Abstract
Relationships between ground disturbance and forest floor vegetation were investigated in Fraxinus platypoda-Pterocarya rhoifolia forest along Ooyamazawa valley in Chichibu, Kanto District, Japan. Six landform types were distinguished along the valley investigated: terrace of debris flow, alluvial fan, scarp of terrace, new landslide site, old landslide slope and talus. Three major species groups were classified by cluster analysis of a releve data set. One of these was characterized by spring ephemerals, storage rhizome and anti-vegetative reproduction. This species group represented the forest floor vegetation inhabiting stable landforms such as terrace of debris flow and alluvial fan. The other two species groups characteristically included annual plants and those with replacement rhizome type. These were peculiar to the landforms scarp of terrace, new landslide site, old landslide slope and talus, located at the foot of sideslopes. In particular, scarp of terrace and new landslide site were extreme in having both the most unstable landform characteristics and floral features.
