Topographical Influence on Snag Distribution in a Subtropical Forest in South China

Snags are highly important for many wildlife species and ecological processes. In this study, we analyzed the relationship between snags and topographic factors in a secondary forest plot in South China. Data on 544 snags were collected and recorded from 236 subplots in a permanent plot (400 subplots). The frequency of Castanopsis carlesii and Schima superba was higher than that of other species. The snags derived mostly from saplings and small trees, and the presence of snags decreased as the DBH and height increased after 25 years of logging. The snags displayed an aggregated spatial pattern distribution, which was strongly correlated with elevation, slope steepness, and slope aspect (p < 0.05), as revealed by canonical correspondence analysis (CCA); however, the response of snags varied with topographic factors. Our results demonstrate that topography is an important factor that affects the snag spatial distribution in the subtropical secondary forest. These results will further improve our understanding of forest dynamics and provide guidance for forest management and biodiversity conservation.