Borassus aethioPum, a Threatened Multiple Purpose Palm in Senegal

PRINCIPES
l48
[Vor.36
Principes, 36(3), 1992, pp. 148-155
BorassusaethioPum,a Threatened
Multiple Purpose Palm in Senegal
BrrxvnNu SeMsou,r Jones E. LAwESSoN,'ANDANDERSS' Bennoo2
t[Jniuersit6 Cheikh Anta Diop de Dakar, FacuJtE des Sciences,
Institut des Sciencesd'e l'Enoironnement, Dakar, Senegal and'
zBotanical Institute, Uniuersity of Aarhus, Nordlandsaej 68,
DK-8240 Risskotl- Denmark
B ora,ssus aethiopum is an economically
and ecologicallyimportant palm tree of the
Sahelianand Sudanianzonesin Africa (Giffard 1967, Gschladt I972). This majestic
representativeof the subfamily Coryphoideae is often found in dense populations
in periodicallyinundateddepressionsin the
Iandscapeor along rivers and lakes (Chevalier 1949, Chevalier and Dubois i938)'
Borassus aethiopurn was originally
describedby C. F. P. von Martius (1838)
who separatedit from the widespreadand
closelyrelated Asian species, Borassusfla'
bellifer, based on a description of Thonning in Schumacher(1829). According to
this, B. aethiopum'ischaracterizedby the
ventricose stem (Fig. l) of old individuals
and the five to sevenmale flowers in each
flower cluster (cincinni) as opposedto ten
to fifteen in B. f'abetlifer. The number of
flowers per cincinni is variable and in B.
aethiopum it is typically B-10, thus it is
not a good distinguishing character. In
other and older works, B. aethiopum' is
either cited in slmonymy with B. f'abellifer
or retained as a variety under this. The
only existingmonographictreatment of the
genusBorassusis that of Beccari(1924}
This work includes seven speciesand recognizesB. aethiopum with three variants:
vat. senegalensis,var. bagamojensisand
the typical form. B. aethiopurn is distinguished from B. f'abellifer by having a
calyx that is connateto the middle and not
split to the baseas in this species.In mod-
ern treatmentsl €.g.: Flore du S6n6gal
(Berhaut 1967), Flora of West Tropical
Africa (Hepper, 1968), Flora of Tropical
East Africa (Dransfield 1986) and, Flore
illustr6e du S6n6gal (Vanden Berghen
I98B) the position of B. aethiopurn is
maintained. We have accePted B.
aethiopurn in this paper basedon the differences given by Dransfield (1986). Borassusaethiopurn is accordingly more massive than B. f.abellifer. The leaves are
more rigid, less deeply folded and greater
in number. Along with the ventricosestem'
this gives a different appearancefrom B.
f.abellifer.
Borassus aethiopum plays an important role in Senegaleserural life where it
is the sourceof a number of products(Niang
1975, Diouf 1982, Sambou1985). It is
"ron" in Wolof dialect from which
called
"r6nier" is derived. Destructhe French
tive agricultural practicesand lack of managementis now threatening populationsall
over the country (Bellouard 1950, Diallo
1987, Sambou 1989). Densepopulations
of Borassas aethiopun't'are {ound in the
southernand southeasternparts of Senegal
closeto rivers and lakes where the groundwater level is high. Natural populationsof
Bora,ssusaethioputn are rare in the northern part of Senegal,but the palm is often
planted in fields (Fig. 2). The best climatic
conditionsfor this palm prevail in the middle part of the country where large populations once occurred.
r9921
S.{\IBOUET AL.: BORASSUS
IN SENEGAL
t49
l-4'
Borassus aethiopum- i.
Old individual. Note the swollenor ventricose stem. 2. palm tree planted
in mixed cropping system. Note the male inflorescence and the persistent leaf sheaths characteristic
of yourg
plants' 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.
PRINCIPES
t50
Overexploitation and habitat degradation is threatening this palm so seriously
that Senegaleseauthorities 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(Governmentof SenegalI973).
Despitethese efforts the destruction seems
to 6e continuing. This paper will first
describesomeof the many usesof Borassus
aethiopum and then mention the various
threats to which it is exposedin Senegal.
Uses
All parts of Borassus dethiopum are
exploited and used for a wide array of
pnipot"t (Table i). The products can b9
airnid"dinto three major groups which will
be treated shortly in the following: ligneous
products (wood, fibers, etc.), food, and
medicine.
A number of parts of the palm are edible. The young gelatinousendospermis a
highly esteemedand 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.cotyledonaryhaustorium of
the germinating seedis soft and sweetand
highly appreciated.The premature folded
leaves of the seedling are collected from
below the soil and eaten. TheY have a
fleshytexture and are very tasty. The palm
heart of Borassus aethiopum is also
exploited although the difficulties involved
in extracting it somewhatlimit its importance 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 Menage
i961).
Borassus aethioputrl is also used for a
number of medicinal purposes (Giffard
1962). An infusion of the roots is used to
treat miscellaneousailments such as stomach ache, throat infections, bronchitis and
syphilis. The flower-bearing branches or
rachillae of the staminate inflorescences
are used to treat venereal diseases.The
stamens are mixed with Shea-butter and
[Vor. 36
Tabte1. TheDffirent Porls olfBorassus
aethiopum Used bY Man
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
used to heal wounds' The mesocarpof the
ripe fruit is usedas a stimulant and against
tetanus. It is said to be a very efficient
remedy againstintestinalparasitestoo. 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 stemof Borassusaethiopurndelivers a hard wood that is resistant to decay
and the damagingeffects of seawater.The
durablewoodis rarely attacked by termites
and funei and is said to have excellent
working-properties. It is used extensively
by local carpenters for multiple purposes'
to mention just a few: furniture, timber in
heavy construction such as bridges and
houses,boardsfor 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-
IN SENEGAL
SA}IBOU ET AL.: BORASSUS
r9921
. -
".
I
r51
I l
1,,t::
Baskets
Borassus aethiopum. 5. A beehive made of the swollen and soft part of the trunk. 6.
5-8.
The fruit mesocarPofers a nutritious snack' The chairs and
braided from the major veins of the leaves- ;.
related to
table are made from leaf petioles. 8. The death of some old palm trees such as these is probably
droueht.
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 Borassus aethiopum make it an interesting plant
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 demonstrated that the staminate rachillae
release potassium upon decomposition
thereby enhancing soil fertility (Maydell
1983). These beneficial effects are
exploited in many parts of Senegal where
agro-forestry systems are based on managed natural populations of Borasszrs
aethiopum.
r52
PRINCIPES
[Vor 36
9 12. Borasus aethiopum. 9. Male (left) and female of Oryctes monoceros Ol. (family ScarabeiI0'
The signs of an Oryctes attack in a juvenile palm. II.
Tapping of sugar from the crown.
4"").
Exploitation has caused the death of the palm tree at the left. 12. Borassui aethiopurn must give way for
the cultivationof millet.
Threats
The destructionof Boras susaethiopum
is either a result of complete removal of
natural populationsor a slower process
where age distribution becomesprogressively more skewed. This process may
eventuallylead to a completelack of young
stagesin the population which can prevent
future regeneration. The factors respon-
r9921
I53
IN SENEGAL
SAMBOUET AL.: BORASSUS
HUMANFACTORS
I
V
Fire
Exploitation ol leaves
Exploitation oi wood
Exploitationof sap
lrom stem
"tii:x'l::
v
monoceros
[l 8:il[: n'n""
/
"ti';:'Hi""* Z:l::::
il::"""'"" Il 3i::T;,
ffi-/
Exploitation
M
ol sap from stem I
Fungi
oryctes gigas
Fire
Exploitation
oi green fruit
Asriculrure
+
|
|
t
*
NATURALFAcroRS >
\
I
{
@
Fire
A g r i c u l t ur e
Exploitation
ol nut
3*:.""'"'
Wkili:i::
/
E x p l o i t a t i o no f e o p h y l l
t
I
t3.
in Senegal.
of Borasszsaethiopumpopulations
Naturaland hman factorscausingdegradation
siblefor destructionof Borassusaethiopum
can be dividedinto two major groups:natural and anthropogenic(Fig. l3).
The most important natural factor
threatening populations of Borassus
aethiopum is probablydrought. A steadily
growing rain deficit during the last two
decadeshas causedhigh mortality among
older palm trees that are sensitiveto fluctuations in the ground water level (Fig. 8).
Destructive insects also represent a seriousthreat to Borassusaethiopum(CastelBranco and Tordo 1956, Lepesme1947).
After the apical meristem has appeared
t54
PRINCIPES
from below the soil, it is exposed to the
attack of three speciesof Oryctes Ildtger
(Scarabeidae)in particular.The two most
common speciesare Oryctes rrlonoceros
Olivier (Fig. 9) and.Oryctes boas Fabricius. The third species,Oryctes gigas Castelneau, is rare but is found in the humid
southern part of Senegal.All three beetles
dig into the base of the apical meristem
(Fig. I0) and suck the sap which often
results in the death of the palm tree. They
can reproducein the swollensubdistalpart
of the stem of old individuals. The partly
decomposeddead stems offer ideal conditions for the development of larvae.
Man's activities have had a severe
impact on natural populationsof Bora,ssus
aethiopum in Senegal.The main factors
contributing to the destruction are agriculture (Fig. I2), fire and, exploitationof
wood, and use of palmheart and sugar sap
tapped from near the apical meristem. The
latter is a very destructive practice where
a hole is drilled through the leaf bases(Fig.
I l) and a sap is tapped from the soft and
fleshy tissues near the apical meristem.
Usually the palm dies after having been
exploited in this way. It should be noted
that in India and SE Asia, inflorescences
of Borassusflabellifer are tappedwithout
damaging the plant.
In some Borassus aethiopum populations, the age-distributionis so skewedthat
certain developmental stages are completely lacking. What appearsto be seedlings are in fact very old individuals, that
remain small due to agricultural practices
such as burning of the ground cover.
Adult individualsof Borassusaethiopurn
deliver a number of productsthat are highly
appreciatedby village people and they are
consequentlythreatened by overexploitation. Thus. reoeated collection of leaves
may severely limit the growth of the palm
and excessiveextraction of green fruits,
germinated seedsor young seedlingsmay
impede the potential of natural regeneration.
[Vor. 36
Conclusion
Borassus aethiopum, a genuine multiple purpose palm tree, is a victim of its
own high utilitarian value. Both human and
natural factors are threatening the natural
populationsin Senegal.As long as the use
of this valuable palm is not regulated, the
situation will probably worsen. Only strict
managementof the remaining natural populations will save an important plant
resourcefor future generations.
Acknowledgments
Soecialthanks are due to the inhabitants
of the villagesof Tchankoumalal, Baghangha, Tendouck and Pire Goureye for their
kind assistancein the field and for providing much valuable information. We are
thankful to A. Goudiabv. Dakar who took
the photographs.R. Roy, Dakar who
determined the collected insects and K.
Tind and A. Sloth who assistedskillfully
with the preparation of illustrations.
LrrnReruRn Crten
Beccaru, O. 1924. Palme della Tribir Borasseae
(ed. Martelli). G. Passeri,Firenze, Vol. I, pp. 1tt.
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For6ts des Tropiques I 4.
BERHAUT,J. L967. Flore du S6n6gal.Clairafrique,
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BISMUTH,H. eno G. MENAcE. 1961. Les boissons
alcooliquesen A.O.F. Bull. IFAN 23 (s6r. B,
I-2):60-II8.
Cesffi-Bnenco, A. J. F. eNo G. C. ToRDo. 1956.
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CHrv,trrnR, A. 1949. R6partition g6ographiqueet
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(Borassus aethiopum Mart.) dans les r6neraies
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P r i n c i p e s , 3 6 ( 31)9, 9 2 ,p p . 1 5 5 1 6 2
Biogeographyof the Coconut
Cocosnucifera L.
HucH C. HeRnros
National Coconut Deuelopment Programne, P-O. Box 6226, Dar es Salaam, Tanzania
ABSTRACT
The conditions under which cocontt (Cocos nucif
era L.) evolved can be quite precisely specified. Thoie
conditions still exist today and the coconut palm can
be found growing in its original habitat where it will
continue to thrive, with or without human intervention. The coconut can be considered as perhaps the
most successful member of the world's oldest and
most durable ecosystem. Yet the major component
of that ecosystem, the coral reef, is constantly changing its form. As a result the precise location of a
center of origin for the coconut will probably never
De Known.
The coconut, like the calabashand the
bottle-gourd.is used as a convenientcontainer wherevermodern man has not yet
brought the ubiquitous benefits of plastic.
Unlike the calabashor the gourd, the coconut comes already filled with a drinkable
liquid. This liquid is pure, it is palatable
and it is portable. Unlike a plastic container the coconut fruit is non-returnable,
absolutely disposableand totally recyclable. Thesequalities are found in the immature coconut and they are well known