Integrated Hydrological Model for Mountain Ecosystem Assessment

Abstract

In Japan, more than 70% of the land surfaces are covered with forest and most of these are coniferous forest plantation for timber production. However, the timber price slump according to the economical depression and declining birthrate and growing proportion of elderly people are accelerating vast forest deterioration. Furthermore, with the global warming, many regions have been experiencing the hydrological extremes such as heavy rainfall and severe floods or droughts. Consequently, most of the farmers and foresters who lived in mountainous area had to settle to the urban area located in the lower reaches of the river basin. Then, most of these abandoned mountainous areas are becoming inadequately managed forest which might frequently cause land surface erosion or severe land slide. To make matters worse, the extreme hydrological events are aggravating the floods, soil erosion and droughts, and are projected to increase until the end of this century (Kitoh et al., 2009). Accordingly, these are damaging to forest and river ecosystems in the mountainous areas.