不同采伐强度对小陇山辽东栎天然林空间结构的影响

应用混交度、角尺度及大小比数3个结构参数，结合Hegyi竞争指数评价小陇山辽东栎天然林不同采伐强度0（对照）、20%（中度）、30%（强度）、40%（极强度）下空间结构的变化情况。结果表明，中、强度采伐下，林分混交程度高，林分结构最稳定；采伐强度对林木大小分化和空间分布格局的影响不明显。分析采伐强度与林分及树种空间竞争关系表明，树种辽东栎竞争指数随采伐强度加大而提高，华山松竞争指数变化趋势呈“凹”型，椴树呈倒“J”型，认为采伐能达到调整林分空间结构和提高林分及主要树种的竞争力的目的，采伐强度以20%或30%为宜，采伐强度不宜过大。研究采伐强度与森林空间结构、林木竞争变化之间的关系，对辽东栎天然林经营有重要意义。

Effect of Different Cutting Intensities on Spatial Structure of Quercus wutaishanica Natural Secondary Forests in Xiaolong Mountains

Combining competition index Hegyi, 3 forest spatial structure parameters such as mingling, uniform angle index and neighborhood were applied to evaluate dynamics of spatial structure of Quercus wutaishanica natural secondary forests occurring in Xiaolong Mountains, which were subject to cutting with different intensities, control (0%), moderate (20%), intensified (30%), and high intensified (40%). The highest mingling degrees and stable structure of the stands were found in those under the cutting intensities of 20% and 30%. No significant influences were found of cutting intensity on the differentiation of stand size and spatial distribution pattern. influences of cutting intensity on the spatial competition between stands or trees species demonstrated that competition index of Q. wutaishanica trees enlarged as the increase of cutting intensity. The change of competition index of Pinus armandii exhibited a concave shaped curve, for Tilia tuan, an upset down “J” curve. Therefore, spatial forest structure would be optimized and competition capacity be enhanced for by using intensity of 20% or 30%. Furthermore, cutting intensity must be proper and high cutting intensity was not suggested. It is significant for discussing the relationship between cutting intensity and spatial forest structure, and competition of trees to Q. wutaishanica natural forest management.