Ecological Studies on the Vegetation of the Boso Mountains I. Distribution and Structure of the Natural Fir-Hemlock Forests

The Boso Mountains are situated on the south-eastern part of Honsyu, where the climate is warm-temperate with yearly mean temperature of ca. 14℃. Since S. Honda (1912), the laurisilva there, composed of Shiia, Cyclobalanopsis etc., has been considered as the climax forest. From the analysis of the old air photographs and the stock maps of University Forest, however, the author concludes that this district had been covered with natural coniferous forest before clearing pressure by man. Its relics are composed of Abies firma, Tsuga Sieboldii, Pinus densiflora as conopy dominants, and Cyclobalanopsis acuta, C. stenophylla, Shiia Sieboldii, Eurya japonica, Cleyera japonica, Illicium religiosum etc. in lower tree layer. The floor vegetation is abundant, 126 species in 0.25 ha of the natural firhemlock forest