Effects of Tree Forest Plantations on Soil Physicochemical Properties in the Arboretumof Ruhande,Southern Province of Rwanda

Different tree speciesare blamed to have negative effects on soil ecosystems by changing soil physicochemical properties, and hence soil quality. However, few researches to verify this statement were done in Rwanda. This study provides prior information on the effects of planted forest tree species on soil physicochemical properties. It was conducted in the Arboretum of Ruhande, in southern Rwanda. Soil cores were collected in plots of exotic, native and agroforestry tree species. Collected soils were analysed for soil pH, total nitrogen, organic carbon, available phosphorus,  aggregate stability, bulk density, soil humidity, cation exchange capacity, and soil texture. Soils sampled under exotic tree species were acidic, richin soil organic carbon, and in soil available phosphorus. Native and agroforestry tree species offer better conditions in soil pH, soil water content, cation exchange capacity, clay and silt. Less variations in soil total nitrogen and soil bulk density were found in soils sampled under all studied forest types. Research concluded that studiedtree species have different effects on soil physicochemical parameters. It recommended further studies to generalize these findings. Key words: soil, exotic, native, agroforestry, soil propertie