Study On Spatial Structure Of Primitive Broad-Leaved Korean Pine Forest In Xiaoxing’an Mountain

In order to discuss the structure and function of primitive forest ecosystem, and provide scientific basis for protecting reasonably and managing primitive forest, as well as provide close-to-nature management template for the reconstruction and management of natural secondary forest at the same location, a nearly30hm2permanent broad-leaved Korean pine forest sample plot, which located in Liangshui national nature reserve, Heilongjiang Province, was taken as the study object. Species composition and diameter class structure of the broad-leaved Korean pine forest were studied in this paper, and the uniform angle index, mingling and neighborhood comparison were adopted for the study of spatial structure characteristics, finally, point pattern analysis namely O-ring statistics was used to analyze the spatial distribution pattern and association of main population in the stand and in different layers.The result shows that:the whole tree species which DBH≥1cm in the plot was23in the tree layer, the composition of tree species were complicated and its density was very different. The diameter class structure of all individual trees in the stand presented as a typical inverse "J" curve, which distributed reasonably, and the diameter class structure of main population was also inverse "J" curve or similar to skew normal distribution. The community and main population had enough seedlings and saplings for maintaining themselves update. The community was in growth or stable stage.The average uniform angle index of plot was0.523, which indicated that the stand was in unstable aggregate distribution state. The average mingling was0.756, illustrating that isolation degree among tree species was great and the broad-leaved Korean pine forest was a complicated forest community with different tree species in transitional phase from intensive to extremely intensive mix. The value range of average mingling of tree species was0.66-0.90. The average DBH and tree height neighborhood comparison were0.501and0.510respectively, both in moderate state. The value range of DBH and tree height neighborhood comparison of each tree species was0.27-0.72, which indicated great differentiation in DBH and tree height. The dominance degree both in DBH and tree height of the stand and all species maintained consistency. Replacing tree height neighborhood comparison with DBH neighborhood comparison was feasible in explaining stand heterogeneity in vertical direction.The distribution pattern of main species in total and in different forest layers showed consistent regularity, mostly presenting aggregated distribution and the aggregate intensity was higher at small scale and decreased with the increase of scale. The association between species was very different, but significant positive correlation or no correlation was presented mostly between species, and negative correlation was rare, which indicated that the competition between species was not intensity. The spatial association of all species in different layers and intraspecific spatial association in different layers of all species were different. Interspecific spatial association of all species in different layers was very complicated, having various association, and presenting as promoting or inhibiting growth or independence mutually. It was also found that the association among all species was significant positive by analyzing the overall association among multi-specific in the stand. All species were of mutualism, sharing habitat resources together, and presenting harmony in using environmental resources, which indicated that the community was in stable developing stage.