The current distribution of tropical rain forest in Central Africa corresponds to a single point in a long history of climate change covering several millennia. Since 3,000 BC the region has been strongly influenced by humid and dry climatic phases and shifts in human demography (Bantu migrations) and technology. Through this period West Central Africa has seen three major climatic phases:

• A humid episode characterized by forest expansion from 9,000 to 1,500 BC

• A warm, dry episode from 1,500 BC to 600 AD during which the forest block was fragmented with important spaces opened of savanna
• The return of humid conditions since 600 AD resulting in a new phase of forest expansion
• During this period Stone Age hunter gatherers were replaced around 2,000 BC by sedentary Neolithic peoples who were, in turn, replaced by iron working peoples around 500 BC.