Abstract
Beds of andosol blown and beds mulched with straw mats were prepared to inplant on a banking of river bed material, which is designed to mitigate the esthetic defect of the huge concrete dam constructed in one of the main views among the national park. The investigation in detail for 3 years yielded the following knowledge: the latter can prepare good condition for flying invaders to establish; the former can prepare good bed for young seedling to grow; these resulted from the difference in moisture retention character and in temperature modification characters. Seed dispersal in a broad river bed and improvement of bed preparation with aggregating agent are discussed also.
