不同采伐强度对阔叶红松林主要树种空间分布格局和物种空间关联性的影响

Impact of logging intensity on the spatial distribution and association of dominant tree species in a broadleaved Korean pine mixed forest

分析采伐后森林群落中物种的空间格局有助于认识该格局形成的生态学过程、种群的生物学特性及其与环境因子之间的相互关系,并对制定可持续的森林经营方案具有重要意义。以长白山地区经历不同采伐方式形成的阔叶红松林次生林为研究对象,利用空间点格局分析的研究方法,探讨了采伐对阔叶红松林主要树种空间分布格局、种间关联性以及更新的影响。研究结果显示:较低强度的择伐对阔叶红松林主要树种的空间分布格局、种间关联性的改变较小,群落可以在较短时间内恢复。中等强度的择伐减少了成年树种对幼树的抑制作用,可以促进森林的天然更新。皆伐后,森林的群落结构,物种的空间分布格局、种间关联性都发生显著变化,尽管更新状况良好,但要恢复到伐前水平仍需要较长时间。择伐不仅通过改变主要树种的密度对阔叶红松林群落结构产生影响,还通过改变物种空间关联性改变群落的结构动态。因此,在制定森林生态系统经营管理方案时,不仅要选择适合的采伐强度,还要综合考虑采伐时物种的选择以及种间关系。

Spatial distributions of trees after selective logging can vary according to the method whereby trees are selectively removed for harvest, because removal of these trees will affect the correlation between unlogged trees and post-logging regenerations. Quantification of these effects on post-logging forest regeneration and spatial relations among trees can facilitate a better understanding of the mechanisms underlying forest ecosystem structure dynamics in managed forests. This, in turn, may enable the development of improved guidelines for sustainable forest management. In the present study, we identified several factors related to maintaining species coexistence in broadleaved Korean pine mixed forests in northeastern China. We evaluated three different selective logging schemes in nine stands and one uncut （control） stand. We examined the stand structure and composition and analyzed the spatial distribution patterns among the dominant tree species. We showed that low-intensity selective logging had a low impact on the structure of a broadleaved Korean pine mixed forest; moderate-intensity selective logging improved regeneration of the dominant tree species; and clear-cutting improved regeneration of the dominant tree species in a broadleaved Korean pine mixed forest, but increased the time taken for the community to return to the start of the successional stage. We further showed that, to promote natural regeneration and maintain a sustainably diverse structure of post-harvest forests, interactions between trees should be considered; moreover, the density of highly competitive species such as Korean pine should be controlled when selective logging schemes are implemented.