is
The United States is the second largest im- the other major wood user, but it primarily uses porter of tropical wood products and little of softwoods, for which the United States and this wood is reexported. U.S. hardwood im- Canada are major producers. Many tropical naports in 1978 amounted to $682 million, with tons import paper, and the papermills located tropical countries (principally Southeast Asia) in the Tropics still import most of their softsupplying 82 percent of the total. Imports of wood pulp from the temperate zone. Some tropical wood (logs, lumber, plywood, and ven- tropical nations have begun to use their own eer) averaged $430 million annually from 1974 natural pine forests, pine plantations, and, in to 1978. Although the dollar value of these im- a few cases, hardwoods as a source of pulp. ports seems high, on a volume basis they ac- But tropical forests still produce no more than count for only 1 to 2 percent of all wood used 10 percent of the world's paper and paperin this country (85). U.S. demand for tropical board. wood has been growing at rates well above our
population and the gross national product This is likely to change in the next few decgrowth rates. ades. New technologies, some developed by the
U.S. Forest Products Laboratory and U.S. forBoth in the Tropics and in the importing na- est industry, make it possible to produce hightions, industrial hardwood is used mostly in the quality paper pulp from 100 percent hard4 1

Photo credit: i Bolinger
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 Because tropical moist forests contain so species (84). International demand for tropical many species, each species must compete with hardwood chips is expected to rise substantial- and defend itself against many potential enely as the new technologies are installed in miles, and one way to do this is by developing papermills in wood-scarce Japan and in Eur- alliances (e.g., symbiosis) with other species. ope, where wood shortages are anticipated. Thus, tropical forest species are highly interacJapan already uses hardwood chips for over tive. The millions of plant and animal species half of its pulpwood needs (46). also have had time to develop complex chemiDemad fr hrdwodsfor ape prducion cals that help them interact with other species. Demand for hardwoods for paper production I sbcueo hs booial cie
also will increase within those tropical nations checas a the rop ical acidthat have growing economies. As income in- eed th rhest s oress of pontial creases, demand for paper products rises rapid- dgs. ly among relatively poor consumers as long as
wood supplies are abundant (17). Today, medical science is highly dependent
Fuelwood and charcoal enter commerce for on chemicals produced naturally by plants. both household use and industry. Wood fuels One-fourth of all U.S. prescriptions contain have become much more important for indus- ingredients from higher plants (27). In 1974, the tries in tropical nations since the rapid rise in United States imported $24.4 million worth of fossil fuel costs. Wood is the least expensive medicinal plants to produce about $3 billion energy source available for many cottage in-of these dustries and charcoal the highest quality local
source for some uses. For example, Brazil has prescription items are included, the value
1.5 million ha of eucalyptus plantations estab- doubles (28). lished to supply charcoal to the iron and steel Although chemical screening has been done industry in the state of Minas Gerais (31). on less than 1 percent of the tropical species, The Philippine Government is planning two260 South American plants have large wood-consuming industrial facilities in benidentifie as havi al for fer the province of Ilocos Norte. The first of a num- conto Some 0tical forties are ber of 3-megawatt "dendrothermal" electric beiee t he atiCancer oetie h71 powerplants dependent on wood from fastgrowing trees as boiler fuel is under construc- s t 35,000 h e plat eisf
tion. Another project that will involve two large tivit aainst ae ou977, a ti00 pig-iron blast furnaces and will rely on char- th ad demsrtereproie tv coal from local wood is being planned (36). tyandca small numbe ere aroite for tropical trees, for example, are being tested
Products for Medicine clinically in the United States as antitumor
The importance of the tropical forests, espe- -drugs. cially the moist forests, as a source for medi- One tropical plant, the rosy periwinkle, has cines is largely a result of their high biological had a profound effect on treatment of leukediversity. Some of these forests contain com- mia. In 1960, people suffering this disease munities of species that have existed for 60 mil- faced one chance in five of remission. But belion years, making them the oldest continuous- cause of two drugs developed from the rosy ly established land ecosystems known. Their periwinkle, the chances of remission are now great age and ecological stability have allowed four in five (41). Tabebuja serratifolia, Jacaranevolution to proceed in a relatively undisturbed da caucana, and Croton tiglium are tropical manner, and it is probably due to this stable trees, and each produces a unique anti-cancer history that tropical moist forests developed compound whose effectiveness has been their extreme biological richness (45). proved in the laboratory (51).

Ch. 2-Importance of Tropical Forests 51

Tropical forest plants are significant in treat- Other Forest Products ing other medical problems, notably hypertension (2,41,44,67). D-tubocurasine, made from Top f pro vie a broad rranonthe South American vine Chondrodendron to- woo srldcted Soe are Oued in patamentosum, is widely used as a muscle relax- tionsiofnselectedoresps otersaret
ant in surgery in the United States. Chemists erdgi a foest an boghtto ae have been unable to produce it synthetically through adfse syste cllector and
in a form having all of the characteristics of emn Tes are te c m or frthe natural product (52). The drug's supply, et s althg ther impae Fr therefore, continues to rely on extracts from qetyi rae hnta emipis o
wild p ont example, tropical forests provide essential oils,
wild pants.exudates, gums, latexes, resins, tannins, sterols, Tropical forest animals are also necessary to waxes, esters, acids, phenols, alcohols, edible medical science. Primates are the most impor- oils, rattans, bamboos, flavorings, sweeteners, tant group. They are used widely in medical spices, balsams, pesticides, and dyestuffs. research and pharmaceutical trials.' Tropical
primates are especially important because of ew naio he ollctd ont comtheir similarity to humans. For example, re- mca ve o ts e nonwood
search into malaria, cardiovascular diseases, ucts ne eot a, wher n on
cancers, hepatitis, and other diseases common- ferotar e worth ot $135 on
lysre monkeys, m nes, acageen industrial timber (48,69). Indian forests also
squirrels, dw mnes produce a substantial quantity of animals used
monkeys,for food, scientific research, and other purSome 34,000 primates were imported into the poses. In Indonesia, rattans generate an export United States in 1977 for drug safety tests and trade worth up to $5 million per year. The drug production (5). Virus-free polio vaccine world trade in rattan end products now totals perhaps is the most important of the drugs pro- $1.5 billion (22,37). duced this way, using many thousands of trop- World trade in essential oils and spices from ical forest African green monkeys. The Central and South American owl monkey is the cal fort lla, a camo, cas
only known nonhuman animal suitable for ma- cardalon ciroea, and nao ecd laria chemotherapy and immunology studies $orbillio per year h tes n
(5). Few of these important animals are raised orts au 10,0t p ye of the kind in captivity; most are captured, and they are o ils5and5spiceswta valesf o $0 becoming scarce as their forest habitat is be-products used by the forest-dwelling people of the Tropics might
lead to increased use of these materials and further enhance the economic importance of the

'See Workshop Proceedings on Plants: The Potentials for Extracting Protein, Medicines, and Other Useful Chemicals (Wash'See ongoing OTA assessment "Alternatives to Animal Use ington, D.C.: U.S. Congress, Office of Technology Assessment, in Testing and Experimentation." OTA-BP-F-23, September o983), for additional information.

52 Technologies to Sustain Tropical Forest Resources

Endangered Species forests. Degradation and destruction of tropical forests and woodlands could precipitate a
Tropical habitats contain a significant num- fundamental shift in the course of evolution ber of the world's endangered species. As dis- (45). Of more certain concern is the loss of cussed earlier, tropical moist forests are both potential resources, not only chemicals and the most biologically complex and species-di- animals that may be used directly in medicine, verse* biome on Earth. The complexity is both agriculture, and other industries but also gedynamic (highly interactive) and stable (able to netic information with great potential for biomaintain itself for long periods). Yet the stabil- technology development. ity depends on an important provision-that
external forces do not exceed certain critical
thresholds. Human intervention may easily ex- Migratory Animals
ceed these thresholds.
Tropical forests provide habitats for many of
Because of geographic confinements and the world's migratory and endangered species.
specialized ecological requirements, tropical About two-thirds of the birds that breed in moist forest species are unusually susceptible North America migrate to Latin America or the to extinction (46). Many species are found in Caribbean for winter (74). In general, forest only one small area, so even a limited amount habitats are more important for migratory of deforestation can exterminate entire species. species than was previously thought. Many miFurther, species are highly interdependent. For gratory species winter in tropical highlandsexample, Brazil nuts are probably the most areas that have been rapidly pre-empted for
commercially significant food gathered from agriculture. Since migratory species concenforests. The nuts will grow only where a par- rate often in smaller areas in winter, the efticular type of bee lives, as only this bee can fects of clearing 1 ha of forest in Mexico probpollinate Brazil nut flowers. The bee, in turn, ably are equivalent to clearing 5 ha in the lives only where a particular type of orchid is Northeastern United States (74). found, because it must obtain a chemical from
the orchid to attract its mate. Thus, the tree has Migratory species have economic, environnot been domesticated away from the forest mental, and esthetic values in the United
where the bees and the orchids are found. Fur- States. For instance, some migratory birds play ther, for some of the nuts to serve as seeds, the an important role in integrated pest managenuts must be chewed by a rodent to soften the meant systems for agriculture in the Eastern fruit, allowing seed germination. Thus, Brazil United States, yet they could become more nut tree reserves must be large enough to sup- scarce as their wintering grounds in the Tropport a breeding population of this rodent. Such ics are lost to deforestation. complex systems of interdependence are
another reason why entire species can be Climate
threatened by small changes (75).
At least three-quarters of the projected ex- The question of whether tropical deforestatinctions worldwide until the end of the cen- tion can disrupt the stability of world climates tury are expected to occur in tropical moist is highly controversial. The scientific understanding of the climate effects of deforestation
*Biological diversity includes two related concepts, genetic is still theoretical. When forests are removed, diversity and ecological diversity. Genetic diversity is the amount
of genetic variability among individuals in a single species, more solar heat is reflected back into space (the whether the species exists as a single interbreeding group or as "albedo" effect). Some scientists believe that a number of populations, strains, breeds, races, or subspecies. this can lead to changes in global patterns of Ecological diversity (species richness) is the number of species
in a community of organisms. Both kinds of diversity are fun- air circulation, with potential impacts on agridamentaf to the functioning of ecological systems (17). culture (53,60).

Ch. 2-Importance of Tropical Forests 53

Another effect of forests on global climate is bon dioxide will produce a "greenhouse effect" their role as a carbon reservoir in the carbon leading to a global warming trend. Doubling cycle. As large areas of forest are converted to of the atmospheric carbon dioxide would probnonforest, the carbon that had been stored in ably raise the average global climate by several wood and in organic material in the topsoil is degrees centigrade. Some scientists hypothereleased to the atmosphere as carbon dioxide. size that increased cloud cover and other enWhen croplands, grasslands, or degraded environmental change will confound the greenbrush replace moist forest, the new vegetation house effect. The effects of such trends on stores much less carbon. Thus, net annual de- agriculture on the world's hydrological sysforestation adds carbon dioxide to the atmos- teams are unknown. Likewise, the role of the phere (90). world's forests and the effect of substantial
Thedeforestation are still uncertain. Some scienatmosphere has been increasing oxidevnrth twists consider deforestation to be a significant decades,pere n ireasing fosrl factor in the concentration of atmospheric carfuels than from deforestation. Scientists agree 3490) that continued increases in atmospheric carPOLITICAL IMPLICATIONS
Stability of the renewable natural resource human settlement, with relatively untapped base in tropical countries affects both the eco- supplies of natural resources, historically are nomic viability of U.S. investments overseas a source of new employment opportunities. Toand the political stability of the host nations. day, however, the remaining frontiers are mostForeign assistance projects funded by the U.S. ly infertile or dry lands unable to support large Government and development projects funded numbers of people using current technologies. by the U.S. private sector are being undercut Thus, many rural unemployed persons migrate by flooding, siltation of reservoirs, pest out- to the cities. As unemployment climbs, changes breaks, and other problems associated with de- in the distribution of income within societies forestation. For example, the reservoirs used further aggravate social inequities and political to operate the Panama Canal are rapidly filling stresses (11). with silt (85), as are hydroelectric reservoirs inPakitan Thalan, te Phlipinenoneia bone dioideqwhile ofthesd inblty of0,12,15,19

taing country governments to create sufficient and many other nations (49). jobs is that people emigrate to countries with
Food and jobs are critical for political stabil- slower population growth and greater per capiity in developing nations and both are reduced ta resources. The flow of refugees from Haiti by inappropriate deforestation. Food supplies to Florida is sometimes cited as an example of and employment can be increased in the long the economic and social disruption caused, in run, however, by reforestation of degraded part, by tropical deforestation and consequent land and by forest management. Frontiers of environmental deterioration (9).

Tropical forests have particular importance without expensive inputs of irrigation water or to future generations. With few exceptions fertilizers. But scientific study of natural present agriculture systems cannot accomplish ecosystems, in concert with applied research sustained productivity on infertile or dry sites to develop technologies, possibly can discover

54 Technologies to Sustain Tropical Forest Resources

how sustainable agriculture can be achieved sects because of sticky hairs on its leaves, but on this land. Such research has hardly begun this resistance has not been useful to agriculand it is a slow process. Thus, the tropical ture because the wild plant cannot be crossed forests serve future generations by the infor- with domesticated kinds of potatoes. Now the mation they reveal to science and by maintain- sticky-hair characteristic is expected to be ing the quality of the land until sustainable transferred with new biotechnology methods. systems for more intensive use are developed. If it works, the result could be new potato
The Tropics are thought to be the repository tid alat Thiseimpliesesubstantial
of two-thirds of the world's approximately 4.5
million plant and animal species, only about gains in production of this important food and 500,000attendant environmental benefits from reduced means that about 2.5 million of the tropical accrcy what germ pasile neded in
species are yet unknown to science (58). These tefure. unknown species are resources of incalculable
importance for the future. Undoubtedly, new With the gradual consumption of fossil fuels sources of food, drugs, fuel, and products lie and other nonrenewable resources, the United undiscovered in tropical forests. States and other nations are expected to turn
Althughverebraes re enerllythoght increasingly to biological systems for industrial Although vertebrates are generally thoughtand for solutions to to be well known on a worldwide basis, only pollution and other environmental problems about 60 percent of the estimated 5,000 species
of fish in the fresh waters of South America m89) sme coleical s an se
have been scientifically described and named, more imple booa pros can be
even though these comprise a large proportion found in nature. of the diet of local people. A principal source
of meat for Paraguayan farmers is a peccary, Genetic materials and basic systems found made known scientifically only in 1977 (58). in nature can be reproduced or adapted with
Tropical forests offer potential resources for clon ri tcan micr-org ni s lr plant breeding, genetic engineering, and other earning labto iologiss sreex
biotechnologies. Because farming environ- ast ing a orthr pio o seful
ments are constantly changing as pests or plant cheicasm ore rdytan eff l
diseases threaten or as weather changes, agri- thaninathempast.oTe newly depinth culture relies on the continued input of genet- ni e or ge e nipla ofeopporic diversity for plant improvement. Germplasm niies o adapt exi ion o new
is the resource to which plant breeders turn for uses 79). desirable characteristics-resistance to pests or
stress, or improved growth qualities. A Peru- For example, tropical forests have a greater vian species, for example, contributed "ripe proportion of alkaloid-bearing plants than any rot" resistance to American pepper plants and other biome (6,39,56). Many of the plant species a wild melon in India was the source of resist- contain hydrocarbons as well as carbohydrates ance to powdery mildew that threatened de- in their tissues. These plant tissues can be restruction of California's melon crop (47). A newable sources for many chemicals, includwild relative of the potato from Peru has been ing fuels, now derived from nonrenewable fosknown for decades to be highly resistant to in- sil sources (13,38). Since tropical forest species usually are restricted to small geographic areas,
opportunities are lost wherever the forests are
*No one knows how many species exist. Some estimates put removed before their unique biota has been 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). ness (83).

Ch. 2-Importance of Tropical Forests 55

Political Interests U.S. Stake in Tropical Forests
* The United States has strong commitments programs are being affected adversely by
to world peace, economic and social stabil- deforestation-related problems.
ity, and maintenance of the Earth's basic The United States and other nations have
life-support systems, commitments that raised humanitarian concerns about indigrequire concern about the integrity and enous populations whose cultures and very
long-term productivity of the global natural existence may be threatened by destruction
resource base, including the tropical forest of the forests.
component. The United States increasingly is being
* The United States is party to a broad array requested by governments and internaof international resolutions, strategies, and tonal development organizations to proagreements that call on all participating na- video technical assistance and financial suptions to promote and undertake improved port for forest-related activities in developmanagement of the forest resource. ing countries.
* U.S. public institutions and private firms Environmental Interests
conduct activities that directly and indi- U.S. public institutions have statutory and
rectly affect the forests of other nations and, policy responsibilities to protect and mantherefore, are in positions to influence the age wisely the environment and natural
attitudes and actions of host governments resources of our Nation, as well as those of
and local citizens toward the United States other areas within and outside U.S. jurisby their attention or inattention to sound diction in which U.S.-sponsored or U.S.resource management. assisted activities are carried out.
Economic Interests The United States shares, with South and
* The non-oil-exporting developing countries Central America and the Caribbean area,
purchase one-third of all U.S. exports. Ad- hundreds of species of migratory animals,
verse domestic natural resource conditions including birds, insects, marine turtles, and
could seriously affect the ability of these mammals, whose survival depends to varycountries to buy U.S. goods and services. ing degrees on tropical forests.
* U.S. economic growth requires a sustained The United States is committed to helping
supply of wood and wood products at a rea- preserve the world's flora, fauna, and vulsonable price. The United States will con- nerable ecosystems by virtue of domestic
tinue to look to imports from tropical coun- legislation and national policies, and by
tries to help meet the demand for certain being party to a large number of internahardwood products. tonal conventions and agreements. Princi* Sizable U.S. investment in international pal among these measures are the Endandevelopment assistance programs can be geared Species Act of 1973, the Convention
undercut by deforestation-induced prob- on International Trade in Endangered Spelems (i.e., intensified flooding and siltation). cies of Wild Flora and Fauna, and the Con* The world's closed tropical forests contain mention on Nature Protection and Wildlife
numerous little-known or undiscovered Preservation in the Western Hemisphere.
plant species, many of which are likely to Large-scale destruction of the Earth's rain
have important uses as food crops, medi- forests runs a risk of triggering global clicines, resins, and other industrial products. mate change, with uncertain but potentially Many others are already used for such adverse consequences for world food propurposes. auction and human well-being.
Humanitarian Interests Educational and Scientific Interests
* The United States is committed to meeting The influence of tropical forest ecosystems
basic needs and supporting economic and on global physical, biological, and geosocial development in the less developed chemical processes is poorly understood
nations of the world which, in turn, is and requires long-term study.
linked inextricably to the quality and integ- o The unique flora and fauna of the tropical rity of the world's natural resource base. forests continue to provide outstanding
With increasing frequency, development scientific and educational opportunities.
SOURCE: U.S. Interagency Task Force, The World's Tropical Forests* A Policy, Strategy, and Program for the United States, Department of State Publication 9117. 1980.

56 Technologies to Sustain Tropical Forest Resources


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13. Calvin, M., "Hydrocarbons From Plants: Ana- Potentials for Extracting Protein, Medicines,
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1982, William C. Clark (ed.), p. 4. Chicago, mimeo. In: Myers, 1982.

Ch. 2-Importance of Tropical Forests 57

29. Food and Agriculture Organization/U.N. En- Plantas Medicinales Utilizadas para Regular la
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30. Food and Agriculture Organization, Map of the paper,1982.
Fuelwood Situation in the Developing Coun- 46. Myers, N., "The Conversion of Tropical Fortries, 1981. tests Environment 22(6):6-13, 1980.
31. Food and Agriculture Organization/U.N. Envi- 47. National Research Council, Ecological Aspects
ronment Program, "Tropical Forest Resources," of Development in the Humid Tropics (WashFAO Forestry Report No. 30 (Rome: FAO, ington, D.C.: National Academy Press, 1982).
1982). 48. Pant, M. M., "Forestry Sector-Its Contribution
32. Food and Agriculture Organization, "Yearbook to Gross National Product," Indian Forester
of Forest Products, 1969-1980" (Rome: FAO, 103(11):739-769, 1977.
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33. Gallegos, C. M., et al., "Technologies for Technologies for Tropical Forests," OTA comReforestation of Degraded Lands in the missioned paper, 1982.
Tropics," OTA commissioned paper, 1982. 50. Perry, L. M., Medicinal Plants of East and
34. Gribbin, J., "The Politics of Carbon Dioxide," Southeast Asia (Cambridge, Mass.: MIT Press,
New Scientist, Apr. 9, 1981, pp. 82-84. In: 1980). In: Myers, 1982.
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35. Gupta, K. M., and Bandhu, D. (eds.), "Man and in Tropical South America," Progress Report to
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36. Hyman, E. L., "Analysis of the Demand for 52. Plotkin, M., and Schultes, R. E., "Tropical ForWoodfuels by Rural and Urban Households in tests as Sources of New Biodynamic Coithe Province of Ilocos Norte, Philippines," En- pounds," Threatened Plant Newsletter, 1982.
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37. International Development Research Center, 53. Potter, G. L., Ellsaesser, H. W., Maccracken, M.
"Rattan: Report of a Workshop, Singapore, June C., and Ellis, J. S., "Albedo Change by Man: Test 4-6, 1979" (Ottawa, Canada: International De- of Climatic Effects," Nature 291(5810):47-49,
velopment Research Center, 1980). In: Myers, 1981. In: Myers, 1982.
1982. 54. Prince, L. H., "New Crop Development for
38. Johnson, J. D., and Hinman, T. W., "Oils and Industrial Oils," journal of the American Oil
Rubber From Arid Land Plants," Science Chemists' Society 56(9):845-848, 1979. In: My208:460-464, 1981. In: Myers, 1982. ers, 1982.
39. Levin, D. A., "The Chemical Defenses of Plants 55. Pryde, E. H., Princen, L. H., and Mukherje, K.
to Pathogens and Herbivores," Annual Review D. (eds.), "New Sources of Fats and Oils,"Monof Ecology and Systematics 7:121-159, 1976. In: graph No. 9 (Champaign, Ill.: American Oil
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1977). In: Myers, 1982. for Millions" (Bombay, India: TATA Press,
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Tropics, Mayagiiez Institute of Tropical Agri- 58. Raven, P. H., "Basic Research-A Necessary culture (Mayagiiez, Puerto Rico: AID, ARS/ Prerequisite for Adequate Development of
USDA, 1975). Technologies to Sustain Tropical Forest
43. Meggers, B. J., "Amazonia" (Chicago: Aldine- Resources," OTA commissioned paper, 1982.
Andlerson, Inc., 1971). 59. Rose, E. J., "Use of the Universal Soil Loss
44. Moreno, A. R., and Schwartzman, B., "268 Equation to Predict Soil Erosion in West Afri25-287 0 84 5

58 Technologies to Sustain Tropical Forest Resources

ca," Soil Erosion Prediction and Control, G. R. 73. Tejwani, K. G., Gupta, S. K., and Mathur, H. N., Foster (ed.), Soil Conservation Society of Ameri- "Soil and Water Conservation Research," ICAR ca, 1978, pp. 60-74. Publication No. 68, New Delhi, 1975. In:
60. Sagan, C., Toon, 0. B., and Pollack, J. B., "An- Pereira, 1982.
thropogenic Albedo Changes and the Earth's 74. Terborgh, I., "The Conservation Status of NeoClimate," Science 206:1363-1368, 1979. In: tropical Migrants: Present and Future," MiMyers, 1982. grant Birds in the Neotropics: Ecology, Behav61. Sanchez, P. A., Gichuru, M. P., and Katz, L. B., ior, Distribution, and Conservation, A. East
"Organic Matter in Major Soils of the Tropical and S. Morton (eds.) (Washington, D.C.: Smithand Temperate Regions," Non-Symbiotic Nitro- sonian Institution Press, 1980).
gen Fixation and Organic Matter in the Tropics, 75. Timberlake, L., "Saving the jungles," World
Symposia Paper No. 1, 12th International Con- Press Review, September 1982, pp. 31-33.
gress of Soil Science, New Delhi, India, 1982, 76. Tinker, I., "Household Energy and Rural Wompp. 99-114. en," Proceedings, Second International Sym62. Schultes, R. E., "The Amazonia as a Source of podium on Appropriate Technology, Denver,
New Economic Plants," Economic Botany Col., October 1980. In: Shaikh, 1983.
33(3):259-266, 1979. In: Myers, 1982. 77. United Nations, Water Development and Man63. Segerstrom, Gunnar, "Creating Work and Car- agement: Proceedings of the United Nations
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64. Shaikh, A., Qadri, T., and Hale, S., "Fuelwood 78. U.S. Congress, Office of Technology AssessTechnologies to Sustain Tropical Forest Re- meant, Energy From Biological Processes, OTAsources," OTA commissioned paper, 1983. E-124, July 1980.
65. Singh, T. (ed.), Studies in Himalayan Ecology 79. U.S. Congress, Office of Technology Assessand Development Strategies (New Delhi, India: meant, Impacts of Applied Genetics: MicroEnglish Book Store, 1980). In: Myers, 1982. organisms, Plants, andAnimals, OTA-HR-132,
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67. Soejarto, D. D., Bingel, A. S., Slaytor, M., and The Next 20 Years, OTA-HR-157, February
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In: Pereira, 1982. 88. Wharton, C. H., "Man, Fire and Wild Cattle in

Ch. 2-Importance of Tropical Forests 59

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Chapter 3
Status of Tropical Forests


Highlights 63
The Data Base . 63
Extent of Remaining Tropical Forest 64 Closed Forest . 64 Open Forests and Shrublands. 67 Forest Fallow 68
Forest M anagem ent 69 Forest Legislation and Policy 69 Forest O w nership 70 W ood Production 70 Natural Forest Management 73 Plantations 74
Destruction of Forest Resources 75 Deforestation 75 Resource Degradation 78
Projection of Changes 79 Chapter 3 References 82

List of Tables
Table No. Page
3. Estimates of Per Capita Closed Forest Areas and Deforestation Rates in
Tropical Africa, America, and Asia 76 5. Annual Deforestation, 1981-85 79 6. Forest Area Projections 81

List of Figures
Figure No. Page
12. Classification of Woody Vegetation 66 13. Areas of Woody Vegetation in 76 Tropical Nations 67 14. Overall Area of Tropical Woody Vegetation 69 15. Comparative Production of Wood, 1980 71 16A. Wood Production in Tropical Africa, 1969-80 72 16B. Wood Production in Tropical America, 1969-80 72 16C. Wood Production in Tropical Asia, 1969-80 73 17. Plant Nutrient Loss Caused by Logging in Tropical v. Temperate Forests 80

Chapter 3

Status of Tropical Forests


The area planted with trees in tropical re- The acreage within tropical forests that is
gions each year is only about one-tenth of followed or abandoned is growing rapidly.
the forest area cleared. Some of this will naturally return to forest
Gradual resource degradation, especially in cover, but most of it does not regain producthe drier open forest areas, may have a tivity without a concerted reforestation
greater long-term impact on human welfare effort.
than deforestation. Most tropical forest is owned by national or
Landsat imagery has greatly improved State governments, but locally recognized
knowledge of closed tropical forests and this rights to use the resources greatly complicate
is enhancing forest management. However, management efforts.
data on open forests and forest resource Tropical forestry historically has tended to
degradation are still imprecise. neglect the basic needs of people who live
Forest data aggregated by region may sug- in and near the forests. This is changing as
gest that no global problem exists. However, titud es iv m oreti tofeswoods ad country-by-country analyses show that rates to relation w fery and
of deforestation are high and forest area per tre.
capita is already low in many tropical nations.

Data on the extent and condition of tropical gramme (UNEP) (3,4). The FAO/UNEP study forest areas are abundant but widely scattered is the first where the definitions of forest types and frequently inaccurate. Some of this infor- and conditions are consistent across countries. nation is based on old, imprecise measure- It covers 76 nations; 73 nations are tropical or ments or estimates that have been updated partly tropical, and 3 nations are outside the through simple extrapolation. Accuracy is fur- Tropics but are directly influenced by tropical ther impaired by lack of standard definitions monsoons. It does not include the tropical and classifications of forest types; thus, the data regions of China, Australia, islands off the are difficult to compare across studies. Micro- coasts of Africa, the Pacific islands, or Puerto level studies of project areas or watersheds con- Rico. Some of the forests included are in places tai some of the most reliable and detailed in- where the climate is more temperate than tropformation on forest resources and land use, yet ical. this information is hard to obtain because it is The FAg/UNEP study relies mainly on data supplied by governments. Most measurements
A comprehensive synthesis of data about the and estimates in various categories of forest world's tropical forest resources was con- were made in the 1970's. Then, using the ducted by the United Nations Food and Ag- estimated rates of change from one category riculture Organization (FAO) with the assist- to another, the figures were projected to repance of the United Nations Environment Pro- resent the situation in each nation as of 1980.


64 Technologies to Sustain Tropical Forest Resources

Several nations did not have complete data, forest cover over time. Hence, only a few of and for 13 of these FAO commissioned new the estimated deforestation rates given in the Landsat analyses. Some of the government FAG/UNEP study, presented later in this chapestimates used by FAO are also based on Land- ter, are based on remote sensing data. The rest sat data. are mainly subjective estimates. In addition,
Datasince expertise and computers to analyze Landgram has greatly enhanced the accuracy of a sat data are not available in some tropical naformation on the extent of forests. By using tion ma es his etod is mor
computers to study Landsat data, investigators secti n les sensveto sm le
can distinguish primary forests from second- chan e in fes ae narie some
ary forests, closed forests from open forests caes iages t e udaese of coud and grasslands, and dominant types of trees cover. (e.g., broadleaved, coniferous, mangroves).
Unfortunately, Landsat data have not been
collected long enough to reveal trends in the


Closed Forest Another 14 percent of the total closed forest
is productive forest that has been logged but
Tropical nations contained some 1.2 billion is not under active forestry management. Ivory hectares (ha) of closed forest at the end of 1980. Coast, Togo, Benin, Sri Lanka, and Belize all Tropical America has 57 percent of the world's have at least 60 percent of their closed forest closed tropical forests, while Asia has 25 per- in this condition. Some other countries have cent, and Africa has 18 percent (fig. 13). These had extensive logging but register little forest forests are unevenly distributed among the in the logged condition because farmers quicktropical nations. Brazil alone has nearly two- ly convert the logged forest to temporary or fifths of the world's total closed tropical forests permanent cropland. A prime example is Thaiand Indonesia and Zaire each account for near- land, which has had extensive logging but ly another tenth (table A-i in app. A). shows no forest in the logged condition.
The condition of closed tropical forests maybe cse o
be divided into several categories: undisturbed,
logged, managed, physically unproductive, and ical forest is classified as managed. Much of protected areas. Table A-2 in appendix A this is in logged-over condition, but significant shows the percent of forest in each category investments are being made to manage natural for each of the 76 nations. regeneration. India classifies 63 percent of its
closed forest as managed; Burma and Malaysia
Over half (56 percent) of the total tropical each classify about 12 percent as managed. Exclosed forest is classified as undisturbed forest. eluding these three countries, only 0.3 percent This forest has commercial potential, but most of the rest of the tropical closed forest is of it is relatively inaccessible to human popula- classified as managed. Most of that is in Ghana, tions. When Brazil and Zaire with their enor- Uganda, Kenya, Sudan, and Zambia. mous remote forests are excluded, the remaining tropical nations have two-fifths (41 percent) Another one-quarter (23 percent) of the of their closed forest in the undisturbed cate- closed forest is unproductive for physical gory. 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, semideciduous, 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 monocotyledons) 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 generally 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 productive 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 includes 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 industrial use.

66 Technologies to Sustain Tropical Forest Resources

Social and environmental plantations are designed for soil and water protection or to produce fuelwood and charcoal, polewood or construction wood for local use, or nonwood products, such as gum arabics. The category excludes plantations for nonwood commodities such as rubber, palm oil, coconuts, cloves, coffee, and cocoa. It also excludes trees planted to
shade agricultural crops.
Shrubland 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

Natural forests Plantations

Composition/ Closed Open
density forest forest


Production U
capacity Productivp u Productive productive industrial and
(wood for environmental
status/ Withou With For For
physical intensive intensive physical legal
accessibility management management reasons reasons

Past Un- Loggedlogging 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 noninincludes forest where the trees have no poten- dustrial products and for essential environmential 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 proleast 20 million ha of forest unproductive for section 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

Closed forest


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

Tropical Asia

C osed forest
Closed forest 305.510
Closed forest
Shrublands Open woodland
442,740 fallow
104,335 Shrublands ,pe woodlands
Closed forest 35,503 30,948
61,646 Plantation Open woodland
Plantation forests fallow
forests 5,111 3,990
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. Shrub/and 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 land, grassland, or desert primarily depends on
in just four countries-India, Zaire, Indonesia, how dry the climate is and on the moistureand Brazil. Despite the legal status of park holding capacity of the soil. To an increasing
lands on paper, many of these forests in fact extent, however, it also depends on humando not receive much protection (3). caused factors (11).

Generally, closed forests grow where average

Open Forests and Shrublands annual rainfall is above 1,600 millimeters (mm).
Open forests are found where rain is from 900 Tropical nations contain some 746 million to 1,200 mm. In areas with 1,200 to 1,600 mm
ha of open forest and 624 million ha of shrub- of rain, the natural cover may be either open
land. Whether the natural vegetation of a trop- or closed forest, depending on fire history, soil,
ical area is closed forest, open forest, shrub- frequency of drought, and other environmen-

68 Technologies to Sustain Tropical Forest Resources

tal factors. Shrublands grow where rain is are important for nonindustrial products and below 900 mm. In transitional areas, fires and services. Much, perhaps most, of the open livestock grazing can convert closed forest to forest is used for livestock grazing and open forest and open forest to shrubland. Con- fuelwood collecting. These forests protect soils versely, closed or open forests can be reestab- and watersheds in the semiarid regions and lished in some places when fire and other pres- their wildlife is important as food. Further, sures are eliminated (4,11). many of the trees are legumes capable of conOpenverting atmospheric nitrogen to fertilizer, and ly distributed among tropical nations. The data ty a e cmoprandst
describing these types of forests are much less
accurate than for closed forests. This is partly Parks and protected areas account for 9 perbecause boundaries between open forest, cent of the African tropical nations' open forshrubland, grassland, and fallow agricultural tests. Tropical America has given protected area land are difficult to determine. It is also be- status to just 1 percent, and tropical Asia has cause there has been less interest in measur- designated 2 percent for protection. ing or monitoring open forests and shrubland.
Table A-3 in appendix A shows estimates for Forest Fallow
areas of open forest and shrubland in each of
the 76 nations. Together, the African nations The closed tropical forest regions include have most (65 percent) of the tropical open for- some 240 million ha of land in forest fallow. ests, but Brazil again dominates with 157 mil- Overall about 1 in 6 ha in the closed forests are lion ha. Zaire has 71 million ha; Angola has 51 being used for shifting agriculture. But in many million ha. nations, shifting agriculture has claimed a larger part of the closed forest. Sierra Leone has
Shrublands also are mainly (71 percent) five times as much forest fallow as closed forfound in Africa. Sudan has 87 million ha of est. Five other nations in tropical Africa, four shrubland, and other African nations with in tropical Asia, and four in tropical America large expanses of shrubland include Tanzania, have from 50 to 100 percent as much forest falCentral African Republic, Zambia, and low as closed forest. Table A-4 in appendix A
Ethiopia. In tropical America, Brazil has 61 shows the ratio of forest fallow to forest for million ha; Paraguay, Bolivia, and Mexico also each of the 76 nations. It is likely that much have extensive shrublands. Among the tropical of this fallow land will not be returned to forest Asian nations, Thailand, Kampuchea, Laos, uses. Under unfavorable site conditions and and Indonesia all have substantial shrubland short fallow periods, much of this land may areas. eventually become unproductive for agriculSince open tropical forests are more easily ture as well.
penetrable than closed forests, nearly all of Estimates of forest fallow areas are not acthem have been cut, burned, or grazed by curate. However, shifting agriculture is by no
livestock. Hence, no open forests are classified means limited to moist areas. In dry regions, as undisturbed. Two-thirds of tropical fallow serves to restore moisture as well as
America's open forest is classified as organic matter and plant nutrients to the soil.
productive-having potential to produce wood The FAO/UNEP report estimates that about for industry. In Africa, where these forests are one-fifth of the land reported to be open forest generally drier, only one-third is classified as is in fact forest fallow. Livestock graze on both productive; just over one-fourth is classified the forest fallow and the open forest that has productive in tropical Asia. not yet been used for crops.
Although few open forests fit the FAO/UNEP Figure 14 shows relative areas of each vegetadefinition for "productive," these woodlands 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

Land surface of the 76 countries studied

Land s f
woody vegetation

forests Open


forests Plantations
SOURCE: Food and Agriculture Organ ization/Un ited Nations Environment Programme, Tropical Forest Resources Assessment Project (GEMS): Tropic s of t c d ricaic Trpopi- Asia slTropical America, 4 vols. (Rome: FAO, 1981).


Forest Legisleelon and Policy Ohrpoietplc susicueacl

Forest legislation and policy are evolving in teinwarsdicesngnetvsfo tropical countries to reflect a growing aware- inutalpnaiosndfrfreryad ness of the social and environmental implica- lgsaiespotfrrfrsigcmua tions of forestry decisions. Many tropical na- land. Social issues, too, increasingly are being tions substantially revised their forestry laws recognized (e.g., the needs of slash-and-burn during the 1960's and 1970's. In many cases, cultivators and nomadic grazers, domestic fuelhowever, the laws look good on paper, but are wood requirements, and release of forest lands not well-enforced (7). to settled agriculture). Many tropical countries
Some issues have become more prominent now view conservation as important to ecoin the last 5 to 10 years. For example, many o teeopsustan tiuse oorests,
countries have revised their logging laws and policies to be more restrictive regarding timber preserve biological diversity, maintain parks allocation from public land, lease terms, con- an ro es, cession fees and taxes, annual allowable cut limits, regeneration methods, and export of un- Some gaps, however, still need to be adprocessed logs. dressed. There is a need to evaluate tropical

70 Technologies to Sustain Tropical Forest Resources

forest resource policy, but no organization has the forest land for continuous cropping and such a program. The connection between grazing. State control over forest lands has
forests and policies in other sectors such as been a gradual process, taking place mainly land tenure and agrarian reform also needs to over the past 30 years. The central government be assessed. in Nepal and some states in India such as West
Bengal took control of all forested land from
Forest Ownership the villages in the 1950's. Papua New Guinea
and most of the Pacific Islands are exceptions
In order to understand the use and loss of to this general rule. There, forests are owned forest resources and to devise effective policies by clans and tribes and the government has to for managing forests, it is important to know negotiate with them for the right to use forest the legal and de facto ownership of forest lands resources. and trees. The legal status of land may not indicate who has practical control of land use.
For example, owners of large properties may Wood Production
appropriate adjoining public iands. Also, slash- The 76 nations covered by the FAO/UNEP and-burn cultivators and other landless poor study of tropical forests produce 1.4 billion may occupy communal forests. In fact, tree ten- cubic meters of wood annually (measured as ure may differ from land tenure. round logs extracted from the forest). As figThe FAO/UNEP report (3) summarizes forest ure 15 indicates, this is about half of all the ownership by regions and provides some de- wood production in the world, and most (86 tails at the national level. In tropical America, percent) of it is used for firewood or charcoal. forest ownerships may be public, private, or The rest is "industrial wood" used for domestic communal. Most conifer forests in Brazil and and export production of sawlogs, veneer logs, in Central American nations are privately lumber, poles, pulpwood, wood panels, and owned. The much larger broadleaved forests other processed products. Figure 16 indicates are public property, but national laws regard- changes in wood production for each of the ing forest ownership often are contradicted by tropical regions over a 12-year period. local practice. The production of industrial wood varies
The situation is more complex in tropical Af- with economic conditions. Generally economic rica where private ownership of forests is rare. development during the 1970's, resulted in inTraditional use rights in most forest areas are rec- creasing demand for industrial wood in all the ognized for hunting, gathering nonwood prod- tropical regions. Industrial wood production ucts, acquisition of fuelwood and construction increased most rapidly in tropical Asia and in wood, and shifting cultivation or grazing. Peo- West Africa with the growth of markets for ple may have exclusive rights over trees that sawlogs and veneer logs from those regions. they plant on communal lands. Local com- More recently, slowing economies have conmunity ownership of forest lands in many for- strained the growth in production. If rapid mer British colonies is recognized in national economic growth resumes, tropical America forestry laws. In former French colonies, local may experience substantial industrial wood rights are not recognized at the national level production increases. and all forests are considered state property. Significant investments were made in mills
In tropical Asia, 80 to 90 percent of the forest and infrastructure during the 1970's, but these land is state-owned and under the legal con- have operated below capacity because of weak trol of the forest departments. However, a large markets. In Asia and West Africa, depletion of part of this land is illegally occupied by forest resources is likely to constrain sawlog and farmers, both those who practice traditional veneer log production, but resurgence of shifting agriculture and those who try to use economic growth should create domestic

Ch. 3-Status of Tropical Forests 71

Figure 15.-Comparative Production of Wood, 1980 U.S.

25% Tropical Africa
Other Tropical America
64% 5%
Tropical Asia Tropical Africa Tropical Asia
34% 23% 6%

Fuelwood Industrial roundwood


Tropical Africa


Tropical Asia

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

markets for wood chips to produce pulp and dominance will become greater where ecoother wood products made from a wider varie- nomic growth continues to be slow.
ty of trees. Looking at figure 16, one might expect that

tropical forestry efforts would be concentrated The increase in total wood production is mainly on fuelwood production. However, undriven by a steady increase in fuelwood pro- til recently forestry departments in tropical
duction. However, the data on fuelwood appar- countries, international assistance agencies,
ently are obtained by multiplying unchanging and multilateral development banks have conestimates of per capita consumption by each centrated most of their efforts on industrial
country's population. Thus, the growth in pro- wood production. Industrial production atduction is probably not so steady as figure 16 tracts investment in the forestry sector because suggests. Nevertheless, fuel is certainly the it can earn foreign exchange and concession dominant use for wood in the Tropics and that 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

Fuelwood Sawlogs and Other industrial
veneer logs roundwood
400,000350,000a 300,000


0 200,000



1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
Years 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
Fuelwood Sawlogs and Other industrial
veneer logs roundwood

350,000i 300,000


0 200,000I


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)

Ch. 3-Status of Tropical Forests 73

Figure 16C.-Wood Production in Tropical Asia, 1969-80 700,000
Fuelwood Sawlogs and Other industrial veneer logs roundwood

200,000100,0001969 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 Much more wood is consumed in tropical tropical forestry activities. countries for fuelwood, however. Serious shortThe problem of ensuring an adequate indus- ages of fuelwood, lumber, poles, paper, and trial wood supply for international trade* is ote fet roucts nation ar seo
more tractable than problems associated with igm troughtinterana trde bcuero fuelwood supply, impacts of deforestation on hig tr ori costs a ersen t pvr soil and water resources, or maintenance of ty.cFur m onflits eteen and
biological diversity. First, nearly 75 percent of cutrar i n
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 Only small areas of tropical forests are under wood can come from plantations. One recent intensive management (3). In tropical America,
estimate is that 140 million ha of well-managed management is increasing. For example, Mexplantations could, theoretically, supply all the ico is managing watershed forests through conindustrial wood consumed in the world in the trolled logging. Belize, Brazil, Guatemala, and year 2000 (8). That would be an area equal to Paraguay are designing management plans for 5 percent of the present forested area in the natural resources. Silvicultural trials and world. research efforts to develop suitable technolo*See the OTA assessment Wood Use: U.S. Competitiveness gives for managing natural forests are under and Technology, OTA-ITE-210, August 1983, for an analysis of way in Brazil, Costa Rica, French Guyana, world markets for industrial woods. Mexico, Peru, and Venezuela.

25-287 0 84 6

74 Technologies to Sustain Tropical Forest Resources

Some African nations, when they were Brit- Forestry plantations are usually monoculish and Belgian colonies, had developed har- tures, often of exotic species, planted not where vesting regulations and working plans for man- forest cutting is occurring, but rather on land aging natural forests, but these have been aban- that has been cleared for some time, such as doned over the past two decades. Nigeria, abandoned farmland (5). Most industrial wood Zaire, and Tanzania previously managed large plantations in East Africa are softwoods (pines areas of natural forest, but no longer do so. and cypress), while in West Africa hardwoods Uganda reports a large managed area, although (principally teak) are planted. In tropical it is doubtful that the management plans have America, pines are usually grown for saw timbeen implemented. The Congo also is prepar- ber, while eucalyptus and gmelina are planted ing plans that set the allowable cut for natural for pulpwood. Eucalyptus frequently is grown forests and indicate appropriate silvicultural for pulpwood in India, while teak is grown for practices. timber in India and Indonesia.

The deciduous and conifer forests of South Two-thirds of nonindustrial plantations in Asia-Burma, Bangladesh, India, and Paki- Africa are for fuelwood; the rest are mainly for stan-have a long history of intensive forest gum arabic production or watershed protecmanagement. India alone contains 60 percent tion. In tropical America, three-quarters of the of all the managed forest in the 76 tropical na- plantations classified as nonindustrial are eucations. However, the remaining tropical forests lyptus trees planted to supply charcoal to the of South Asia and the forests of Southeast Asia iron and steel industry in the Brazilian State are not intensively managed for a number of of Minas Gerais. Most of the rest is for producreasons. Informationon forest ecology and dy- tion of forest fruit, such as "palmito." Only namics is scarce. Forestry departments lack about 100,000 ha of plantations in tropical trained personnel to manage the forests. The America are intended primarily for soil and emphasis in forestry has been on commercial watershed protection; Mexico has most of exploitation so that little attention has been these. In Asia, most nonindustrial plantations given to silvicultural treatments (3). are intended to produce locally consumed firegivenwood and these are being planted at a rate of about 1 million ha/yr.
The rate of forest plantation establishment
Plantations is much too low to replace the amount of forest
About 11.5 million ha of tree plantations had aea plaed topa derted a ally is been established in the 76 nations by the end aboute to roa frit isn1atoy29; of 1980 (table A-5 in app. A). Most (68 percent) and in tropical A a it is 1 to ) r of these are in just three countries: Brazil, In- moe mstrorestati s arthcrdia, and Indonesia. About 7 million ha are in- me ot reforestation aks ae In tended to produce sawlogs, veneerlogs, pulp- ril, or exe platation ae cocen
wood, or industrial poles. Only 4.4 million ha train thexSouth, wea s re c ngenhave been planted for fuelwood and charcoal, crai in the Norh. for environmental protection, and for nonwood
products such as gum arabic. The greatest discrepancy between reforestation rates and the demand for wood and other
The estimated rate of planting in the tropical forest products is in Africa. In Asia, reforestanations is about 1.1 million ha/yr (4). Current tion is closer to deforestation because planting is intended mainly (53 percent) for deforestation rates level off as the remaining lumber, paper, and industrial poles, but a grad- forest is left only in inaccessible areas and ual shift to fast-growing trees to produce fuel- because severe wood shortages in heavily wood and charcoal is occurring as a result of populated areas are leading to greater planting changing objectives in tropical forestry. efforts (4).

Ch. 3-Status of Tropical Forests 75


Distinguishing between deforestation (also bandry practices were considered as well. called "clearing" in this report) and degrada- Table A-6 in appendix A shows estimated areas tion of forest resources is important. The FAO/ of closed forest converted to nonforest annuUNEP study estimates deforestation rates for ally for each of the 76 countries. 1976-80 and projects rate estimates for 1981-85. It does not, however, estimate degradation The overall tropical deforestation rate is
rates. Unlike deforestation, degradation is not strongly affected by the status of the forests in easy to identify through time-series Landsat or a few tropical nations that have very large forother remote-sensing analyses. est areas relative to their population. Thus, the
0.5 and 0.6 percent/yr figures obscure both subDefrestationstantial differences among nations and the Dofoe~tulonoverall severity of tropical deforestation. Each year about 0.5 percent of the remain- Closed forest area per capital is already less ing closed tropical forests and 0.6 percent of than 0.05 ha in 17 of the 76 nations. Over half the remaining open tropical forests are con- the rest have deforestation rates between 1 and verted to nonforest land uses or to wasteland. 6.5 percent/yr. Table 3 indicates forest areas This is an aggregation of estimated deforesta- per capital and deforestation rate estimates for tion rates from the 76 countries covered by the each country. FAO/UNEP report. In some countries, the de- Table 4 shows the 76 nations divided into
forestation rate has been estimated by compar- nine categories of closed forest area and popuing Landsat or other remote-sensing data from nation size. Several countries, including Gabon, two time periods; for some, information on Congo, French Guiana, Surinam, and Guyana, population growth, farming, and animal hus- have such large forests and so few people that their deforestation rates are very low. Clearly, closed tropical forests will exist in these naDeforestation and Degradation tons for many decades, although even a
Much of the confusion over rates of change relatively small population can cause resource
in forest areas stems from the failure to dis- degradation over large areas. Other nations, tinguish between deforestation and degrada- such as Liberia and Honduras, have large tion. As defined here and in the FAO/UNEP amounts of forest but also have high deforestareport: tion rates. If current rates of deforestation and
Deforestation is the conversion of forests population growth were to continue, these two
to land uses that have a tree cover of less nations would, in just 15 years, reduce their than 10 percent. Thus, logged-over areas, forest area per capital to half what it is. In some including clear-cut areas, are not classi- nations, deforestation can be expected to slow fied as deforested if the forest is in the as the forests are reduced to inaccessible areas process of regenerating. that are unattractive to farmers. However, ex* Degradation of forests refers to biologi- experience in nations such as Haiti, El Salvador,
cal, physical, and chemical processes that Jamaica, Costa Rica, Nepal, Sri Lanka, Angola, result in loss of the productive potential and Ghana indicate that deforestation can conof natural resources in areas that remain tinue rapidly even when only limited forests
classified as forest. Soil erosion and loss remain.
of valuable or potentially valuable genetic
types are examples of degradation. In In tropical Africa, deforestation rates are
some cases, forests can recover naturally highest in the West African nations. Nigeria from degradation within a few decades. and Ivory Coast together incur almost half (45 In other cases recovery may take much percent) of the continent's total annual deforlonger, if it occurs at all. station 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 capita per year Country (1,000 ha) per capita 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 Nicaragua 4,496 1.6 2.7
Rwanda .120 b 2.7Niaau. .4,91627
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

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 Suia 4803.
Cameroon .17,920 2.0 0.4 Surinam. 14,830 37.1 c
Ethiopia. 4,350 0.1 0.2 Guyana.18,475 23.1c
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 iBurma 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 capita.
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, Honeach year, and the nations of Burundi and duras, Guatemala, Columbia, and Mexico) conRwanda, 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. Alare cleared-262,000 ha/yr together-but like though deforestation in Brazil is low when exBrazil 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 MilAfrican 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 size sizeb rate Region/country sizea sizeb rate
Tropical Africa: Costa Rica Small Small 2.0
Kenya. Small Large 1.7% Jamaica. Small Small 3.0
Uganda Small Large 1.3 Belize. Small Small 0.7
Ghana Small Large 1.3 Trinidad and Tobago. Small Small 0.4
Mozambique. Small Large 1.1- ------------------------------------.
Tanzania Small Large 0.7 Guatemala. Medium Large 2.0
Sudan Small Large 0.6 Paraguay Medium Medium 4.7
Burundi Small Medium 2.7 Honduras Medium Medium 2.4
Rwanda Small Medium 2.7 Nicaragua Medium Small 2.7

Senr .Leoe. Small Medium 0.8 Panama Medium Small 0.9
hirr a en ml Medium b.
Chad-. Small Medium 0.4 Ecuador. Large Large 2.4
Upper Volta Small Medium d Colombia.Large Large 1.8
Zimbabwe. Small Medium d Mexico. Large Large 1.3
Mali. Small Medium d Venezuela. Large Large 0.4
Niger Small Medium d Peru. Large Large 0.4
Senegal.Small Medium d Brazil. Large Large 0.4
Malawi.Small Medium d Bolivia.Large Large 0.2
Guinea-Bissau. Small Small 2.6 Surinam Large Small d
Togo. Small Small 0.7 Guyana. Large Small d
Equatorial Guinea.Smell Small 0.2 French Guiana .Large Small d
Botswana Small Small d ______________________Gambia. Smadi Small d Tropical Asia:
Namibia. Small Small d Nepal Small Large 4.3
. Sri Lanka .Small Large 3.5
Ivory Coast Medium Large 6.5 Bruneli. Small Large 1.5
Nigeria. Medium Large 5.0 Bangladesh Small Large 0.9
Angola. Medium Large 1.5 Viet----- .-. .- .-.7
Ethiopia Medium Large 0.2 Pakistan Medium Large 0.3
Guinea Medium Medium 1.8 Bhutan Medium Small 0.1
Zambia.Medium Medium 1.3 0.3. .
Somalia Medium Medium 0.2 Laos.Large Medium 1.2

Liberia.Medium Small 2.3 Papuhew Guinea Large Medium 0.1
Central African Republic Medium Small 0.1
. . Thailand Large Large 2.7 Madagascar Large Large 1.5 Malaysia Large Large 1.2
Cameroon Large Large 0.4 Philippines Large Large 1.0
Zaire Large Large 0.2 Viet Nam Large Large 0.7
Gabon Large Small 0.1 Indonesia.Large Large 0.5
Congo .Large Small 0.1 Burma Large Large 0.3
Tropical America: India Large Large 0.3
Cuba Small Large 0.1
Haiti. Small Medium 3.8
El Salvador Small Medium 3.2
Dominican Republic Small Medium 0.6
acoe forest size classes for this tsbie are: large-more than 6 miiiion hectares; medium-2 to 6 million hectares; small-less than 2 million hectares. bopopuiation size classes for this tabie are: large-more than 7.5 miiiion people; medium-S to 7.5 miiiion people; small-less than 3 miiiion people. C~eforestation rate is the percent of the 1980 closed forest area that is being cleared each year during 1981 to 1985. dindicates the annual deforestation rate is less than 0.05 percent.
SOURCES: Population Reference Bureau, 1,983 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. Based on current and planned rates of tree Colombia and Mexico together account for plantation establishment, the areas reforested
another third. in the Tropics as a whole are about one-tenth
Three-fifths of the closed forest cleared in of the areas deforested. tropical Asia each year is logged-over produc- Deforestation also occurs in open tropical tive forest and about one-quarter is previously forests. Trees are cut and burned both by tradiundisturbed forests. The highest deforestation tonal shifting agriculturists and by farmers inrate in Asia is 4.3 percent/yr in Nepal, and a tending to establish permanent croplands. Exsignificant portion of this cutting occurs in tracing wood for fuel or industrial use, fires, temperate forests on mountain watersheds. In and excessive grazing all cause deforestation Sri Lanka, deforestation is 3.5 percent/yr, and by reducing tree cover to less than 10 percent. in Thailand it is 2.7 percent. Brunei, the Philip- The open forest area data are poor, however, pines, and Bangladesh also have very high and the estimates of deforestation rates are
deforestation rates. even less precise. Deforestation in the dry open
Rates of deforestation are calculated as the forests is typically a gradual process and thus estimated area deforested per year divided by is more difficult to see than in moist areas the estimated 1980 forest area. Thus, these where the tree canopies are more dense. Furrate shuld ot e cnfusd wt heeti ther, the open forest lands are often under the rates should not be confused with geometric
rates of change, such as population growth jurisdiction of agencies that consider grazing rates. Acceleration or deceleration of deforestation rates are influenced not only by popula- is likely to be classified by its herbaceous cover tion growth but also by many other factors such rather than its tree cover. as rural to urban migration rates, land tenure The FAO/UNEP study does not list countrychanges, and especially road-building activi- specific deforestation rates for open forests, but ties. Much too little is known about how these it does provide overall estimates of open forest factors interact to predict how deforestation clearing for tropical Africa, America, and Asia. rates will change over any long period. These are shown in table 5. As a rough indiThe FAO/UNEP study does draw some infer- cator of the pressure on open forest resources, ences about changes in the accessibility of the
remaining forests. The area of closed tropical area per capital for each of the 76 nations. 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 Resource Degradation
previous decade the closed forests in heavily
populated countries of West Africa generally Resource degradation, the long-term loss of were reduced to sites that are unattractive to productive potential, is much more difficult to farmers. H-owever, the rate probably is ac- measure than deforestation. Reduction of soil celerating in some nations. Deforestation in quality and loss of superior genetic types of Latin America, on the other hand, probably is trees have been documented for specific forest increasing because additional forested areas locations (6). But so little is known about the are becoming accessible as new roads and ecology of the tropical forests or the economic
bridges are built. In tropical Asia, deforesta- potential of the many tropical forest species that tion is also thought to be increasing, but the degradation can be a highly subjective term. rate probably will level off in the 1990's as the Forest resource degradation is undoubtedly ocforests are reduced to inaccessible areas or curing (3,6) and, especially in the drier open sites where agricultural clearing is not worth- forests where recovery is slower, it may be a while. 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 with the logs. Machinery is available to harvest
causes. Logging practices can cause degrada- whole trees and to use multiple species to protion by damaging residual trees, damaging soil, duce pulpwood. Although these technologies or failing to create an environment where nat- are not yet widely used in the Tropics, they ural regeneration of valuable forest species can could accelerate the loss of soil fertility (2). Furoccur. Forests in tropical America and Africa thermore, many tropical tree species seed irregtypically contain a large number of tree species ularly or at long intervals (once in 5 to 7 years). per hectare, but just a few are commercially If clearcutting is practiced, natural regeneravaluable for timber. Logging in these areas usu- tion of these species may not occur. Clearcutally means felling and extracting only the best- ting also reduces regeneration of trees, such shaped, large individuals of selected species. as Dipterocarps, whose seedlings need to grow Yet, substantial and lasting damage is often in partial shade (1). done to the residual trees as a result of mechanized logging and skidding operations (10). As Conifer and mangrove forests in all three much as one-half of the residual stand may be tropical regions and certain other forests in damaged (e.g., broken stems and branches or tropical America (e.g., "cativo" and "sanjo"
disturbed roots) and one-third of the logged forests of Panama and Colombia) also have a area may undergo soil damage (2). low diversity and often are clearcut or cutover
so severely that soil conditions are unable to
Some tropical forests, such as the Diptero- support natural regeneration. carp forests of South and Southeast Asia, have
a large number of commercially valuable spe- Even where clearcutting is not practiced, logcies per hectare and are clearcut. This can going roads can lead to degradation. For examcause soil erosion that reduces the potential for ple, in Sabah and the Philippines, approximatenatural regeneration. In tropical moist forests ly 14 percent of forest concession areas are a large proportion of the ecosystem's nutrients cleared for logging roads (3). Poorly designed are tied up within the biomass of trees rather or constructed roads cause erosion and water than the soils (fig. 17). Thus, a large share of drainage problems and may increase the severthe nutrients may be exported from the forest ity of landslides.

The FAO/UNEP study provides some straight-line projection of the FAO/UNEP estiestimates of rates at which forests are being mates, while not a forecast, can provide an changed from one category to another during understandable way to describe the magnitude
the period 1980-85, although quantitative data of resource changes that may occur. Table 6 on natural resource degradation in areas that shows the projected forest areas for each of the remain classified as forest are not available. A 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

5,068 6,438
total ecosystem
nutrients 10%
Nitrogen harvest 2%


Phosphorus 39%



Potassium 28% 14%


Calcium 20%2 5%


Magnesium 57% /6%

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
Forest Category 1980a 1985a 2000b years (%) 1980a 1985a 2000b years (%) 1980a 1985a 2000b yeara
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
bSOURCE: 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- est land in tropical America in recent years has
rent rates of logging and deforestation in trop- been to make cattle pasture, although this use
ical Africa, the area of undisturbed forest generally is not sustainable in moist forest
would decline 15 percent by the year 2000. areas. The area of closed forest that is unproSome of this is because timber harvest will con- ductive for physical or legal reasons is also devert undisturbed forest to logged forest. The dining significantly, suggesting that this land
logged forest category also includes secondary is not so inaccessible as its definition implies.
forest on land that is recovering from use for
shifting agriculture. However, in spite of these The change rates for tropical America's open
additions, the logged forest area is decreasing forests imply degradation of forest from the
because this category incurs most of the defor- productive category, simultaneous clearing of
estation for agriculture. Since the land does not the unproductive forest, and a net increase in
sustain continuous cropping, the forest fallow open forest fallow that can account for only a
area is expected to increase over the 20-year fraction of the reduction in the forest categoperiod by one-third. Changes in the open for- rides. Again, this means a net conversion of
ests of Africa would be even greater. The open open forest into cropland, grazing land, and
forest fallow is already larger than the fallow degraded land where forests do not regenerate
area in Africa's closed tropical forests. It would naturally, and it means a substantial decline
increase by another 28 million ha as produc- in the quality of the remaining open forest.
tive open forest is degraded to the unpro- T A
ductive category and both are cleared for shift- Trcal ia shoste h reduction
ingalthough such forest has already been reducThe projection shows a 14-percent reduction ed to an area much smaller than in tropical
in the area of productive undisturbed forest in Africa and America. The logged-over area is
tropical America. It also shows a 4 percent in- increasing slightly, probably because forestry
crease in the area of logged forest, which sug- departments in several Asian nations have
gests that logging of undisturbed forest out- some control over the spontaneous clearing for
paces clearing of logged forest only slightly. cropland that follows logging operations. The
Meanwhile, the forest fallow area in tropical area of forests unproductive for physical or
America would increase by only about half as legal reasons is increasing in tropical Asia,
many hectares as are lost from the forest cate- though whether this is a result of more parks
gories, implying that large areas are being con- being established or of severe degradation of
verted to nonforest uses other than shifting ag- the logged-over forests is not clear. Open forriculture. The main reason for converting 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- ficult to identify from aerial photography or tion and deforestation is similar. satellite imagery, and by no means easy to be
sure about when one is actually there standing
Reviewing the FAO/UNEP study's findings in it. What is happening to these forests toon deforestation and resource degradation, day, under the impact of a variety of presWestoby (12) declares that the situation is most sure, can best be visualized as a steady pushalarming in the drier areas, where the data are ing along the spectrum, a general downgradleast precise: ing, with the result that very substantial areas
every year slide out of sight and can no longer
Among the one and a half thousand million be considered as forest on even the most genor so hectares of open forest and shrub land, erous definition. But what should be giving there is an infinite gradation of forest and concern is not so much the 4 million or so hecshrub, ranging from less dry and reasonably tares that are sliding off the visible spectrum
wooded forests at one end to extremely arid as the general degradation which is sapping
shrub formations at the other, with the bor- away at the drier tropical forests through the
derline between what can still be regarded as whole spectrum.
forest and what is irretrievably lost, vague, difCHAPTER 3 REFERENCES

1. Abraham, F., "Practices and Experience of 6. Myers, N., Conversion of Tropical Moist ForNASIPIT Lumber Co., Inc., and Affiliates in Its ests (Washington, D.C.: National Academy of
Natural and Artificial Regeneration of Forests Sciences, 1980).
and Plantations," Proceedings of a Conference 7. Schmithusen, F., "Recent Trends of Forest on Improved Utilization of Tropical Forests Legislation in Developing Countries," Pro(Madison, Wis: U.S. Forest Service Forest Prod- seedings: XVII IUFRO World Congress, Diviccts Laboratory, 1978). sion 4 (Vienna: International Union of Forest
2. Ewel, J., "Environmental Implications of Trop- Research Organizations, 1981).
ical Forest Utilization," International Sympo- 8. Sedjo, R., and Clawson, M., Global Forests sium on Tropical Forests Utilization and Con- (Washington, D.C.: Resources for the Future,
servation, F. Merger (ed.) (New Haven, Conn.: 1983).
Yale University Press, 1981), pp. 156-167. 9. Spears, J., Tropical Reforestation: An Achievable
3. Food and Agriculture Organization/United Na- Goal? (Washington, D.C.: World Bank, 1983).
tions Environment Programme, Tropical Forest 10. United Nations Economic, Social, and Cultural Resources Assessment Project (GEMS): Tropi- Organization, Tropical Forest Ecosystems (Parcal Africa, Tropical Asia, Tropical America (4 is: UNESCO/UNEP/FAO, 1978).
vols.) (Rome: FAO, 1981). 11. Weber, F., "Combating Desertification With
4. Food and Agriculture Organization/United Na- Trees," OTA commissioned paper, 1982.
tions Environment Programme, Tropical Forest 12. Westoby, J., "Halting Tropical Deforestation: Resources, Forestry Paper No. 30 (Rome: FAO, The Role of Technology," OTA commissioned
1982). paper,1982.
5. Gallegos, C., et al., "Technologies for Reforestation of Degraded Lands in the Tropics," 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 Fuelw ood Gatherers 91 F ires 93 W arfare 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 0 In many tropical areas, political, ecocomic,
degradation are caused by subsistence and social forces lead to overexploitation
agriculturalists, livestock raisers, firewood and underinvestment in management of
collectors, and loggers. tropical forest resources.
0Regardless of what activities are responsi* The agents of tropical forest loss vary in ble for forest removal from tropical lands,
prominence among the three major tropical the soil plays a large role in determining forest regions (American, Africa, and Asia). whether agriculture, new forest growth, or Many times, the combination of these activ- barren wastelands will replace the forest in
ities exacerbates forest resource problems. the long run.

Deforestation of tropical lands is not solely to replace the forests. Fire and axe were used a recent phenomenon. In fact, the main loss to clear forests for ranching as well. Forest of forests in some places occurred in the 19th cover had shrunk to 53 percent by 1900. With century, when forests were cleared to estab- the declaration of the Republic in 1902, and the lish plantations of export crops such as sugar, subsequent heavy influx of foreign capital into abaca, coffee, indigo, and tobacco (36). the Cuban economy, forests continued to shrink.
Small farms were swallowed up by large planSugar plantations swept away the Caribbean stations. The farmers were driven to eke out a forests in turn: first Barbados, then the Lee- living in the hills where their struggle for surward Islands, Jamaica, and Haiti. The slave re- vival, together with the insatiable fuel demands bellion in Haiti left the country in ruins and of the sugar mills, took a heavy toll on the upmade possible the sugar boom in Cuba. land forests. By 1946, forest cover was down
Cuba's story is typical and better docu- to 11 percent of the land area. The average mented than that of other parts of the Carib- yearly deforestation had been 1.7 percent of the bean (7). Upon reaching the northeast coast of forest area that existed in 1900. Cuba in 1492, Christopher Columbus was im- The history of Brazil, which was the world's pressed by the island's rich forests. A few years largest sugar producer until the middle of the later, priest Fray Bartolome wrote that it was 17th century, illustrates the severe damage that possible to walk from one end of the island to deforestation can inflict. The northeastern rethe other without leaving the shade of trees. gion of the country is notorious for its poverIn 1812, forests still covered 89 percent of ty. The densely populated coastal region reCuba. But thereafter, fields of sugar cane began ceives substantial rainfall and when the area


86 Technologies to Sustain Tropical Forest Resources

was forest-covered, its soils were described as and depopulated hills and mountains in South fertile and rich in humus. But the forests were China attest to the severity of past land-use cleared for sugar plantations, which were aban- practices and the inability of the forest to doned as the soils wore out. Now the infertile, regenerate naturally (46). eroded soils only support savanna. Rainfall is
rapidly shed as runoff so that streams and stor- In the African Sahel, resource degradation ages dry up during protracted droughts. As a of dry forests has for centuries been caused by consequence, the region frequently gives rise a combination of processes including dry and to mass emigrations (50). erratic climate, brush fires, trans-Saharan
trade, gum arabic trade, agricultural expanSimilarly, little of South China's tropical for- sion, and cattle. Herodotus and others, writing ests remain except in the extreme southwest around 450 B.C., described an active transand in the interior of Hainan Island. Fire and Saharan trade based on precious stones called cultivation took a heavy toll as these forests "carbuncles," gold dust, and slaves. This trade came under increased human pressure about had great adverse impacts on the land. For in1,000 years ago (45). Fire was used widely to stance, large areas were cleared of Acacia radclear forests for grazing lands and croplands. diana to produce charcoal. In the late 18th cenOvergrazing and poor agricultural practices tury, huge caravans of 4,000 camels and 1,000 further reduced the likelihood that forests men would stop at the desert margin and cut would ever reestablish naturally. Timber was wood for charcoal to cook and trade. The charused to build houses, temples, and ships, and coal even was used as emergency rations for wood was cut to supply fuel for cooking and the camels (34). heating. Forests probably were eliminated in
part to destroy the habitat of dangerous wild The resulting encroachment of the desert animals or to minimize the hiding places for margin encouraged a southward shift of bandits. Today's partly grass covered, eroded, drysteppe vegetation. This, in turn, altered ecoChin atestto heeveity ot crdt:T and-us

Eve i aeaswih bunan rinflldeoretaio ca bprmnen Bren lfianSapel, rsnaongc teradto coastoofdChinarwere deforestednhundredseof yearsdabo alombntowfpoese nldn r n
erai ciae buhfretas-aaa


stacelage rea wrePleaedo Accia rTsadEve i araswih aunantranflldeoretaio ca tupryahent aravdsas o 4,00laels and 1,000ut coast omenhwouldestopeatrtheeddesertemarginyandscut

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

logical relationships and amplified the impact For centuries, tropical deforestation has been of hazards such as drought (27). Even though associated with poverty (17). People displaced the human populations in the Sahel had suf- by development processes are often the direct fered periodic droughts for centuries, far agent of deforestation. While peasant cultivagreater harm was caused during the 1970's tors and herders have done the actual tree cutwhen drought was coupled with a seriously de- ting and burning, the causes lie in a chain of graded natural resource base. This is the ex- events that have left these people few options pected response of a resource system where but to destroy the forest or starve. 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).

Soils, by themselves, are not a direct cause Although the soils on certain deltas, young of tropical deforestation. They do, however, set volcanic materials, and flood plains may be ferthe stage in many tropical regions for the prac- tile, most soils in hot, wetlands have signifitice of shifting cultivation, which causes defor- cant fertility problems. These soils are formed station. When it is cleared, forest land com- by chemical weathering of rocks. High monly loses its fertility, produces declining temperatures and high rainfall combine to accrop yields, and ultimately is abandoned. If celerate leaching of nutrients from the rock and forest soils could sustain agriculture, continual soil mineral particles. The residual minerals relocation of farm fields would be less likely tend to be composed mostly of aluminum, silito occur and fewer forests would be cut down. con, iron, oxygen, and water, a chemical coBut few tropical forest soils can sustain pro- position so restricted that many food or tree ductive agriculture over the long term. The crops planted on such soils will have stunted presence of large areas of either heavily growth or will not survive. In some of the soils,
leached soils of low fertility, thin erosion-prone silicon and iron concentrations are so low, and soils, or dry soils makes the establishment of aluminum so high, that the soil may approach permanent farming sites extremely difficult. or reach the composition of bauxite, an alumiTherefore, regardless of what activities are re- num ore.* responsible for cuing tropical forests, the under- These soils have other problems when ferlying soil materials play a large role in de- tilized with certain essential plant nutrients. termining whether agriculture, new forest Phosphorus becomes so tightly held by certain growth, or barren wastelands will be the long- clay minerals, aluminum, iron, and manganese term results. oxides that plants cannot extract enough for
A simple but useful way of discussing tropi- their own benefit (4,13). In the Amazon Basin, cal forest soil is to divide the forest lands into
eae*See Van Wambeke (47) and Fripiat and Herbillon (12) for more 1. hot, wetlands; detailed information. These are good references on soils of the
arid/semiarid lands; and hot, wet tropics that not only contain the commonly cited inforimation on agriculture, soil names, etc., but also provide discus3. mountainous lands. sions of mineralogical and chemical processes.

88 Technologies to Sustain Tropical Forest Resources

for example, 16 percent of the soils suffer this mus, the web of roots, and the recycling sysproblem. Overall, 90 percent of the Basin's soils ter. (table 7) have a phosphorus deficiency (37).
Some 15 percent of the Amazon Basin soils In hot, dry lands physical breakdown of
have a poor ability to hold potassium and other rocks and soil minerals plays a larger role in common plant nutrients (low cation exchange soil formation. In this process, the particles becapacity). If such nutrients are added to the soil m eal the eal opoinras fertilizer, they can be expected to be leached minisly thsa aneain of o
awaycur in a number of ways; for instance, day and In addition, an estimated 2 percent of these night temperature variations cause rocks and soils will harden irreversibly upon drying (47), minerals to expand and contract and, in time, severely limiting reestablishment of vegetation crack. Salts and other substances collect in
(21). In some cases, soil hardening is so com- cracks, expanding when wet and contracting plete that the hardened material can be crushed when dry, further breaking the grains (3). and used as gravel for road building (24). Another mechanical way particles become
Undisturbed tropical forests have an efficient smais throu impact o o w ln nutrient recycling system. As long as the forest rais a of cuet growth of ant
is undisturbed, the nutrient supply remains root is ao r l a tinbean
stable. Soil shaded by the closed forest canopy
is cool enough for the abundant organic mate- In arid/semiarid areas, nutrients needed by
rial to decay gradually. Thus, the forest soils many plants commonly are in the soil but betypically have a substantial humus content and come available to the plants only if sufficient can hold the nutrients released by micro- water is available (6). if most of the water evaporganisms until they are absorbed back into the orates from the soil surface rather than percoweb of tree roots to be recycled again. Slash- lasting down into the soil, dissolved solids or and-burn agriculture takes advantage of the salts can accumulate as crusts at or near the
humus and of the rapid release of nutrients land surface in concentrations that few plants
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- Mountainous lands, though generally cooler
ganic inputs are reduced. Soil with less humus than the other two categories, exist in both wet is less able to hold nutrients, and when rain and dry climates and, thus, either chemical falls the soil fertility fades. If the land is re- or physical processes may dominate. Rather turned to forest fallow soon enough, a new than percolating into the ground to form thick
growth of trees can reestablish the soil's hu- 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
Aluminum toxicity. 315 73
Low potassium reserves 242 56
Poor drainage and flooding hazard t116 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) .e30 6
Laterite hazard if subsoil exposed 21 4
SOURCE: P. A. Sanchez, 0. E. Bandy, J. H. Villachica, and J. J. Nicholaides, eAmazon 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. plant growth as well as helping to reduce The soils that do form are easily eroded. Con- erosion; sequently, soils in mountainous lands, in gen- 9 releases essential nutrients as it decays; eral, are likely to be rocky and thin, except per- e holds nutrients from fertilizer in storage haps on the lower slopes (6). Deforestation in until the plants need them; and mountainous regions is one of today's most enhances the abundance and distribution
acute and serious ecological problems (10). of vital biota (31).
The presence of organic matter is an impor- Therefore, deforestation, by reducing organic tant factor in the soil's productivity because it: matter, lowers the potential productivity of
contributes to the development of soil ag- tropical lands. Thus, when tropical land is
gregates, which enhance root development manot occura repnatin the forest
and reduce the energy needed to work the be difficu
increases the air- and water-holding capacity of the soil, which is necessary for

Subsistence In contrast, recent occupants generally are
*less knowledgeable about local environments
Shiftng Cltivtorsand apply farming systems that are more deShifting cultivation is common in the Trop- structive of resources (23). These people also ics. The techniques are basically similar every- cut and burn part of the forest. But unlike where: farmers fell and burn the woody vegeta- native populations, they may farm the same tion; then cultivate the cleared ground for 1, plot until the fertility of the soil is exhausted 2, or 3 years; and then abandon the site for a or shorten the fallow period so that the vegetalong period to forest or brush cover (forest fal- tion cannot recover. This type of cultivator is low). There are four reasons for shifting to new often a "colonist" who comes to the forests for fields: decreasing soil fertility, reduced soil land because ownership there is ill-defined or moisture, pest outbreaks, or excessive weeds badly protected. that raise labor requirements. Long fallow pe- Generally, the new lands are only marginalpods generally allow the land to recuperate ly productive for agriculture. In addition, reand become, productive once more. cent occupants bring with them dietary prefShifting cultivators fall into two broad classes: erences and agricultural technologies that are indigenous groups and recent occupants. In- suited to intensive culture of the more fertile digenous groups have long experience with the lowlands. By applying inappropriate farming local environment and use farming practices systems on fragile soils, they often destroy the that tend to be resource conserving. These land's productivity. farmers traditionally have practiced shifting
ctiva;tion culingatethod plarticulrn tor hmAlre1,t ftearcltrlpplto

2,iof Latin America farms on steep slopes. Popand woven into their family and tribal customs, ulation growth often leads to increased clearand sometimes into their religion. Usually the
choice of land to be cleared is based on knowl- ance o or atershes oes any edge of nature and soils. The timing of various
agricultural activities is determined by specific *In most of the tropical countries of Latin America, over 30 indications of nature, such as the blossoming percent of the agricultural population is on steep slopes, includof wild plants, the emergence of particular in- ng 50 percent in Peru and Colombia, 40 percent in Ecuador, 5 percent in Guatemala and Haiti, and 45 percent in Mexico
sects, and so on. (33).

25-287 0 84 7

90 Technologies to Sustain Tropical Forest Resources

creased. These shorter cycles do not allow enough time for forests to restore adequate soil fertility. The result is even more extensive forest clearance and a gradual decline in human living conditions.

cen deads coonzaio by farmerst whot nrassi sit
ting cultivation to population pressure and paadhequate land outside the forests. But other important factors are involved as well. In many places, good farmable land is reserved for the privileged and not used intensively to produce needed food crops for domestic consumption. plneGovernments may build highways and proEvnmote colonization projects as alternatives to land reform (as has happened in Latin Ameri ca). Some colonization projects are viewed as an effective way to occupy empty territory. This is especially true near frontiers in Brazil and Mexico (28). Still, indications are that forest clearing by peasant farmers will continue to expand with or without government encouragement and assistance. p_ Livestock Raisers

e Nomadic herders in open forests are analogous to shifting agriculturalists in wetter tropical forests. In arid andsemiarid areas, nomadPhoto credit: H. Bomlinger ic herding is a major land use (43). At one time, Forested hillsides such as this one in Guatemala are the nomadic way of life probably did not debeing cleared for agriculture throughout the Tropics grade the limited resources of dry regions sign part because of population increases and nificantly because there was a long fallow peinequitable land distribution Tiod before an area was reused. It is likely that
an ecological balance among man, animals, the forests as they go, even into the inhospitable and the surrounding natural vegetation existed. humid lowlands of the Amazon Basin. In re- This has changed, however. cent decades, colonization by farmers whowi
practice shifting cultivation has taken place tie tok esand wiz waltht agnove bar-e ercouaeials and ainsrance.aantftr

throughout tropical Latin America. Coloniza- disasters (44). Cattle herds have increased in tion was primarily spontaneous in the 1940's the Sahel in response to economic conditions. and 1950's, but became more systematically For example, the French-speaking Sahel had planned by government agencies in the 1960's a fivefold increase in cattle during the 25 years and 1970's. preceding the 1968 drought (14). Cattle, howEven traditional shifting cultivation practices ever, are poorly adapted to Sahelian condiare breaking down under increasing popula- tions: their conversion efficiency of plants to tion pressures. Commercial exploitation and animal products is poor; they require substansubsequent colonization leave less land for tra- tial quantities of water; and they are highly additional cultivators. With limited land and in- prone to stress. Further, their feeding habits creasing populations, fallow periods have de- are incompatible with the Sahelian environ-

Ch. 4-Causes of Deforestation and Forest Resource Degradation 91

Phot credit J Ch vaie fo FAG4,

I'm W-s

Ps T e credit: J. Chevaier for FAr
Overgrazing by poorly managed livestock herds is a major cause of deforestation and resource degradation in open forests and shrublands of Mauritania and throughout the semiarid tropics

ment. Since cattle are largely grazers, not forage sites. Meanwhile, parts of the remainbrowsers, they must be moved very frequent- ing trees in the vicinity of the wells are lopped ly or they may completely eliminate perennial off for animal feed, and goats overbrowse grasses. The reduction of dry-season grasses shrubs. triggers a number of degradation processes These effects accelerate desertification, a
once the seasonal rains begin. Raindrops strikinegrae thelsre adine udcintyr tha els.estatsrasdsetlk athsaon
nthe sol surface haa i n ltrat. then oeral- villages or waterholes as a consequence of conlyw il tinued excessive pressure on the natural enviland waterfiow erodes the si.ronment. Desertification is serious in tropical High-yielding wells have been built during Africa, Latin America, and Asia. recent droughts to alleviate chronic livestock water shortages. This has led to a rapid in- Fuwed athirers crease in the number and size of herds of cattle and small ruminants, which in turn have Cutting trees and woody vegetation to meet overgrazed the land in the vicinity of wells. the growing demand for fuelwood has accelNatural vegetation has disappeared in general- rated the process of deforestation and now ly concentric circles around the wells until the seriously threatens the environmental stabiligrazing resources are so distant from the well ty of large areas. Such situations prevail in Afthat animals nearly starve before they reach rica (especially in the ad and semiarid areas

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