POPULATION STRUCTURE AND REGENERATION TYPES OF DOMINANT SPECIES IN AN EVERGREEN BROADLEAVED FOREST IN TIANTONG NATIONAL FOREST PARK, ZHEJIANG PROVINCE, EASTERN CHINA

This study was carried out in the evergreen broad-leaved forest of Tiantong National Forest Park, Zhejiang Province, China. We identified and measured all trees in quadrats established in the forest to quantify the community structure of the forest. The population structures of the different tree species were categorized into five regeneration types based on their size-class frequency distribution patterns: Unimodal, Sporadic (multimodal), Inverse-J, L and Unibar type. The population size structure of a species reflects the biological and ecological characteristics of that species. The forest community was comprised of 69 tree species with six co-dominant species. Unimodal type species, such as Pinus massoniana, Liquidambar formosana, Sassafras tzumu etc., are shade intolerant, pioneer species or long-lived pioneer emergent trees which only regenerate on the bare ground following severe disturbances or in very large canopy gaps. Sporadic (multimodal) type species, such as Schima superba, Symplocos heishanensis, Machilus thunbergii etc., were late seral stage species that regenerate in large gaps and have intermediate shade-tolerance. Inverse-J type species, such as Castanopsis carlesii, C. fargesii, Lithocarpus harlandii etc., are shade tolerant, climax forest species that can regenerate through seedling bank or sprouting under the closed forest canopy. L type species, such as Neolitsea aurata var. chekiangensis, Ternstroemia gymnanthera etc., and Unibar type species, such as Camellia fraternna, Symplocos stellaris etc., are understory, shade tolerant shrubs and treelets. The successional stage of the forest was classified as a late seral stage community that would develop into a climax community dominated by Castanopsis carlesii and C. fargesii.