This book representing the research efforts of a dozen hydrologists and climatologists from around the world, grew out of the strongly felt need in the scientific community for an objetive and quantitative assessment of the effects of deforestation or reforestation on climate and hydrology and the regional extent of these effects. Of particular note in this volume, considerable attention is directed to improvements in experimental method and the collection of necessary data and in the application of computer models of atmospheric circulation for the simulation of climate effects of vegetation change.