An ecological survey of vegetation was made in the Muronouchi crater in Mt. Sanbe. On twelve zones in the crater, the vegetation was analyzed by using the quadrat method. As the result of the survey, following vegetations were elucidated. They are Quercus dentata community, Quercus crispula community, Quercus acutissima community, Castanea pubinervis community, Salix Daiseniensis community, Sasa pectorius community and Miscanthus sinensis community.
Thick community of Sasa pectorius, Salix daiseniensis and Miscanthus sinensis was seen aroud the peak of Mt. Otoko-Sabe, Mt. Ko-Sanbe and Mt. Me-Sanbe. These peaks stand in the most harsh climatic condition in the investigated area. A thin community of Salix Daiseniensis and Quercus dentata was seen on the north slope of Mt. Oohira which is influenced by the strong north-west winds of all seasons. The Quercus crispula community has developed on the north-east slope of Mt. Mago-Sanbe whose climate condition is comparatively mild. On the alluvial fan at the bottom of the crater, the community of Quercus acutissima, Q. crispula and Castanea pubinervis have grown thick. Near the end of the fan, the Pinus Thunbergii community was seen. In the developed Miscanthus sinensis community on the hillside of Mt. Ko-Sanbe, small communities of Quercus dentata, Salix daiseniensis, Weigela hortenis forma spontanea, Castanea pubinervis and Pinus Thunbergii are growing gradually.