Amelioration of Soil by Trees

Abstract

1.Land use systems in which effects of trees on soils play an important part are protective forestry, reclamation forestry (of eroded or salinized land or moving sands), production forestry, agroforestry and applications of these in watershed management. 2.There are some 20 distinct agroforestry practices, defined as arrangements of trees and herbaceous components in time and space. 3.Eleven processes are listed by which trees may improve soils, not all of which are proven. 4.A computerised model, Soil Changes Under Agroforestry (SCUAF), indicates a potential for agroforestry to achieve a steady state of soil fertility under productive use; some critical assumptions in the model require experimental testing.