Dispersion pattern and mortality of seeds and seedlings of Fagus crenata Blume in a cool temperate forest in western Japan

The seed and seedling mortality of Fagus crenata Blume after a mast year (1993) was examined in relation to density and distance from the nearest conspecific adult tree in a mixed conifer-hardwood forest in Ohdaigahara, western Japan. The mortality of fallen seeds during winter amounted to 93.7%, and 79.2% of the current-year seedlings died in the first growing season. The most important factor of death for both seeds and seedlings was predation by vertebrates. The mortality of seeds during winter was positively correlated with sound seed density. The mortality of seedlings was positively correlated with density but not significantly related to the distance from the nearest crown edge of a conspecific adult tree. Mortality patterns varied with stages and spatial scales due to the behavior of predators; it is thus important to investigate the spatial pattern of seeds and seedling mortality at various temporal and spatial scales. After the first growing season, the difference in seedling density between distance classes was nor significant at < 4 m from the nearest adult trees due to density-dependent mortality. However, seedling density was significantly lower in the greater than or equal to 4 m class than in the < 4 m classes.