後氷期のオオシラビソ林の発達史

分布特性にもとづいて

抄録

The process and causes of the differentiation of the mountains in their development of Abies mariesii forests were discussed based on the results of ecological geography and paleoecology studies. A. mariesii is adapted to the wet and snowy oceanic climate, and makes stands on mesic sites which develop in such climates. A. mariesii tolerates poorly drained soils well and as a result, is distributed around flats or slightly inclined slopes where water from melted snow collects. As the Last Glacial Age ended, blank spaces where the quasi-alpine zone had originated were formed by the decline of subarctic coniferous forests along the Japan Sea coast because of the remarkable environmental changes. A. mariesii was a minor species during the continental climate of the Last Glacial Age, but it expanded its range by filling up the blank niche during the oceanic climate of the Postglacial Age. The core stands of the expansion inhabited poorly drained and less sharply inclined slopes at relatively lower altitudes. Therefore, the extent of less sharply inclined slopes controled the success of the range expansion of A. mariesii on each mountain.