The Role of Deciduous Species in the Structural Development of a Restored Warm Temperate Forest in Japan

We examined the effects of deciduous tree species on the structural development of the 23-year-old warm temperate forest restored by tree plantation in an isolated seaside area of Tokyo Bay. In order to compare two different afforestation sites established by different planting densities of deciduous trees, we investigated plantation factors through as-built drawings of 1980 and performed field surveys and laboratory analysis for vegetation, microsite environments and birds. We also surveyed one natural forest as a reference site in order to evaluate the floristic and environmental characteristics of the two types of afforestations. In our results, two afforestations presented significant differences in vegetational structure and regeneration patterns and these differences might be deeply related to the planting density of deciduous tree species. Our data supported that the deciduous trees in warm temperate forests can improve the structural diversity and self-sustainability by facilitating the occurrence and colonization of late-successional species. And it was estimated that the vegetation diversity of restored warm temperate forest may be more strongly affected by the planting density of deciduous trees than the total planting density.