preliminary studies on forest structure

7/23/2019 Preliminary studies on forest structure

1/14

Journal f Tropical

Ecology (1990)

6:307-320. With

figures

Preliminary

studies on

forest

tructure nd

floristicson Volcan Barva, Costa Rica

ANGELA

HEANEY and

JOHN PROCTOR

Department

of Biological

and Molecular

Sciences,

University

f Stirling, tirling

FK9

4LA,

Scotland

ABSTRACT. Volcin

Barva,

Costa

Rica,

has on

its

northern

lope

an

unbroken

equence

of

rain

forest n

volcanic

parent materials

romnear sea

level

at La

Selva Field

Stationup

to its sum-

mit at

2906

m. It provides good

area to study

forest hangeswith

ltitude nd their auses.

In

the

present paper we

describe the forests s a

backgroundfor soil and

litterfall tudiesfrom

1

ha plots

at each of the

following ltitudes: 100 m, 500

m, 1000 m, 1500 m,

2000 m and

2600 m. The

canopy

heights with heightof the

highest

mergent

n

parentheses)

anged

rom

35-40 m

(45 m) at 100 m to

20-23 m (32

m) at 2600 m; basal area

was least (22.7 m2)

at

1

00

m

and highest 51.2

m2)

at

2600 m; the tree

>10

cm

dbh) density angedfrom

91 ha-'

at 500

mto 617 ha-' at

2600 m. Most treeswere

dentified nd on samples

of themwe

recorded

presenceof buttresses,

ianes, kiophytic

limbers, ascular piphytes nd

bryophytes; nd drew

profilediagrams. n the classification f Whitmore 1984) the two lower plots are evergreen

lowland

rain forests; he other four

are lower montanerain

forest.

pecies richnesswas highest

in

the

plot at 500 m,with at least

135 species of tree, nd

least at 2600 m, with at

least 35

species. The

Volcin

Barva forestaltitudinal

sequence is briefly

ompared with those else-

where.

KEY

WORDS: altitudinal

onation,Costa Rica,

lowland rainforest,

montanerainforest.

INTRODUCTION

There

have

been several studies of

forest

onation

on

single

tropical

inountains,

e.g.

Brown

(1919)

for Mount

Maquiling

in

the

Philippines,

Grubb &

Stevens

(1985) in Papua New Guinea, Proctor et al. (1988) in Sabah, and Whitmore

(1972)

and

Whitmore

& Burnham

1969)

in

Malaya. Apart

from

Beard's

(1944,

1946,

1949) descriptions of

small mountains in

the

Caribbean such

studies

were

apparently

lacking

for the Central

American

tropics.

In

1985

the

oppor-

tunity

arose

to

work on Volcain

Barva,

Costa Rica, which

has

on its northern

slope,

an

unbroken

sequence of rain forest

from

near

sea

level

up

to

its summit

at

2906

m

(Figure

1). The

forests n the lower part of this

sequence

include the

the

area

around La

Selva Field

Station

whilst

the

upper

part

is within

the

Braulio

Carillo

National Park. The Barva

vegetation

has

been

briefly

described

in a general way by Hartshorn & Peralta (1987). Our aim in thepresentpaper

is

to

provide

preliminary

descriptions

of

six plots

as

a

background

for studies

(307)

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2/14

308 ANGELA HEANEY AND

JOHN

PROCTOR

Puerto

Viejo.

*

a

Selva

Field

Station

500

m

1500m

P

Vcan

Cacho

Negro

2000

m

A

N

2600

m

A&

VoIcan

Barva

2900

m

o

5

10 km

l

l

l

N

ICARAGUA

COSTA

RIC

Figure

1. The locations

ofthe

study

plots

on

Volcin

Barva,

Costa Rica.



3/14

Forest on

Volcan

Barva

309

on

their

soils

(Atkin & Proctor

1988, Grieve

et al. 1990, Marrs

et

al.

1988)

and litterfall

Heaney &

Proctor 1989).

THE STUDY PLOTS

The study was carried out

along

a

transect

fromthe

La

Selva

Biological

Station

(100 24' N,

840

00'

W) up

the

northern

lope

of Volcain Barva.

One

plot

of 1

ha

of

largely

mature-phase

forest

was investigated

at each

of six altitudes:

100,

500, 1000,

1500, 2000

and 2600 m. The plots were

permanently

marked

and

each

sub-divided nto

twenty-five 0

X

20

m

sub-plots. The

locations are

shown

in

Figure

1

and a

summary

of

some features

of

the

topography

including

the

slope) and

vegetation of the six plots is

given n Table 1.

At La Selva the mean annual rainfall (1957-1979) was 4210 mm and the

mean annual

temperature

240C. The

rainfall s

relatively

aseasonal

(Figure

2).

Rainfall

data

are

not

available

along

the

transect,

but

data

collected

from

elec-

ted

stationsnearby (Table

2) suggest that it may be

greatest

n the

mid-region

of

the mountain. The

temperature apse rate

is

not known.

Ground

frostswere

observed

in

a

clearing at

2600 m on

several days

in

April

1985,

but not

during

continuous

daily observations between 5

March and 5 April 1985

in a

clearing

at 1800 m.

Table 1. Some

details of the

1

ha study-plots nd trees

> 10 cm dbh) at a range f altitudes

n Volcin

Barva,Costa Rica.

Tallest

No. of

No.

of

Plot

Basal

Canopy

tree No. of missing

uniden-

altitude

Slope area

height

height

indi-

No. of speci-

tified

(m)

(0)

Aspect

(Mi2) (m) (m) viduals

species mens trees

100

7

E

22.7 35-40

45

494

111

1

4

500

7

N

24.3 30-35

50

391

135

6

4

1000 7

NE

31.2 30-35

45

546 109 12 6

1500 7

NE

29.2 25-30

38

553

65 15 39

2000

10

NW

28.6

20-25

35

448

69

13

19

2600

15 N

51.2

20-23

32 617

35

1 35

Table

2. Mean annual rainfall or fiverainfall tations

t a

range

of

altitudes

near the

forest

tudyplots

(from

Hartshorn Peralta

1987).

Distance

km)

Altitude

f

and direction

nearest Duration

of

Altitude

from

nearest

studyplot

Rainfall observations

Name

(m)

study plot

(m) (m)

(yrs)

La

Selva

42 3, N

100 4015

26

San

Miguel

500

11,

W

500 4627

17

Cariblanco 970 10,W 1000 5096 5

Vara

Blanca

1804

5, W 2000

3426 21

Sacramento

2260

8, S 2600

3268 11



4/14

310

ANGELA HEANEY AND JOHN PROCTOR

1200

1000

800L

0

E

E

E600-

400-

200

-

0

J F

M A

M

J

J A S

0

N D

Time (calendar month)

Figure 2.

Mean annual

rainfall or

1

October 1957

-

31 December 1979

for

La

Selva Field

Station,

Costa

Rica.

The vertical

bars

indicate

maxima and

minima

for

each

month

during

the

measurement

eriod

(La Selva Field Station unpublished).

Some aspects of the soils have been described by Marrset al. (1988). The

parent materials are basaltic and andesitic lavas of Plio-Pleistocene age with

a

trend towards tuff or agglomerate-likematerials with increasing levation.

The

soils all have low concentrations of available phosphorus and exchangeable

bases with no

clear altitudinal trends. The highest

concentrations were

in

the

plot

at

2600 m. Rates of nitrogen mineralization and nitrification

howed

a

clear

trend of decrease with altitude.

MATERIALS AND

METHODS

The

six

1

ha

plots were measured out without slope correction. The 100 m

altitude was judged from a map, the others were estimated using

an altimeter.

Five

of

the plots were 100

X

100 m but that at 2000 m was of an irregular

shape

to

avoid a ravine which was about 3 m away from the south-western

edge

of

the

plot.

All

trees

(>10

cm

dbh) were enumerated and

their

diameters measured,

usually

at

breast

height (1.3 m) except for those with buttressesor prop

roots

which

were

measured 30 cm

above

the protrusion's unction

with

the bole.

Some

trees had multiple stems (>10 cm dbh) and each stem was

measured

separately. A transect (60 X 7.5 m), which had a substantial proportion of

mature

forestwas

selected

for

a profile diagram of trees >6 m high).

At

each

site,

a

sample of 100 trees 80

at

2600 m)

was

selected

in

their

order



5/14

Forest on

Volcan

Barva 311

of enumeration from a random

point.

For these selected trees the

following

were

recorded: the presence or absence of contacts with photophytic climbers

(lianes) in three size categories, skiophytic climbers (defined by Grubb

et

al.,

1963), and vascular epiphytes; and the percentage cover of epiphytic mosses

on the bole above the ground at 2 m. The trees have mostly been identified

(by

G.

S. Hartshorn) at least to family evel and separate taxa recognized

to

allow construction of species-area curves. The number of missing specimens

and wholly unidentified trees (which were not included in the species-area

curves) in each plot is given n Table 1.

RESULTS

The profile diagrams (Figures 3-8) give an impression of the overall appearance

of the

forests nd show the changes in stature with altitude.

Some

forest structural characteristics are given in Tables 3-5. The

most

consistent altitudinal

trend is the decrease

in

tree height Table 1).

The

plot

at

2600

m has a

high

basal area

(51.2

m2)

compared

with

the lower

plots (Table

1). The relatively small differencesbetween the plots for percentage of trees

45 _

40,

Ho

Figure 3. Profilediagram 60 X 7.5 m) of forest t

10)0

m on the

Volcain

Barva transect, osta Rica.

Trees

less than 6 m high excluded. Symbolsfor identified rees over 10 cm dbh: Bi, Brosimum

actescens

(Moore) Berg; Ca, Casearia arborea Rich.) Urban; Em, Euterpe

macrospadixOerst;Ga, Guatteria erugi-

nosa Standl.; Gr,

G'uarea

rhopalocarpa Radlk.; Gx, Guarea sp.; Ho, Hieronymaoblonga var.

benthamii

(Tul.)

Muell.

Arg.; 1,

nga longispicaStandl.; Ip, I. punctata

Willd.;

Lix, Licania sp.; Mm,Miconia

multi-

spicata Naud.; Nn, Naucleopsis naga Pittier; a, Pourouma aspera Trecul; Pc, Protium ostaricenseRose)

Engler; Pg, P. glabrum Rose) Engler;

Pm, Pentaclethramacroloba

(Willd.)

Kuntze; Pp, Protium

pana-

mense (Rose) I. M. Johnston;Qb, Quararibea bracteolosa (Ducke) Cuatr.; Vh, Vochysia

hondurensis

Spragne;Wg,Welfia eorgiiWendl.



6/14

312 ANGELA HEANEY

AND

JOHN

PROCTOR

40

O-

Figure 4. Profilediagram 60 X 7.5 m) of forest t 500 m on the

Volcain

Barva transect, osta Rica. Trees

less than 6 m high excluded. Symbols for dentified rees over 10 cm dbh: Ax, Ardisia sp.; Cp, Couepia

polyandra (Kunth.) Rose; Cs, Colubrina spinosa Donn. Smith;

Dm,

Dussia macroprophyllataD.Sm.)

Harms; Dp, Dystovomita

ittieri

Engl. W.G. D'Arcy; Gy, Guarea sp.; Ig, riartea igantea

Wendl.;

t, nga

thibaudiana D.C.; Lax, Lauraceae sp.; Mc, Macrolobium costaricenseW. Burger;Pac, Parathesis hryso-

phylla Lundell; Rx, Rubiaceae sp.; Ry, Rubiaceae sp.; Vf, Vochysia errugineaMart.

40

E~~ ' v

0A0.

35

-

~

W~-

30(-

k

V

25

-j~

20

15~

5

0-

Figure 5. Profile diagram 60 X 7.5 m) of forest t 1000

m

on

the

Volcan Barva transect,

osta

Rica.

Trees

less

than 6

m

high excluded. Symbols for dentified rees over

10

cm dbh:

Bic,

Billia

colombiana

Planch

&

Lind.; Ca,

Casearia arborea (Rich.) Urban; Ce, Cassipourea lliptica Poir.; Dp, Dystovomita

pittieriEngl.W.G. D'Arcy; Em, Euterpe macrospadixOerst.;Gg,Guareagrandifolia C; Hx,Humiriaceae

sp.; Ix, Inga

sp.;

Lay,

Lauraceae sp.; Liy, Licania sp.; Ny, Neea sp.; Nx, Nephelea sp.; Po,Pseudolmedia

oxyphyllariaDonn.

Smith; Rg, Rubiaceae sp.; Rh, Rubiaceae sp.; Sx, Sapotaceae sp.; Vf, Vochysia

ferruginea.



7/14

Forest on

Volcan

Barva

313

35

30

Pam

~

~~~~~~~~~~)~~~~~~~~~~~~~~~~~~~~~~~~~-

15-

0

Figure

6.

Profile diagram 60 X

7.5 m) of forest t 1500

m on the VolcainBarva transect, osta Rica.

Trees less

than6 m high xcluded.

Symbolsfor dentified

reesover 10 cm dbh: Bh, Billia

hippocastanum

Peyritsch; x, Clethra p.; Cz,

Cyatheaceae; Da, Dendropanax arboreus

L.) Dcne. & Planch.; Dw, Drimys

winteri

orst.; Ea,

Elaegia

auriculataHemsl.; Ex,

Eugenia storkii tandl.;

Go, Guatteria liviformis onn.

Sm.; Hp, Hieronymapoasana

Standl.; II, Inga longispica Standl.;

Laz, Lauraceae sp.; Mg, Matayba

sp.;

Mam,

Macrohasseltia

macroterantha

Standl.

&

L.

Wms.)

L.

Wms.;

Ox,

Ossaea

sp.; Pad,

Parathesis

denan-

theraHook.

f.; Pam,Persea americanaMill.; Rf,

Rapanea ferrugineaR. & P.)

Mez.

30

Figure 7. Profilediagram 60 X 7.5

mn)

of forest t 2000 m on the

Volcain

Barva transect,Costa Rica.

Trees less than 6 m high excluded. Symbols for

dentified rees over 10 cm dbh: Ap, Ardisiapalmana

Donn. Smith; Bc, Brunelliacostaricensis tandl.; Cw, Cinclima p.; Cy, Cyatheaceae;

Dip,

Didymopanax

pittieriMarch.; Hy, Hamamelidaceaesp.; Hp, Hieronyma oasana

Standl.; Mx, Miconia sp.; My,Miconia

sp.; Mz, Melastomataceae p.; Px, Piper sp.; To,

Tu4rpinia

ccidentalis SW.) Don; Tx,

Tetrorchidiu4m

p.;

Vm,

Vibu4rnum

exicanum nomen).

in different iameter classes (Table

3) is remarkable. The frequency of buttres-

sed trees remains relativelyhigh with increasingplot altitude (Table

4)

although

the actual numbersof tall (>1 m high) buttresseson the sampled treesdecreases

markedly: there were 22 at 100 m,

39 at 500 m, nine at 1000 m, three at

1500 m, four at 2000 m, and five at

2600 m. Lianes decreased in

numbers

with



8/14

314 ANGELA HEANEY AND JOHN PROCTOR

30-

20-

CtA\t2

I~~~~~~~~~~~~~~~~~~~~~I

oL

Figure 8.

Profile

diagram 60

X 7.5

m)

of

forest

t

2600

m

on the

Volcin Barva

transect,

osta Rica.

Trees less

than

6 m

high excluded. Symbols for identified

rees

over

10 cm dbh:

Ay, Ardisia sp.; Bc,

Brunellia costaricensis tandl.; Cx, Clethra sp.; Dx, Dendropanax sp.; Iv, Ilex vulcanicola Stand.; Vm,

Viburnum

mexicanum nomen).

Table

3.

Percentages

f trees

>

10

cm dbh) in

a

range

of

diameter-classesn six plots on Volcan Barva,

Costa Rica.

Plot

Diameter-class

cm)

altitude

(m)

10-20

20-30 30-40 40-50 50-60

60-70

70-80 80-90

90-100

>100

100

66.7

17.0 6.2 3.1 3.1

1.8

0.6

0.2

-

0.2

500 57.8 19.8 11.6

3.6 3.1

1.0

1.5

0.2

0.2 1.0

1000

59.6

18.5 8.9

6.0

2.7

1.3 1.3

1.3 0.2 0.2

1500

51.4 24.5

13.4

6.5

1.8

0.9

-

- -

1.4

2000

44.1

26.6 16.9

5.2

2.5

2.0 0.7

-

0.2

1.8

2600

51.4

22.8

8.5

7.2

4.6

2.0 1.0

0.6

0.3

1.6

Table 4. The percentageof sampled trees N

=

100 except for the plot at 2600 m where N

=

80) with

buttresses, ianes, skiophytic limbers, ascular piphytes, nd with more than 50% of

the boles covered

by bryophytes

t

2

m

from

he

ground, n plots at a range f altitudes n Volcin Barva,

Costa Rica.

Buttresses

Lianes

Plot of heights cm) of diameter cm) Bryophytes

altitude

Skiophytic Vascular (>50% cover

(m)

50-100

>100

>1-5 >5-10

>10 climbers

epiphytes

at

2

m)

100

23

6

51

40

2

75

89

5

500

23

8 45

25

7

82 86

4

1000

17

5

33 12 2

71

92 32

1500 7

3

18 7 0 95

99

79

2000 14 3 7 4 0 85 100 72

2600

16

5

14

0 0

18

100

80



9/14

Forest on

Volca'n

Barva

315

140-

130- 0

O Om

50

m

120-

0

l

OOOm

A 1500m

110- *

2

OOOmX

A

2600m

100

5

o

90-

*

80-

.0

70-

E

560-

u

50-

cn

40-

30-

20-

10-

5 1

1'5

20

25

Sub-plots (number

of 20x20m)

Figure9. Species-area curves

for trees > 10 cm dbh) on the six plots on Volcin

Barva. The numbers f

missing pecimens

and

unidentified rees not included in these curves

s

given

n Table

1).

Each

curve

follows

he

orderof enumeration

f the twenty-five0 X 20 m sub-plots.

altitude and

none >5

cm

diameter were recorded

from

the

highestplot. Vascu-

lar

epiphytes were abundant at all

altitudes whilst bryophyte cover increased

markedly

with

altitude.

There

is

a

trend

of

reduction of species richness with altitude

(Table

1

and

Figure 9) although the

plot

at 500

m is much richer than

that at 100

m.

An

increase

in

the number of

missing or unidentified pecimens

partially accounts

for

the drop

in

species numbers between 1000

and

1500 m.

Above 500

m

there

is

a trend of decreasing

species numbers and the plot

at

2600

m

is

by

far

the

most

species poor.

Table 5 shows dramatic changes in tree family composition with altitude.

At 100 m

there is a

high proportion

(32.9%

of

the

basal

area)

of the

Mimo-

saceae

of

which most

(28%

of

the basal

area)

is

contributed

by

Pentaclethra

macroloba. The

Mimosaceae

are

still

the

leading family (11.9%

of the basal

area)

at

500 m

although Pentaclethra

macroloba

is

absent.

At

1000 m the

Meliaceae

(10.4%)

and the

Mimosaceae

(10.1%)

are commonest

and

similar

n

their

proportion of the

basal area, whilst the Euphorbiaceae have the

highest

percentage

of

basal area at

1500 m (14.5%)

and

2000

m

(21.7%).

Tree

ferns

(Cyatheaceae)

make a

substantial contribution

to the

basal area

at 1500 m

(9.0%)

and

2000

m

(10.6%). The plot at 2600 m has a

preponderance

of

Araliaceae (25.7%) and Aquifoliaceae (21.9%) whilst oddly, in view of their

abundance

at 2000 m, the Euphorbiaceae are

absent.



10/14

316

ANGELA HEANEY

AND

JOHN

PROCTOR

Table 5. The tree familieswith their

percentage

f total basal area and theirnumbers

f ndividual

rees

(>

10

cm dbh)

in

the six studyplots at a range f altitudes n Volcin

Barva,Costa Rica.

Plot altitudes

100

m 500 m 1000

m 1500 m 2000 m

2600 m

BA

(%) No.

BA

(%) No. BA (%) No. BA

(%)

No.

BA

(%)

No.

BA

(%)

No.

Actinidiaceae 0.48

2

0.03

1

Anacardiaceae 2.15

4

3.09

4

Annonaceae

1.42

30

3.82

15 0.58

5

4.80

29

Apocynaceae 0.23

4

Aquifoliaceae 0.06

1 21.91 72

Araliaceae

3.33

14

3.09

10

0.81

3

5.40

25

3.91

16 25.68

134

Betulaceae

2.32

4

Bignoniaceae

0.14 1

Bombacaceae 0.28 4 0.24 2

Boraginaceae 0.84 5 0.03

1

Brunelliaceae

0.35 2 3.97 15 6.87

65

Burseraceae 7.29 47 4.30 28

Caesalpiniaceae 0.99 9

4.06 15

Capparidaceae 0.05

2

Caprifoliaceae

4.69 25 0.63

7

10.74

128

Caricaceae

0.05

1

Celastraceae 1.10

5

0.12

1

Chloranthaceae

0.43

7 0.03

1

Chrysobalanaceae

0.04

1

5.77 17 3.63

13

Clethraceae

0.13

2

0.26

2

3.75 18

Clusiaceae

0.38 2 0.49

1

0.16

4

Combretaceae

0.56 2 0.64

2

Compositae 0.31 1 0.62 19

Coinaceae

1.37 3

Cunoniaceae

0.29

2 1.23

5

12.75

12

Cyatheaceae

3.01 50 8.96

73

10.59

60

1.74

35

Dichapetalaceae

0.04 1

1.22

3

Dilleniaceae 0.45 9

0.04

1

Elaeocarpaceae 0.08 1

0.54

6

0.39

1

Erythroxylaceae 0.04 1

0.85

7

Euphorbiaceae 4.0

10

5.40

10

3.98

13

14.50

63

21.74

60

Fabaceae 1.38 12 5.82 9

5.18 17

Fagaceae 1.68

4

Flacourtiaceae

2.16

11

1.82

11

2.92

15

2.67

9

Guttiferae

0.16

2

0.78

9

6.39 26 8.49

35

0.48

3

Hamamelidaceae

6.48 24

Hernandiaceae 1.81 5

Hippocastanaceae

2.61 3 5.64 21 3.25

14

2.34

4

0.06

1

Humiriaceae 1.25

1

0.05

1

2.65

7

Icacinaceae

0.57

10

1.21

15

Lacistemataceae 0.05 1

0.65

6 0.06

1

Lauraceae 1.14 11

1.64

14

3.90

14

5.82

19

4.76

22

4.33

32

Lecythidaceae

0.58 1

1.18

2

Malpighiaceae

1.23 2

0.69

2

Malvaceae

0.06

1

0.12

1 0.06

1

Margraviaceae

0.04

2

Melastomataceae 0.10

2 1.64

10

1.12

13

1.10

16 6.83

61

0.28

11

Meliaceae 3.90

17

6.92 32 10.38 52 0.29

7

0.78

6

Mimosaceae

32.94

69 11.85

40

10.09

33

6.99

35

Moraceae

5.82

35 3.34

11

2.66

21

0.08

2

Myristicaceae 1.76 8 2.23 5 0.53 6

Myrsinaceae 0.14 3 2.20 13

0.33

3

1.70 24 5.10

39

3.24

36

Myrtaceae

0.14

2 0.28 2

1.03 24

1.00

18

1.30

7

Nyctaginaceae

1.67 21 0.36

1



11/14

Forest on Volcan Barva

317

Table 5

-

continued

Plotaltitudes

100 m 500 m 1000 m 1500 m 2000 m 2600 m

BA

(%) No.

BA

(%)

No.

BA

(%)

No.

BA

(%)

No. BA

(%)

No.

BA

(%)

No.

Olacaceae 0.99

5 2.27 3

Palmae 10.02 114 0.57 7 3.40 55

0.07 2

Piperaceae

0.04 1 0.52 11 0.02 1

Polygonaceae

0.33 1

Quiinaceae 0.07 1 0.06 1

Rhamnaceae 0.14

2 0.40 3

Rhizophoraceae 0.12 2 0.11 2 0.16 2

Rosaceae

0.76 7 0.17 1 0.08 1

Rubiaceae 0.99 11 2.51 50 2.88 47 3.00 30

2.70 8

Sabiaceae

0.36 2 2.07 6

2.87 13

Sapindaceae 0.09 4 0.71 3 0.05 1 0.35 4

0.27 2

Sapotaceae 2.82 9 3.15 8 7.08 17 3.35 10

Simaroubaceae 0.94

2

Solanaceae

0.70 8 0.11

4

Staphyleaceae

2.29 3 6.14 18

Sterculiaceae

0.18

2 0.30 2

Styracaceae 0.04 1

Symplocaceae

0.14 1

0.49 3 2.41 10 0.18 1

Theaceae

3.27 1 0.09 11 0.58 3 0.11 1

Tiliaceae

3.66 10 1.82 3 0.21 2

Verbenaceae

3.35

1

0.52 3

Vochysiaceae 5.10

2 4.66 5 11.27 10

Winteraceae 0.23 2

2.28 7 0.11 1

Unidentified 0.05 5 0.89 10 3.16 18 14.97 54 7.76 32 4.9 36

or missing

specimens

DISCUSSION

Forest

types

Further nformation

on the

La

Selva

forests and

those

of

the

Barva

transect

is

in

Frankie

et

al.

(1974),

Hartshorn

(1983),

Hartshom & Peralta

(1987)

and Heaney (1988). In the classificationsystemof Whitmore 1984) the two

lower plots

are

probably evergreen owland

rain forest

and the

other four

are

lower montane rain forest although we lack the

leaf-size information

which

is

the most

objective

criterion

for

the classification.

From

Hartshorn

&

Peralta

(1987)

the

plots

are said

to

fall

nto

the

following

Life Zones

(Holdridge

et

al.

1971):

100

m, Tropical

wet;

500

m, Tropical wet,

cool

transition;

1000

m, Premontane rain; 1500

and

2000 m,

Lower

montane

rain; 2600 m,

Montane

rain.

The Life

Zone classification

system

remains

vague,

however,

and

objective

definitions

n terms

of

structure

nd

physiognomy

are

lacking.

The lowland forestsat 100 m and 500 m have a tall statureand are species

rich

by

Central

American

standards

(Hartshorn 1983, Holdridge

et

al.

1971).

The forest of

Corcovado,

Costa

Rica

which

has

100-120

tree

species

haI

was



12/14

318 ANGELA HEANEY

AND JOHN PROCTOR

described by Hartshorn (1983) as

'undoubtedly

the

richest forest in Central

America'. The plots described in the

present paper

at

100, 500

and 1000

m

which have at least 111, 135 and 109 species respectively,

require

this state-

mentto be reassessed.

It is beyond the scope of this paper to review altitudinal changes

in

wet

tropical forests n general. Many

of

the

trends in structure

and

floristics on

Volcain

Barva

(Tables 1, 3,

4 and 5 and

Figures 3-10)

could be

predicted from

other studies (e.g. Grubb 1977) although

regrettablywe

have no information

on

leaf size and shape, frequency of

pinnate leaves, and frequency

of cauli-

flory. The most surprising features on

Volcan

Barva were perhaps that the

largest tature and most species-rich lot was at 500 m ratherthan at the lowest

altitude 100 m) and that the greatest

basal area occurred in the highestplot.

In

view of the recent paper on litterfallHeaney & Proctor 1989) it is

useful

here to compare the stature of the Volcain Barva forests with that of other

montane forestswhere production and

nutrient yclinghave been studied.

The

plots at 1500 m and above on

Volcain

Barva have taller stature trees than:

Jamaican

forests

at

1550

m

(with canopy trees up

to

18

m

tall) (Grubb

&

Tanner

1976); Gunung Mulu, Sarawak

(where

the tallest

trees were 21

m

high

in a

plot at 1310 m, 15 m at 1860 and 5

m near the summit at 2340 m) (Martin

1977); and Gunung Silam, Sabah

(where above 700 m the tallest trees were

21

m) (Proctor

et al.

1988).

Taller

montane forests n which the trees

exceed

the

height of those in the two upper

Volcain

Barva plots are those at ca. 2500

m

on Mount Kerigomna, Papua New Guinea, which have a canopy of 27-33 m

with

emergents p to 37

m

(Edwards

&

Grubb 1977); and at Merida, Venezuela

at

about 2300 m with a canopy

height of 35-40 m (Grimm & Fassbender

1981).

At

present

there is

no unifyinghypothesiswhich satisfactorily xplains

the

altitudinal changes of the forests on

Volcain

Barva and the differences etween

these

forests nd those elsewhere.The likelihood that decreasing nitrogen upply

with altitude

is

important

on Volcain Barva

is

discussed

by Heaney

& Proctor

(1989)

and

Marrs

et

al. (1988). Generalizations fromecological work

on Volcan

Barva

are

hindered because of the

non-uniformity f the

mountain's

lithology

and its lack of really low stature upper montane or sub-alpine forest.The

answers

to

many of the questions about forests of wet tropical mountains will

be facilitated

by long-term nd experimental studies. In this respect the Volcain

Barva forests

are

ideal since they now have a fully protected status and are

close

io

the excellent facilities of the

La Selva Field Station. The six plots

discussed

here and others set up later are

currently eing monitored for growth

and

regeneration

studies

by

D. and

M.

Lieberman

who

are also

obtaining

more

detailed

climatic

nformationfromthe mountain.

ACKNOWLEDG

EMENTS

We thank

National

Parks

Service of Costa Rica forpermission to work in Braulio

Carillo,

The

Organization for Tropical

Studies for permission to work in the



13/14

Forest

on

Volcan

Barva

319

grounds of

La

Selva Field Station, Operation Raleigh for

support,

its staff

(particularly Mr K.

Hamylton-Jones) and venturers for help, and Dr G. S.

Hartshorn for help

in

the

field and

for his tree

dentifications.Drs P.

J.

Grubb,

D. L. Kelly and E. V. J. Tanner are thanked forcomments on themanuscript.

The

work was supported financially by the British Ecological

Society, the

Carnegie Tru'st, the Leverhulme Trust and the National

Environmental Re-

search Council.

LITERATURE

CITED

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Accepted June 1989

BOOKS RECEIVED

DDT and its deriviates

-

environmental aspects. Environmental Health Criteria, No.

83.

World Health Organization. 1989. 98 pages. ISBN 92-4-154283-7. Price:

Sw. fr.

13.-;

US$ 10.40. Order no. 1160083.

This small book considers the effects of DDT and its metabolites on populations of organisms

in the environment from an ecotoxological point of view. The opening sections deal with the

properties of these substances that help to explain their resistance to degradation, their

widespread persistance in the environment, and their high potential for bio-accumulation.

The major part of the book is concerned with their toxicity to micro-organisms, and aquatic

and terrestrial animals, with the emphasis on fish and birds. Ecological effects from field

application are also discussed. Numerous controlled laboratory experiments documenting

direct and sublethal effects are cited (20 pages of references). In the final evaluation, the

book

concludes that these compounds should be regarded as a major environmental hazard.

Obtainable from: World Health Organization, Distribution and Sales, 1211 Geneva 27,

Switzerland.

KARTIKASARI,

S. N.

&

WHITTEN, A. J. 1989. The natural resources, ecology and

environ-

ment of Java and Bali: a

bibliography.

(in English

and

Indonesian). EMDI, Jarkarta.

320

pages. ISBN 979-8115-00-7.

Obtainable from: Publications Office, EMDI, Kantor Menteri Negara, Kepen Kependudukan

dan Lingkungan Hidup, Jalan Merdeka Barat 15 Jakarta 10110. Indonesia.

ZEIN AHMED

ZEIN &

HELMUT KLOOS, (eds). 1988.

The

ecology of

health

and disease

in

Ethiopia. Ministry of Health, Addis Ababa.

xi

+

319 pages.

This

book reflects

the main

concerns

and

issues

in

health

development

in

Ethiopia today.

Adopting

an

ecological approach,

it identifies

and

suggests

solutions

for some

of

the

major

health problems

of

the population. Contributors are

from various fields

in

public

health

and

the

medical and social sciences, and it

is

intended

for

Ethiopian graduate

and

undergraduate

students

in

these disciplines, as well as medical and public health researchers, planners

and

policy-makers.

Obtainable

from: Ministry

of

Health, Planning,

and

Programming Bureau, through:

Zein

Ahmed, PO Box 109, Gonder, Ethiopia, and Helmut Kloos, PO Box 31609, Addis Ababa,

Ethiopia.

preliminary studies on forest structure

Documents