. World-agroforestry-centre, htm d) US Geological Survey ? invasive species reports and links : http://biology.usgs.gov/cro/invasive.htm B5. Ressources en eau et en sol a) The hydrological and soil impacts of forestation in the Tropics, Forests, water and people in the humid tropics. CUP, 2004.

F. Land and W. Division, stm c) FAO Soils Bulletins. N°57 " Soil and water conservation in semi-arid areas " , N°64 " A study of the reasons for success or failure of soil conservation projects " , N°68 " Field measurement of soil erosion and runoff, N°50 " Keeping the land alive. Soil erosion : its causes and cures " . All documents are available at www.fao.org