集中豪雨型表層崩壊・ハゲ山・治山砂防工事
1999 年 52 巻 1 号 p. 28-34
詳細
1999 年 52 巻 1 号 p. 28-34
A model of the process of bareland formation is presented. The model explains the whole history of devastation process of forestland to bareland in Japan. The history of the past century of devastation of mountains in Japan is deviled into three periods by the predonnant erosion type. i) Surface erosion type ‹Period of bareland› ‹1900-1965›. Barelands predominate sediment production, ii) Shallow landslide type ‹Period of surface soil slips and mudflow › ‹1966-1985› Poor forest covers by repeated cutting weakened the shear strength of surface soil, which accerelates the simultaneous occurrence of great number of surface slips and mudflow. iii) Deep landslide type ‹Period of natural erosion› ‹1986-› All forest except the former bareland areas has recovered. Erosion on forested hill-slopes has returned to natural process of erosion. Landslides of deep soil deposits and deeply weathered rocks predominate.
