Site environments and maintenance of Betula (birch) forests in the Soto-Chichibu Mountains, central Japan

Abstract

Betula spp. (birch) are key forest species in deciduous broad-leaved forests on the Pacific side of eastern Japan. However to date, there have only been a few reports on the site environments and maintenance of Betula forests. Field surveys were conducted to study the site environments and maintenance of Betula (Betula davurica, B. platyphylla var, japonica, and B. grossa) forests in the Soto-Chichibu Mountains, central Japan. Betula forests were distributed on the landslide sites in the area dominated by Quercus serrata. Those landslide sites were formed by the landslide event in 1948. Therefore, it is considered that Betula trees were able to invade within open sites of landslide, and form their own forests. The formation of Betula forests depends on the formation of open site due to geomorphic disturbances of landslide. Then, the Soto-Chichibu Mountains often experience geomorphic disturbances of landslide by mechanism and process of landforms of Mikabu green rocks, resulting in the formation of open site by landslide event. For that reason, we consider that Betula forests will be maintained by frequent geomorphic disturbances in the future.