The nations in the southern and eastern part of the African continent have economies that are mostly reliant on the mining. They have numerous valuable metals, as well as diamonds, and coal. In order to be able to extract them and the mining to take place, the terrain has to be cleared, and usually it is the forests that are having the worst of it, as large portions of them are totally destroyed.
While this may be good for the economies of these nations on the short run, on the long run, the destruction of the forests can be fatal for them. The reason for that is that the metals, diamonds, coal, are non-renewable resources, they are limited, and once their reserves end, these nations will find themselves in a situation where they would have totally destroyed environment and no mining activities to run their economy.