Ivory Coast lies in the middle of the
tropical rain forest belt stretching along the northern coast of
the Gulf of Guinea.
The study area is located between Liberia and the Taï National Park. In this area the deforestation process is more recent than elsewhere in the country, but it is more important.
In Côte d'Ivoire, as in most tropical countries, deforestation has reduced the extension of large forests to the limits of national parks. The largest part of the recently deforested area has been converted into agricultural land, including patches of secondary growth, with little islands of primary residual forest stands. Forest fragments smaller than 1000 ha. are generally ignored from global or state inventories, however their area can represent between 10 to 30% of all forested area, and represent the only forest resources of rural community because larger forest are generally protected and managed by state authorities.
Tai National park
The Tai National Park covers an area of 454.000ha,
it is the last and the biggest rain forest area of West Africa.
Many species are endemic. It has been classified as a Biosphere
Reserve in 1982 and inscribed on the World Heritage List in 1984
The satellite pictures clearly show that there is nearly no more forest in rural area. Human pressure reach directly the Park and other protected forest limits. It is now difficult to keep the people out to prevent plant and animal extraction.
Deforestation and fragmentation history in Taï Zagné area
In 1974, most of the area was covered by forest (80'000
ha.). Until 1984, the rate of deforestation was about 2.5% per year.
The main process of fragmentation happened between 1984 and 1990, when mass implantation of cacao and coffee crops took place; the deforestation rate reaching 11% per year.
In 1990, the forest patches left among the agricultural landscape (18'000 ha) consist of a mosaic of 6000 fragments with a mean size of 5 ha. Since then, further felling of remaining forest fragments took place for conversion to agricultural land. This phenomenon is not restricted to the proximity of old villages, but also takes place in remote areas, where migrants originating from the north of the country recently settled.
Spatial analysis and conservation
Spatial analysis of forest fragmentation, combined
with floral inventories are tools to define the minimum forest size
requirements for tree population to survive. The important influence
of forest fragment density on secondary forest regeneration should
promote the conservation of forest fragments near villages.
In 2000, forest fragments (small green patches) cover an area of 15'000 ha. Local populations have increasing difficulty to find land to establish crops, as well as forest products for their daily needs. Diminution of plant diversity through loss of forest fragments will certainly reduce the ability of fallows to regenerate in secondary forests.
Importance of remaining forests
Eupatorium fallow in Zagné
Presence of fragmented forests in rural areas allows persistence of forest animal and plants species, which are used for food, health, building and domestic fire. However, ecological conditions of these fragments are far from representing intact primary coverage. Presence of forest is important for soil and water balance in the landscape, and allows soil reconstitution for agriculture.
Population in Tai district increased from 3200 in 1971 to 57000 in 1991. In year 2000, only 10% of the population is native whilst 90% is result if immigration.
Poster Quick Look
Research conducted by: Cyrille Chatelain, Botanic Garden, Geneva