Abstract
Forests are among the best land use types for erosion control as well as environmental conservation . They reinforce not only the soil surface to reduce surface erosion but also the surface layer to control shallow failures. The effects of roots on slope stabilization emerged into the spotlight with only a few considerations of negative effects of forest load. The portion over the slope surface, i.e., their trunks and canopies, act as surcharge load for slope stability. Although roots have no effects on deep slides that sometimes appear with heavy rainfall and severe earthquakes, these negative effects have seldom been examined. Hereby, an assessment of slope stability with forest surcharge has to be taken in order to ensure the slope stability analysis when it comes to planning against landslides. Three different types of forest slope (conifer forests and a broad-leaved tree forest) were chosen as test slopes in this study, and analyzed by non-circular slip surface analysis with different forest felling types, i.e., 50%, 80%, 100% felling from the top and no felling.
Consequently, it is found that there are some cases in which its effects reaching up to approximately 4% of their safety factor. Notwithstanding, it is found that the 50% felling from the top makes sufficient effect on the slope stabilization in some slopes. However, almost cases, the forest surcharge was found to be virtually harmless to the slope stability even with severe seismic forces.
