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Betula spp. are distributed primarily in deciduous broad-leaved forests on the Pacifi c side of eastern Japan. Theyexhibit characteristics of pioneer species and their distributions are governed by environmental conditions.However, the precise factors that control their distributions remain unclear. In this study, we aimed to elucidatefactors that influence the distribution of suitable habitats for four Betula spp. (B. platyphylla var. japonica, B.davurica, B. grossa, and B. schmidtii) in the Soto-Chichibu Mountains. The habitats of B. platyphylla var. japonicaand B. davurica were mainly distributed along the upper slopes of Sambagawa metamorphic rocks area. Areascontaining Sambagawa metamorphic rocks often experience geomorphic disturbances, such as landslides, whichresults in the formation of open sites and gentle slopes. The habitats of B. grossa and B. schmidtii were distributedmainly along the upper and lower slopes (B. grossa) and the rocky ridges (B. schmidtii) of the Chichibu paleomesozoicrocks area. These areas contain steep ridges and slopes due to land formation and they often experiencesurface soil disturbances, such as soil movement, which result in the formation of canopy gaps. In contrast, steep,rocky ridges, such as dwarf forests, are relatively stable areas. Thus, we concluded that the distribution of thehabitats of the four Betula spp. was controlled by landform conditions associated with geological differences. |
