At the slopes of Mount Elgon there are still some patches of tropical rainforest. The typical Highlands vegetation is found on the most part of this territory. Rift Valley and Highlands Speaking generally, altitude and winds in this region are the cause of a moderate and mild climate. Obviously, temperatures drop at higher altitudes. The night lows are equally cold in the Aberdare region.
Rainfall is usually plentiful in the rainy season, with higher levels in the long rains.
The savannah, the most peculiar and typical lanscape in this region of the world, is actually nothing but a transition between rainforest and the arid steppe, and its origin as a natural or man-made ecosystem is controverted. It is mainly a grassland, dominated by gramineae and with variable presence of trees and bush, especially acacia. Species of the Acacia genus, belonging to the Mimosa family, growing as tree or bush, are the most common and typical in the savannah. Acacias are easily distinguished by their flat top, their hard thorns, their composed leaves, their cylindrical clustering flowers and their leguminous-like fruit. Their bark is rich in tannin and is used for manufacturing dies and pharmaceutical products.