Man and tree in tropical Africa: Three essays on the role of trees in the African environment

Contains following essays:

• The role of the tree in tropical Africa;
• Wood-fuel and nutrition: the complementarity of tree cover and food supply;
• Shifting cultivation: soil and vegetation, nutrient pumps, and nutrient cycling.

The first paper examines, in general, the role of the tree in tropical Africa. Highlighted are the variety of products that can be obtained from the forests, the vital role of trees in nutrient cycling and in soil and water conservation, and their influence on both micro and macroclimate. The second essay addresses the ever important question of wood-fuel supplies. With increasing petroleum prices, greater demands than ever before are being placed on wood, and with decreasing supplies prices are rising. Wood-fuel shortages have led to a switch to other fuel sources such as manure and crop residues, which has in turn started a vicious circle of decreasing crop yields and environmental degradation. The final essay examines the age-old practice of shifting cultivation. Suggestions advanced here for tailoring new ideas to this traditional practice may well make it possible to modify or improve the system to meet modern realities. Methods involving zero tillage and the use of trees as 'nutrient pumps' seem to offer particular promise in this regard.