Environmental factors controlling the distribution of forest plants with special reference to floral mixture in the boreo-nemoral ecotone, Hokkaido Island 森林植物の分布と環境要因、特に北海道の森林フロラの混在様式に関する生態学的研究

博士論文

Effects of climatic factors on the plant distribution were examined by means of direct gradient analysis, and the relationship of forest flora, life form and phytogeographical distribution was examined. Subsequently, leaf phenology of forest plants were analyzed to evaluate the adaptive significance in relation to the environments in forest understory. In the boreo-nemoral forest ecotone, Hokkaido Island, northern Japan, co-ccurrence of northern and southern plants in a certain forest site is more notable in the understory than in the crown, and this dates back to the late-uaternary period, where the decrease in temperature associated with the glacial period forced the understory flora to adapt their life form or leaf habits to snowcover and light conditions of the interior forests.