This study was carried out to clear the details of the natural forest vegetation of the Oki Islands. According to the phytosociological study by the Braun-Blanquet approach, 6 forest communities were recognized.
The vegetation of Oki Islands are based by the floristic composition of the class Camellietea Japonicae. However, in these vegetation, the many floristic compositions of the class Fagetea crenatae were mixed, and the phenomena of compressing mingling of the vegetation zones were recognized. This peculiar phenomena are originated from the results of the vegetation change of the isolated islands in the Japan sea since the late glacial period.