Abstract
In the past, as a part of the project for erosion and sediment control, we have encouraged afforestation in the de-nuded or devastated areas. But in recent years, the main body of the work method changed from hillside works to tor-rent works (check dams or channel works), because of their easiness to evaluate the effect and stability. However, with the increase in public awareness of the environment, there has been pressures to look for ways to avoid the load on the ecosystem.
Therefore, the investigations on the stability of hillside works at a downpour and the development of the root sys-tem of natural seeding trees in the representative hillside work areas were carried out to clarify the management stan-dard with hillside slope for erosion and sediment control.
Here it was indicated that the stability of the hillside works was no less than that of natural slopes. As a result, the hillside slope management as Sabo project should be divided into three periods, that is, (1) period for hillside work construction and for growth of the planted vegetation, (2) period for smooth regeneration of the natural seeding trees and the maintenance for sediment yield reduction, (3) period for continuous succession of the satisfactory forest.
