Spatial Distribution Pattern of Abies faxoniana in Northwestern Sichuan

A studied diameter distribution and importance value of Abies faxoniana was made based on the field survey in a plot with an area of a 1 hm2 of A. faxoniana forest in Wanglang Natural Reserve， Sichuan Province.In the study Ripley’s K function was used to analyze spatial pattern and spatial association of A. faxoniana at different growth stages. The result showed that: A. faxoniana was dominant species in the community with highest importance value， and there were many medium and big trees in the plot. A. faxoniana at different growth stages mainly showed aggregated distribution， indicating the way of seedling dispersal. Saplings and small trees were aggregated distributed at all scales， and aggregation intensity tended to increase first and then decreased as scale increased. While big trees tended to be clumped as scale increased.As age increase （sapling→small tree→big tree）， aggregation intensity tended to reduce. Saplings and small trees showed positive association， while A. faxoniana at all growth stages were positively associated with standing dead trees， varied with spatial scale. The spatial pattern and association of A. faxoniana indicated the species′ shadetolerance characteristic， positive relationship among age classes， and mechanism of gap disturbance affecting regeneration. Based on its spatial character and regeneration mechanism，it is suggested that some measures can be taken to facilitate the development of A. faxoniana.