ABSTRACT
Inadvertantly man has here and there in Japan destroyed the mantle of vegetation on the sloping lands, and has thus unleashed forces of erosion. The works of human agency will avail little unless the natural forces such as rainfall, vegetation, and time are enlisted. The unmistakable evidence of this in Japan is the former covered condition of the areas where erosion is at work. Erosion control has its most immediate promise in those regions where unwise treatment by inconsiderate man has set in motion processes which have destroyed a former cover of vegetation. The policy of erosion control in Japan is based largely upon saving valuable food producing lands from destruction, rather than upon profit from restored lands. Erosion control and torrent regulation are not entirely of recent development. As the population increased in the later middle ages with enlarged demands on the forests, deforestation brought about an increase in torrential development.
