Spatial distribution pattern of coarse woody debris (CWD) in two typical forest types in Tianbaoyan National Nature Reserve

The spatial distribution pattern of coarse woody debris of two typical forest ecosystems was conducted with Taylor's power law, Iwao's distribution function, and seven aggregation indexes in Tianbaoyan National Nature Reserve. The results showed that: 1) the spatial distribution pattern of CWD were aggregated, and the aggregation intensity declined with the scale increased; 2) Compared with natural disturbance, the aggregation intensity of logs and snags were increased by human disturbance; 3) It was tested by Blackith's method, the spatial distribution pattern of CWD tend to be susceptible by the external environment condition in small-scale. The spatial distribution pattern of CWD was formed by long-term interaction between natural environment and external disturbance. To some extent, based on these results, we will directly acquaint ourselves with the forest death patterns in the population development, then reveal how the external disturbance, environmental heterogeneity and individual biological features influence the population dynamics, thus provide theoretical basis for predicting population dynamics.