Natural population distribution pattern of Sinojackia rehderiana in an evergreen broadleaf forest

Objective  To reveal the spatial distribution pattern in different life cycle stages, and to provide a scientific basis for protection of Sinojackia rehderiana, which was naturally distributed in Yongxiu County, Jiangxi Province. Method  To probe causes of the spatial distribution pattern formation, the adjacent lattice sampling method, the spatial sequence method instead of time sequence, and the O-ring Completely Random Zero Model method were used to analyze the spatial distribution pattern and spatial correlation of individuals in different life cycle stages of a natural population of S. rehderiana. Result  The DBH class structure and height class structure of S. rehderiana were complete, and the number of seedlings and saplings occupied an absolute advantage for the entire population. Population renewal, which belonged to the growth population, was in a favorable condition. In the process of development from seedling to adult tree, the population of S. rehderiana had an aggregated distribution on a small scale, and had a random to uniform distribution on a large scale. As the age class increased, the aggregated distribution receded. On a small scale, at different life cycle stages of S. rehderiana, there was a significantly positive correlation or no correlation(P=0.05); however, on a large scale there was a negative association or no correlation. The spatial association between seedlings and middle-aged trees, saplings and middle-aged trees, and saplings and adult trees was significantly negative (P=0.05). Conclusion  In a natural state, the distribution pattern of S. rehderiana was influenced by its own biological factors, intraspecific competition, and interspecific competition; seedling and sapling growth was limited but plentiful; and the population was not currently in a stable state.