Abstract: The population structure and dynamics of Castanopsis eyrei in the evergreen broad-leaved forest on the Tiantai Mountain of Zhejiang Province were studied by means of spatial sere substituting for time sere. The results show: the shapes of size-class distribution diagram in various plots of Castanopsis eyrei population are basically similar; the population survival cures are of remarkable linear; the population age structure is stable. The population density of Castanopsis eyrei is reduced with its diameter class becoming larger, and the relevant pattern between density and diameter class is: D= 8.5178 ?104A-1.7497. The distribution patterns in the population plots are indicative of clump. The distribution patterns of seedlings, treelets and saplings in various plots are of clump;medium-sized trees are of clump or possion; big trees are of possion.

Key words: rice straw returning, nifH, gene abundance, community composition, diversity.