Geoscience Reference
In-Depth Information
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Kola Nuts
Kola nuts are the seeds of an evergreen tropical
rainforest tree (Sterculia acuminata) in the fam-
ily Sterculiaceae, the same family as cacao. Kola
nut trees can grow to 60 ft (18 m) tall. They are
indigenous to West Africa, growing in the for-
ests of Sierra Leone, Liberia, C
vines, and other light-loving plants, but it is not
nearly as diverse as the other rainforests of the
world.
Since little light penetrates beyond the upper
canopy layers, the plants in the shrub layer must
be able to survive under limited light conditions.
Certain families of shrubs are common in the
understory. They include the smaller trees and
shrubs of the melastome, coffee, composite, leg-
ume, and pepper tree families previously men-
tioned above, along with nettles (Urticaceae),
ferns, and seedlings and saplings of the higher
canopy trees.
The forest surface is sparsely populated with
ferns, herbs, and seedlings of canopy trees. The
ground layer is composed mostly of dead, decay-
ing plants and animals, and the organisms that
decompose this material. The layer of decompos-
ing material makes the recycling of nutrients
throughout the forest possible. It is a crucial facet
of the African rainforest. Ferns, mosses, orchids,
ginger (Zingiberaceae), sedges (Cyperaceae),
aroids (Aracaceae), and African violets (Gesneria-
ceae) are common in Africa as well as other
rainforests.
ote d'Ivoire, and
Nigeria. They also grow along rivers in Central
Africa in Gabon and the Congo River Basin.
The fruit of the kola nut tree forms a star-
shaped cluster of pods, with each pod enclos-
ing 4
^
10 chestnut-size seeds. Kola nuts have
important uses in traditional medicines and
ceremonies and are cultivated for local and
export markets. They are used by indigenous
people as a stimulant and are high in caffeine
(2.5
-
3 percent) as well as theobroma. Kola nuts
are also used as an antidepressant and are
thought to reduce hunger and fatigue, aid in
digestion, and work as an aphrodisiac. In some
West African cultures, kola nuts are given as
gifts or expressions of hospitality. They convey
a sign of respect or an offering of peace.
Kola nuts were used in the early production
of many tonics and soft drinks, such as Coca
Cola. Even today, the kola nut is used in the
production of natural cola drinks and as an
extract used in natural medicines. Kola nuts are
produced commercially in Africa and South
America (where they were introduced from
Africa) for export into Europe and North Amer-
ica for use as a flavoring. However, most of the
trade in kola nuts is concentrated within Africa.
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African Rainforest Trees
Trees of the African rainforest share characteristics
with tropical trees in other tropical regions. These
trees tend to have thin bark, usually less than 0.5
in (1.2 cm) thick, in a variety of colors from light
to dark, with or without splotches. Tree bark is
typically smooth to discourage the growth of vines
on the tree. Some bark is thorny to discourage
animals. The wood is often hard and dense as pro-
tection against the wood-eating insects. This adap-
tation makes the wood a valuable hardwood resource. Like in other rainforests,
many emergent trees found in the African rainforest have buttresses at the base of
the trunk. These provide support for tall trees that typically have a shallow network
of roots. Buttresses can be 15-32 ft (5-10 m) high where they join the trunk. Aerial
or stilt roots are also common, particularly in palm species.
Although flowering can occur throughout the year, fruiting typically occurs
over a multiyear cycle. The result is intervals of mass production of several tons of
