华北油松林油松种群的空间分布格局

Spatial Distribution Pattern of Pinus tabulaeformis Populations in North China

以内蒙古黑里河、北京松山及山西太岳山的油松林监测样地为对象,分析了油松(Pinus tabulaefor-mis)种群的空间分布格局,探讨了油松不同生长阶段(幼树、小树和大树)之间的空间关系。结果表明,黑里河、松山、太岳山样地中胸径≥1 cm的油松种群密度分别为1 741、467和722株/hm2。3块样地中油松种群具有一致的空间分布格局,主要呈聚集分布。随着油松种群发育(幼树→小树→大树),聚集强度逐渐减弱甚至趋向于随机分布,一定程度上体现了油松种群的生存策略及其适应机制。不同生长阶段之间的空间关联性受油松植株大小影响,大小差异越小彼此间的空间关联性则越大。

Three Pinus tabulaeformis plots along latitude from north to south （Heihhe Natural Reserve of Inner Mongolia, Songshan Natural Reserve of Beijing, Taiyueshan Research Station of Shanxi Province） were built in north China in 2007. Spatial pattern and spatial association of P. tabulaeformis at different growth stages were discussed based on Ripley＇s K-function. Among the three plots, Heilihe had the highest density of tree stem and owned the most abundant seedlings and saplings, while Songshan had the lowest stem density, and big trees in Taiyueshan were richest. The stem densities of P. tabulaeformis with diameter at breast height greater than or equal to 1 cm in Heilihe, Songshan and Taiyueshan populations were 1741,467 and 722 individuals per hectare, respectively. Ripley＇ s K- function showed that P. tabulaeformis in the three plots mainly had an aggregated distribution, and spatial patterns were various at different spatial scales. As population grew （from saplings to small trees and to big trees）, it tended to be random distribution or less clumped, indicating the survival strategy and adaptability of P. tabulaeformis in certain degree. Spatial association was closely related to tree size, namely the associations would be more significant if there was less difference in tree size between saplings and small trees or small trees and big trees.