择伐强度对天然林树种组成及物种多样性影响动态

Dynamics Effects of Selective Cutting Intensity on the Species Composition and Diversity of Natual Forest

定量分析不同强度采伐(弱度13.0%、中度29.1%、强度45.8%、极强度67.1%和皆伐)作业对天然针阔混交林乔木层树种组成及物种多样性的动态影响。结果表明:经过伐后10 a的恢复,弱度、中度择伐对优势种的影响不大,强度择伐和极强度择伐林分结构略有变化,而皆伐引起林分结构的变化最大,由此说明择伐作业基本上能保持原有的林分结构和种的数量,随着择伐强度的增大,林分结构的改变也随之增大;10 a后弱度择伐物种丰富度最大,而中度择伐多样性指数最高,各择伐样地多样性指数均超过伐前,而皆伐样地多样性指数则比伐前下降;均匀度指数随着择伐强度的增大而增大,生态优势度则呈相反趋势。对于天然针阔混交林的科学经营,从物种多样性的保护和发展出发,应尽量采取弱度或中度择伐方式。

The dynamics effects of cutting intensity on the tree layer species composition and diversity of natural mixed stand of conifer and broad-leaved trees （low intensity, 13.0% ;middle intensity,29. 1% ;high intensity, 45.8% ;over-high intensity,67. 1% ） were surveyed and quantitatively analyzed. The results show that through 10 years restoration the selective cutting of low and middle intensities caused a light variation to the tree layer flora, but the selective cutting of high and over high intensities caused changes to some extent. The more intensive of cutting, the more changes of the tree species and importance value. The rational selective cutting （ low intensity and middle intensity） benefits the restoration and maintenance of species, but the cutting operation results in adverse influences. Species richness peaked at low intensity and species diversity peaked at middle intensity. Selective cutting operation is propitious to the development of tree layer species diversity, but the clear cutting results in greastest destruction,and the tree layer species diversity decreases. Evenness index increase with intensity of cutting, while domination index showed the opposite trend. By these explanations, selective cutting operation, especially low intensity and middle intensity,is favorable to management of natual forest.