Structure characteristics and spatial distribution of Abies fargesii population in Shennongjia National Nature Reserve, China
湖北神农架地区巴山冷杉（Abies fargesii）种群结构特征与空间分布格局

Life history characteristics and spatial distribution of Abies fargesii population in Shennongjia National Nature Reserve was studied using the life table, age structure and survivorship curve of the Abies fargesii population in Shennongjia nature reserve to explain: 1) population growth characteristics, and 2) how can biological and environemental factors affect population distribution and dynamics? Abies fargesii is distributed mainly on certain attitude that ranges from 2000 m to 3104.5m in shennongjia nature reserve. We sampled trees in 30 plots(20m×20m),and,in each plot, we chose 5 grids(5m×5m) for shrubs, 10 grids(1m×1m) for grasses, and 10 grids (1m×1m) for regeneration layer. The diameter at breast height(DBH) of each tree was recorded. We determined the life table, age structure and survivorship curve of the Abies fargesii to analyze population structure and dynamics. The age structure of the population indicates that Abies fargesii population is a developing population. The survivorship curve of Abies fargesii population generally matches a Deevey Type I, although seedlings is rare and have low survival rate due to high crown density. The spatial distribution in different growth periods are clumped or random. Populations tend to clump when interspecific competition is not severe in a wet and cold habitat in shennongjia nature reserve. Intraspecific competition also affects the clustering intensity of different growth periods.