2020 Volume 102 Issue 1 Pages 31-37
We analyzed the mortality factor and spatial distribution of trees in a sedimentation-dominated riparian forest in a warm-temperate mountainous region by using the monitoring data of 7 years, forest dynamics with a special focus on suppression. Based on the results, we discussed a part of a coexistence mechanism of coppice woodland species and aestatilignosa forest species (CA species) with five major evergreen broadleaved species within the same geomorphic unit. A generalized linear model (GLM) of survival rate detected overstory stem density as a significant explanatory variable for the CA species and the major evergreen broadleaved species, except for Persea japonica. The CA species showed the lowest survival rate, indicating remarkably lower shade tolerance than that of the evergreen broadleaved species. Among the major evergreen broadleaved species, Quercus gilva demonstrated relatively lower shade tolerance than the other species. The CA species tend to be distributed on sites close to the channel. Q. gilva had a significant distribution bias toward the sites derived from large-scale disturbance. These results suggested that frequent but less intensive disturbances might provide constantly better light environment by restricting establishments of evergreen broadleaved trees, which allows the coexistence of CA species with evergreen broadleaved species. Among the major evergreen broadleaved species, Q. gilva seemed to depend partially on large-scale gaps for its coexistence with other evergreen species.
