Front Cover
 Title Page
 Table of Contents
 Ecological description of the terrestrial...
 Succession in agricultural...
 Ecosystem compartmentalization
 Inputs: Fallout and rainout
 Forest products used by man
 Literature cited
 Detailed plans for Phase II studies...
 Harvest procedures
 Procedures for determination of...
 Extensive collecting
 Analytical procedures
 Data evaluation
 Work schedule
 List of persons on contract

Group Title: Bioenvironmental and radiological-safety feasibility studies : Atlantic-Pacific Interoceanic canal
Title: Phase I - Final Report : Terrestrial Ecology
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00082070/00001
 Material Information
Title: Phase I - Final Report : Terrestrial Ecology
Series Title: Bioenvironmental and radiological-safety feasibility studies : Atlantic-Pacific Interoceanic canal
Physical Description: Book
Language: English
Creator: McGinnis, John T.
Publisher: Battelle Memorial Institute
Publication Date: 1967
Subject: Caribbean   ( lcsh )
Panama Canal
Canal Zone
Spatial Coverage: North America -- Panama -- Panama Canal Zone
 Record Information
Bibliographic ID: UF00082070
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Title Page 1
        Title Page 2
    Table of Contents
        Table of Contents 1
        Table of Contents 2
    Ecological description of the terrestrial communities occurring in the proposed Route 17 and 25 areas
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
    Succession in agricultural areas
        Page 20
        Page 21
    Ecosystem compartmentalization
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
    Inputs: Fallout and rainout
        Page 58
        Page 59
        Page 60
        Page 61
    Forest products used by man
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
    Literature cited
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
    Detailed plans for Phase II studies - Objectives
        Page 86
        Page 87
    Harvest procedures
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
        Page 92
        Page 93
        Page 94
    Procedures for determination of transfer rates between compartments
        Page 95
        Page 96
        Page 97
        Page 98
        Page 99
        Page 100
    Extensive collecting
        Page 101
    Analytical procedures
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
        Page 106
        Page 107
        Page 108
        Page 109
    Data evaluation
        Page 110
    Work schedule
        Page 110
        Page 111
        Page 112
        Page 113
    List of persons on contract
        Page 114
Full Text






John T. McGinnis
Frank B. Golley
and associates

Institute of Radiation Ecology
University of Georgia

April 19, 1967

Prepared for Battelle Memorial Institute, Columbus
Laboratories under Atomic Energy Commission
prime Contract No. AT(26-1)-171

Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201






John T. McGinnis
Frank B. Golley
and associates

Institute of Radiation Ecology
University of Georgia

April 19, 1967

Prepared for Battelle Memorial Institute, Columbus
Laboratories under Atomic Energy Commission
prime Contract No. AT(26-1)-171

Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201


Ecological Description of the Terrestrial Communities Occurring
in the Proposed Route 17 and 25 Areas .. . ....... 1

Description of the Route 17 Area Forest Types .. ... 1
Description of the Route 25 Area Forest Types . .. 14

Succession in Agricultural Areas .. .......... .. 20

Ecosystem Compartmentalization .. . . ...... 22

Bases for Compartmentalization .......... ... .. 22
Detailed Description of the Compartments ...... .. 23

Inputs: Fallout and Rainout ... ........ . .. 58

Forest Products Used by Man .... ... . .... ... 62

I. Output of the Natural Terrestrial Environment to the
Cuna Indians . . . . . . 62
II. Output of the Natural Terrestrial Environment to the
Choco Indians . . . . . .. 64
III. Output of the Natural Terrestrial Environment' to the
non-Indian Population: Negroes, Mestizos .. ..... 66

Recommendations . .......................... 76

Literature Cited . . .... . . .. 78

Detailed Plans for Phase II Studies Objectives. .. . ..... 86

Reconnaissance ... . ....... .. .. 87

Harvest Procecures . . . . . .. 87

Selection of Study Areas ...... .... ........ 87
Preharvest Program ...... ...... ........ 88
Harvest Program . . . . . . 91
Drying and Preparation of Samples in the Field .. ..... 94
Numbering and Recording Data ................. 94

Procedures for Determination of Transfer Rates Between Compartments 95

Leaf Fall .. ..... ...... ...... 96
Litter Decomposition ........ .......... ... 96
Fall of Twigs and Branches ....... ... ........ 96
Movement of Elements in Rainwater . . . 96
Analysis of Rainfall Patterns .. .. ... . . 100

Extensive Collecting .. ........... . 101

Analytical Procedures ..... .... ....... ..... 101

Preparation of Unknowns ................. 101
Analysis of Stable Elements ................... 102

Data Evaluation . . . . . . 110

Work Schedule .. .......... ..... 110

Reconnaissance . . . . . .. 110
Harvest Program .......... ........... 111
Transfer of Biogeochemicals ............... 111
Extensive Sampling. .. . . . . . 113
Analytical Studies ...... .. .......... 113
Data Evaluation ............... . ..... 113
Report Preparation .. ........ ...... 113

List of Persons on Contract. . ............ .. 114



Ecological Description of the Terrestrial Communities
Occurring in the Proposed Route 17 and 25 Areas

The vegetation in eastern Panama and northwestern Colombia is dominated
by tropical forest types The only exceptions are the areas that have been
converted from forests to agricultural uses--such as pastures and cultivated
fields--and the extensive marshes in the Rio Atrato floodplain. The different
types of forests are the result of a variety of factors and their interactions--
seasonal and annual precipitation, temperature regimes, altitude, slope effects,
and salinity.
Six major vegetation types were distinguished along the two proposed
canal routes (Figures 1 and 2). These types were classified in this report on the
basis of the Holdridge system(28) for two reasons: (1) most of the available
literature utilized that system in discussing the plant formations occurring in
these areas and (2) the aerial photographs indicated a close correlation between
distribution of structural types and the published information, Several vegeta-
tion types based on the Holdridge system were subdivided where there appeared to
be distinct vegetation types of considerable areal extent. Thus the agricultural
region of the San Bias, the upland and lowland transitional humid tropical forests,
and the mangroves are separated in the Route 17 area, and the swamp forests and
marshlands of the Atrato basin are separated in the Route 25 area.
The information available for each formation seemed to be directly
related to its proximity to navigable water, so that the lowland forests have been
much more adequately described than have those at higher elevations.

Description of the Route 17 Area Forest Types
Mangrove. The Caribbean mangrove forests in the Route 17 area are
quite restricted in extent. They are most pronounced around stream mouths and in
protected bays, while on the shores open to the sea they occur as very narrow
bands or are absent. They are short forests made up primarily of the red mangrove
(Rhizophora mangle). Coastal margins and islands having mangrove vegetation are



Gulf of \
Panoama *

MangroveE Very humid subtropical forest

Agriculture Transitional humid tropical forest (lowland)

Humid tropical forest Transitional humid tropical forest (upland)




Figure 2.

M Gulf
Ira Humid tropical forest Oma
gowsma a of
ar a aof
P- --- Uraba
Very humid tropical forest .-:-:..jE TE
a T
qlon D.teNfl
SV e ry h u m id s u b tro p ic a l fo re s t a ,. ... -.-; a" ",
a a r~~a Goa a
a se a a ar aaaa
^IJ*V%%Vt nil 1It -
a i a IIa, al a an a A
SVery humid lower montane forest Su"s"a asosne
MI a a aI
0 aa a a 0 a I I
.a ,:,a 0,a.0 M I

a a a : IL
SSwamp forest and marshland monsoon a a -
an "I 0iI vKalIiDi
=== ,,,,:.":.:.:.:.;=:= / r

/rr~ ~ ~~ afp-?? ^ a a
s^./ ;:-;: *"::':$ =

1^ *" *::-::--:-:-."t \ ==
Republic of Panamaasn i

\ Tll al -4 OF* -\l
a M a
i n 8i n lU

A .' I"I l S. I : a
0% 8 LOr-8-

0 i n [ a a,1 a n a aI
a a a a8.
0 a M 0 a a a a -a

X-" \ ~ ~ ."".".0.:::"...^ :..*.*.. \
., ,Ia

Ocean Ii '" """"""
I a aa

a aM 0 aM
a a a a
a P OF T aT 25 AA a
F 0a aa aa
a a 0 0
0 a a a

a a a a a 0
a 0 0 n a a v a
Pacific n aa 0 a 0 a
aaaaa a a~ I
n 0 a a a a a n
Oena a 0. a-

apparently avoided by the San Bias peoples because of insect pests (James Duke,
personal communication).
Extensive mangrove swamps occur along the Pacific coast, in the Gulf of
San Miguel, and for certain distances upstream from these coastal waters. Colored
mangrove (Rhizophora brevistyla) exists as a band of tall, dark trees along the
water's edge. Behind this band occurs a lighter, shorter vegetation that is
dominated by the black mangrove (Avicennia germinans), and between these types
exists a transitional area of trees grading in size between them.
The colored mangrove forest is virtually monospecific 49and reaches
heights of from 25 to 35 meters (m). The trees are large, straight, and tapered.
Large prop roots up to 3.5 m in height characteristically branch and extend for
several meters out from the trunk. The roots and lower portions of the stems are
normally inundated twice a day by saline tidal waters. Stems and roots possess
an abundant growth of algae and many mollusks. The relatively open canopy cover
(53.5 percent) allows constant regeneration of saplings, and, concomitantly, the
smaller DBH (diameter breast height) classes are most abundant, the number of
individuals decreasing with increasing DBH. A person may be seen at distances as
great as 100 m because of lack of shrub flora. A fern, Acrostichum aureum,
apparently competes with the colored mangrove for space in coastal areas. However,
it is normally shaded out, except where it can attain a sufficiently dense growth
to suppress the colored mangrove.
The soils are muddy and have a surface layer about 10 cm thick formed by
fine roots, which give it a fibrous texture. The surface soil is chestnut brown
in color, while the subsurface soils have a blackish-blue color streaked by fine
lines of moving water.
The black mangrove forest is also monospecific, except for a few
Rhizophora that may be intermixed. It occurs along the coast behind the band of
Rhizophora, but as one goes upstream, the latter thins out until the black man-
grove occurs along the water's edge with only scattered mangroves. Acrostichum
aureum also occurs commonly near the water in these forests. The regularly spaced
trees have a thin but continuous canopy with a cover of 66.2 percent. In the more
open areas, new base sprouts are abundant and form a thick, homogeneous thicket.
However, the number of sprouts is greatly reduced in undisturbed black mangrove
forests. The top of the canopy is usually about 20 m in height. Size-class
distribution shows a greater abundance of the smaller trees, except in the very
smallest size groups, which show a slight decrease in numbers. A person can be
observed moving through these forests from a distance of up to 110 m.

Prop roots are only weakly developed, although openings can be seen in
the bases of these trees. Numerous pneumatophores, 10 to 12 cm high, arise from
the shallow horizontal root systems. There is a gradual decrease in the number
and thickness of roots down to 45 cm, where 90 percent have disappeared. However,
some roots have been found to a depth of 1.2 m, the level of the water table.
Many dead and rotten branches are scattered about the soil surface, but few
fallen leaves are present at any one time.
The soil is firm, aggregated, and a brownish-gray to bluish-gray. The
numerous crab holes are surrounded by a fine, greenish material, which is suppose-
dly the result of excavation but which could also be fecal materials.
Melendez noted the white mangrove, Laguncularia racemosa, in Darien on
higher ground, which is inundated by less saline tidal waters than is the black
mangrove. However, the community has not been reported in detail, and it could
not be distinguished from aerial photographs.
Humid Tropical Forest. Holdridge and Budowski(67) report this forest
type from the Cordillera on the eastern side of the Route 17 area. It occurs
along the Caribbean coast in undisturbed areas and up the mountains to all but the
higher peaks. It is also found on the western slopes, but is replaced by the
transitional humid tropical forest below approximately 300 m. From the aerial
photographs, it appears to have a more even and denser canopy than the transition
zone to the west. A light-gray-appearing tree, probably cuipo, is also much less
abundant in this area.
Espinal and Montenegro(18) provide the following information on this
forest type as it occurs in northwestern Colombia. The emergent trees reach more
than 40 m in height and 2 to 3 m in diameter. There are several strata of trees,
and herbs, bushes, lianas, etc. The high humidity also favors the growth of
epiphytes and parasitic forms in the upper branches and on the trunks in these
regions. Areas of poor soil or poor drainage are characterized by a forest
reduced in size and variety. In a 50 x 10-m area, the following measurements of
forest were reported:
Basal area 1.122 m2 (22.4 m2/hectare)
Volume 12.202 m3 (244.0 m3/hectare)
A list of the common trees and shrubs found in the humid tropical
forests of northwestern Colombia is given in Table 1.(18)
Cain(14) studied the vegetation along the Rio Leon in the vicinity of
Chigorodo, Colombia, an area Espinal and Montenegro included in the humid tropical
forest formation. However, the forest has only half as many tree species per

hectare as several other tropical forests studied by Cain. This fact and the


Common Name

Spondias mombin
Cedrela odorataa ?)
Tabebuia pentaphylla
Cavanillesia platanifolia
Hura crepitans
Couroupita guianensiss ?)
Lecythis sp.
Eschweilera sp.
Anacardium excelsum
Pentaclethra macroloba
Luehea seemannii
Genipa americana
Trema micrantha
Bursera simaruba
Cecropia spp.
Inga spp.
Erythrina spp.
Ouararibea spp.
Virola spp.
Castilla elastica
Basiloxylon sp.
Sterculia apetala
Ficus sp.
Croton spp.
Piper sp.
Nectandra sp.
Jacaranda sp.
Heliocarpus sp.
Vismia sp.
Ochroma lagopus
Ceiba pentandra

Rob le
Ceiba blanca
Bala de canon
Olla de mono
Olla de mono
Guacimo colorado
Indio desnudo
Y arumos






Snprific NawmeP

LUj FV_- J-L. J %..Ll "LL -

_------ ~~

large number of cativo (Prioria copaifera) indicate that the area is probably
either a swamp forest or a transition between the swamp forest and the drier,
more upland humid tropical forest formation. A summary of Cain's description
The forest in the Rio Leon area is evergreen, as only scattered trees
will lose their leaves at any one time and then only for periods of up to 2 weeks.
It is a tall forest with an undulating canopy comprised of some trees that reach
from 50 to 55 m, although most of the main canopy layer reaches from 40 to 45 m.
Twenty-one species were observed to exceed 35 m. Quantitative data suggested the
presence of an intermediate layer 23 to 27 m and a lower layer around 13 m, but
layers are not readily evident in the stands. The percentage of the basal areas
and numbers of stems for the species that dominate in each strata are given in
Table 2.


Site 1 Site 2 Site 3

Area Sampled, acres 1.4 0.3 0.5
Total Species Sampled 30 22 24
Superior Stratum (upper level of the canopy)
Basal Area 73.6 92.1 85.7
Number of Stems 42.4 29.7 27.3
Transition (Middle Level of the Canopy)
Basal Area 13.5 2.6 2.2
Number of Stems 30.0 15.6 19.3
Intermediate Stratum (Lower Level of the Canopy)
Basal Area 2,4 1.9 5.5
Number of Stems 7.8 20.3 14.0
Other Less Common Species in the Canopy
Basal Area 10.5 3.4 6.6
Number of Stems 19.8 34.4 40.4

From the air, one can, through openings, occasionally see palms 13 to

17 m above the ground, but the ground itself is not visible.

The principal results of stand-composition studies are given in Table 3.
Three species, cativo (Prioria copaifera), caracoli (Anacardium excelsum), and
"olleto", provide an actual dominance as measured by basal area (greater than 75

percent), and together comprise the upper strata.


DBH of Trees Surveyed, Number of Number of Basal Area,
Sample inches Species Stems per Acre m2/acre

1 4 22 213 57
2 2 4 24 114 25
3 >10 30 155 74

The forest contains many lianas and herbaceous and woody epiphytes in
the upper branches of tall trees. Epiphyllae, including mosses, liverworts,
algae, and fungi, were abundant on the upper surfaces of leaves in all strata.
Filmy ferns in the lower strata indicate the high humidity there, while xerophytic
forms, such as the Orchidaceae and Bromeliaceae, occur in the tree crowns. The
Araceae, including Philodendron and Monstera, are also common.
Trees of the 1 to 3-inch and larger DBH classes numbered 1440/acre. The
undergrowth included patches of wild pineapple, shrubs of the Melastomaceae and
Piperaceae, Heliconia, and occasional members of the Zingiberaceae, Cannaceae,
and Marantaceae. Only a small number of herbaceous plants occur under the dense
shade of the forest. There is a rather frequently encountered sedge of the
Cyperaceae and an occasional grass. Selaginella stellata (Selaginellaceae) is
occasional, and an herbaceous geophyte is locally common. However, both the
shrub and herb layers are very sparse, and most of the cover near the ground is
made up of tree seedlings.
Very Humid Subtropical Forest. Holdridge and Budowski(67) report the
very humid subtropical forest type from the upland areas of the eastern Cordillera.
It is normally a tall, dense forest, except on the higher mountaintops, where it
becomes somewhat lower and thinner.
The aerial photographs suggest that this type is very limited in extent.
It is found on some slopes and mountaintops above about 600 m, but was most

prominent on the eastern slopes and ridges of the Cordillera. It appears as a

very dense, even-canopied forest with consistently dark foliage showing none of
the light-colored species.
This type has been described in northwestern Colombia(18) as a high,
evergreen forest. A list of the common trees and shrubs of the very humid
subtropical forest in northwestern Colombia is given in Table 4.
Transitional Humid Tropical Forest. Holdridge and Budowski(67) consider
the forests from the foothills on the western side of the Cordillera to the
Pacific coast to be a transitional tropical forest. This area contains the
forests dominated by the cuipo (Cavanillesia platanifolia), the gallery forests,
and the mangroves, the last of which have already been discussed.
Three forest types can be differentiated from the aerial photographs,
excluding the mangroves. The most extensive is a lowland type strongly dominated
by cuipo, that has an irregular, open upper canopy. However, in certain areas
this pattern is broken up by what appears to be cativo (Prioria copaifera) swamps
in poorly drained areas. Here, cuipo disappears and the canopy is more closed
and even in height. The forests on the Pacific coastal slopes have a denser
canopy, but cuipo still has high importance. The openness of the forest and the
great dominance of cuipo in the intermontane valley may be the result of selective
cutting, which was not carried on as intensively along the coast. Definitive
historical descriptions of forest-product utilization and the kind and extent of
agriculture practiced has not been seen.
Melendez49) refers to this as the mixed forest, which is described as
follows: "It is an open forest with many areas where the trees have been cleared
and replacement is by bushes and herbs. In a 10 x 100-m sample area, 237 trees
of 68 species were counted. The trees had an average volume of 4.44 m and the
larger trees were irregularly dispersed. The most characteristic tree of this
formation was cuipo. The volume of trees in a hectare was estimated to be 1052.67
3 2
m and the basal area was 55.76 m Of this total, cuipo made up 65.72 percent
of the volume and 50.10 percent of the basal area of the stand. The overlapping
of the discontinuous canopy with emergents about 35 m high, and a discontinuous
lower strata results in a 78 percent total cover. A moving person may be observed
in these forests at distances of up to 40 m."
The dominant species of trees, their numbers, basal areas, and volumes
are presented in Table 5.
Heatwole and Sexton(27) described the forest in the upper portion of
the Rio Chepo, which they stated was similar to that along the upper Rio
Chucunaque. They found 167 trees/acre above sapling size and a mean DBH of 25 cm



SDecific Name

Cupania sp.
Alchornia sp.
Trichanthera gigantea
Persea coerulea
Trema micrantha
Cecropia sp.
Albizzia carbonaria
Ochroma lagopus
Inga densiflora
Inga edulis
Miconia caudata
Miconia theaezans
Erythrina edulis
Erythrina glauca
Montanoa sp.
Saurauia choriophylla
Coussapoa sp.
Urera sp.
Piper sp.
Hamelia erecta
Acalypha macrostachva
Boehmeria (caudata ?)
Cordia alliodora
Fiscus sp.
Cassia spectabilis
Cassia strobilacea
Aiphanes caryotifolia
Guilielma gasipaes
Gynerium sagittatum
Guadua angustifolia
Croton sp.
Calliandra sp.
Clusia sp.
Warscewiczia ciccinea
Ladenbergia sp.
Condaminea corymbosa
Tabebuia pentaphylla
Tabebuia chrysantha
Tecoma stans
Bocconia frutescens
Oreopanax sp.
Clethra sp.
Heliocarpus popayanensis
Rapanea guianensis
Solanum sp.
Billia colombiana

Common Name

Quiebrabarrigo, nacedero
Guamo macheto
Guamo santafereno


Nogal, canalete
Canafistulo macho
Corozo chiquito
Barba del gallo

Guayacan rosado
Pestana de mula

-- --- -- -- --- ------- -- ----- --- ------



The Values are Given on a per-Hectare Basis

Number of Area, Volume,
Species Individuals m2 m3

Caranillesia platanifolia 13 27.87 691.90
Quararibea asterolepis 14 12.83 18.60
Gustavia superba 18 4.24 3.32
Astrocaryum standleyanum 15 3.20 2.65
Swartzia sp. 12 3.08 2.62
Unonopsis pittieri 10 2.97 3.49
Others 155 1.57 330.09
Total 237 55.76 1052.57

and a maximum DBH of 2.2 m. There were 372 sapling-size trees/acre, of which 27
percent were palms. The average tree height was 27 m, with a maximum of 36 m.
The mean height at the lower edge of the canopy was 11 m. There were vines or
lianas around 47.8 percent of the trunks, and 13 percent of the trees had buttres-
ses while 1.3 percent had stilt roots. The other trunks were all straight and
epiphytes were not abundant. The herb layer was low, with 42 percent of the herbs
shorter than 30 cm and 77 percent 1 m or less in height (in a 100-m transect).
The average herbaceous cover for 25 1-m2 plots was 38 percent. In the same plots,
the average leaf-litter cover was 83 percent and averaged 4.5 cm in thickness.
The average ground cover from fallen logs and branches was 19.3 m2/acre.
A few notes on the vegetation along the lower reaches of the Rio
Chucunaque were also reported, where from 133 to 235 large trees/acre and from 330
to 603 saplings/acre were sampled in several different forests. In these areas,
16 to 37 percent of the large trees had buttresses, and there were from 25 to 33
trees over 40 cm DBH per acre.
The aerial photographs suggested differences in forest types in the
transition area on the upper slopes of the Pacific coastal mountains at elevations
above 200 to 300 m. The vegetation appeared to have an even-topped canopy with
similar tree crowns than in the surrounding lowlands. The light-crowned forms
were also present in the dense canopy, but were more scattered and smaller.
The gallery forest is a third type found in the transitional zone. It
exists as a belt along river floodplains and in poorly drained, topographical

depressions scattered throughc-t the lowland areas. The aerial photographs show


a band of gallery forests along the larger rivers, which decrease in width as the
terrain becomes more broken and the river valleys become narrower. There also

appears to be a narrow band of dark trees with a dense canopy immediately adjacent
to the rivers. There are few cuipo intermixed with this vegetation, which
probably represents the Mora swamp forest. Behind this band of vegetation exists
another, less homogeneous forest in which cuipo is more in evidence. This
probably represents the cativo swamp, since it has an open canopy and many clear-
ings that may have resulted from lumbering operations. This formation shows a
gradual transition into the mixed forest as one moves away from the river. The
extent of cativo swamps varies with the width of the floodplain and completely
disappears in more rugged areas. There also exist many depressions in the inter-
montane valley, some of them of large extent, which are covered by what appear to
be cativo forests.
Melendez(49) separates the gallery forests into two types, the Mora and
the cativo forests, which he describes as follows.
The Mora forest has a relatively closed canopy (86 percent cover) with
few emergents and an average height of about 25 m. Regeneration is very poor
because of the dense canopy, as is shown by the many dead and decaying sprouts,
but many sprouts and grasses develop when the canopy is opened. Smaller trees are
the more abundant, and, as the DBH size classes increase, there is a decrease in
abundance of larger trees. Most of the smaller trees present were cativo. He
noted that a moving person may be seen from a distance of up to 45 m. The Mora
typically has prominent laminar and ramifying roots that may perch up to 20 cm
above the ground. It is not a monospecific type, although Mora constituted 55
percent of the trees in the sample, and Mora and cativo combined made up 88 percent
of the sample. Mora normally occurs in freshwater swamps adjacent to mangroves
and along stream banks. In the latter situation, it is found on depositing shores.
In many cases, there is a band of grasses and vines along the edge of the water,
followed by stands of a large araceous plant, Montrichardia arborescens, which may
be mixed with Heliconia at the edge of the forest. The Montrichardia stands are
quite dense (728 stems/100 m2) and reach heights up to 6 m. The tree species of
the Mora forest and their numbers, basal areas, and volumes are shown in Table 6.
The cativo forests are heavily lumbered along the rivers, so that the
second growth produces a dense forest with a very irregular canopy up to 35 m high
and a cover of 89 percent. Again, the smaller trees are more common, and the
numbers in increasing size classes gradually drop off. Melendez found that
cativo makes up 90 percent of the trees in this forest. A moving person could be

observed in this forest from distances of up to 35 m. The roots and leaves


formed a mat 3 to 4 cm thick on the soil surface. He also found that 90 percent
of the roots were in the top 15 cm of soil, and that those below this level were
small. The forests are normally found in areas of poor drainage or along fresh-
water streams, where they occur inland from the Mora, or along the river on erod-
ing banks. The tree species of the cativo forest and their numbers, basal areas,
and volumes are shown in Table 7.


The Values are Given on a per-Hectare Basis

Number of Area, Volume,
Species Individuals m2 m3

Mora oleifera 164 37.12 375.97
Priora copaifera 98 13.30 74.92
Astrocaryum standleyanum 18 0.34 2.05
Pterocarpus officinalis 8 0.55 5.19
Carapa guianensis 5 0.13 1.07
Pachira aquatic 3 0.09 0.58
Posoqueria latifolia 1 0.01 0.04
Total 297 51.54 478.90


The Values are Given on a per-Hectare Basis

Number of Area, Volume,
Species Individuals m2 m3

Prioria copaifera 429 46.62 573.45
Mora oleifera 19 1.02 6.62
Carapa guianensis 7 0.46 4.16
Pterocarpus officinalis 6 0.41 4.33
Astrocaryum standleyanum 6 0.12 0.81
Tabebuia rosea 3 0.11 1.12
Pentaclethra macroloba 3 0.51 6.39
Total 473 49.25 596.88


Description of the Route 25 Area Forest Types
The Swamp Forest and Marshland. This habitat exists primarily along the

Atrato River valley, but also to a lesser extent in other river valleys and along
the Pacific coast. The swamp forest may be divided into two types: (1) brackish
and salt-water mangroves and (2) freshwater Mora and cativo swamps.
The mangrove forests on both coasts are very limited in extent. The

only large area of mangrove on the Pacific coast occurs around the Curiche
Estuary, and from aerial photographs it appears identical to the forests at the
western terminus of Route 17. The mangroves at the Caribbean terminus of Route 25
occupy a narrow strip of land along the seaward edge of the Rio Atrato delta. It
appears to be a better developed formation than that found farther north in the
Route 17 area.
The freshwater swamps occupy large areas in the Rio Atrato floodplain

and along other rivers at sites where floodplains broaden. The most prominent of
the latter situations are found along the upper Rio Salaqui and the lower portions
of the Rio Jurado. These forests appear similar to those in the Route 17 area on
the aerial photographs.
The marshes are concentrated in areas between the natural levees border-

ing the Rio Atrato and the swamp forests. They are lighter toned and the vegeta-
tion is shorter than the surrounding forests, and many small to large bodies of
water are interspersed.
The mangroves on the west coast of Colombia and the freshwater swamp

forests are similar to those described in the discussion of the Route 17 vegeta-
tion and will not be covered here.
The vegetation of the Atrato Delta has been described as follows.(83)
The mangrove communities that occur in the tidal zone show a gradual

change of dominance in species depending on salinity. The dense red mangrove
(Rhizophora mangle) forests dominate the shore community; inland, a band of the
white mangrove (Languncularia racemosa) occurs; and finally, a shrub or low tree,
Muellera frutescens, which forms the innermost band of mangroves flourishes. The
red and black mangroves normally have a dense canopy that is only about 7 to 10 m
high. Undergrowth is made up primarily of the following herbs and scrubs: Pavonia
racemosa, Hibiscus tiliaceus, Drepanocarpus lunatus, Dalbergia ecastophyllum, and
Rhabdadenia biflora. The giant fern Acrostichum aureutn, is also locally abundant
in the mangrove community.
Marsh and levee communities appear in association with the Rio Atrato

above the influence of brackish water. The levee vegetation is dominated by three


tree species, Raphia taedigera, Pentaclethra macroloba, and Pachira aquatica,
which form dense forests 10 to 15 m in height. The backside of the levee, away
from the river, is occupied by a palm community. This appears to form a transi-
tion between the natural levee vegetation and the marshes, as it shows a gradation
into both habitats. It is dominated by the following palms: Phytelephas Seemani,
Ammandra decasperma, Euterpe rhadoxyla, and Mauritiella sp. The giant aroid,
Montrichardia arborescens, is also a member of this community. The marsh com-
munity is found in the backwaters of the floodplain between the levees and the
swamp forests, both of which occur on higher ground. The marshes are dominated
by grasses of the genera Paspalum and Scleria, and the sedge Cyperus gigantia,
which reaches a height of about 4 m. Scattered clumps of the palms, Euterpe
rhadoxyla and Mauritiella sp. may be found in the marshes at sites of old,
degenerating natural levees. The many lakes within the marshes are normally
choked with aquatic vegetation and are continually being naturally filled. The
most common aquatic plants are a type of water hyacinth, Eichhornia azurea, a
water lily, Limnanthemum humboldtianum, and an aquatic, emergent herb, Sagittaria
Two other smaller communities described by Vann(83) are the depositional
bar and sandy beach habitats. The bar vegetation is dominated by a low-growing
vine, Cydistra aequinoctialis, and its outer edge and by dense stands of the
aroid, Montrichardia arborescens, in the older, inland portions of the bar. The
beaches are dominated by low shurbs, vines, and creepers such as:

Hibiscus tiliaceus shrub
Hibiscus bifurcatus- shrub
Entada gigas low climber
Canavalia rosea herb
Cordia macrostachya climbing shrub
Rhabdadenia biflora low shrub
Wedelia brasiliensis creeping herb
Ipomoea pescaprae creeping vine

Very Humid Tropical Forest. The very humid tropical forest occupies
the Pacific coast region of Route 25 and extends eastward until it is replaced by
the humid tropical forest in the mountain foothills west of the Atrato basin.
The area has rugged topography ranging from sea level up to about 1500 m. The
forest appears very dense and has a generally darker, more even canopy than the
adjacent humid tropical forests. The trees show a regular decrease in canopy
size as the altitude increases. Thus along the coast and river valleys, there are
many large trees with broad canopies, which gradually decrease in size up to
elevations between 800 and 1500 m where the forest forms a veritable mat of


densely packed vegetation. The foothills adjacent to the Atrato basin represent
a transitional area. Here, the humid tropical forest extends up the river valleys
while the very humid tropical forest is found only on the mountain slopes above
approximately 300 m. The swamp forests occur in many of the broad river valleys
in this region.
Espinal and Montenegro (18)have provided the following description of
this forest type.
The trees of the virgin forest are in several strata, which may reach
heights of 45 to 50 m, and occasionally higher. High humidity and high tempera-
ture allow for an abundance of epiphytes, including ferns, mosses, "air plants",
bromeliads, lichens, and other plants, which may completely cover branches and
tree trunks. The trees are large in diameter (2 or more m) and buttresses are
commonly observed. Completing the structure are abundant palms, cane, and
climbers of many kinds.
In some regions which are periodically inundated, there exists a homo-
geneous formation almost totally made up of cativo, Prioria copaifera, and
accompanied by the guino, Carapa guianensis, and Pterocarpus officinalis.
A list of the common trees and shrubs compiled by Holdridge from the

very humid tropical forest in Colombia is given in Table 8.
Very Humid Low Montane Forest. The very humid low montane forest is
restricted to elevations in excess of 1000 m, and is only found on some of the
higher mountains along the Panamanian border. The aerial photographs indicate
that it has an even canopy which is dark in color and extremely dense. Holdridge
and Budowski(67) state that it is a tall forest made up of veritable thicket of
trees, many of which reach quite large dimensions. It is also a very moist
forest and is found primarily in rugged terrain(18) The common trees and shrubs
as listed(18) are given in Table 9.
Humid Tropical Forest. This formation is virtually identical to the
forests of the Panamanian Cordillera separating Darien and San Blas provinces,
where it is found on all but the highest slopes of the mountains. It occurs
between the swamp forests of the Rio Atrato and the Caribbean coast, and the
higher mountains to the west of the bodies of water. A small tongue of this
formation also extends south from the Republic of Panama along the extreme
northwestern coast of Colombia. The aerial photographs indicate that where it
occurs on low mountains it forms a moderately dense forest with an irregular
canopy and scattered, lighter colored trees. However, in the flatter floodplain
areas, it takes on a much more open appearance, which is probably the result of

previous cultivation and/or lumbering. This is evidenced by the development of



Specific Name Common Name Specific Name Common Name

Ceiba pentandra
Huberodendron patinoi
Hampea sp.
Ochroma lagopus
Pachira aquatica
Quararibea spp.
Ina marginata
Inga sapindoides
Inga spectabilis
Pentaclethra macroloba
Calliandra sp.
Pithecolobium sp.
Bauhinia spp.
Brownea ariza
Brownea sp.
Cassia reticulata
septentrionalis ?
Schizolabium parahybum
Swartzia panamensis
Andira inermiss ?)
Coumarouna oleifera
Centrolobium sp.
Machaerium sp.
Peltogyne sp.
Dussia macrophyllata
Erythrina poeppigiana
Platymiscium sp.
Pterocarpus hayesii
Pterocarpus officinalis
Cecropia obtusifolia
Cecropia sp.
Castilla elastica
Clarisia sp.
Ficus (colubrinae ?)
Ficus Lapathifolia
Brosimum utile
Olmedia (falcifolia ?)
Pourouma (sapera ?)
Coussapoa sp.
Cariniana pyriformis
Eschweilera sp.
Gustavia sp.
Apeiba tibourbou
Heliocarpus sp.
Belotia sp.
Luehea seemannii
Sloanea sp.
Dialyanthera otoba


Cacao de monte


Pata de vaca
Palo cruz

Cucharo colorado


Sangre de gallo

Caucho negro

Perillo, sande

Fruta de indio

01la de mono

Peine de mico

Guacimo colorado


Virola (guatemalensis ?)
Anona sp.
Guatteria sp.
Rollinia microsepala
Xylopia sp.
Piper aduncum
Pouteria sp.
Coccoloba sp.
Chrysophyllum sp.
Triplaris sp.
Aegiphila costarricensis
Vitex cooper

Vitex gigantea

Jacaranda (lasiogyne ?)
Jacaranda copaia
Tabebuia pentaphylla
Cedrela (angustifolia ?)
Guarea (aligera ?)
Guarea sp.
Basiloxylon sp.
Cordia allidora

Cordia sp.
Turpinia paniculata
Cespedesia macrophylla
Ouratea sp.
Acalypha sp.
Alchornea sp.
Hieronyma alchorneoides
Hura crepitans

Croton gossypiifolius
Croton sp.
Sapium sp.
Myriocarpa longipes
Urera caracasana
Urera sp.
Terminalia amazonia
Ocotea (cernua ?)
Anacardium excelsum
Spondias mombin
Tapirira sp.
Bursera simaruba

Protium sp.
Clusia sp.



Cedro macho
Cedro macho






---- -- -- --


TABLE 8. (Continued)

Specific Name Common Name Specific Name Common Name

Vismia sp.
Tovomita sp.
Didymopanax morototoni
Dendropanax sp.
Gilibertia sp.
Capparis sp.
Lacmellea panamensis
Stemmadenia sp.
Genipa americana
Ladenbergia sp.
Palicourea sp.
Pallassia stanleyana
Psychotria sp.
Clethra (lanata ?)
Cestrum (panamensis ?)
Solanum sp.
Hibiscus sp.
Simaba sp.
Simaruba (amara ?)
Licania sp.
Dipterodendron costarrice
Allophylus ? sp.
Carica sp.
Jacaratia pyramidale
Rinorea sp.
Cochlospermum sp.
Zanthoxylum sp.
Vochysia ferruginea
Trema micrantha
Bravaisia integerrima
Vernonia sp.
Miconia sp.
Psidium sp.
Bixa orellana
Pereskia sp.
Quiina sp.
Caryocar costaricense
Diospyros sp.
Casearia sp.
Siparuna sp.
Vantanea sp.





Arenillo, loro









Specific Name Common Name Specific Name Common Name

Schefflera uribei
Cordia acuta
Cordia salviaefolia
Cordia archer
Viburnum anabaptista
Clethra fagifolia
Hedyosmum bonplandianum
Weinmannia pubescens
Befaria glauca
Cavendishia pubescens
Phyllanthus salviaefolius
Croton magdalenensis
Alchornea sp.
Xylosma benthami
Vismia sp.
Clusia sp.
Macrocarpea mocrophylla
.Eschweilera antioquensis
Persea crysophylla
Gaiadendron tagua
Nectandra macrophylla
Miconia ibaguensis
Meriania nobilis
Blakea sphaerica
Tibouchina lepidota
Inga archeri
Geisanthus kalbreyeri
Rapanea guianesis
Rapanea ferruginea
Myrica pubescens
Eugenia foliosa
Myrica popayanensis
Siparuna lepidota
Godoya antioquensis
Piper archeri
Monnina angustifolia
Panopsis yolombo
Roupala sp.
Palicourea caloneura
Drimys granadensis
Saurauia ursina
Cestrum meridanum
Escallonia floribunda
Turpinia heterophylla
Lippia hirsuta
Ilex sp.
Oreopanax sp.


Brazo de tigre
Sauco de monte
Uvito de monte




Siete cueros

Verraco, liberal
Canelo de paramo

Chilco colorado


Quercus humboldtii
Brunellia subsessilis
Lepechinia bullata
Passiflora sphaerocarpa
Freziera chrysophilla
Buddleia sp.
Cecropia spp.
Ceroxylon sp.

Cinchona pubescens
Montanoa sp.
Rhus sp.
Chusquea sp.
Datura glauca



Palma de


what appear to be scattered patches of a low and extremely dense vegetation, which
is most likely second growth. As mentioned previously, the humid tropical forest
forms a transition with the very humid tropical forest in the mountain foothills
west of the Rio Atrato.
The descriptions from the literature of this forest type have been given
for the Route 17 area, and will not be discussed here.
Very Humid Subtropical Forest. This formation is also a continuation of
similar forests occurring on the Cordillera peaks that separate the San Blas and
Darien provinces of Panama. It occupies only a small part of the Route 25 area
where this mountain range enters Colombia. It appears to be a dense forest on the
aerial photographs, and has an even, dark-colored canopy. The descriptions from
the literature of this forest type have been given for the Route 17 area, and
again, will not be discussed here.

Succession in Agricultural Areas

The most prominent area of slash-and-burn agriculture occurs along the
Caribbean coast below the 100-m contour line. Additional areas of cultivation are
found scattered throughout the region, also at low elevations, primarily along the
larger rivers. No information is available on the vegetational succession in the
Route 17 region, but succession on Barro Colorado Island in the Canal Zone has been
described(33). A summary of the description follows and probably does not differ
greatly from that found in the Route 17 area.
On newly cleared ground, the most conspicuous plants are grasses and
sedges. The grasses include Panicum, Paspalum, Digitaria, Setaria, Cenchrus,
Andropogon, Axonopus, Eleusine, and Chloris. The sedges include Cyperus and
Scleria. Local "weedy" plants are frequent, the Amaranthaceae, Phytolaccaceae,
Euphorbiaceae, and Solanaceae being well represented. The Fabaceae furnish Mimosa
and Meibomia. There are extensively trailing curcurbits and sweet potatoes that
run wild. The Compositae appear conspicuously with such widespread genera as
Tridax, Emilia, Eclipta, and Erigeron. Most of these early-appearing plants are
annuals. The aspect of the formation is not unlike that of a recently abandoned
field in the temperate zone.
After a year, the grasses persist, with a few coarser ones coming in.

Large-leaved monocotyledons put in an appearance, of which the most conspicuous are
the Heliconias and the Panama hat palm. Heliconias will sometimes form almost pure
stands. There are numerous coarse composites, such as Verbisina, Clibadium,

Neurolaena, Baccharis, Veronia, and Wulffia, and also the equally coarse plants of


Solanum and Triumfetta. The predominant shrubs are Piper and Phyllanthus. A
number of the trees prominent in this early stage, such as Trema, Cecropa,
Luehea, Apeiba, Heliocarpus, Ochroma, Didymopanax, and Cordia, become flourishing
saplings. Lygodium and certain grapes, passion flowers, Cissampelos and a few
other lianas help to complicate the tangle, which by this time averages 2 m high
and is almost impenetrable.
After about 2 years, the pioneer trees become conspicuous. The
Cecropias are perhaps most striking in appearance and rapid in growth. Ochroma,
the balsa, is abundant and almost as rapid in its growth as Cecropia. Trema is a
very frequent pioneer and occurs with Apeiba, Luehea, Heliocarpus, Didymopanax,
Miconia, and Cordia. Bombacopsis comes in as a pioneer, but persists and becomes
the largest tree in the climax on Barro Colorado. The largest palm on the island,
Attalea, also comes in as an early pioneer.
In the older pioneer forest, 15 to 50 years after clearing, a large
proportion of the just-named species persist, but many new species come in.
Species of Ficus, Inophloeum, Olmedia, Castilla, Coccoloba, Ina, Zanthoxylum,
Protium, and Sapium also appear. In places, there are relatively pure stands of
Gustavia. An array of small trees or shrubs of Melastomaceae may appear. Lianas
are numerous, conspicuous among them being Bauhinia. In places, the climbing
bamboos, Chusquea and Arthrostylidium, almost dominate the landscape, and a number
of new palm species come in. Ferns, Selaginella, and numerous monocotyledons such
as Xiphidium of the Haemodoraceae, the Commelinaceae, Zingiberaceae and Maranta-
ceae, are found on the forest floor. In fact, the curve representing the number
of species probably reaches its high point at this time, declining somewhat as
climax conditions are established. This forest has more undergrowth than does the
climax, and is more difficult to penetrate.
The climax forest follows with its sparsely distributed large trees and
the crowded trees of the story below, the floor being shaded to such an extent that
the undergrowth is relatively sparse.
In areas where soil slides have occurred, a new surface is stabilized
and colonized by mosses, liverworts, the fern Pityrogramma, Begonia, Kohleria,
Tibouchina, Phyllanthus, and a few other herbaceous plants. In certain parts, the
next step seems to be a knee-high thicket of Lycopodium and the fern, Dicranopteris.
If protected from erosion, the succeeding stages are pioneer shrubs, such as Piper
and Phyllanthus, pioneer trees, and then climax trees.
A stream-valley succession type dominated by ferns, including the filmy
fern (Trichomanes), tree ferns, a marattiaceous fern (Danaea), and by plants of

the Polypodiaceae and Gesneriaceae, some aroids, and certain palms has been noted.


This type of pattern is also probably present along waterways in the Route 17
To summarize, the order of the clearing succession is, for the first
year, a grass and annual-weed association; for the second year, an association of
Heliconia, Piper, Phyllanthus, and coarse Compositae; for the third to the
fifteenth years, a pioneer forest of Cecropia, Ochroma, and Trema; for the fifte-
enth to the fiftieth years, a mixed secondary forest of comparatively small trees
of many species with considerable shrubbery and herbaceous undergrowth; and the
climax-forest stage, with scattered large trees of several species, numerous
smaller species, and less undergrowth.

Ecosystem Compartmentalization

The compartments within each terrestrial ecosystem are defined by their
function in intercepting, incorporating, concentrating, and cycling radionuclides,
so that representative analyses can be made to predict these functions and the
outputs to man.
The compartments can be classified as follows:
(1) Leaves and petioles of upper-canopy trees
(2) Stems and branches (lianas included)
(3) Leaves and petioles of ground vegetation (lower strata)
(4) Roots
(5) Fruits and seeds
(6) Litter
(7) Soil, humus, duff, and peat
(8) Epiphytes
(9) Epiphyllae
(10) Animals
(a) Herbivores
(b) Carnivores.

Bases for Compartmentalization
Classically, tropical rain forests have been described by their gross
physiognomy, internal stratification, and species composition. Richards70
recognizes that, typically, there are between three and five strata in most
tropical forests. The concept of stratification is of functional importance,
especially from the standpoint of gravity-controlled radionuclide input from
rainout and dustout from the atmosphere.
Furthermore, within forest types, definite synusiae are recognized. A
synusia is a major structural unit containing plants and animals that make similar


demands on the habitat. The concept of synusiae integrates the functional and
structural roles of the biota and offers an ecologically oriented classification
The compartments described below integrate the concepts of stratifica-
tion and synusiae in an attempt to organize the biota of the ecosystems into

categories that, it is hoped, will reflect their importance within the system.
Notations are made of possible sites of radioisotope concentration and expected
pathways. Whenever possible, estimates of standing crop and nutrient content are

Detailed Description of the Compartments

(1) Leaves and Petioles of Canopy and Subcanopy Trees. This compart-
ment includes the photosynthetic units of the canopy and subcanopy (Zones A and B
of Richards ), viz., the leaves, petioles and buds of trees, lianas, climbers,
twiners, and stranglers. Leaves in this stratum are bascially medium sized,
xeromorphic, sclerophyllous, sun-tolerant, and as a group are distinct from leaves
in the lower strata(70). Owing to their basic morphology, anatomy, function,
position, and contribution to the standing state, these units have been lumped and
are considered as a distinct compartment.
Delimitation of this compartment will be difficult within some of the
forest types, e.g., the transitional humid forest and the plant forest where
it is difficult to separate the subcanopy flora from that of the lower strata. In
the mangrove forests, the two layers are well defined as the upper and lower
As shown in Figure 3, this compartment occupies the uppermost segment of
the forest and includes a major portion of the standing-crop biomass. Because of
its position, this compartment acts as an important filter and interceptor of
input materials controlled by gravity and an important link in the radionuclide
Figures on the biomass of leaves in American tropical forests is scarce,
yet some data are available (Table 10). The dry weight of leaves in established
vegetation may account for 30 percent of the total dry weight within an 18-year-
old forest stand in the tropics Table 11 shows the percentages of oven dry
weight of six common nutrients in the Puerto Rican forest vegetation
Input to this compartment is divided into three major pathways: (1)
foliar absorption, (2) foliar adsorption, and (3) nutrient uptake and trans-
location from roots, stems, and branches.






Upper- 8 Sub-Canopy

8 above ground




Pounds Per Acre (Except as Indicated)

Leaf Area
Litter Fall Underground Per SquarE
Site and Authority Leaves Wood Roots Litter Per Year Animals Roots and Peat Meter, m2

Tabanuco forest
Puerto Rico(a5 7,241 -- -- -- -- -- -- 6.4

Red mangrove,
Puerto Rico(b) 6,940 49,122 8,893 small 4,230 57 401,400 4.4
35,680 large

Mixed forest,
Kade, Ghana(c) -- 184,900 48,300 88,900 -

18-yr-old mixed forest, 4,817
Yangambi, Congo(d) 5,800 104,000 28,000 20,500 10,972
Rain forest, Colima and 7,600
Chinchina, Colombia(e) 10,700 -- -9,098 --

Mixed forest,
Ituri, Congo() -- -- -- 7,582 -- --

Mixed forest,
Yangambi, Congo(g) -- -- -- -- 11,060

(a)Odum, Copeland, and Brown (1963).
(b)Golley, Odum, and Wilson (1962).
Greenland and Kowal (1961).
)Bartholomew et al (1953).
Jenney et al (1949).
Brynaert personnel communication with Gorham and Bray (1964).
(g)Laudelot and Meyer (1954), from Gorham and Bray (1964).




Numbers Represent Average Percent of Oven
Dry Weight Over Individuals and Species

Na K Mg Ca P N

Leaves (44 spp.) 0.21 1.10 0.37 1.00 0.08 1.59
Branches (47 spp.) -- 0.39 0.11 0.49 0.03 0.43
Roots (38 spp.) 0.11 0.29 0.15 0.69 0.03 0.55

Foliar absorption, at least in temperate forests, is well recognized as
an important factor in radionuclide uptake. Studies have shown that uptake from
leaf surfaces is more important than that by roots, especially with introduced
(34) (34)
radiocesium. For the tropical forests of Puerto Rico, Kline ) suggested
that aerial contaminants were being absorbed by the leaves, since there were
differences in the amounts of contaminants in the soil compared to the leaves.
Other work in the tropics(44) indicated that commercially grown coffee (Coffea
65 32 2
arabica) absorbed more Zn, P, and N (from urea) when they are sprayed from
the air than when they are conventionally applied to the roots. Thorne
mentioned that intake is most rapid during the first few hours after spraying and
continues during the entire period when free water is present on the leaf surface.
Factors that regulate the rate and ability of a leaf to abosrb nuclides
are many and can only be suggested in a general way. The element itself will have
its own peculiar attributes, but will generally be affected by its size, carrier,
ionic state, and solubility in water, and by the presence of fats. Diffusion and
osmotic gradients will also affect uptake rates. Leaves affect the rate of uptake
by their surface area and texture, in that the greater the surface area and
pubescence, the greater the trapping and absorption of contaminants. As noted
earlier, leaves of this stratum are generally smooth, yet as a compartment they
offer a large cross-sectional area (5 to 1) (Odum, personal communication) to
gravity-controlled rainout or dustout.
The second major input pathway is foliar adsorption. The degree of
contamination through this route is highly dependent on the mode of input,
especially particle size. It has been reported for semiarid foliage that particle
size decreases with greater distances from the fallout source and that external


beta contamination is primarily a result of particles 44 microns and smaller in
Translocation from woody tissue constitutes the third major source of
input. Here again, the actual elements and appropriate rates will probably be
species and element specific and deserve further examination. Work with the
translocation of 134Cs(62,63,64,86) showed that, in a temperate forest, the
isotope moved from the woody tissue to the leaves following overwintering and
that cesium is easily translocated throughout the plant and may accumulate more
in young leaves and flowers.(20) It was also reported that concentrations follow-
ing overwintering may equal the concentration of the initial inoculation.
The first two pathways outlined will probably be important immediately
following the initial aerial contamination and should become of decreasing
importance with time. Conversely, translocation should become more important in
time as contaminants are incorporated into surface soils, then in new growth, and
Pathways of output from this compartment include (1) reabsorption,
(2) grazing, (3) leaching, (4) dilution due to growth, and (5) leaf fall.
Reabsorption is here considered an important pathway, since large
numbers and amounts of elements move back into the supportive tissue prior to
leaf abscission.(62) Some elements are typically immobile and are not re-
absorbed, however.
Reabsorption prior to abscission could be of considerable importance
in concentrating elements in the woody tissue and the next annual leaves. Within
the expansive transitional humid forest and the other forest types that are
partially deciduous, reabsorption will cause a major change in the standing
state of this compartment and needs to be investigated.
Considerable data are available on the seasonal changes in nutrient
content of leaves for temperate species; however, few data are available for
tropical species. Recently, changes in the levels of 21 trace and essential
elements were noted in extensive studies on three species of deciduous trees in
England.(25) The following points of interest regarding mobilities and areas of
concentration may be applicable to tropical species:
Calcium immobile in pholem; gradually accumulated in
mature leaves
Phosphorus very mobile; not accumulated in mature leaves;
transferred in pholem to growing parts


Iron movement and areas of concentration highly dependent
on a number of factors

Calcium, tin, barium, boron, silicon, and all nonessential metals -
accumulated in mature leaves (suggests immobility)
Phosphorus, potassium, zinc, copper, and magnesium did not
accumulate in leaves

Zinc and sodium increased in concentration level toward
The potassium substitute, Cs, is reabsorbed from leaves prior to
abscission.(7)Tracer studies(41) using P showed the following trends for tree
species of Puerto Rico:
(1) Phosphorus content varies among species at different sites,
and the level of illumination is not a factor
(2) Mature leaves contain significantly less phosphorus than
young leaves on the same tree

(3) The phosphorus content of roots is equal to or higher than that
of mature leaves, although it is less than that of decomposing
leaf matter in contact with the roots
(4) Nonleaf debris is significantly lower in phosphorus than leaves
ready to fall, or the litter itself.

Leaching as an output pathway has been noted by Kline (34)and Tukey(79)
in the humid tropical forests of Puerto Rico and by Nye 57in Ghana. Organic
and inorganic materials, including minerals, are leached from a wide range of
plants by all forms of precipitation. Mineral leachates in tropical forests are
influenced by the species, wettability of the leaves, and physiological age79)
as well as conditions of precipitation, temperature, antecedant soil-moisture
condition(85) and light.(80) Further studies(62 of leaching of 137Cs, 134Cs,
90 60o 137
Sr, and Co showed that C as a leachate contributed up to 20 percent of the
134 90
total litter burden and that Cs was leached at a rate twice that of Sr,
6Co. In 1961, Nye(57) presented data on leachate inclusions from a tropical,
moist forest in Ghana, where the average annual rainfall was about 65 inches.
His results indicated that little fixed nitrogen was washed out of the canopy
and that only small amounts of ammonia and nitrate were leached out of the leaves.
He added that, compared to the amounts falling in the litter, very large amounts
of potassium and significant amounts of phosphorus and magnesium were lost from
leaves in rain, but only small amounts of calcium and nitrogen were lost. The
main anion accompanying leaf drip was carbonate, with some sodium, chloride, and
sulfate leachable.
Since the pioneer works of Bray 12), utilization of canopy leaves

has been investigated in more detail. Grazing of the upper canopy levels by


chewing arthropods was calculated to be between 1 and 5 percent. 1758)Removal
of materials by birds, mammals, and sucking insects was not considered in either
of these papers. Estimates made from fallen leaves may overestimate the actual
amounts of leaf material consumed since the whole size apparently increases, in
that many leaves are eaten while they are growing.
Using 5 percent as a conservative estimate of the foliage consumed by
all consumers in the tropical forests, where 8 to 10 tons/ha/yr are being produced,
one can see that a considerable amount of this compartment enters the herbivore
food chain before leaf abscission.
Factors responsible for differential use in different species include:
abundance and control as influenced by specific foliage-gleaning birds and leaf
palatability demonstrated by the relationship between leaf utilization and nutrient
content. (The vertical position of the leaves also determines the degree of
utilization, i.e., the stratum in which they occur.17
Probably the single most important output pathway is leaf fall. Whether
the compartment releases its units gradually throughout the year or synchronously
within a season, a large portion of the photosynthates and adhering organic and
inorganic substances are flushed to the litter compartment. Nye(57) estimated
that in Ghana 9,400 Ib/acre (oven dry) fell as litter, leaves forming two-thirds
of the total; Jenny et al(31), working in Colombia, estimated 7,000 to 9,100/lb/
acre and Laudelout and Meyer(36) working in the Congo, 11,000 lb (see Table 10).
The effects of synchronous and seasonal leaf fall, as it occurs in the
transitional humid tropical forest and to a lesser degree in the upland and very
humid forests, are that the standing state and crop of the compartment are
completely changed. Consequently, foliar uptake to this compartment is halted or
altered, and the potential input to lower strata is increased. Thus, in general,
leaf fall influences not only standing crop and state of the upper and subcanopies,
but also decreases interceptive capacity for the leachate output to the underlying
strata, increases the direct input of aerial contaminants, and increases the
standing state and crop of the litter layer.
Flowers are considered as part of the foliage compartment because they

show a similar vertical distribution(70) and pattern of mineral uptake and
concentration. The similarities are probably due to the general movement and
incorporation of nutrients in the rapidly growing portions of the plant. Menzel
and Heald(51) found rubidium and cesium in the flowers as well as the leaves of
millet, oats, buckwheat, sweet clover, and sunflowers. ORNL reported that the
leaves and flowers of corn contained more radioactivity than did other parts of


the plant; however, trees on the reserve concentrated more radioactivity in leaves
than in flowers.60 It has been suggested that cesium accumulates in young
leaves and flowers more than other elements because of its greater mobility(20)
although many elements may be absorbed by fruits, flowers, and bark of branches
and twigs as well as by the leaves of trees.(88) Carbon-14 is incorporated by
leaves, and the resulting photosynthates move to active growth points such as the
flowers. 21 Thus, the flowers may be considered a source of radioactivity to
herbivores and to the litter compartment just as the leaves are. Animals that
collect nectar or pollen may be important in concentrating isotopes from this
In evergreen tropical forests, flowering extends throughout the year,
and although some trees may blossom continuously, maxima occur at certain times of
the year--normally at the beginning and end of the dry season. The canopy vegeta-
tion usually has a more seasonal flowering cycle than does the understory and
stream-side vegetation, which are less affected by drying conditions.70
(2) Stems, Boles and Branches of All Strata. This compartment includes
the aboveground living nonphotosynthetic supportive tissue in all strata, including
stilt roots, buttresses, boles, stems, branches, and twigs of trees, shrubs, and
lianas. In general, some more important and unifying characteristics of the
compartment are that it:
(1) Constitutes a major fraction of the standing-crop
biomass and volume

(2) Incorporates a large percentage of the net annual
(3) Acts as a major contributor to the litter and detritus
food chain, and thus plays a key role in nutrient cycling
(4) Provides resources exploited by man, primarily as timber
(5) Exerts a major control over the microenvironment, which
provides and maintains a multitude of niches for epiphytes
and heterotrophs.
Within each of the vegetation types, this compartment will contain the
bulk of the total volume and total biomass per unit area. For the forests of the
Chucunaque valley and the mountain regions, biomass is expected to be of similar
magnitude to the values shown in Table 10. 71) In a 50-year-old secondary
forest in Ghana, 150 tons of dry matter was present on 1 acre, of which 100 tons
was in living and dead wood.(24) Over 175 tons/hectare have been reported in an
18-year-old Belgian Congo forest.(71) As succession proceeds, the weight of the
production stored in the woody materials increases rapidly to approximately three
times that of the other compartments. Annual production estimates for the


moist forest of Ghana(57) place the average at 10,000 Ib/acre (0.5 g/m2 day); in a
mature forest, annual production of timber will equal timber fall.
According to Golley, Odum, and Wilson ( (see Table 10), the biomass of

aboveground roots, branches, and trunks was 5,507 g/m (49.122 lb/acre) for a red
mangrove (Rhizophora mangle) forest in Puerto Rico. Total gross production was
estimated at 8 g C/m2/day or 16 g organic matter/m2/day.
Although the greatest amount of total volume and biomass in each forest
vegetation type will belong to this compartment, a difference between types is
expected. This is shown in Table 12 for five associations of inudated forests in
Darien, Panama. Comparison of the Cativo swamp and Canvellisia mixed forest
as a unit with the Mora black and colored mangrove forests as a unit show (1) that
the timber in the mixed forests is two to four times greater in total volume and
one to two times greater in basal area, and (2) that the average tree is one to
eight times greater in volume, but both types are about equal in the total number
of trees.
Relatively little work has been done on the nutrient content or standing
state of tropical forests. The stand nutrient content of a late secondary forest
in Ghana and in a Puerto Rican forest are given in Tables 11 and 13, respective-
ly. 2465 Table 13 shows that the woody tissues contain the greatest weights and
percentages of the six nutrients studied.
With respect to radionuclide uptake and concentration, the supportive
tissues will be subject to the same input pathways as other compartments.
Absorption and adsorption will come primarily from stem flow and will be depend-
ent on season, intensity of rainfall, surface texture, canopy structure, epiphytic
growth, and the quantity and composition of the stem-flow liquids. In general,
tropical trees and shrubs are relatively smooth barked 70); hence, the smooth
surfaces can be expected to shed stem flow and thus reduce retention and
absorption, yet, the thin bark may facilitate uptake. A few investigators of
temperate forests have noted that isotope uptake does occur through the bark of
some trees, yet there is a paucity of data on tropical species and only very
limited information on the chemical composition of stem-flow liquids.
Nye(57) has measured the quantity of stem flow in Ghana and Voght has
made similar studies on Barro Colorado. Their results indicate that the quantity
of stem flow is dependent on the structure of the canopy as well as the intensity
of rainfall. Of the total rainfall recorded in the open forest on Barro Colorado,
stem flow ranged between 1.6 and 14.6 percent, with the least noted on rough-



Avicennia Rhizophora Mora Prioria Cavanillesia-Bosque
germinans brevistyla oleifera copaifera mixto
Characteristic (Black Mangrove) (Colored Mangrove) (Mora) (Cativo) (Quipo Forest)

Number of trees with
DBH of 10 cm or
Basal area, m
Volume, m

Average volume of
tree, m

Average height of the
canopy, m

Percent cover

Visibility, m




































100 10.7 3.4


--- ----


Salinity 44



In pounds per acre (Percentages of the
nutrient content immobilized in each
vegetation component are given in


191 (10.5)

10 (8.2)

78 (9.6)

130 (5.4)

39 (11.2)


459 (25.1)

30 (24.6)

182 (22.4)

473 (19.9)

64 (18.4)

























-- -- -- --


barked species. Nye reported that the canopy intercepted 0.07 in/rain day, and
an average of less than 1 percent of the total rainfall flowed over stems.
Table 14 is a quantitative analysis of stem-flow liquids collected in a
Haitian cloud forest.(16) The properties of the liquids were described as fol-
lows: pH = 5.7; total dissolved solvents, 102 ppm; and ash content of the dry
solids, 20.4 percent. There were small inclusions of mosses and liverworts in
the liquids. Ammonium nitrogen greatly exceeded nitrate nitrogen (35:1), and
magnesium was 7 times more abundant than calcium. Tests for amino acids, pro-
teins, and reducing sugars proved negative; however, tests for catechol tannins
were positive.
With regard to uptake of ions and organic inclusions in stem flow, the
shift in composition of leachate as affected by abscission of the canopy leaves
in the semideciduous forest will be of interest, since there is a correlation
between the period of leaf fall and an increased capacity of wood to conduct
Besides stem flow and direct input from rain and dust, this compart-
ment will receive contamination by translocation and reabsorption from leaves and
translocation and ion uptake from the root system.
Where growth is seasonal, e.g., in the transitional humid forest, uptake
and fixation can be expected to be greatest during the growing season (June
through December). Moreover, regardless of the forest type, fixation and concen-
tration of isotopes will be associated with the growing tissues (young leaves and
To determine whether contaminants are received via the root system or
foliage will require on-site studies. However, such factors as the availability
of substances in soils, the uptake potential of the roots, and the conductance

of the xylem will determine what compounds are transferred from roots to other
woody tissues. Not to be overlooked is the transportation of photosynthates and
other compounds from the leaves to the phloem and growth sites. Of special
interest are compounds containing potassium or phosphorus, which are known to be
absorbed from the surface of the leaf and translocated proximally.
Once an element or compound is fixed in the woody tissue, it is re-
leased to the other compartments of the system by one of four processes: it is
removed as a leachate, grazed or harvested, contributed to the litter, or trans-
located to other compartments. One important difference between this compartment
and the leaves, petioles, and buds is that the turnover rate of the nutrient




Inorganic ion concentration in liquid
collected from trunk of Eugenia jambos
Ion Ionic Ion Concentration, m moles Molar Ratio












Al -











K +











capital is much slower, and thus any fixed contaminants can be expected to remain
in situ for longer periods.
Presently, only limited and inconclusive information is available on
the contribution of compounds in woody tissue to leachate. Theoretically, any
exudates and water-soluble compounds are potential leachate inclusions.
Harvesting by herbivores and man will account for the major export from
this compartment of volume and weight, and from the forest in general. Of course,
the utility and species composition of the stand will influence the magnitude of
removal by man. The quantity of supportive tissue consumed by herbivores can at
present only be conjectured. In general, tropical forests contain few browsers,
and most of the primary consumers feed on the more fleshy tissues. Of the ani-
mals known to consume woody tissues, deer, rodents, and certain insects are the
most important. Although there are no supportive data, the loss of materials
from this compartment by grazers is probably less in terms of weight than from
the leaves, petioles, buds, and flowers.
Finally, output of mobile materials by translocation is recognized.
Although adequate data on tropical species are wanting, one might expect a net
movement of storage products from the woody tissue to the actively growing
leaves and roots. Of course, the periods of greatest movement will be pronounced
within the seasonally controlled forest and more subtle and constant within the
evergreen and mangrove forests.

(3) Leaves, Buds, and Petioles of the Lower Strata. This compartment
embraces the photosynthetic tissues of vascular plants between ground level and 2
meters, including the leaves and herbaceous materials of herbs, grasses, ferns,
and tree seedlings (strata C and D of Richards) Features of the environment
and characteristics of the foliage that make it distinct from the upper and sub-
canopy level are:
(1) Features of the environment
(a) Narrow temperature range
(b) Higher and more uniform relative humidity
(c) Much reduced sunlight intensity and shorter photoperiod
(d) Minimal air movement
(e) Slightly higher CO2 level than that of air above canopy
(f) Primarily indirect rainfall, received following interception
by upper strata
(2) Morphological and anatomical characteristics of the foliage
(a) Leaves predominantly of the mesophyll size class, but in general
larger than upper-canopy leaves
(b) Leaves darker green, commonly varigated, and more shade tolerant


(c) Many leaves and petioles with pulvini
(d) Leaves less xeromorphic, thinner, and less leathery
(e) Surface texture not glossy, sometimes velvety; drip tips common
(f) Mostly simple leaves, but more compound leaves than in upper strata
(g) Microenvironment and leaf structure optimum for epiphyllae
(h) Gradual leaf replacement
(i) Fewer deciduous species
(j) Low leaf transpiration pressures.
It is anticipated that species diversity, volume, and biomass of this
compartment in the Route 17 area will increase in the following order: mangrove
forests, transitional humid tropical forest lowland, upland, humid tropical
forest, and the very humid tropical forest. A correlation of diversity and rain-
fall is effected. Relative to the foliage biomass in the upper and subcanopies,
the lower stratum probably constitutes only 1/4 to 1/3 of the total. However,
dependent on the season, the lower stratum may contain more biomass because of
the deciduous nature of the overstory.
Input will follow basically the same pathways outlined for the upper
and subcanopy foliage. Within the deciduous forests, e.g., the lowland transi-
tional humid tropical forest where approximately 90 percent of the upper canopy
trees lose their leaves (J. Duke, personal communication), the environment and
susceptibility of the understory will be altered. During this period (January
through April), the quality of input materials will be very similar to that of
those received by the upper strata. Differences in the quality of the input
material will be governed largely by the compositional change in rainwater as it
flows over the upper foliage and dissolves and suspends exudates and dust
particles. The abundance of epiphyllous vegetation in this compartment adds to
the effectiveness of the foliage to filter incoming contaminants.
Pathways of export are expected to be similar in mode to the upper
foliage, although the types of grazers and amounts consumed will vary, especially
as the lower foliage is consumed by the larger herbivores. Utilization of under-
story foliage by insects is about twice that found in the upper canopy.
De la Cruz(17) found the percentage of utilization in a Costa Rican forest was
between 1.85 and 4.78 percent, whereas estimates for Puerto Rico was somewhat
higher at 8 percent.

(4) Roots. This section is concerned with all the below-ground living
woody and herbaceous tissues of trees, shrubs, and herbs. The pneumatophores of
mangrove species and roots that lie on the soil surface (except buttresses) are


As shown in Table 10, roots constitute between 14 and 40 percent
(28,000 to 48,000 lb/acre) of the standing-crop biomass. Generally, the weight
of roots exceeds that of leaf and branch material combined. )Annual produc-
tion estimates of roots have been placed at 2,300 Ib/acre by Greenland and
Kowal(24) for a successional tropical forest. The standing-crop biomass and
annual production estimates suggest a turnover time between 10 and 20 years,
which suggests that this compartment is important in biogeochemical cycling. In
general, roots in tropical forests, especially under moist conditions, are dis-
tributed primarily in the upper horizons. Roots greater than 1 inch in diameter
contribute most to the total biomass of the compartment, yet they differ markedly
in nutrient content when compared to smaller roots (see Table 15).(24)
Tables 13, 15, and 16 summarize available data on nutrient content of
roots in three tropical forests. Of the six elements, N, K, P, Mg, Ca, and Na,
N is the most abundant. In forests with a large number of leguminous plants, a
greater concentration of nitrogen would be expected. Calcium, Mg, and K are
about equal in weight per acre and also as a percentage of the dry weight. Phos-
phorus, as shown in Table 15, is found most abundantly in smaller roots (i.e.,
those with rapidly growing tissues). The potassium substitute, Cs, also con-
centrates in actively growing tissues. In Puerto Rico, 32P content of roots was
equal to or higher than that of mature leaves, but less than that of the decom-
(42) 32
posing leaf matter in contact with roots In addition, P was absorbed by
roots at or near the surface, and movement was rapid, which resulted in a low
concentration of phosphorus.
In tropical forests, where roots are often limited in distribution by
strong competition for oxygen and nutrients, the upper soil horizons are densely
matted with roots. Whether root grafting is as frequent in the tropics as it is
in the temperate forests is unknown; if so, the effects of root grafting on the
translocation of radioisotopes may be of considerable importance.
Because of the positioning of this compartment within the soil sub-
strate, the composition of the environment and subsequent input will differ from
those described in the preceding sections. Incorporation of nuclear by-products
is expected to enter by one or all of the following means: translocation from
other plant parts (especially leaves), root absorption, and root adsorption.
Again, detailed studies of nutrient uptake and movement in tropical species are
wanting. However, one might expect tropical plants to behave like temperate
species. Thus, the specific requirements of the plant and such properties as the


Mean Root
Diam., in.

Dry Weight,

Nutrient Composition, perce

nt by weight Nutrient Content, Ib/acre
Ca Mg N P K Ca Mg

0-1/4 4,450 1.37 0.079 0.56 0.88 0.10 61 3.5 25 39 9.0

1/4-1/2 3,850 1.19 0.074 0.58 0.78 0.18 49 2.9 22 30 9.6

1/2-1 5,210 0.91 0.048 0.48 0.68 0.05 47 2.5 25 35 13.6

>1 8,590 0.41 0.014 0.07 0.30 0.08 34 1.2 6 26 7.2

Total 22,100 191 10.1 78 130 39.4




Part of Total P as Avail- Exchangeable Exchangeable Exchangeable Total
Vegetation N able P04 K Ca Mg C

Total vegetation 2.6 0.093 0.72 0.96 0.95

Roots 24.7 1.14 7.4 17.7 8.5 4.0


_ __ __ __ __
__ __ __


pH, cation-exchange capacity, field capacity, and texture of the soil will affect
uptake and deserve special attention.
With respect to output, roots are important contributors to the total
radioactivity of the soil.(42'87) Root die-off and leaching were determined to
be major sources to soil. Grazing on this compartment is anticipated, but in
minor quantities. A few large herbivores are known to consume roots, including
man, who uses some tubers and roots for medicinal purposes as well as for a sup-
ply of water and food. If the soil and litter become a nuclide sink, i.e., a
trap for contaminants, as has been suggested 63), the proximity of roots to this
pool and subsequent uptake will also be a major pathway in nutrient recycling.
Since roots function not only as nutrient and water ways but as stor-
age organs, their potential as concentrators in tropical forests needs to be
examined. This has been exemplified by a white oak forest, where the concentra-
tion of radioactivity in roots was 1 to 68 times as high as in the surrounding
litter and soil.(87)
In seasonally wet and inudated forests, availability of water will
exert a major influence over nutrients dissolved and incorporated by root
systems. In the very humid forest, where roots are superimposed upon the soil
surface, the role of roots as filters for absorbing inorganic and organic com-
pounds is a potential area of heavy concentration.(34)

(5) Fruits and Seeds. Seed production in tropical forests may occur
regularly through the whole year, several times a year, or only once every few
years. In Trinidad, 75 percent of the trees in the climax tropical forest fruit
during the dry season when they are bare of leaves.(8) The seeds in these
forests are normally large, and as a result are dispersed more by birds and mam-
mals than by wind. In contrast, the secondary forests produce their fruit
throughout the year.(72) The seeds are more abundant than in the well-developed
forests, and their smaller size is adapted for wind dispersal.
Fruits used directly by man are derived more from secondary forests, as
they are more varied and abundant there than in the climax forests. However, a
number of animals may provide links in a food chain leading from this compartment
to man in both the secondary and climax forests. The nutrients from any fruits
and seeds not used by man or animals will be recycled through the litter com-
partment. The concentration of readily available nutrients by this compartment
may be a source of C 32 6), 5Zn9 and certain other elements(15)
that could be a hazard to man. While the quantities of certain isotopes of
rubidium, cesium, and several other elements were lower in fruits than in other


parts of the plants 20,61), the brazil nut was found to have 100 times as much
90Sr as do plants in general68. The seed kernel itself appears to contain less

radioactivity than do corn husks and wheat chaff35. This may be related to
surface absorption of isotopes89); however, the seeds of cacao were found to
contain more P than the pericarp(56). Thus, absorption and translocation are
probably the two main sources of radioactivity for fruits and seeds. Adsorption
may also play a part, but it is probably less important than in other compart-
ments because of the reduced surface area relative to volume.

(6) Litter. Traditionally, litter has been defined as the uppermost
layer of unaltered dead plant and animal materials overlying mineral soil; the
layers immediately underlying have been designated the fermentation and humus
layer For this study, it has become necessary to include all three layers
in the litter compartment and in addition, any dead plant or animal material
standing erect or attached to trees. Thus, all dead and dormant organic
materials that are readily distinguishable as to origin and easily separable from
the mineral soil are considered litter, or, perhaps more descriptively, detritus.
Briefly, a few members of this compartment are the dead or fallen leaves, twigs,
branches, boles, bark, roots, flowers, seeds, fruits, epiphyte fragments, ani-
mals, and all the living microorganisms restricted to this compartment which
derive their energy from these materials.
Depending on vegetation type and seasonal effects on litter production
and decomposition, the bulk of the litter biomass may either be located immedi-
ately overlying the mineral soil, standing erect, or attached to trees. By
comparing abundance and distribution of litter in Mora and mangrove forests with
that of the transitional humid tropical forest, some differences may be noted.
The mangrove forests are practically void of ground-litter accumulations through-
out the year, although there is a continual litter fall and a significant amount
of dead material standing in the system. Within the transitional humid forest of
the Chucanaque valley, litter does accumulate and is greatest during the early
months of the dry season. During the latter part of the wet season, ground lit-
ter is expected to be minimal, the mass of detritus being located aboveground.
In the forests that have a more evergreen nature, i.e., those that are ever-
growing with a constant leaf replacement and twig growth (not seasonally
influenced), the distribution of detritus should be more uniform. Forests of
this type are generally very moist and optimal for litter decomposition so that


large accumulations of ground litter do not occur. Hence, reports of litter bio-
mass are often misleading unless some information on seasonality is provided.
Tables 10 and 17 summarize the available data on litter in tropical
forests. On the average, 19 percent of the total forest biomass (oven dry
weight) is in the form of dead branches and leaves. The branches constitute
about 19 percent of the total (Table 17). In terms of weight, an average tropi-
cal forest has a standing-crop biomass of approximately 228,000 lb/acre oven-
dry weight, with up to 41,000 Ib/acre of the total as litter.(66) The values in
Table 17 are averages and fail to reflect the variation in litter among various
tropical forests, but are useful as a basis for comparison. Table 10 emphasizes
the variation in standing stock of detritus for two African forests, which ranged
from 20,500 to 88,900 Ib/acre.(57) Measurements of leaf detritus in four dif-
ferent forest ecosystems in Costa Rica indicated a range between 2,300 and 13,380
b/acre (17), the lowest values representing the tropical moist forest, where con-
ditions were optimum for decomposition, and the higher values representing drier
seasonal forests.
As weight and vertical distribution of detritus are expected to vary
among vegetation types, so is the composition. Variation will depend primarily
on species diversity, degree of stratification, life forms, annual production,
time of fruiting, and grazing. The average composition of litter has been
reported as follows:
Leaf 60-76%
Fruit 1-17
Branches 12-15
Bark 1-14
Other (flowers, bud scales,
epiphyte fragments,
and insects) 1-25

These percentages point out the variability in composition types and also the
importance of leaf material. In tropical climates, nonleaf litter generally
makes up 27 to 31 percent of the total.
As mentioned, litter production in many forests is seasonal, yet few
studies have dealt with determining annual input by months or seasons. Measure-
ments of monthly leaf and fruit fall in the El Verde forest of Puerto Rico show
that during April, May, and June leaf fall is about twice that of the remaining
months, when leaf fall is relatively constant at 1 g/m2 /day (8.9 Ib/acre/day) (84
Fruit fall ranged between 0.1 and 0.4 g/m2/day (0.89 to 3.56 Ib/acre/day).
Studies in a tropical lower montane wet forest between July and August
showed an average rate of leaf fall of 6.6 Ib/acre/day(17)


Pounds Per Acre

Branches and Understory Dead Branches
Leaves Leaves Roots Plants and Litter Total

Minimum 2,228.5 47,600.8 14,084.1 178,280.1 17,471.4

Maximum 22,641.5 245,313.4 78,888.9 1,069.7 68,905.2 416,818.9

Average 9,181.4 133,442.7 39,043.3 3,654.7 42,787.2 228,109.4

Average as Percent of

Total Biomass 4.0 58.5 17.1 1.6 18.8 100.0

(a) Adapted from Ovington.(66)

(b) Eight stands of a mixed tropical rainforest.


Rates of decomposition are important especially with regard to turn-
over of organic materials and release of nutrients to the soil. To determine the
rate of decomposition, the formula A x dT = kL x dT was derived, where
A = litter fall per annum
L = amount of litter on the floor
k = is the annual decomposition constant
dT = small time element.

The annual decomposition constant of litter in moist evergreen forests in
Colombia was 40 to 60(31) and 76 for the moist evergreen forest in Yangambi.(36)
The rate of decomposition in an old secondary forest in Ghana was determined with
this formula to be 1.3 percent/day( which is considered a very high rate.
Other estimates include 0.20 to 0.35 percent/day in Puerto Rico (84) and 50 per-
cent in 35 days for forests in Costa Rica.
Relatively few data are available on the animal inclusions in litter.
Table 18 summarizes the classes and average number of soil organisms found in the
El Verde forests.(84) The most common litter organisms include mites, collembola,
diptera, millipedes, insect larvae, snails, spiders, pseudoscorpions, ants, ter-
mites, bugs, and numerous microbial populations. Common microbial constituents
of the Costa Rican forests include Flavobacterium, Pseudomonas, Salmonella, and
Litter and soil function significantly in the turnover of organic
materials and the cycling of nutrients. The nutrient content of litter inclu-
sions of a tropical forest in Ghana are shown in Table 19. The nutrient content
of various litter fractions shows that the dead wood is the poorest in all nu-
trients per unit weight, especially phosphorus, nitrogen, and potassium. The
fresh leaf fraction is richer than the forest-floor litter in all elements
listed. A number of authors have noted a rapid release of many of the nutrients
shortly after leaves are contributed to the forest floor.
The addition of elements to the soil and litter layers comes from five
sources: direct rainfall, rain wash (leachates), leaf fall, timber fall, and
root die-off. Table 20 shows the sources of element addition to the soil and
litter. Leaves noticeably add the greatest quantity of the nutrients, and
lesser amounts are derived from rain wash and timber fall, which are almost
(7) Soils. The soils of the proposed routes will contain a great
variety of elements since they are a heterogenous mixture resulting from the



All values are per 100 cm.

Organism Area 1 Area 2

Acarina (mites) 208.6 191.6

Chelonethida (pseudoscorpions) 3.7 3.1

Collembola 15.7 14.4

Hymenoptera (ants) 19.9 0.0

Isoptera (termites) 5.7 0.0

Other insects 7.2 11.9

Myriapoda 3.4 5.9

Araneida (spiders) 0.6 0.6

Other arthropods 1.9 1.9

Homoptera 3.7 7.6


N P K Ca Mg

Fresh Litter

Kade, Ghana (Moist tropical mixed spp.) 1.90 0.069 0.65 1.99 0.43

Yangambi, Congo (Moist tropical, mixed spp.) 1.80 0.066 0.39 0.85 0.43

Fresh Litter Leaf Fraction Only

Kade, Ghana 2.10 0.087 1.00 2.02 0.54

Eastern United States 0.68 0.14 0.65 2.07 0.35

Litter on Forest Floor

Kade, Ghana 1.54 0.057 0.45 1.98 0.24

Dead Wood

Kade, Ghana 0.32 0.026 0.05 0.73 0.07


weathering of folded parent rocks with subsequent mixing, sorting, and movement
by wind and water. The number of elements and the quantity of each will vary
considerably from soil to soil, depending on the origin and composition of the
parent materials.
The soils of Darien Province have been derived from igneous and sedi-
mentary rocks. The bulk of the rocks of the Route 17 area are sedimentary,
according to the geologic report on the region
.. ..-. -. The area consists of folded beds of limestone, sandstone, and
shales. The highly folded nature of the rocks adds to the diversity of these
Detailed studies on the soils of the area are lacking, but it is
possible to anticipate classes of soils that may be found in the areas of the
proposed routes. The anticipated textural classifications based on the described
geologic formations are given in Table 21. In general, texture of the soils
can be expected to range from silts through clays. The texture of surface soils
will be modified by the amount of organic matter present, while the subsoils
will be medium to heavy textured. Drainage may be restricted in the case of
heavy-textured subsoils.
The soils of Darien have been placed in a broad category described as
hilly, low mountain soils (Atlas of Panama). A translation of the description
is as follows:

Pounds Per Acre Per Annum

Oven- Dry
Source of Element Weight of Material N P K Ca Mg
Litter fall 9,400 178 6.5 61 184 40
Timber fall ca. 10,000 32 2.6 5 73 7
Rain wash 11 3.3 196 26 16
Total 221 12.4 262 283 63



Rock Type


Clayey limestone

Sandy limestone

Cherty limestone


Textural Classification

Clays and silts

Clays and silts

Loams and silt loams

Stony or gravelly loams

Silt loam to heavy loam


Frequently reddish
topsoil and/or

Red to yellow soil
depending on
hydration state

Sandy shale


Coarse grained

Fine grained

Basement Complex

Igneous agglomerate

Sandy loams

Coarse sandy soil

Silt loam to loam

Sandy loams to clay loams

Heavy clay soils

Red to yellow soil
depending on
hydration state

Red to yellow soil
depending on
hydration state


__ __ __ __ __ __ ___ __


- --
- --- -- -I ---


There is a great diversity in the characteristics of the soils
that are found where the slope varies between 10 and 40 percent and
the elevation is less than 800 feet. The predominant soils are red-
drab [red-brown?] or grayish, moderately friable, ranging in depth
from 3 to 6 feet. The surface is covered with a fine, superficial
layer, rich in organic matter. In areas of limestone and shale or
on steeper slopes, the soils are darker, more plastic and thin.
The texture of the subsoil is clayey, generally stoney, and contains
mottles ranging in color from gray to yellow, red and brown. These
soils are moderate to strongly acid and of low fertility.

The chemical composition of parent material varies considerably, and
hence the chemical composition of soils formed from the weathering are also
expected to vary. To illustrate the abundance of naturally occurring elements
in various rocks, examples of rock compositions are given in Table 22.(2) The
abundance of calcium, magnesium, and potassium in sedimentary rocks are essen-
tially the same as those reported by Emerson.
The elements listed in Table 22 all have naturally occurring radio-
isotopes, with the exception of barium and strontium. All are gamma emitters
with the exception of 48Ca, 147m, 148Sm, Sm, and Re. Thorium-232 and
U and their associated daughter products may be found in soils throughout the
world. Radium-226 was given attention as a soil constituent as early as 1914(55)
Recent work by Lowder(40)showed that 226Ra can be found in the various soils of
the United States, and it has been clearly shown in the soils of Darien Province,
(34)40 226
Panama.(34) The quantity of the naturally occurring radioisotopes K, 226Ra,
and 232Th in the top 6 inches of soil have been reported to be of the order of 1
0mc/acre(50) The amount of 90
to 10 mc/acre. The amount of Sr was reported to be of the order of 0.01
to 0.1 mc/acre of plow layer.(1) The strontium content of soils is approximately
0.02 percent, about 1 percent of which is present as exchangeable cation.(52)
137 90 95
The activity levels of man-made isotopes of 137Cs, Sr, and Zr are
present in much lower concentrations in soils than some of the naturally occurring
radioisotopes. The gamma spectral scan(34) of the tropics would suggest that
fallout fission products would have to be increased severalfold to equal the
amounts of naturally occurring radionuclides now present in soils, and in fact,
quantitative resolution of introduced radionuclides may be difficult unless
elaborate separation techniques are employed.
Strontium-90 has received the greatest attention of the man-made iso-
topes. Data based on the results of worldwide soil sampling in 1958 showed
highest deposition of Sr in the north-temperature latitudes and lowest in the
equatorial regions. Deposition increased slightly with latitude in the southern
hemisphere(2). A summary of these data is presented in Table 23. Two of the


Parts Per Million

Eat' Crust -

Earth's Crust

2.6 x 104

3.6 x 104

3.1 x 102

3.0 x 102

2.5 x




1.1 x 104

3.9 x 104

2.7 x 102


1.7 x















2.7 x 104

2.2 x 104

3.0 x 102

1.7 x 102

4.6 x














2.7 x 103

3.0 x 105


4.0 x 102
8.0 x 10

1.2 x 102

5 10




_ __ -_ _~



Latitude Strontium-90, mc/mi2

80-70N 7.8

70-60N 24.2

60-50N 26.4

50-40N 34.8

40-30N 25.8

30-20N 29.8

20-10N 10.5

10-ON 5.8

0-10S 6.8

10-20S 4.6

20-30S 6.1

30-40S 7.8

40-50S 9.6

50-60S 9.2


sampling sites in the equatorial regions were in the Panama Canal Zone, one at
Fort Clayton and the other at Fort Amador. The levels of Sr were 9.0 and 7.1
mc/mi.2 The values, at Bogota, Colombia, and Caracas, Venezuela, were 4.7 and
90 2
5.2 me of Sr per mi respectively.
Limited information is available on the vertical distribution of 90Sr
in soils. Vertical distribution may be restricted, as suggested by the work of
(2) 90
Alexander et al.(2) The study reported on the movement of 90Sr in two sandy
soils, one from Illinois and the other from Georgia. It was found that the
greatest amounts were retained in the 0 to 2-inch layer, with 1 percent or less
reaching the 6 to 12-inch layer. Russell, working in England, found that the
living root mat of permanent pastures was very effective in intercepting 90Sr
before it reached the soil.(2) In both studies, the work was done on vegetated
and undisturbed soils.
The top 2 inches of soil may serve as a "sink" for radionuclides, as
indicated by the work of Johnson et al.(32) In a study on the transfer of fall-
out Cs from soil to dairy-cattle feeds, it was found that absorption from the
soil was unimportant. The upper 2 inches of soil from a permanent pasture was
collected and taken to a greenhouse for plant-uptake studies. It was stated
137 2
that the cumulative fallout deposition of Cs was 80,000 pc/mi Corn grown in
the contaminated soil in the greenhouse for 45 days was harvested and analyzed
137 137
for Cs by gamma-ray spectrometry. No Cs was detected in the plant
material. By comparison, corn plants growing in local fields contained 1500
pc/kg of plant material. Thus, it was concluded that uptake from soil was
negligible and that foliar absorption from contaminated rainout was responsible
for the contamination of the standing crop. A similar soil-uptake response was
noted in a Puerto Rican experiment.(34)
The composition and amount of colloidal material in the soil will deter-
mine to a great extent the absorption, retention, and release of radionuclides in
the soil system, and hence, the cycling of radionuclides. The colloidal fraction
is the center of the ion-exchange phenomenon in soils and is divided into the
inorganic and organic fractions. The inorganic fraction is composed of the
various silicate minerals and the hydrous oxides of iron and aluminum. The
organic fraction is the humus or organic matter. The colloidal system may be a
mixture of these various colloids, and quite frequently one particular type of
silicate mineral will be dominant. The various colloids have one property in
common which is of importance in the retention and cycling of stable elements
and radionuclides: cation exchange. It is here that the nature and quantity


of the colloid present in the soil becomes important. The cation-exchange
capacities of the various colloids are as follows:

Cation-Exchange Capacity,
meg/100 g dry material
Type of Colloid Range Average
Organic matter 150-300 200
Montmorillonite 80-120 100
Illite 15-40 30
Kaolinite 3-15 8
Hydrous oxides 4

These values are based on 100 g of clay or organic matter. In actual
soil, the percent clay will vary over a wide range, and the amount and type of
clay will affect the exchange capacity of the soil. This is shown graphically
in Figure 4. Where the dominant colloid in the soil is kaolinite or hydrous
oxides, such as in the lateritic soils of tropical regions, each percent in-
crease in the organic-matter content of the soil will add considerably to the
cation-exchange capacity of the soil system. As a general rule, for each 1
percent increase in the organic-matter content, the cation-exchange capacity
may be increased by 2 meg/100 g of soil. Thus the first 2 inches of soil may
take on a dominant role in the interception, retention, and cycling of radio-
nuclides, as this is the region in the profiles where the highest concentration
of organic matter occurs.
The effects of plant residues added to the soil and the uptake of Sr
have been studied to some extent. The Sr concentration in plants was reduced
to 20 to 40 percent of that on untreated soils when dried and ground lettuce
leaves were added at the rate of 10 g of leaves for 100 g of soil.50

(8) and (9) Epiphytes and Epiphyllae. For the purposes of this study,
epiphytes and epiphyllae are defined as plants that grow perched upon larger
plants, which lend them support and serve as a source of nutrients. These two
types of plants have previously been categorized on the basis of size into macro-
scopic forms (epiphyllae and vessel-bearing plants, or vascular epiphytes) and
microscopic forms (microbial epiphytes). They will be defined in this report on
a functional rather than a size basis, and termed simply epiphytess" and "epi-
Both types occur in similar environmental conditions of constantly high
humidity and shade(70), but become different with respect to potential inputs to
food chains. When a grazer consumes epiphyllae, not only is the epiphyllae




= 80

S70- Montr

Z 60

c 40

c 30


10 Kaolinite

10 20 30 40 50 60 70 8(

Percent Colloidal Material In Soil

noril lonite



0 90 100


consumed but also the leaf upon which it was perched; this confounds or in-
creases the complexity of the food web. Consumers that selectively graze on

young, growing leaves will exclude epiphyllae from their diets, but more general
grazers will consume more varied leaf types and will include epiphyllae. Epi-
phyllous growth is more prevalent on subcanopy vegetation( and consequently
could serve as an important nuclide input source, particularly to large grazers
on the forest floor.
The plants are distributed vertically in patterns, with the more
light- and desiccation-tolerant species occurring in the upper canopy. The
separation of the forest into upper and lower canopy also separates these groups
by species and functions.
Succession patterns for epiphytes and epiphyllae are generally pre-
dictable; the time since forest disturbance is an important factor for epi-
phytes succession and the age of leaves is an important factor for epiphyllae
succession. Epiphyllae tend to become best developed on understory leaves that
persist for more than 1 year. The first invaders are microbial nitrogen-fixing
organisms and bacteria(71). With increasing excretion of substrate materials
from leaves at leaf maturity when the leaves are more easily leached by water,
colonization by other microorganisms and multicellular organisms occurs. The
first bacteria are oligotrophic; they are followed in sequence by algae, yeasts,
and lichens, plus flagelates, amoebae, myxomycetes, and ciliates, and sometimes
by arthropods, liverworts, mosses, ferns, and phanerogams.
These perched organisms are important in elemental cycling in forests
for several reasons. First, many of the organisms fix nitrogen, especially the
epiphyllae; consequently, they may play an important role in the nitrogen
metabolism of the forest system(71). Second, these organisms are efficient at
assimilating and storing nutrient elements that come into the forest in rainfall
and also nutrients that become dissolved in rain. Third, the absorption of
input and dissolved, leached nutrients results in a lag in the rates at which
elements are cycled in the system. Fourth, the position of epiphyllae on the
upper surfaces of leaves and of epiphytes on stems results in a roughened sur-
face that could significantly affect the interception and retention of parti-
culate particles in fallout dust and rain. As in the case of retention of dis-
solved elements, an important time-lag function with respect to the time elements
reach the forest floor and soils compartments would occur.
Bromeliads, for example, are particularly well adapted to interception
and storage of materials from above, in that divergent leaf bases hold large


amounts of water and that nutrient uptake from the contained water is efficiency.
Also, the fibrous root material enhances the ability to accumulate fallout
materials from runoff.
From works already performed in the Panama project area, gamma spectro-
metric analyses indicate that plants of epiphytic habit have a markedly higher
144 137
content of 144Ce and 137Cs than other kinds of living plants.
It is felt that these two compartments in the terrestrial system
(based on studies of other nuclide-contaminated experimentation and field obser-
vations) will pose most interesting situations with respect to movement and
storage of fallout materials.

(10) Animals. In keeping with the scheme of compartmentalizing the
biotic segments of the forest ecosystems by function, all animals (excluding
soil-litter organisms) are treated as a unit. As noted, autotrophs vary signi-
ficantly in their effects on the flow of radionuclides, and similar trends are
anticipated among heterotrophs. To cope with the complexity of the faunal seg-
ment, organisms of similar feeding habits, regardless of taxa, are considered
to be more functionally alike than organisms of closely related species with
different feeding habits. Tentatively, the following categories and subcate-
gories are considered to group animals of similar function:

Herbivores Sanguivores
grazers bats
frugivores ticks
nectivores mosquitoes
granivores flies
exudavores Omnivo
flesh eaters
carrion eaters

Further categorizing may be necessary, depending on the quality of foods
removed from the various strata. Difficulty is anticipated in determining the
origin of foods to animals of high mobility, such as the scansorial (climbing)
and flying vertebrates and invertebrates, which traverse a number of strata.

Large ground birds and mammals and other more restricted or sedentary animals
will not pose this problem.
One advantage of considering the animals of similar feeding habits
as a category is that the quality of potential internal contaminants will be
basically homogeneous in composition. For example, bats and insects feeding on


the same fruit are theoretically exposed to the same kinds of contaminants.
Discrepancies in the products assimilated and fixed are anticipated because of
differences in assimilation, specific metabolic requirements, and biological
halflives. However, differences between the levels of contamination in the two
unrelated groups should be small compared with those of organisms of the same taxa
that feed on different kinds of materials.
It is clear that most of the large vertebrates are representative of
the third and fourth trophic levels. The very large and the very small animals
are primarily herbivorous.
Tropical forests, as a rule, are well stratified, especially botani-
cally. Highly mobile animals, on the other hand, complicate the neat botanical
stratification, but there are some general trends in the distribution of animals.
The distribution and food habits of the birds and mammals in a Malaysian and
Australian tropical rain forest have been summarized as follows(26)
(1) Upper air community: birds and bats that hunt above the
canopy; mostly insectivorous, but with a large proportion
of carnivores

(2) Canopy community: birds, fruit bats, and other mammals
confined to this zone, predominately feeding on leaves,
fruit or nectar, but with a few insectivorous and mixed

(3) Middle-zone flying animals: birds and insectivorous bats;
predominately insectivorous, with a few carnivores

(4) Middle-zone scansorial animals: mammals that range up
and down tree trunks, entering both the canopy and ground
zones; predominately mixed feeders, with a few carnivores

(5) Large ground animals: large mammals and rarely birds
living on the ground without climbing ability, but of great
range, either by reaching up into the canopy or by covering
a large area of the forest; plant feeders, feeding largely
by browsing on leaves, but exceptionally feeding on fallen
fruit, or rooting for tubers, etc. (pigs), with attendant
larger carnivores

(6) Small ground animals: birds and small mammals, capable of
some climbing, which search the ground litter and the lower
parts of tree trunks; predominantly either insectivorous
or mixed feeders, but with a fair proportion of vegetable
feeders, and some carnivores.

The majority of invertebrates and lower vertebrates, in both numbers and
species, live near the ground rather than in trees.(3) As noted earlier, litter


organisms are abundant in numbers and species and form a community with a highly
developed trophic structure.
Variations in the complexity of food webs will vary considerably
between the less diverse mangrove types and the more complex upland and moist
forest. Concomitant with change in the forest structure (development of the
various strata and litter layer), there are changes in the diversity and com-
plexity of the fauna. The mangrove forests, which are basically simple botani-
cally and faunistically, are interesting in that a few well-developed food chains
exist, with several of the products leading to man.
In denser forests, where the litter compartment is well developed,
and assuming that a large amount of the long-lived nuclear by-products will con-
centrate in the litter and soil, those large organisms that derive their energy
from this area also deserve special attention. Among these are the armadillos,
peccary, feral pigs, anteaters, predaceous ground birds, and mammals.
Contamination of this compartment is of two types: internal and exter-
nal. In general, external contamination by inhalation or the settlement of
particulate matter on the animal will be of minor importance, except immediately
after detonation. Internal contamination from the consumption of contaminated
plant tissues or ingestion of soil is of major importance.
Output pathways from this compartment include: excretion, death,
secretion, molt, natural decay. Affecting both the input and export of con-
taminants from this compartment will be such factors as physical half-life,
biological half-life, bioelimination rates, rates of consumption, turnover
rates, periods of animal activity, mobility of nuclides, absorption and adsorp-
tion qualities, localization, and time and distance from detonation. One- and
two-compartment models have been developed for the movement of materials through
food chains, and the major problems of defining and measuring input variables,
and of estimating biological half-lives, unexplained compartmental losses, dis-
tribution of sample data, and importance of physicochemical state of fallout
have already been reported(194546475981)

Inputs: Fallout and Rainout

The two major sources of input to the terrestrial system will be rain-
fall and the deposition of particulate matter (fallout) on the foliage. Limited
information is available on annual rainfall and rainfall distribution throughout


the area of study. Various reports suggest that annual precipitation may vary
from 70 in/yr on the Pacific side to approximately 130 in/yr on the

Caribbean side. Increased amounts of rainfall are expected at the higher eleva-
tions. Two stations that have collected rainfall data are La Palma on the Pacific
and Naragana on the Caribbean (Table 24). These data suggest that the duration
of the dry season may vary from 2 months on the Caribbean coastal area to 3
months in the La Palma area. The rainfall is relatively uniform in amount for
the wet season months.
Foliar applications have been used for some time to correct minor ele-
ment deficiencies in plants. Radioisotope studies have confirmed that foliarly
applied materials can be absorbed, translocated, and utilized by plants. Studies
on the absorption of radioisotopes from diluted solutions indicate that greatest
uptake occurs in the first 24 hours after application 10'13) and that moisture
conditions on the leaf surface affect the amounts of P absorbed from foliar
applications. 10) Moist leaf surfaces absorbed 43 percent of the foliar applied
P during a 12-hour period versus 23.5 percent absorption by dry leaves during

the same time interval. Studies with the radioisotopes 42K, 5Fe, Zn, 32
and 35S have shown that these elements can be absorbed by the bark of fruit
trees and that they contribute to the nutrition of the underlying areas.8
The deposition of radionuclides by rainout is here considered a method
of foliar application. Cleansing of the atmosphere of particulate matter in the
zone of precipitation is assumed to be fairly complete with 0.1 inch of rain.(37)
The fate of radionuclides from rainout will be governed to a great extent by the
intensity, duration, and frequency of rainfall rather than total annual rainfall.
Studies on foliar absorption suggest that the percent material absorbed may be
linear for the first 24 hours(10'13) hence the residence time of a contaminated
solution on the foliage is of importance in foliar absorption. If it is assumed
that Libby's figure of 0.1 inch of rain is sufficient to cleanse the atmosphere,
then a rainfall in excess of this will result in the greatest percentage of the
material's being transferred to the litter layer.
In a review on the retention of rain by vegetation 54, data were
presented from Surinam on the amount of rainfall retained by the canopy. This
information is presented in Table 25. The authors state that these figures are
in general agreement with data from the Belgian Congo and other countries and
suggest that in a tropical forest only about three-fourths of the annual rainfall
reaches the soil. Considering a 0.1-inch (2.5-mm) rain, Table 25 suggests that
only 48 percent will be retained by the canopy. Thus, it is possible to postulate



La Palma Naragana
Monthly Percent Monthly Percent
Rainfall, of Annual Rainfall, of Annual
Month in. Rainfall in. Rainfall

January 0.5 0.7 3.5 3.61
February 0.0 0.9 0.93
March 0.8 1.00 0.7 0.72
April 3.6 4.93 3.6 3.72
May 7.1 9.72 13.8 14.24
June 8.9 12.19 8.5 8.77
July 9.3 12.73 11.3 11.66
August 8.5 11.64 9.9 10.22
September 8.7 11.91 8.7 8.98
October 11.1 15.20 11.3 11.66
November 9.7 13.28 15.3 15.79
December 4.7 6.43 9.3 9.60

Total 73.0 96.9



Rainfall, mm: 1 2.5 5 7.5 10 15 20 30 40

Amount Retained
in the Canopy, mm 0,8 1o2 1.6 2.0 2.5 3.2 4.2 6.0 7.8

Retention 80 48 32 26 25 21 21 20 19.5

that as the intensity and duration of rainfall increases, the amount of radio-
nuclides absorbed by the foliage decreases and the amount reaching the forest
floor increases.
The next consideration is given to the deposition of particulate mat-
ter in the dry state on the surfaces of the foliage. Many factors, such as
particle size, type of leaf and nature of leaf surface, aspect of the leaf, and
moisture status of the foliage, will determine the fate of particulate matter
deposited on the foliage. For foliar absorption to take place, the particulate
matter has to be placed in solution; hence, rainfall becomes important. Once
in solution, the material can be treated as a foliar application and the same
factors governing uptake by foliar application will again be applicable.
It has been reported that approximately all of the particulate matter
can be removed from leaves by washing with distilled water.(53) Grass-clover
90 137
mixtures were sprayed with solutions containing 90Sr and Cs and then exposed
to rain at intervals of 1, 4, and 20 days after contamination, and it was found
that rain removed 60 percent of the radioisotopes, regardless of the time inter-
val between spraying and rainfall.60 In a study with bean plants, it was
found that only 6 ml of water were required to remove 90 percent of the residue
remaining after the application of one drop of labeled P solution to the upper
surfaces of bean leaves.(13) Foliar-uptake studies using 22Na, Cl, S, and
55-59Fe indicate that the rate of absorption varies greatly for each of the four

elements (13) Sodium-22 was more readily absorbed, followed by 36C, S, and
Fe in decreasing order of absorption.
Bukovac and Wittwer(13) have classified elements on the basis of rela-
tive mobility in the bean plant following foliar absorption; these are listed in
Table 26. This ranking of elements is considered to be approximate by




Mobile Partially Mobile Immobile

Rubidium Zinc Magnesium
Sodium Copper Calcium
Potassium Manganese Strontium
Phosphorus Iron Barium

Chlorine Molybdemum

(a) The elements are listed in order of decreasing mobility.

Biddulph(10) because conditions of application were not comparable and lack of
control over moisture conditions during the tests may have affected the uptake

Forest Products Used by Man

I. Output of the Natural Terrestrial
Environment to the Cuna Indians*

Most of the vegetable products eaten by the Cuna Indians are now cul-
tivated. Hunting has become secondary in some areas with the availability of
purchased food and the use of domestic animals. The following game animals are
hunted to supplement the diet:


Food Habits
Herbivore (browse-leaves, stems)
Herbivore (seeds, nuts, fruit)
Herbivore (leaves)

* Reference sources for the section on forest products used by man are References
(4), (5), (23), (39), (43), (48), (67), (73), (74), and (75), and a report of a
trip to the Route 17 area in October, 1966, by George Child.


Mammals (Contd.)

Spider monkey
Capuchin (white-faced monkey)
Coati mundi


Macaw and other parrots
Wild turkey
Pigeons and doves

Food Habits (Contd.)

Herbivore (leaves, roots)

Herbivore (leaves, roots)
Omnivore (mostly vegetarian)
Omnivore (mostly vegetarian)


(nuts, seeds)
(fruit, seeds)
(nuts, seeds)

(fruit, seeds)

Sea turtle
Iguana and eggs


Land crab

Herbivore (marine vegetation)
Omnivore (vegetation, insects)

Herbivore (also detritus)

Herbivore (and detritus)

The preparation of food may have direct bearing on the possibility of
contamination with radionuclides not found in the food itself. Meat and fish
are usually roasted or boiled for meals and smoked for storage. The wood fires
used for cooking permit particles of smoke to come in contact with the food.
Bananas, plantains, and tuberous roots are baked.
Certain wild plants are encouraged to grow, although they are not cul-
tivated. Some of these products are used for purposes other than for food:

Ivory palm edible root substance
Pijibay or pezebae (Guiliema utilis or G. gasipaes) a palm with a
mealy-textured fruit which grow in clusters


Building materials
Cocobolo (Dalbergia sp.)
Cacique (Diphysa robinoides)
Guayacan (Guajacum sp.)

Jira (Socratea sp.)
Mangrove bark
Cana blanca
Guagara (Chrysophita guagara)




Pillars add supports of houses

Walls and siding

The leaves are used for thatch

Miscellaneous uses
Calabash (Crescentia cujete) water vessels
Pino amarillo dugout boats
Black palm spears
Coconut husks charcoal

II. Output of the Natural Terrestrial
Environment to the Choco Indians

The diet of the Choco Indians is similar to that of the Cuna, but less
varied. Access to marine organisms is limited to those who live near the Pacific
coast, although fish are taken from freshwater rivers. The amount and manner of
subsistence of a Choco family depends on their needs and the conditions of the
environment. Most of the vegetable products are cultivated, though only for use
by the individual family, with the exception of plantain. A few domestic animals
are raised for food, but much of the protein in the diet comes from game animals
and fish. Among the hunted animals are the following:

Spider monkey

Food Habits
Herbivore (leaves, roots)
Herbivore (leaves, roots)
Herbivore (browse-leaves, stems)
Omnivore (mostly vegetarian)


Mammals (Contd,) Food Habits (Contd.)
Howler monkey Omnivore (mostly vegetarian)
Capuchin monkey Omnivore (mostly vegetarian)
Marmoset Omnivore (mostly vegetarian)

Mammals hunted for fur
Jaguar Carnivore
Ocelot Carnivore
Puma Carnivore
Otter Carnivore

Curassow Herbivore (nuts, seeds)
Pigeons and doves Herbivore (seeds)

Iguana Omnivore (vegetation, insects)

These animals are usually hunted by gun, bow and arrow, and, infre-
quently, blowgun. The poison for blowgun darts is made from the latex of
Perebia sp., or from skin secretions of the frog, Dendrobates tinctorious; the
darts are made from Cecropia. In the Darien region, they are little used because
of the scarcity of the frog; but in Colombia, it is more prevalent.
Many natural vegetative products are used for purposes other than food.
Most of the following are invaders of fields abandoned in the process of slash-
and-burn agriculture:

Passion fruit (Passiflora sp.) edible fruit
Guamos (Inga sp.) edible fruit
Jobo (Spondias mombin) edible fruit

Building materials
Palma negra (Astrocaryum standleyanum) house supports
Gasipaes palm (Guilielma gasipaes) flooring
Jira bark (Socratea sp.) covering for the floor
Iraca (Carludovica palmata) thatch

Miscellaneous uses
Wild fig (Ficus sp.) bark cloth
Jagua (Genipa caruto) body paint, dye
Achiote (Bixa sp.) body paint, dye


Miscellaneous uses (Contd,)
Balsa (Ochroma sp.) tool for applying paint
Kidai (Piper sp.) licorice-flavored stain for teeth
Pokeweek (Phytolacca sp.) medicine
Rubber (Costilla sp.)
Giuarumo (Cecropia sp.) darts and carvings
Cedro amargo (Cedrela mexicana) for making boats
Cedro espinoso (Bombacopsis fendleri) for making boats
Jigua negro (Nectandia) for making boats

III. Output of the Natural Terrestrial Environment
to the non-Indian Population: Negroes, Mestizos

These people are in closer contact with cities and trade than are the
Indians. They carry on a similar agriculture, but more of their products, such
as rice, corn, beans, name, plantain, yuca, various fruits, and sugarcane, are
grown for export as well as for support of the individual family. Domestic ani-
mals are also raised in part for export.
The Negro people make use of fish and game, using firearms to hunt many
of the same animals used by the Indians, with the exception of monkeys. Alliga-
tors, iguanas, turtles, and their eggs are eaten by some of the Negros.
Natural products which are used for purposes other than food are as

Building materials
Cana brava (bamboo) walls of houses
Cocobolo (Dalbergia sp.) walls of houses
Cacique (Diphysa robinoides) walls of houses
Guagara (Crysophila guagara) roofs
Jira (Socratea sp.) floor covering

Commercial lumber
Mahogany (Swietenia macrophyle)
Cedar (Cedrela sp.)
Oak tree (Tabebuia pentaphylla)
Tachuelo (Zanthoxylum sp,)
Espinoso (Bombacopsis quinatum)


Commercial lumber (Contd.)
Cabimo (Mora megistrosperma)
Cativo (Prioria copaifera)
Tangare (Mortisa sp.)

IV. Products Used by Man From(a
Compartments of the Terrestrial Ecosystem

A. Stems, boles, and branches.
Man contacts the following products from this compartment primarily
through using them in house construction, boats, and household tools,
or as charcoal for cooking fires:
Lumber, stems, boles, branches
t algarrobo (Hemaea curbaril; Pithecolobium saman) used in general
carpentry and interior construction, flooring, paneling, furniture
and cabinets
/ almendro (Terminalia catappa) used in tanbark; other species of
Terminalia (T. amazonia, T. lucida) are used for charcoal, boat
frames, decking and planking, bridges, dragline mats, fence posts,
carpentry, siding, flooring, cabinets and furniture, plywood core-
stock, and railroad ties
V amargo (Bocconia frutescens) a tree with;yellow latex
/ amarillo (probably Berbeus latifolia; B. lutea; Aspidosperma vargasii)
Aspidosperma megalocarpon is used for flooring, furniture and cabi-
nets, ornamental boxes, inlay and turned work, heavy construction,
beams, rafters, and railroad ties
V balsamo (Myrospermum salvatoriensis; Toluifera pereiae; *Citharexyleum
V bariba (Capromis)

(a)Symbol Key:
/ Scientific name from Lexicon de Fauna y Flora.
Scientific name from Common Trees of Puerto Rico and the Virgin Islands.
t A plant yielding two or more products.


cana blanca used for house siding
caoba (Swietenia maciophyla) mahogany
V cavtivo (Prioria copaifera) used for carpentry and interior con-
struction, paneling, rough boxes, and plywood corestock
V carbonero (Albizzia, Bejaria, Capparis, Cassia biflora, Colubrina
reclinata, Salvia sessiflora) used for charcoal (?)
V cedro amargo (Cedrella glasiovii, *C. odorata) Cedrella tonduzzi,
C. mexicana, C. fissilis are used for veneer, general carpentry,
siding, paneling, windows, doors, furniture, cabinets, plywood
corestock, and boats
cedro cebolla
cedro espinosa (*'Trichilia hirta) Trichilia tuberculata can be used
for firewood, even when green; Bombacopsis fendleri is used for
V cedro macho (*Hulefandia pendula, or it may be the same as cedro
amargo, C. odorata)
t V coco (Cocos nucifera) coconut palm
V cocobolo (Cocoloba and Dalbergia sp.) sturdy wood; used in construc-
tion of houses
V corotu (Enterolobium; also called timbo) used for veneer, gun
stocks, paneling and interior trim
espave (Anacardium excelsum)
espinoso (Bombacopsis quinatum)
/ frijolillo (Lonchocarpus latifolium)
V quachapali (Acacia guachapele) the resins of A. farnesiana are used
for cement, perfumes and incense; the wood is used in tool handles
guarumo (Cecropia) darts, carvings
/ guayacan (Guajacum officinalis; Lignum vitae)
/ guasimo colorado (Guazuma ulmifolia) used for charcoal, tool handles,
and cordage
v higueron (Ficus gigantea, F. glabrata, F. indica)
jira (Socratea sp.) used for house siding


/ laurel (Ocotea latifolia) Ocotea veraguensis and 0. tra are used in
veneer, carpentry, furniture and cabinets
V macano or cacique (Diphysa) used for fence posts and living fences,
house posts, and railroad ties
mangle (Rhizophora, Laguncularia, Avicennia) bark used
/ maria (Calophyllum calaba) Calophyllum braziliense var. Rekoi is
used for boat decks, wheelstocks, bridges, fence posts, general
carpentry, siding, windows and doors, furniture, and railroad ties
V mora or cabimo (Maclura tinctoria; chlorophora tinctoria) Mora
megistrosperma is used for siding; "'Mora oleifera is used for dyes,
boat frames, planks, and decks, tool handles, bark cloth, fence
posts, flooring, furniture, cabinets, pilings and dock fenders,
mill foundations, general heavy construction, and railroad ties
t V nance (Malpighia punicifolia, *Byrsonima crassifolia) used for char-
/ naranjo de monte (Citrus sp.)
/ nazareno (Peltogyne purpurea, *Parkinsonia aculeata) used for floor-
ing, windows and doors, furniture, cabinets, ornaments, inlay and
turned work, pilings, and dock fenders
t V nispero (Sapota achras, S. mammosa, Manilkara zapota)
/ nuno (Sisyrinchum nuno)
palma negra (Astrocaryum standleyanum) used for house supports
/ peronil (Makareium peronil)
V quira (Platymiscium polystachium, P. pinnatum) used in flooring,
furniture and cabinet work
V rable (Catalpa, Bignonia, Tecoma, Citharexylon, Ehrectia) may be used
for construction, such as fences
/ sigua or jigua negro (Laurus martinicensis, Nectandra sig ua, N.
boniato) two other species of Nectandra (N. latifolia and N.
salicifolia) are used in carpentry, paneling, interior work, furni-
ture, cabinets, and boats
tachuelo (Zanthoxylum sp.)
/ tamarindo (Tamarindus occidentalis)
tangare (Matisa sp.) commercial lumber


terciopelo (Sloaena quadrivalvis, Miconia aeruginosa) another specieS
Miconia argentea, is used for railroad ties, and S. laurifolia is
used as firewood
zorro (*Pithecellobium saman) Pithecellobium austrinum is used in
carpentry, flooring, paneling, interior construction, furniture,
and cabinets
V cortezos del palo de buba (Jacaranda mimosaefolia, J. gualanday) the
bark is used to cure skin disease
V del nance y hojas de la malva Malpighia punicifolia and others are
used for skin-disease cures
t V ceiba, balsa, barrigon kapok used in pillows
/ ortiga (Pilea lucida) a vine
V poroporo (Cocklospermum vitifolium) a tree
V pitahaya (Cactus grandiflorus, C. divaricatus)
/ penuela (Cyrthopodium anersonii, C. punctatum)
/ palos del cortezo (Apeiba tibourboa) the bark is used for textile
V balsa (Ochroma, Bombax) floating rafts, corks for bottles.
B. Fruits and seeds.
Products from this compartment are used as food:
t algarrobo
V canafistula (Cassia leiantha, C. disticha) the pulp is used as a
V cereza (Cicca elliptica, C. disticha; Freziera cericea)
t coco coconut palm, edible fruits
V coronillo (Scutia buxifolia; Bouganvillea stipitala)
t espave
fruta de pava
guamas (Inga sp.) edible fruit
V granadilla (Passiflora ligularis) passion fruit
/ guayabo de sabana (Psidium pomiferum) tart fruit
higueron (Ficus sp.) edible fruit
V icaco (hicaco; Chrysobalanus icaco) a tree bearing a plum-like fruit


V jagua (Genipa americana) a tree with bittersweet fruit about the
size of goose eggs
jobito depuerco
/ maranon (Anacardium occidentale; cashew) the pear-shaped fruit is
Smadrono de comer (Calophyllum madrono, C. acuminatum, or Rheedia
V membrillo (Cycloma vulgans)
t V nance
t V nispero
/ Panama (Sterculia carthaginensis) a tree bearing fruits comprised of
three capsules with edible seeds
V papayo cimarron pina (Carica papaya, C. digitata; papaya)
pepita de zapateros
el pasa caren) meat seasoning
V naju de espina (ensalada; Abelmoschus esculentris; okra)
semillas de la chigua used in bread
V granos del malagueto chico or malagueto hembra (Pimento acris;
Amomis caryophyllata; Eugenia pimenta; Xilopia cubensis) used for
V vanilla y vanilla chica (Vanilla) vanilla flavoring
V culantro (Eryngium foetidum; Zanthoxylum pterota) coriander, an
aromatic herb
V aguacate (Persea gratissima; avocado)
V anona (Anona diversifolia)
banana (Musa sapientum)
/ chirimoya (Anona cherimolia, A. squamosa, A. specialist) a tree bear-
ing tart fruit
t V granadilla
/ jobo (Spondias lutea, S. purpurea, S. mirobalanus, S. mombin) a tree
bearing yellow, plum-like fruit
lima lime
limon lemon


/ mamey (Achras mammosa, Lucuma mammosa, Mammea americana)
melon or sandia (several varieties of melon)
V mango (Mangifera indica)
t V naranja agria (sour orange)
/ naranja dulce (Citrus aurantium) sweet orange
V palo de pan (Artocarpus incisa, A. communis, Bertholetia excelsa;
bread fruit)
t V papaya
V pina (Bromelia anana, Ananas ananas) pineapple
V pomanosa (Jambosa)
V ciruelas (Spondias purpurea) plum
V platano (Musa paradisiaca; plantain)
V pepino (Sicana odorifera; cucumber)
/ tomate (Lycopersicum esculentum; Solanum lycopersicum)
V aji (Capsicum; chile pepper)
velapalo fruit is used to feed livestock
calabash (Crescentia cujete) water vessel
/ canafistola de purgan (Cassia leiantha) the fruits are used as purga-
/ cabeza de negro (Phytelephas macrocarpus) a palm with large fruit
used as an antisyphilis medicine

C. Leaves of understory vegetation.
Some food plants are in this category:
repollo (cabbage)

D. Leaves of canopy vegetation.
Products from this compartment are used in many ways from building con-
struction to clothing.
V barrigon (Bombax barrigon)
t v/ malagueto hembra
/ cabuya (Agave sp.)
/ chonta (Astrocaryum chonta, Guilielma speciosa, Martinezia equinata,
Bactris ciliata, B. horrida) several varieties of palm
/ pita de zapateros (Agve sp,)
cucira or namaua
t / platano


/ oil from corozo colorado (Acrocomia, Cocos, Elaeis, Alfonsia,
Attalea, Martinezia)
Several palms are used to flavor wine and vinegar, for weaving, and
for bohio roofs: Guagara (Crysophila guagara), etc.
V chumico (Davilla Kunthii) the rough leaves are used to polish and
lighten wood and metal
V toquilla or iraca (Carludovica palmata) used for hats and for thatch
Freziera theoia used to make tea
t V papayo the leaves are used as soap

E. Roots
Root products are used for food, several of which make up staple portions
of the diet:
/ name (Dioscorea alata, D. aculeata, D. sativa) edible root
V camote (Batata edulis) sweet potato
otoe (Xantosoma violaceus)
V papa (Solanum; white potato)
V guandu (Cajanus indicus)
V mani (Moronebea globulifera; peanut)
yuca (Manioc utilissima) edible root is a staple food
zapullo root

F. Epiphytes
V doradillo depalo (Polypodium polypodioides, P. icanum) ferns that
grow on oak trees; are used to make a refreshing tea

G. Medicinal plants
Many of the following are known and used only by the Indians, and infor-
mation about the locations or the vegetative compartments that are used
was not available.
Fever reducers
guavito amargo
V cedron (Aruba (Simaruba) cedron; Quasia cedron)
V canchalagua (Linum catharticum; may be several other species)

nino muerto


V mal casada (Asclepias curassavica)
coquillo (Jatropha curcas)

Emetics and vomitives
gariba de pana
/ frailecillo (Jatropha)

Healing injuries
guamicillo or palo del soldado
V cope (Ternstroemia obovalis)
chico de suelo

V cardo santo (Argemone mexicana)
/ zarzaparrillo (Smilax campestris, S. havanensis)

Poisonous plants
V amancay (Amaryllis aurea)
cojon degato
V manzanilla de playa (Rhus sp.)
/ floripondio (Datura arborea, D. suaveolens) the pleasant scent of
the flowers is harmful is breathed for long periods
madre negra
strychnine of two types for arrow poison

Refreshing potions
/ calaguala (Polypodium and Acrostichum)

Snake-bite remedies
/ hojas del guaco (Aristolo chia, Mikania, Eupatorium, Spilanthes, and

Plants used for dyes

t V macano yellow
hojita de tenir reddish
V/ anil silvestre (Plectropoma indigo, Hypoplecteris indigo, H. bovinus) -
t v/ fruta de jagua violet


kidai (Piper sp.) licorice-flavored stain for teeth

V pulpa de achiote (Bixa orellana) red
arribadla chica reddish

V semilla de ojo de venado (Cordia alliodora)

H. Animals

Most of the animals which are hunted are herbivores which, with the

exception of birds and monkeys, feed on understory vegetation and roots.






Coati mundi

Spider monkey

Capuchin (white-faced) monkey

Howler monkey


Jaguar (hunted for fur)
Ocelot (hunted for fur)

Puma (hunted for fur)
Otter (hunted for fur)




Macaw and other parrots



Wild turkey

Pigeons and doves

Feeding Habi


















Reptiles Feeding Habits
Iguana Browser-Carnivore (insectivore)
Sea turtle Grazer
Alligator Carnivore

Snails Grazer-Detritivore

Land crab Detritivore


Recurring forest types that serve as environs for human inhabitants in
the proposed route areas should be intensively sampled on a biomass basis for
the purpose of relating contract obligations to a fixed or known standard. A
knowledge of standing crops permits coordinate modeling with respect to internal
and external dose computations.
The specific-activity approach should be pursued in some detail in the
forest ecology studies for the terms of the contract period. Some of the forest
products used by man have been shown to retain relatively high levels of fallout
nuclides. In annual agricultural crops, leaf surfaces are not exposed to aerial
contamination for long enough periods of time to build up detectable levels of
nuclides under preshot conditions and in many cases, crop products are not high
in mineral elements and tend to be nuclide diluters. The vegetation of the non-
agricultural areas tend to be perennial in nature with exposed plant surfaces,
with uptake and storage potential such that fallout nuclides occur at detectable
levels in many of the compartments and, hence, give good indication of storage
and transfer rates.
The state of fallout nuclides in the forest ecosystems under present
conditions is relatively stable, with an input having only minor fluctuation in
intensity. Under canal-construction conditions, the input to the systems may
consist of distinct fractionated units giving a nonuniform input, and with
amounts of stable materials reaching large proportions and smaller proportions
of unstable materials. It is therefore suggested that quantities of stable
cesium and strontium be introduced aerially into a representative forest type
and the movement and storage of the elements be studied by compartmental analy-
sis, These two elements are important device yield products and are relatively
uncommon in natural ecosystems.


With the project strongly oriented toward the result to man, it is
necessary that there be cooperative planning among the subcontractors under the
direction of Battelle Memorial Institute so that the complete nuclide input can
be studied and assimilated as a complete unit. This is particularly important in
the case of food-chain analysis and model construction and implementation.
Two compartment types at this point indicate specific interest with
respect to the overall problem. The soils of the lowland forests appear to have
relatively high organic-matter content in the upper horizons, and, as has been
suggested in the literature for other geographic areas, would serve as a nuclide
"sink" with efficient storage and possibly with little transfer to other systems.
It appears that agricultural practices are restricted to periodically disturbed
soils. These soils appear to have a lower organic-matter content, and, conse-
quently, lower exchange capacity. The effectiveness of storage and transfer by
the various important man-use soils needs to be assayed.
Plants occupying perched habitats epiphytess and epiphyllae) tend, by
their nature, to be effective leachate assimilators, and consequently contain
large amounts of materials introduced aerially. They are important in increas-
ing the number of strata from which external exposures would occur and serve as
high mineral-input sources to food chains via the grazers. Specific interest
will be given to the amounts of grazing occurring on leaves of various ages hav-
ing varying amounts of epiphyllae.
It is suggested that for the period of this contract all analyses be
oriented toward a one-way model with respect to input transfer to forest soils
and that recycling functions be studied in later phases.
Further, it is suggested that long-term projects be planned whereby
recycling studies can be performed to complete the information necessary to
develop models for long-term effects and responses.


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The purpose of this program is to study the movement and storage of
radionuclides in tropical terrestrial ecosystems in the regions of Panama and
Colombia under consideration for construction of a sea-level canal, which will be
excavated with nuclear devices.


The objectives of Phase II will be:
(1) To describe and classify the ecosystems by their distribution,
compartmentalization, and function, giving particular emphasis
to the relationships and distribution of peoples within the
ecosystems. The descriptive categories (ecosystems) will
recognize gross differences in vegetation, faunal relationships,
soils, climate, topography, etc.

(2) To describe the specific activity, movement, and storage of
fallout radionuclides within and between the compartments of
the ecosystems. Emphasis will be on naturally occurring elements
and on the biologically important isotopes that will be introduced
by the excavating devices.

(3) To describe the conditions of external radiation exposure by
strata and compartments of ecosystems.

(4) To describe the internal radiation exposure to the indigenous
peoples, by food-chain and food-web analyses. Particular
attention will be given to delineating the pathways of internal
emitters by two methods. The first will be to describe and
follow terrestrial food chains, starting with known foodstuffs
and tracing them to their origin, and second, to study the food
chains from the origin to possible uses by man. The latter
approach may be particularly important in cases of suspected
nuclide-concentrating components in the ecosystems.

(5) To determine transfer of radionuclides between compartments of
ecosystems and to verify suspected special features of natural
ecosystems that may be project-limiting, by introducing known
tracer-amount inputs of fission-product radionuclides and
following their movements and storage.
The specific objectives of the Phase II studies are (1) to determine the
biomass structure of representative vegetation types on the Panama and Colombia
routes; (2) to determine the quantity of selected stable elements in these
communities; (3) to determine the rates of transfer of selected elements into, out
of, and through compartments in these communities; and (4) to determine elemental


content of selected plants and animals over the region of interest. These
objectives are to be achieved by harvest of stands of vegetation during 1967.
Eight or more stands of mature vegetation will be harvested. If time is available,
additional data will be collected in the Mora forest and in secondary vegetation
at different periods of development.
Transfer through the communities and through compartments will be
determined mainly by following rainfall and movement of organic material. In
addition, analyses of rainfall interception by different canopies at different
intensities of rain will provide information on canopy infiltration. Output from
watersheds will be estimated from water samples collected at hydrology water
gages. Comparison of chemical content during the dry and rainy seasons will permit
estimation of transfer from the terrestrial communities.
Chemical analyses of organic materials, soils, water, ion-exchange
columns, and other material will be carried out at Savannah River Ecology Labora-
tory (Aiken, South Carolina). It is anticipated that gamma analyses can also be
made, but the procedures are not described. Sufficient material is being collected
to provide samples to other laboratories at their request.


It is the intent to identify standard terrestrial ecosystems in the
Panama and Colombia regions. Because of logistic support, most work has centered
in Panama and the standard ecosystems there are well organized. The Colombian
reconnaissance will determine whether similar types occur in the Route 25 area. If
they do, samples will merely be collected by compartments for chemical analysis.
If Colombian ecosystems differ radically from those in Panama, harvest studies will
be undertaken to establish their structures.

Harvest Procedures

Selection of Study Areas
The objective will be to locate study areas in representative examples

of four forest types as follows: cuipo, mangrove, montane rain forest, and cativo

swamp or lower montane forest. Representative samples will be chosen after a
reconnaissance of the area. Study locations will be sampled in the dry season and
in the wet season. The specific locations will also depend upon logistic support.
Where transportation is difficult or costly, the study areas should be within a


content of selected plants and animals over the region of interest. These
objectives are to be achieved by harvest of stands of vegetation during 1967.
Eight or more stands of mature vegetation will be harvested. If time is available,
additional data will be collected in the Mora forest and in secondary vegetation
at different periods of development.
Transfer through the communities and through compartments will be
determined mainly by following rainfall and movement of organic material. In
addition, analyses of rainfall interception by different canopies at different
intensities of rain will provide information on canopy infiltration. Output from
watersheds will be estimated from water samples collected at hydrology water
gages. Comparison of chemical content during the dry and rainy seasons will permit
estimation of transfer from the terrestrial communities.
Chemical analyses of organic materials, soils, water, ion-exchange
columns, and other material will be carried out at Savannah River Ecology Labora-
tory (Aiken, South Carolina). It is anticipated that gamma analyses can also be
made, but the procedures are not described. Sufficient material is being collected
to provide samples to other laboratories at their request.


It is the intent to identify standard terrestrial ecosystems in the
Panama and Colombia regions. Because of logistic support, most work has centered
in Panama and the standard ecosystems there are well organized. The Colombian
reconnaissance will determine whether similar types occur in the Route 25 area. If
they do, samples will merely be collected by compartments for chemical analysis.
If Colombian ecosystems differ radically from those in Panama, harvest studies will
be undertaken to establish their structures.

Harvest Procedures

Selection of Study Areas
The objective will be to locate study areas in representative examples

of four forest types as follows: cuipo, mangrove, montane rain forest, and cativo

swamp or lower montane forest. Representative samples will be chosen after a
reconnaissance of the area. Study locations will be sampled in the dry season and
in the wet season. The specific locations will also depend upon logistic support.
Where transportation is difficult or costly, the study areas should be within a


1-hour walk of the camp. Transportation of labor crews should always be kept in
mind when choosing the study areas.
Representative areas will be selected according to the following
criteria: they must (1) be representative of the average topographic situation in
the region of interest, (2) have the same vegetation strata as the average condi-
tions, (3) contain representatives of the obviously important species and (4)
contain trees of the general range of diameters observed on reconnaissance. These
criteria are necessarily subjective. The "best possible choice" is adequate for
our purposes.
After the general site has been selected, the location of 1-hectare (ha)
(100 x 100 m) plot should be determined (Figure 5), and on one side (toward the
base line) a 1/4-ha harvest area laid out. This will always be on the lower left-
hand corner of the study plot. The quarter hectare should be marked at the corners
with metal stakes, and on the sides with orange marking tape.
The quarter hectare will be divided into halves from the base line. The
right-hand 1/8 ha is replication 1, the left, replication 2. At some later time,
the corners of the hectare will also be marked with metal stakes and identified.
Study sites that have already been chosen are (Figure 6):
(1) Cuipo forest near Santa Fe (approximately 3 miles from the camp
on the trocha)
(2) Mangrove (Rhizophora brevistyla) near Boca Grande Camp
(3) Mountain forest near Summit Camp, on the Atlantic side
(4) Lowland forest near Camp Chucunaque.
Four other sites will be selected in the above types of forests but in
different geographical locations. In addition, harvest samples will be taken in
Mora forest (probably near La Palma), second-growth communities near Chepo or
Santa Fe, and swamp grass in the Atrato River drainage.

Preharvest Program
Several kinds of data will be gathered before the vegetation is harvest-
ed. The preharvest program will depend upon the openness of the undergrowth; it
may be necessary to begin harvesting so that access to the area is easy.
First, diameters at breast height (DBH) will be determined for all trees
and lianas that are taller than head high (about 6 feet). This will be accomplish-
ed by holding a metric ruler at breast height against the trunk at a representative
location, avoiding swellings, branching, etc., and recording the diameter to the
nearest 0.1 cm. Large trees will be measured with the diameter tape in inches,
which will be converted to centimeters before the data are tabulated. Since this

I 2 3 4

5 6 7 8

9 10 I 12

13 14 15 16

Numbering of 1/16-ha Plots

Santa Fe


















Secondary Forest














































which will be marked with orange tape. At least 15 cans will be
set out; these will be checked at about 3 to 4 day intervals,
depending upon other work.

(8) Sweeping of ground vegetation for insects during study. One
hundred sweeps will be taken per sample and the number of insects
per 100 sweeps will be recorded. At least 12 samples will be
taken. The object will be to collect sufficient numbers for
chemical analysis, which will require about 30 dry weight for all
insects and invertebrates.

(9) Setting out of mammal traps when available. Medical Ecology may
supply live traps in return for bleeding of any mammals captured.
Plantains will be satisfactory bait. The traps will be placed
more than 15 paces apart. The trapped mammals will be identified
as closely as possible. After the mammals have been bled by
Medical Ecology, approximately 10-g wet-weight samples of thyroid,
liver, muscle, brain, and bone will be collected and preserved in
formalin (4%) or alcohol (70%).

Harvest Program
The harvest program will be divided into the following parts by

(1) Understory
(2) Overstory
(3) Epiphytes, epiphyllae, and fruits
(4) Roots
(5) Soils.
Understory. Depending upon the density of the understory, either all

of a 1/4-ha plot will be cleared or sample plots will be taken. If all of a
plot is cleared, undergrowth will be cut with a machete. The leaves and stems
will be separated and weighed on a beam balance. One person will record the
weights in pounds. Leaves and stems will be discarded separately in five piles
in each replication, and five samples of leaves and of stems will be selected per
replication, one from each pile. The wet weights of these samples will be d
determined. Ten samples of about 500 g of leaves and ten samples of about 500 g
of stems will be collected for determination of their dry weights and chemical
If a plot is not to be completely cleared, five 30-m2 plots will be
taken per replication (or enough plots to sample 120 m2, which is 10 percent of
1200 m ). If the weight is not sufficient to make 500 g per sample, the size of
the samples will be increased.
Overstory. Sampling of the overstory will depend on the frequency

distribution of DBH. At least a 10 percent sample of each diameter class will be

chosen (which may be 1-cm divisions to about 10 cm). The trees and palms will be


harvested separately. The plants will be cut at the ground and the leaves
separated from the stems. Five piles of stems and five of leaves will be built
for sampling. Weights will be determined by tree or by group of trees to give
sufficient weight for accurate use of the beam balance (over about 5 Ib or 15 lb,
depending upon the scale used).
It will not be possible to sample large trees completely. The lengths
of their boles, and the diameter at the top and the bottom of boles will be
measured. One- or 1/2-m sections of boles will be cut; their diameters will be
measured and they will be weighted on a beam balance. Then the number of branches
of approximately equal diameter will be counted, and two to three of them selected
for sampling. The leaves will be cut and stripped. The branch wood and leaves
will be weighed separately.
The average wet weight of the stems and leaves for each diameter class
(l-cm divisions to 10-cm DBH, larger divisions depending upon the stand) will be
required as will five samples of about 500 g of leaves and of stems from each
replication for overstory leaves and stems.
Palms will be classified by size and length, and the weights of their
boles determined as for other trees. The number of fronds for each palm will be
counted and the weight of a sample of fronds will be determined. The palms will
be added to the sample of overstory leaves and stems.
Lianas will be sampled with the trees. The leaves of the lianas will be
pulled off when they occur on trees and grouped with the tree leaves. The same
will be done with the stems. The lianas will be taken into consideration when the
large trees are being selected; an attempt will be made to select trees with a
typical number for their weight class.
Epiphytes, Epiphyllae, and Fruits. These smaller compartments will also
be carefully sampled. When epiphytes are encountered, they will be separated from
the tree and weighed. If epiphytes can be kept separate by diameter classes, then
calculation of the total biomass for the stand can be made. If possible, five
500-g samples of epiphytes should be collected per replication for analysis.
Samples of leaves from the understory and overstory will be collected
and bagged during the course of the harvest for samples of epiphyllae. The wet
weight of the sample will be determined, and the sample will be shipped to the
Canal Zone. Epiphyllae will be removed at the laboratory. The use of soap to
remove epiphyllae will be avoided if possible. Epiphyllae will be weighed and
their weights related to the weight of the leaves. Samples of both leaves and
epiphyllae will be saved for analysis in Aiken.


measurement will be subjective, care should be taken to hold the ruler in the same
way and to read the ruler from the same distance. Where there are several
branches, the main one will be chosen for measurement. Branches that are separate
from below a height of 6 to 12 inches, but that have one rootstock, will be
measured and recorded separately. Palm fronds will be measured separately. Palms,
vines, and trees will be identified by a code when data are being taken. This job
will require two persons, one to do the readings and one to record data. Measure-
ments will be transmitted in English, unless a Spanish-speaking person is the
In the laboratory, the diameter data will be recorded in the project
daybook by replications and by a frequency distribution by 0.5 cm divisions to

about 10 cm. Inspection of the data will indicate coarser divisions for larger
Other jobs that may be started before harvest begins are:
(1) Determination of the average height of canopy with an abney
level. This will require two men, one of whom can be a
laborer. Several readings will be taken for each tree that
is selected for measurement. Several trees will be measured.
The maximum and average heights of the canopy will be determined.

(2) Location by random plots (Figure 6) of ten litter sample areas
in the unharvested 3/4 of the hectare. These will be marked
with white tagging tape on the borders of the trails and in the

(3) Construction of ten litter boxes about 1 m2 which will be on
legs and will have a fiber-glass-cloth bottom.

(4) Placing of litter boxes in the field. Obvious accumulations
.of unusually heavy litter or open areas with no litter will be
avoided. In mangrove, boxes will be placed on prop roots above
the reach of tides.
(5) Collection of litter on ten 1 m within 5 m of the litter boxes.
The litter will be bagged and weighed to the nearest gram and the
weights recorded. The bagged litter will be dried and used for
analysis. These litter samples will not include fallen logs,
which will be measured in the same way as trees so that their
weights can be calculated.

(6) Cleaning off of litter and twigs from ten 4-m2 twig plots within
5 m of the litter box. All twigs and large leaves will be removed
and the area marked with stakes and tagging tape. Plots will be
2 m on a side. These plots will be examined later for twig fall,
which will be too large to enter the litter boxes.

(7) Setting out of pit traps for insects. Tin cans (coffee cans are
best) will be placed in the ground with the top at soil level.
About 1 inch of 4% formalin will be placed in the can, and the top
of the can will be loosely covered with a leaf or twig. Cans will

be placed along the borders of trails in undisturbed locations,

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