Chie KUROIWA, Shinya HIRAMATSU and Taijiro FUKUYAMA
Local torrential rain frequently causes serious damage to hillslopes in mature stand. In this study, we examined relationship between stand age and collapsed area ratio, collapse depth in reforested sites in Miyagawa]dam basin, Mie prefecture, Japan. We report our findings as follows:1) Area ratio of landslides was highest after 6 years of reforestation, and declined after 20 years. After 30 years of reforestation, there occurred little landslides. 2) However many landslides occurred by typhoon T0421 in forestation sites after 15|20 years of reforestation. 3) Positive regression was shown between the stand age and the landslide depth. 4) In Japanese cedar stands, landslide depth was greater than those of Japanese cypress stands.