The AA. examined the effects of forest harvesting on the frequency of landslides and debris flows in the Sanko catchment using 9 aerial photo periods covering 1964 to 2003. Trends of new landslides and debris flows correspond to changes in slope
stability explained by root strength decay and recovery; the direct impact of clearcutting on landslide occurrence was greatest in forest stands that were clearcut 1 to 10 yr earlier with progressively lesser impacts continuing up to 25 yr after harvesting
. Sediment supply rate from landslides in forests clearcut 1 to 10 yr earlier was about 10-fold higher than in control sites. To estimate the effect of forest harvesting and subsequent regeneration on the occurrence of mass wasting in other regions, changes
2008
[b1] Graduate School of Life and Environmental Science, University of Tsukuba, Ikawa University Forest, Shizuoka, Japon