Variations of the forest structure and forest vegetation geography in the North-Eastern Asia

Okitsu, S. (Chiba Univ.)

Japanese mountains contains diverse vegetation types such as Fagus crenata forest, Quercus mongolica forest, Picea-Abies forest, Betula ermanii forest, Pinus pumila scrub. They develop under per-humid climate which is characteristics among Japanese mountains. This study focuses on the vegetation geography of those vegetation types with a comparison of vegetation of martime-oceanic regions of northeastern Asia. Fagus crenata forest is endemic to Japan, while others have ecologically relevant vegetation of martime-oceanic regions of northeastern Asia. Quercus mongolica forest corresponds to Picea. sect. Picea forest humid stands of Sikhote-Alin. Betula ermanii forest exactly corresponds to that of the Kamchatka peninsula. Pinus pumila scrub is considered to be a southern expansion of Larix gmelinii forest in Eastern Siberia. Geographical distribution of the major components of those vegetation types are: 5 of Okhotsk type, 3 of East Siberian type, 2of Bering type and 1 of circum polar type. This finding suggests that subalpine vegetation of Japanese mountains in the Last Glacial contained also humid-per-humid components, and offered them refugia．