This band of marginal savannas bordering the dense dry forest extends from the Atlantic coast of
Guinea to
South Sudan, corresponding to a climatic zone with relatively high rainfall, between 800 and 1400 mm. It is an often unresolvable, complex of secondary forests and mixed savannas, resulting from intense
erosion of primary forests by fire and clearing. The vegetation ceases to have an
evergreen character, and becomes more and more seasonal. A species of acacia, Faidherbia albida, marks, with its geographical distribution, the Guinean area of the savannas together with the area of the forest-savanna, arboreal and shrub, and a good part of the dense dry forest with prevalently deciduous trees.