Effects of Deforestation of Slopes

The creep and stability of slopes before and after logging have been analyzed. The following effects of vegetation were included in the theory: (1) The root system provides mechanical reinforcement of the soil; (2) vegetation provides a vertical surcharge; (3) wind in trees causes surface shears and moments; and (4) soil moistures content and water level are modified. It has been found that immediately after log removal the reduction in the overburden decreases the creep rate. Also, this reduction and the drop in wind loading increases the slope stability. The immediate effect of deforestation is, therefore, favorable, but adverse effects become evident when the root system decays and when a drop in evapotranspiration causes a rise in the water table.