Abstract
The relationship between tree occurrence and decaying log microsites was examined in a forest site and a windfall site on Mt. Fuji. In the forest site, the population density of trees, mostly softwoods, on decaying logs was higher than that on the ground irrespective of tree size. The population size (i.e. actual number of individuals) of trees on decaying logs was diminished more greatly than that on the ground as their size increased. In the windfall site, the density of softwoods on decaying logs was higher than that on the ground, while every hardwood took the reverse pattern. The population size of trees, especially hardwoods which appeared only in this site, was negligible on the decaying logs. The decaying logs contributed to the survival of specific trees in a specific site, but less frequently led them to canopy replacement of the forest. The state of decaying logs changed due to bryophyte dynamics in the windfall site. The authors focused on this change and discussed the reason why decaying logs contributed less to forest canopy replacement and to occurrence of hardwoods.
