2021 Volume 38 Issue 1 Pages 49-66
Betula costata Trautv. (Betulaceae) is a canopy tree species found in mixed broadleaved-coniferous forests and is widely and continuously distributed in continental Northeast Asia. This species is also found in the mountains in the central of Honshu in the Japanese archipelago, meaning that it has a disjunct geographical distribution. However, there have been few studies on the types of forest vegetation in which this species appears in Japan. Here we surveyed the habitat and species composition of forest vegetation in which B. costata appears in central Honshu, Japan using a phytosociological approach for the first time. A total of 19 relevés of the B. costata forests of Japan were collected and classified into four community types belonging to the class Fagetea crenatae:Alnus firma-Betula costata community, Abies homolepis-Betula costata community, Aesculus turbinata-Betula costata community, and Pterocarya rhoifolia-Betula costata community. The occurrence of B. costata in these communities indicates that this species grows in secondary and disturbed forests in soil with high water retention capacity. Furthermore, we compared the species composition of the B. costata forests of Japan with that of the B. costata forests of continental Northeast Asia and found considerable differences between the two regions. These differences would indicate the outcome of historical climatic and vegetation changes in Japan and continental Northeast Asia.
