基于目标树经营的抚育采伐对云冷杉针阔混交林空间结构的影响

目的]以长白山林区云冷杉针阔混交林为研究对象,分析目标树抚育采伐前后云冷杉针阔混交林空间结构参数的变化,探索目标树抚育采伐对森林空间结构的影响。方法]基于6块面积1 hm~2的样地,首先遵循近自然森林经营的原理进行林木分类,选定目标树,伐除干扰树;再结合结构化森林经营的原理,计算并分析抚育采伐前后目标树空间结构参数和林分空间结构评价指数的变化。结果]表明:经目标树抚育采伐后(1)目标树空间结构单元内的树种隔离程度得到进一步提高;林木透光条件有所改善;目标树的竞争压力得以减小;林木空间分布格局总体上得到优化。(2)林分空间结构评价指数进一步提高,林分空间结构水平稳中有升。结论]通过采取合理的目标树抚育采伐措施能兼顾改善单木水平和林分水平的空间结构状况,在实现优化目标树空间结构的同时,保证林分整体空间结构的稳定。从目标树抚育采伐对林分整体空间结构的影响来看:所有样地的林分空间结构状况均得到进一步改善。

Effect of Thinning on Spatial Structure of Spruce-fir Mixed Broadleaf-conifer Forest Base on Crop Tree Management

Objective] The aim of this study is to provide the guidance and reference for formulating forest management measures and completing the system of effectiveness evaluation of forest management by analyzing the change of crop tree before and after the thinning based on the crop tree management.Method] According to the theory of close-to-nature forest management, the crop trees were selected and interference trees were fell based on 6 Spruce-fir mixed forest sample plots each in a area of 1 hm². The change of the spatial structure parameters of crop trees and evaluation index of the stand spatial structure were computed and analyzed after combining the theory of structure-based forest management.Result] (1) The isolation degree of species within the spatial structure unit was further improved; the light conditions of forest got better; the pressure of competition of crop tree was reduced; on the whole, the spatial distribution pattern was optimized. (2) The evaluation index of the stand spatial structure was further improved and the level of stand spatial structure showed the trend of steadily.Conclusion] The thinning based on the crop tree management can realize the objective of optimizing the spatial structure of crop tree and keep the stabilization of the stand spatial structure. That means that it can accomplish the specific objective of optimizing the growing space of crop tree under the premise that the status of stands spatial structure are not destroyed and the level of stands spatial structure is not lower. The thinning can create more room for promote the economic benefits and ecological benefits of forest. It can provide a reference to the accurate culture and management of similar forest in Changbaishan Mountain regions and the monitoring and evaluation of the effect of forest management.