The influence of Deforestation On the Hydric Balance of Soils in the Lubumbashi Environment (Shaba, Zaire)

At the Luiswishi site, in the surroundings of Lubumbashi (Za?re), on a red zonal soil, three vegetation types are found, belonging to the same succession. Soil moisture followed during a 15-months period. Comparison of soil water reserves indicated that the substitution of the dry evergreen forest, the ecosystem frequently admitted to be the climax of Upper Shaba, woodland produces a clear decrease (64 mm or 5.0% of the mean annual rainfall) for the upper metres. Moreover this modification is reinforced by the reduction of Macrotermes activity, inducing greater number of abandoned termitaria, a more xeric milieu. Protection of soil by the forest thus appears to outweigh any higher rate of transpiration which might be expected to occur in evergreen forest. The next step in environmental degradation, the savanization of the biotope, has less impact soil water reserves but, nevertheless, should be avoided regarding other ecological consequences. Progression of the deforested area around the Upper Shaba mining towns by charcoal and production - today the woodland, for 70 km around Lubumbashi, is threatened with destruction, whilst an area of 30 km radius has already been completely cleared-out ? has alarming consequences, notably decrease of biomass production, rise of the mean annual temperature and of the mean amplitud