Spatial Point Patterns of Snags of Castanopsis chinensis and Schima superba in a Subtropic Evergreen Broad-leaved Forest

We established 1000 quadrats in 10 hm² subtropic evergreen broad-leaved forest located in the Guangdong Kanghe Provincial Natrue Reserve. Using spatial point pattern analysis and marked point pattern analysis with dominant species of Castanopsis chinensis and Schima superba, we determined the spatial point pattern of individual and basal area to explore the formation of spatial patterns of snags. The results showed that the most snags of C. chinensis and S. superba were those with small DBH, and the abundance of snags decreased with the DBH increased. The snags of C. chinensis showed an aggregated distribution at the scale of 0−50 m, and the aggregation declined as the scale enlarged; the snags ofS. superba showed randomly distribution at the scale of 4.4−8.6 m and 14.1−50 m, and aggregated at local scale of 0−4.3 m and 8.7−14.0 m. The basal area ofC. chinensis and S. superba showed that sangs were independent, which indicated no competition among snags. C. chinensis and Schima superba died more in their early stages. The formation of snags of these two species might be influenced by dispersal limitation of seeds and density dependence as well as environment filter, the lager trees might die because of intrinsic aging.