Secondary forests comprise the main forest resource in China. These secondary forests maintain the species composition and habitat of primary forests but differ markedly in terms of structural composition, tree growth, productivity, forest environment, and ecological function. In the montane region of eastern Liaoning province, secondary forests are gradually formed through the destruction of broad鄄leaved Korean pine forests and they cover an area of 1. 2 伊 10 7 hm 2 , representing 84% of the total forest area. Secondary forests play important roles in soil and water conservation, climate regulation, agricultural production, and economic revitalization of old industrial sites. The spatial pattern of these forests is derived from the combined effects of biological characteristics, interspecific or intraspecific relationships, and environmental conditions, and it is an indicator of the adaptation of populations to environmental resources and ecological processes. The spatial distribution pattern reflects the processes of seed dispersal limitation, competition, habitat heterogeneity, etc. Evaluation of the distribution patterns of woody plants facilitates elucidation of the mechanisms involved in determining community structure and underlying ecological processes in forests. In the present study, we analyzed the distribution patterns of species with more than 10 individuals at spatial scales of 0-50 m in a 4 hm 2 temperate secondary forest plot located in the montane region of eastern Liaoning province. First, we found that most species showed aggregated spatial http: / / www.ecologica.cn patterns under complete spatial randomness null models. The proportion of species exhibiting aggregated spatial patterns decreased with spatial scale, whereas the proportion of species exhibiting random or regular spatial patterns increased with spatial scale and mainly occurred at a scale of >32 m. Second, we found that 55.9% of species showed random or regular patterns under heterogeneous Poisson process null models, whereas the remaining species showed aggregated patterns at a scale of < 10 m. The proportion of species exhibiting random or regular spatial patterns increased with spatial scale and mainly occurred at a scale of > 10 m. Finally, we found that, under complete spatial randomness null models, species attributes (canopy layer, mean DBH, and abundance) clearly influenced the population aggregation; under heterogeneous Poisson process null models, species attributes had no significant influence on the population aggregation. Taken together, our results indicate that the distribution patterns of woody plants in secondary forests in the montane region of eastern Liaoning province may be partially explained by seed dispersal limitation, species attributes, and, in particular, habitat heterogeneity. Our findings provide a valuable insight into the mechanisms of biodiversity maintenance in secondary forests.
