Habitat and distribution changes of Picea and Larix in central Honshu since the Last Glacial

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We clarified vertical distribution, temperature, snowdepth, and geography of the habitat of Picea and Larix in central Honshu and Northeastern Asia based on literatures and fieldworks in the areas where those taxa were distributed much. Especially, we studied microtopography and ground conditions of the habitat where those taxa grew and regenerated. We obtained the following results as for the process of distribution changes of Picea and Larix trees since the Last Glacial : 1) The vertical distributions of Picea and Larix trees in mountain areas in central Honshu are generally intervened between subalpine coniferous forest mainly composed by Abies and Tsuga trees and montane deciduous broadleaved forest mainly composed by Fagus crenata and Quercus crispula. 2) Distributions of Picea and Larix trees concentrate in mountains of less snowfall and in temperature ranges between montane and subalpine zone. 3) The site of their growth and regeneration concentrates on rocky place, scraggy ridges, and landslide areas along valley where growth of the other tree species are difficult. 4) Under the cooler and drier condition without disterbance in the Last Glacial stage, Picea and Larix trees dominated over central Honshu. Through warming and heavier snowfall with frequent disterbance in the Late Glacial stages, distribution of Abies and Tsuga trees with deciduous broad-leaved trees expanded and Picea and Larix trees have decreased their distribution into their recent habitat. 5) Picea trees were widely distributed and variation of their cone morphology were continuous in central Japan in the Last Glacial. Since the Late Glacial stage to recent, they were divided into small populations in the middle of mountain where some species and subspecies were formed.