Borassus aethioPum, a ThreatenedMultiple Purpose Palm in Senegal

BrrxvnNu SeMsou,r Jones E. LAwESSoN,'AND ANDERS S' Bennoo2t[Jniuersit6 Cheikh Anta Diop de Dakar, FacuJtE des Sciences,

Institut des Sciences d'e l'Enoironnement, Dakar, Senegal and'zBotanical Institute, Uniuersity of Aarhus, Nordlandsaej 68,

DK-8240 Risskotl- Denmark

B or a,s su s aethio pum is an economicallyand ecologically important palm tree of theSahelian and Sudanian zones in Africa (Gif-

fard 1967, Gschladt I972). This majesticrepresentative of the subfamily Coryphoi-deae is often found in dense populationsin periodically inundated depressions in theIandscape or along rivers and lakes (Cheva-

lier 1949, Chevalier and Dubois i938)'Borassus aethiopurn was originallydescribed by C. F. P. von Martius (1838)

who separated it from the widespread andclosely related Asian species , Borassus fla'bellifer, based on a description of Thon-ning in Schumacher (1829). According tothis, B. aethiopum'is characterized by theventricose stem (Fig. l) of old individualsand the five to seven male flowers in eachflower cluster (cincinni) as opposed to tento fifteen in B. f'abetlifer. The number offlowers per cincinni is variable and in B.aethiopum it is typically B-10, thus it isnot a good distinguishing character. Inother and older works, B. aethiopum' iseither cited in slmonymy with B. f'abelliferor retained as a variety under this. Theonly existing monographic treatment of thegenus Borassus is that of Beccari (1924}This work includes seven species and rec-ognizes B. aethiopum with three variants:vat. senegalensis, var. bagamojensis andthe typical form. B. aethiopurn is distin-guished from B. f'abellifer by having acalyx that is connate to the middle and notsplit to the base as in this species. In mod-

l48

Principes, 36(3), 1992, pp. 148-155

[Vor. 36

ern treatmentsl €.g.: Flore du S6n6gal(Berhaut 1967), Flora of West TropicalAfrica (Hepper, 1968), Flora of TropicalEast Africa (Dransfield 1986) and, Floreillustr6e du S6n6gal (Vanden BerghenI98B) the position of B. aethiopurn ismaintained. We have accePted B.aethiopurn in this paper based on the dif-ferences given by Dransfield (1986). Bor-assus aethiopurn is accordingly more mas-sive than B. f.abellifer. The leaves aremore rigid, less deeply folded and greaterin number. Along with the ventricose stem'this gives a different appearance from B.

f.abellifer.Borassus aethiopum plays an impor-

tant role in Senegalese rural life where itis the source of a number of products (Niang

1975, Diouf 1982, Sambou 1985). It iscalled "ron" in Wolof dialect from whichthe French "r6nier" is derived. Destruc-tive agricultural practices and lack of man-agement is now threatening populations allover the country (Bellouard 1950, Diallo1987, Sambou 1989). Dense populationsof Borassas aethiopun't' are {ound in thesouthern and southeastern parts of Senegalclose to rivers and lakes where the ground-water level is high. Natural populations ofBora,ssus aethioputn are rare in the north-ern part of Senegal, but the palm is oftenplanted in fields (Fig. 2). The best climaticconditions for this palm prevail in the mid-dle part of the country where large pop-ulations once occurred.

P R I N C I P E S

r9921 S.{\IBOU ET AL.: BORASSUS IN SENEGAL t49

l-4' Borassus aethiopum- i. Old individual. Note the swollen or ventricose stem. 2. palm tree plantedin mixed cropping system. Note the male inflorescence and the persistent leaf sheaths characteristic of yourgplants' 3' Cross section of immature fruit. Note the fleshy -".o"urp and the three pyrenes that each contain

the gelatinous endosperm. 4. Roof thatchei with the leaves.

P R I N C I P E S [Vor. 36t50

Overexploitation and habitat degrada-

tion is threatening this palm so seriously

that Senegalese authorities are now trying

to protect it. It is illegal to exploit the wood

foi commer"ial purposes and other laws

resulate its use in the common lands of

thi villages (Government of Senegal I973).

Despite these efforts the destruction seems

to 6e continuing. This paper will first

describe some of the many uses of Borassusaethiopum and then mention the various

threats to which it is exposed in Senegal.

UsesAll parts of Borassus dethiopum are

exploited and used for a wide array of

pnipot"t (Table i). The products can b9

airnid"d into three major groups which will

be treated shortly in the following: ligneousproducts (wood, fibers, etc.), food, andmedicine.

A number of parts of the palm are edi-

ble. The young gelatinous endosperm is a

highly esteemed and nutritious snack (Fig.g). The mesocarp is fleshy when ripe and

can be prepared and consumed in many

ways: grilled, boiled, or mixed with sugar

or honey. The.cotyledonary haustorium of

the germinating seed is soft and sweet and

highly appreciated. The premature foldedleaves of the seedling are collected from

below the soil and eaten. TheY have a

fleshy texture and are very tasty. The palm

heart of Borassus aethiopum is also

exploited although the difficulties involvedin extracting it somewhat limit its impor-

tance as a food source. A sap' which is

very high in sugar content' is tapped from

near the apical meristem at the base of

the palm heart (Bismuth and Menagei961 ) .

Borassus aethioputrl is also used for a

number of medicinal purposes (Giffard

1962). An infusion of the roots is used to

treat miscellaneous ailments such as stom-ach ache, throat infections, bronchitis andsyphilis. The flower-bearing branches or

rachillae of the staminate inflorescencesare used to treat venereal diseases. The

stamens are mixed with Shea-butter and

Tabte 1. The Dffirent Porls olfBorassusaethiopum Used bY Man

used to heal wounds' The mesocarp of the

ripe fruit is used as a stimulant and against

tetanus. It is said to be a very efficientremedy against intestinal parasites too. The

eophyil (the first leaf) of the seedling and

the sap are also used as stimulants. The

sap tapped from the stem is believed to

stimulate the growth of teeth in children'The stem of Borassus aethiopurndeliv-

ers a hard wood that is resistant to decay

and the damaging effects of seawater. The

durable wood is rarely attacked by termitesand funei and is said to have excellentworking-properties. It is used extensivelyby local carpenters for multiple purposes'to mention just a few: furniture, timber in

heavy construction such as bridges and

houses, boards for making floors, walls and

roofs in houses. The soft swollen part of

old trunks serves other purposes (Fig. 5)'

A rich cottage industry is based on the

extraction of the leaves. The blade or seg-

I . Uses based on structural properties

O Stem (timber, boards)

O Leaves-petiole (fences, fibers)-blade (roofs, baskets, mats, rugs'

furniture)

Uses based on nutritional and medicinal

properties

O food-endosperm-cotyledonarY haustorium-palm heart-mesocarp-sap tapped from near the shoot apex

(alcoholic beverage)

O medicinal-room-male rachillae-stamens-mesocarp-hypocotyl-sap tapped from the trunk or near

the shoot apex

[.

r9921

ments of the blade are used with great

ingenuity for making thatch, mats, rugs,

baskets (Fig. 4), bathtubs, etc. The leaf

fibers are extracted and used for brooms

and baskets (Fig. 6). The leaf petioles are

skillfully exploited in arts and crafts (Fig.

7) and are used to build fences around

houses and pastures. In the North, where

the vegetation is sparse, leaf petioles often

serve as firewood.Several aspects ofthe ecology of Boras-

sus aethiopum make it an interesting plant

SA}IBOU ET AL.: BORASSUS IN SENEGAL r 5 1

5-8. Borassus aethiopum. 5. A beehive made of the swollen and soft part of the trunk. 6. Baskets

braided from the major veins of the leaves- ;. The fruit mesocarP ofers a nutritious snack' The chairs and

table are made from leaf petioles. 8. The death of some old palm trees such as these is probably related to

droueht.

from an agricultural point of view. Its

fibrous root system forms a dense mat in

the surface Iayers of the soil which helps

to prevent soil erosion. It has been dem-

onstrated that the staminate rachillae

release potassium upon decomposit ion

thereby enhancing soil fertility (Maydell

1983). These beneficial effects are

exploited in many parts of Senegal where

agro-forestry systems are based on man-

aged natural populations of Borasszrs

aethiopum.

. - " . I I l

1,,t::

r52

Threats

The destruction of Boras sus aethio pumis either a result of complete removal ofnatural populations or a slower process

[Vor 36

where age distribution becomes progres-sively more skewed. This process mayeventually lead to a complete lack of youngstages in the population which can preventfuture regeneration. The factors respon-

P R I N C I P E S

9 12. Borasus aethiopum. 9. Male (left) and female of Oryctes monoceros Ol. (family Scarabei-

4""). I0' The signs of an Oryctes attack in a juvenile palm. II. Tapping of sugar from the crown.Exploitation has caused the death of the palm tree at the left. 12. Borassui aethiopurn must give way for

the cultivation of millet.

r9921 SAMBOU ET AL.: BORASSUS IN SENEGAL

HUMAN FACTORSIV

I 5 3

"tii:x'l:: v / [l 8:il[:

monoceros"ti';:'Hi""* ffi-/ Z:l:::: il::"""'"" Il 3i::T;, n'n""Exploi tat ion M oryctes gigas Fungi

F i r eExploitation ol leavesExploitation oi woodExploitation of sap

lrom stem

sible for destruction of Borassus aethiopumcan be divided into two major groups: nat-ural and anthropogenic (Fig. l3).

The most important natural factorthreatening populations of Borassusaethiopum is probably drought. A steadilygrowing rain deficit during the last two

Exploi tat ion of eophyl l

tI

t3. Natural and hman factors causing degradation of Borasszs aethiopum populations in Senegal.

F i reExploitationoi green fruit

F i r eAg r i cu l t u r eExploi tat ion

ol nut

decades has caused high mortality amongolder palm trees that are sensitive to fluc-tuations in the ground water level (Fig. 8).Destructive insects also represent a seri-ous threat to Borassus aethiopum (Castel-Branco and Tordo 1956, Lepesme 1947).After the apical meristem has appeared

ol sap from stem IAsr icu l ru re | +

| * NATURAL FAcroRS >t\ {

@

/

Wk ili:i:: 3*:.""'"'I

t54

from below the soil, it is exposed to theattack of three species of Oryctes Ildtger(Scarabeidae) in particular. The two mostcommon species are Oryctes rrlonocerosOlivier (Fig. 9) and. Oryctes boas Fabri-cius. The third species, Oryctes gigas Cas-telneau, is rare but is found in the humidsouthern part of Senegal. All three beetlesdig into the base of the apical meristem(Fig. I0) and suck the sap which oftenresults in the death of the palm tree. Theycan reproduce in the swollen subdistal partof the stem of old individuals. The partlydecomposed dead stems offer ideal con-ditions for the development of larvae.

Man's activities have had a severeimpact on natural populations of Bora,ssusaethiopum in Senegal. The main factorscontributing to the destruction are agri-culture (Fig. I2), fire and, exploitation ofwood, and use of palmheart and sugar saptapped from near the apical meristem. Thelatter is a very destructive practice wherea hole is drilled through the leaf bases (Fig.I l) and a sap is tapped from the soft andfleshy tissues near the apical meristem.Usually the palm dies after having beenexploited in this way. It should be notedthat in India and SE Asia, inflorescencesof Borassus flabellifer are tapped withoutdamaging the plant.

In some Borassus aethiopum popula-tions, the age-distribution is so skewed thatcertain developmental stages are com-pletely lacking. What appears to be seed-lings are in fact very old individuals, thatremain small due to agricultural practicessuch as burning of the ground cover.

Adult individuals of Borassus aethiopurndeliver a number of products that are highlyappreciated by village people and they areconsequently threatened by overexploita-tion. Thus. reoeated collection of leavesmay severely limit the growth of the palmand excessive extraction of green fruits,germinated seeds or young seedlings mayimpede the potential of natural regenera-tion.

[Vor. 36

Conclusion

Borassus aethiopum, a genuine mul-tiple purpose palm tree, is a victim of itsown high utilitarian value. Both human andnatural factors are threatening the naturalpopulations in Senegal. As long as the useof this valuable palm is not regulated, thesituation will probably worsen. Only strictmanagement of the remaining natural pop-ulations will save an important plantresource for future generations.

Acknowledgments

Soecial thanks are due to the inhabitantsof the villages of Tchankoumalal, Baghan-gha, Tendouck and Pire Goureye for theirkind assistance in the field and for provid-ing much valuable information. We arethankful to A. Goudiabv. Dakar who tookthe photographs. R. Roy, Dakar whodetermined the collected insects and K.Tind and A. Sloth who assisted skillfullywith the preparation of illustrations.

LrrnReruRn Crten

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DIALLo, M. 1987. Le comportement du r6nier(Borassus aethiopum Mart.) dans les r6neraies

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Pr incipes,36(3), 1992, pp. 155 162

Biogeography of the CoconutCocos nucifera L.

HucH C. HeRnrosNational Coconut Deuelopment Programne, P-O. Box 6226, Dar es Salaam, Tanzania

ABSTRACT

The conditions under which cocontt (Cocos nucifera L.) evolved can be quite precisely specified. Thoieconditions still exist today and the coconut palm canbe found growing in its original habitat where it willcontinue to thrive, with or without human interven-tion. The coconut can be considered as perhaps themost successful member of the world's oldest andmost durable ecosystem. Yet the major componentof that ecosystem, the coral reef, is constantly chang-ing its form. As a result the precise location of acenter of origin for the coconut will probably neverDe Known.

The coconut, like the calabash and thebottle-gourd. is used as a convenient con-tainer wherever modern man has not yetbrought the ubiquitous benefits of plastic.Unlike the calabash or the gourd, the coco-nut comes already filled with a drinkableliquid. This liquid is pure, it is palatableand it is portable. Unlike a plastic con-tainer the coconut fruit is non-returnable,absolutely disposable and totally recycla-ble. These qualities are found in the imma-ture coconut and they are well known