forest association and phenology of wild coffee in kibale national park, uganda

Afr. J. Ecol. 1998, Volume 36, pages 241–250

Forest association and phenology of wild coffee in KibaleNational Park, Uganda

JOHN M. KASENENE

Department of Botany, Makerere University, P.O. Box 7062, Kampala, Uganda

Summary

A study on the forest association and phenology of wild coffee (Coffea canephoraPierre) was conducted in Kibale forest, Uganda. Nested quadrats were used toenumerate tree species, including coffee and herbaceous plants associated with forestand coffee stands. A total of 150 coffee trees was marked along transects and monthlyscans carried out to score for fruits, flowers, leaves and leaf insect damage. Pre- andpost-dispersal predation levels and coffee yield estimates were made by examiningfruits from trees, forest floor and seasonal fruit falls into demarcated plots.

In the forest, wild coffee stands are associated with low-quality forest types interms of timber species (about 10.5 canopy species/study site) and low stockingdensities of trees[ 50 cm d.b.h. (average 38 trees ha−1 for each site) and poor forestregeneration. In the forest, wild coffee reproductive phases overlap with ripening,coinciding with flower bud and flower production. The variable peak ripening seasonfalls between November and April. The wild coffee yields are generally low (averageof 3.5 intact fruits 16 m−2 month−1), with low insect fruit/seed damage (4–19%) buthigh levels of wastage due to monkeys, bats and birds.

Key words: phenology, wastage levels, wild coffee, yield

Resume

On a mene dans la foret de Kibale, en Ouganda, une etude sur les associationsforestieres et la phenologie du cafe sauvage (Coffea canephora Pierre). On a utilisedes quadrats imbriques pour enumerer les especes d’arbres et aussi les cafeiers et lesplantes herbacees associes aux forets et aux endroits ou pousse le cafe. On a marque150 cafeiers le long des transects et on a fait des controles mensuels pour relever lapresence de fruits, de fleurs, de feuilles et de dommages causes aux feuilles par lesinsectes. On a realise des estimations des taux de predation avant et apres dispersionet de la production de cafe en examinant les fruits sur les arbres, sur le sol forestieret les chutes de fruits saisonnieres dans les quadrats delimites.

Dans la foret, la presence de cafeiers est associee a des types forestiers dequalite mediocre en terme d’exploitation de bois (environ 10,5 especes hautes paremplacement etudie), a une faible densite d’arbres d’au moins 50 cm de diametre(moyenne de 38 arbres/ha, a chaque endroit) et a une faible regeneration forestiere. Enforet, les phases de reproduction du cafe sauvage recouvrent celles de la maturation,coıncidant avec l’apparition des boutons et des fleurs. Le pic variable de la saisonde maturation tombe entre novembre et avril. Les recoltes de cafe sauvage sontgeneralement basses (moyenne de 3,5 fruits intacts/16 n2/mois), de meme que les

1998 East African Wild Life Society.

242 John M. Kasenene

dommages causes aux fruits et aux graines par les insectes (4–19%), mais les pertesles plus elevees sont dues aux singes, aux chauves-souris et aux oiseaux.

Introduction

Currently, both the conservation ecologists and managers of protected areas contendthat forest resources have been historically utilized by the local societies. They arguethat one guarantee for their appropriate management is continued communityparticipation and an appropriate reward by way of resource sharing (Swanson &Barbier, 1992). However, past forest management often neglected the valuable non-timber resources such as wild coffee that can be sustainable and have low impact inextraction (Kasenene, 1987; Struhsaker, 1988) compared to logging for timber, fuelwood and charcoal.

In October 1993, the former Kibale forest reserve was given the status of KibaleNational Park, currently under the new Uganda Wildlife Authority (UWA). Thechange in status to National Park also meant changes in overall managementobjectives which currently emphasize multiple and non-consumptive uses of theforest such as ecotourism, research, training and the harvesting of minor forestproducts such as wild coffee. In this case, much interest lies in benefiting the localcommunities based upon the resources offered by the forest.

The wild coffee plant (Coffea arabica) is indigenous to Africa, more specificallythe highland forests of Ethiopia (Smith, 1985). Also indigenous to African andUgandan tropical forests as components of the understorey are Coffea eugenioidesS. Moore, C. canephora Pierre and C. liberica Bull ex Hiern. Coffea liberica isrestricted to the cool and wet highlands of central western Uganda and the othertwo species are more widespread, with strong adaptations to rainfall and soil types(Thomas, 1944; Cambrony, 1992).

The two common coffee species in Kibale National Park include C. canephoraand C. eugenioides (Smith, 1985; Kingston, 1967). Coffea eugenioides is ubiquitousin small amounts, whereas C. canephora is more habitat-restricted but very abundantwhere it occurs.

Coffea canephora is the most important commercial wild coffee species, coveringabout 78 km2 of forest (Fig. 1). It attains optimum development in the forestunderstorey strata. Historically, communities near the Kibale forest boundary har-vested wild coffee for traditional uses such as chewing, exchange as gifts, burialceremonies, blood-brotherhood rituals and some small-scale trade. However, thelocal coffee trade collapsed in the mid-1970s, following the expulsion of Asian tradersand economic mismanagement, whereby inflation cut into the purchasing power ofproduct prices which were usually fixed. Secondly, the low prices of coffee were alsonot usually paid on time, resulting in a further decline in their purchasing power.Besides the commercial potential, both species of wild coffee also present untappedgenetic resources for the development of alternative cultivars.

There is currently an expanding farming population peripheral to the KibaleNational Park (KNP). Its dependence and impact on the wild coffee resources arelikely to increase with time. Therefore, the study was aimed at generating some basicinformation on the ecology and productivity of wild coffee that will assist in themanagement of a commercially viable non-wood forest resource. This study presentspreliminary findings of a planned long-term monitoring on: (a) the wild coffee and

East African Wild Life Society, Afr. J. Ecol., 36, 241–250

Wild coffee in Kibale National Park, Uganda 243

Fig. 1. Approximate location of major wild coffee stands in Kibale National Park.

forest association in the KNP, and (b) the ecology of wild coffee communities,including abundance, recruitment and growth, regeneration success and productivity.

The study was conducted in the Ngogo area of Kibale National Park in WesternUganda (Fig. 1). The forest is equatorial and lies on a plateau of 1590 m in thenorth and 1110 m in the south. Kibale forest rainfall is low to moderate (average=1700 mm/year) and comes in a typical tropical pattern of two nearly equal maximaand minima (Struhsaker, 1975). Because of the high altitude, low rainfall andtemperature, the KNP is classified as medium altitude tropical moist forest (Langdale-Brown, Osmaston & Wilson, 1964), but physiognomically similar to lowland tropicalrain forest.

Materials and methods

Wild coffee stands were visited at Ngogo and Karambi in Kibale forest to select thebest sites for long-term study. Three coffee stands at Kibuguta, Kisororo andMagambe, no less than 5 km apart were selected for the study.



Wild coffee and forest association

In each study site, five line transects cutting through nested quadrats (20×25 m)were systematically located at 100 m intervals for the enumeration of all tree speciesincluding coffee trees (13 cm d.b.h.). In 10×20 m plots, all coffee and other woodyspecies poles (5–13 m d.b.h.) were sampled. The sampling of all woody species(2–5 cm d.b.h.) were in 5×10 m plots, whereas seedlings of all woody species(< 2 cm d.b.h.) and the ground vegetation were sampled in 2×4 m plots. All plantswere identified to species or voucher specimens collected and treated for herbariumwork.

Wild coffee phenology

The descriptive and observational phenological methods as used in Leigh (1970)were employed. A total of 50 reproductive trees for Kibuguta and Kisororo and 150for Magombe were permanently marked in the forest understorey or forest gaps.The trees were scanned at the end of each month. The phytophases sampled includedfruits, flower buds and flowers, leaves (young and mature) and leaf insect damage.Each category of phytophase and insect damage was given a relative score of 0, 1,2, 3 or 4 representing none, very few, some and many structures, respectively.

Coffee fruit and seed predation

Pre- and post-dispersal fruit/seed predation levels were estimated. Twenty fruits werepicked from two trees in each 10×10 m plot before and during the ripening season.Twenty more fruits were also picked from the ground at the base of the trees andbagged separately. The number of fruits and seeds infested and/or damaged and thenumber of larvae extracted from them were recorded. The coffee epicarps and seedswere examined carefully for signs of predators (or coffee seed dispersal agents).The insects and larvae from the fruits and seeds were preserved for subsequentidentification.

Coffee yield estimates

The ground area of 50 randomly-selected, marked and mapped mature coffee treesin each study site was cleared of all litter and debris. All the fallen ripe fruits werepicked, counted and weighed in the field before sun-drying. Estimates of annualcoffee yields are obtained from the average density of productive coffee trees, sizeof coffee crops and the coffee predation (or loss) levels.

Results and discussion

Wild coffee and forest association

The most important canopy tree species in Kibuguta and Magombe study sitesinclude (in order) Chrysophyllum gorungosanum Engl, Diosphyros abyssinica (Hiern)F. White, Funtunica latifolia (Stapf.) Schlechter, Celtis durandii Engl., and Markhamiaplatycalyx (Bak) Sprague (Table 1). A total of 13 and eight tree species constitutedthe forest canopy in Kibuguta and Magombe study sites, respectively. Compared to



Tabl

e1.

Stan

dta

ble

ofco

mm

ontr

eesp

ecie

s(N

o.ha−

1 )fo

rmin

ga

cano

pyab

ove

coff

eest

ands

in(a

)K

ibug

uta

and

(b)

Mag

ombe

stud

ysi

tes.

Size

clas

ses

(cm

d.b.

h.)

10–1

515

.1–2

020

.1–2

525

.1–3

030

.1–3

535

.1–4

040

.1–5

0>

50

Tre

esp

ecie

sa

ba

ba

ba

ba

ba

ba

ba

b

Chr

ysop

hyllu

mal

bidu

m18

1220

1424

1016

189

56

119

95

8D

iosp

yros

abys

sini

ca36

1710

2012

195

47

61

100

72

11C

elti

sdu

rand

ii13

115

53

101

11

22

25

71

2M

onod

ora

myr

isti

ca0

00

01

01

00

00

00

02

0F

untu

mia

lati

folia

1124

59

02

10

23

10

71

811

Mar

kham

iapl

atyc

alyx

86

116

43

36

03

11

13

07

Cel

tis

afri

cana

10

00

00

00

00

00

30

03

Aph

ania

sene

gale

nsis

20

00

11

10

02

00

00

00

Lov

oasw

ynne

rton

ii2

00

00

00

00

00

00

00

0C

ordi

am

illen

ii2

00

00

01

01

00

01

00

0B

alan

ites

wils

onia

na4

00

00

01

00

00

02

01

2U

nide

ntm

ksku

310

180

30

00

00

00

00

00

Str

ombo

sia

sche

ffler

i0

00

00

01

02

02

03

010

1

Tot

al=

13/8

128

7069

4048

3631

2922

2113

2432

2732

44



other Kibale forest types without coffee in the understorey (Kasenene, 1984, 1987;Skorupa, 1988), these exhibit very low regeneration and poor stocking densities ofstems both in the juvenile, intermediate and large size classes (Table 1). In otherKibale forest types devoid of coffee, there are usually more than 55 tree species thatform the forest upper canopy, with an abundance of stems in the various size classes(Langdale-Brown et al., 1964; Kingston, 1967; Struhsaker, 1975; Kasenene, 1987).In the Kibale National Park, therefore, the most commercially viable wild coffee,C. canephora, occupies the forest types with mediocre quality, both in terms of forestregeneration, timber species and stocking densities.

In terms of regeneration and recruitment into the various size classes, wild coffeeplants seem more successful than the associated tree species. In Kibuguta study sites,the average density of coffee seedlings, saplings and poles was 58,750, 6416.7 and2438.7 stems ha−1, respectively, whereas the large trees (5–10 cm d.b.h.) had a densityof only 740 stems per hectare. The corresponding figures for Magombe study sitesare 31,125, 5000 and 1108 coffee seedlings, saplings and pole stems ha−1 and 722(5–10 cm d.b.h.) trees per hectare. The coffee stands at Kibuguta show significantlyhigher stocking densities for all size classes than stands at Magombe (all PΖ0.01,Wilcoxon signed rank test). For all study sites, there was almost a 98.6% reduction(through various mortality factors) in the density of coffee from the seedling classesto maturity. This observation requires immediate investigation in order to understandthe recruitment, growth and survival strategy of wild coffee.

In the forest understorey and semi-open areas, the most important herbs andshrubs, in order of importance, included Leptaspis cochleata Thwaites, Afronomumsp., Palisota schweinfurthii CB. CL, Polia condensata CB. CL., Piper umbellatum L.and a diversity of fern species, Dracaena and Setaria. The correlation between treespecies density (No. 500 m−2) and the herb/shrub density with coffee seedlings andsapling density was very weak (all rΖ0.38). However, the coffee seedling and saplingdensity was generally inversely correlated with the percentage ground vegetationcover, more especially of Leptaspis cochleata (r=–0.58). It seems, therefore, thatcompetition and other factors such as soil characteristics, differential herbivory andpathogens could be influencing wild coffee recruitment and development.

Wild coffee phenology

There was continuous coffee fruit production for coffee stands because of individualtrees exhibiting various reproductive phases out of synchrony (Fig. 2). All monthsin the year showed either green young fruits or green big fruits, indicating continuouscoffee production. For all coffee stands studied, the ripe fruits appeared on the plantsfor a prolonged period from December–January to as late as July of the followingyear. The magnitude of production and ripening varied between months and coffeestands and the peak coffee ripening period seemed to fall between December andApril.

The periods of high flower bud and flower production (July–September andDecember–March) coincided with low coffee yields. This is another indication of anunspecified wild coffee production season. It is not clear whether Kibale wild coffeehas two distinct coffee production periods, as reported by Kingston (1967), or onelong period of overlapping phenophases at varying intensities, as suggested by thisstudy. Kingston (1967) observed two peaks in coffee production during the dry



Fig. 2. Wild coffee fruit production in the forest understorey at Kibuguta (KU), Magombe (MU) and inforest gaps at Magombe (MG) study sites in Kibale forest.

seasons of December–March and June–September of each year. Further research istherefore needed to explain whether the currently unpredictable weather and climateof Kibale National Park has had an influence on the phenological cycles of theforest wild coffee.

The pattern of understorey coffee production and maturing periods for Kibuguta(Fig. 2, KU) and Magombe (Fig. 2, MU) are similar. However, coffee plants inclearly defined forest gaps (Fig. 2, MG) appeared to be the most healthy and vigorousin activity. Consequently, the coffee flower bud, flowers and fruit production arehighest for the forest gap trees, compared to those in the understorey of other foresttree species (Fig. 2). The mean phenological scores for coffee fruits on trees inMagombe forest gaps was 2.18 (scale 0–4 points), compared to Magombe andKibuguta forest understorey coffee trees, which scored 1.40 and 1.24, respectively.The coffee berries for gap trees reached maturity much earlier and ripened muchmore quickly than those under the forest canopy.

The production of leaf buds and young leaves was also almost continuous (Fig. 3).A high percentage of mature leaves is also retained throughout the year. Leaf insectdamage is continuous and more serious on the mature than young leaves. Leaf insectdamage seems to peak during the dry months, when the coffee stands in Kibugutasuffered a higher percentage leaf damage than those in Magombe. The coffee plantsin the forest gaps (Fig. 3, MG) showed the least insect damage and high densitiesof healthy mature leaves throughout the year. It seems, therefore, that light selectivelogging or minimal forest disturbance that could create gaps in the forest canopyshould be beneficial to the health and productivity of the wild coffee.



Fig. 3. Wild coffee leaf production in the forest understorey at Kibuguta (KU), Magombe (MU) andforest gaps at Magombe (MG) study sites in Kibale forest.

Table 2. Pre- and post-dispersal coffee fruit/seed insect damage in Magombe study sites.Number of fruits sampled site−1 month−1=500

1994 1995

Parameter Jul. Aug. Dec. Jan. Feb. Mar. Apr. May Jun. Jul.

% Fruit intactPre-dispersal 74.8 88.4 93.8 86.2 85.2 79.2 97.0 85.0 29.2 82.0Post-dispersal 75.6 85.6 89.8 85.2 85.2 77.6 80.2 79.2 30.0 90.0

% Seed intactPre-dispersal 77.0 88.7 93.0 89.0 88.5 89.6 90.4 89.0 82.5 65.0Post-dispersal 78.9 87.1 86.6 86.6 88.0 92.1 87.0 88.3 81.5 85.5

% Seed damagedPre-dispersal 18.5 8.4 4.0 8.2 9.1 10.4 10.6 11.0 12.8 11.5Post-dispersal 16.5 10.4 9.6 10.7 11.0 7.9 13.0 11.7 14.5 15.0Mean insect 5.5 1.6 0.0 0.0 0.0 0.0 1.0 2.3 2.6 0.5Larvae/ten fruits 9.6 3.8 0.9 0.3 0.0 0.0 1.5 6.3 3.3 0.4

Coffee fruit and seed predation

Pre- and post-dispersal coffee seed predation estimates show high percentages ofintact fruits and seeds and low insect seed damage (Table 2). There were no significantdifferences in the amounts of pre- and post-dispersal intact coffee fruits and seeds.However, in 80% of the samples, percentage post-dispersal coffee seed damage washigher than pre-dispersal (P Ζ0.01, Wilcoxon signed rank test). The intensity ofcoffee fruit and seeds damaged seemed to increase with advanced fruit maturity,length of post-dispersal period and peaked during the ripening period. Consequently,the number of insect larvae and coffee seeds damaged per fruit were higher for post-dispersal than pre-dispersal fruits and seeds.



Tabl

e3.

Wild

coff

eeyi

eld

esti

mat

esin

clea

red

plot

s/st

udy

site

(n=

50,

4×4

m) 19

9419

95

Par

amet

ers

Stud

ysi

teJu

l.A

ug.

Sept

.O

ct.

Nov

.D

ec.

Jan.

Feb

.M

ar.

Apr

.M

ayJu

n.Ju

l.

Mea

nfr

uiti

ngK

ibug

uta

3.1

3.7

2.8

3.0

3.3

3.4

3.2

3.3

3.6

3.2

2.9

3.2

3.4

tree

s/pl

otM

agom

be2.

22.

92.

21.

92.

22.

42.

42.

41.

82.

62.

02.

32.

1M

ean

inta

ctK

ibug

uta

0.0

0.3

1.2

0.6

7.5

1.4

1.8

0.0

5.7

8.3

6.7

12.9

4.1

frui

t/pl

otM

agom

be3.

62.

95.

75.

54.

83.

22.

80.

02.

93.

31.

54.

21.

1M

ean

seed

less

Kib

ugut

a0.

00.

020.

040.

00.

01.

36.

01.

64.

21.

44.

72.

34.

5fr

uits

/plo

tM

agom

be8.

40.

10.

00.

01.

07.

25.

80.

01.

11.

20.

031.

80.

5



Kibale wild coffee yield estimates

Within the 50 randomly-selected 16 m2 yield plots, the number of fruiting trees persite and month was very variable (Table 3). This indicates another temporal variationin reproductive coffee stand densities and dynamics of coffee production. As soonas the coffee ripening season arrived, heavy pre-dispersal fruit/seed waste and damageby animals begun. The most discernible forms of fruit/seed waste were by monkeys(Red tail and Red Colobus monkeys), bats and birds. These picked mature ripe andsemi-ripe fruits and burst them open. In most cases, the epicarp was ejected and theseeds discarded later on. About 60–80% of the coffee produced for the season waslost or wasted (or perhaps dispersed into the forest understorey) before completeripening and fruit fall.

Consequently, in an undisturbed state, wild coffee is a low-yielding resource withan average of six mature, ripe and intact fruit per 16 m2 during the ripening season.

Acknowledgements

This work formed part of an extensive long-term study of the Kibale forest wildcoffee resources. We thank the Kibale Forest Park and now National Park authoritiesfor allowing the research to be undertaken. The Wildlife Conservation Society, NewYork, provided the funds for the study.

References

C, H.R. (1992) Growing Coffee and Tropical Agriculturist. CTA MacMillan.K, J.M. (1984) The influence of selective logging on rodent populations and the regeneration of

selected tree species in the Kibale Forest, Uganda. Trop. Ecol. 25, 179–195.K, J.M. (1987) The influence of logging intensity and gap size on the regeneration of a tropical

moist forest in Kibale Forest, Uganda. PhD Thesis, Michigan State University, U.S.A.K, B. (1967) The Working Plan for the Kibale and Itwara Central Forest Reserve. Uganda Forest

Department, Entebbe.L-B, I., O, H.A. & W, J.G. (1964) The Vegetation of Uganda and its Bearing

on Land Use. Government of Uganda Printer, Entebbe.L, H. (1970) Phenology in Productivity Studies. An Analysis of Temperate Forest Ecosystems. Chapman

and Hall, London.S, J.P. (1988) The Effects of Selective Timber Harvesting on Rain Forest Primates in Kibale Forest,

Uganda. PhD Thesis, University of California, Davis.S, R.F. (1985) History of Coffee. In: Coffee: Botany, Biochemistry and Production of Beans and

Beverages. The AVI Publication Co., West Park, U.S.A.S, T.T. (1975) The Red Colobus Monkey. University of Chicago Press, Chicago.S, T.T. (1988) Forest issues and conservation in Uganda. Biol. Conserv. 9, 209–234.S, T.M. & B, E.B. (1992) Economics of the Wilds: Wildlife, Wildlands Diversity and

Development. Earthscan Publications Ltd, London.T, O.A.S. (1944) The Wild Coffee of Uganda. Empire J. Expt. Agric. 12, 1–12.

(Manuscript accepted 6 October 1997)


forest association and phenology of wild coffee in kibale national park, uganda

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