Vegetation

African vegetation can be classified according to rainfall and climate zones. The tropical rain forest zone, where the average annual rain is more than 1270 mm (more than 50 in), has a dense surface covering of shrubs, ferns, and mosses, above which tower evergreens, oil palms, and numerous species of tropical hardwood trees.

A mountain forest zone, with average annual rainfall only slightly less than in the tropical rain forests, is found in the high mountains of Cameroon, Angola, eastern Africa, and parts of Ethiopia.Here a ground covering of shrubs gives way to oil palms, hardwood trees, and primitive conifers. A savanna woodland zone, with annual rainfall of 890 to 1400 mm (35 to 55 in), covers vast areas with a layer of grass and fire-resistant shrubs, above which are found deciduous and leguminous fire-resistant trees.

A savanna grassland zone, with annual rainfall of about 500 to 890 mm (about 20 to 35 in), is covered by low grasses and shrubs and scattered, small deciduous trees. The thornbush zone, a steppe vegetation, with an annual rainfall of about 300 to 510 mm (about 12 to 20 in), has a thinner grass covering and a scattering of succulent or semisucculent trees.