Abstract
In Mt. Kamagamine, a forest stand dominated by large-diameter Q. variabilis trees has been established. We attempted to reveal the stand structure and establishment process of the forest stand by using data-obtained in forest inventory, literature survey, and tree-ring analysis. The survey results indicated that the forest stand is more than 30 m hight and has the same amount of above-ground biomass (294.2 t/ha) as that of natural beech forests. The origin of the forest stand was estimated to be the regeneration by sprouting after logging around 1880. In the Q. variabilis trees occupying the forest canopy, growth release of the middle-layer and under-layer trees were detected in three periods of the 1940s, 1970s, and after the 1990s. The growth release of these individuals was assumed to be due to occurrence of canopy gaps by thinning of unnecessary trees, and by pine dieback. The forest stand is a valuable example that deciduous broad-leaved secondary forests dominated by Quercus spp. reached an above-ground biomass comparable to that of natural beech forests in a short period of approximately 140 years. This forest stand would be a good reference in developing abandoned charcoal forests to well-developed mature forests by thinning.
