云冷杉天然林乔木树种组成及物种多样性对择伐强度的动态响应

以吉林省长白山金沟岭林场云冷杉天然林为研究对象,定量分析不同择伐强度(对照0%、弱度择伐20.6%、中度择伐29.9%和重度择伐41.6%)下其乔木层树种组成及物种多样性的动态变化规律。结果显示:采伐后经10年恢复,择伐对原有林分结构影响不大,其中弱度和中度择伐仍能保持择伐前以冷杉占优势、红松和云杉占亚优势的物种结构,重度择伐使林分结构略有改变,但不明显;相比择伐前,择伐后经10年恢复的样地α多样性指数均有所增加,优势度指数均有不同程度的降低,其中弱度择伐样地的物种丰富度指数、多样性指数及均匀度指数的增加量和优势度指数的减少量均最大,说明弱度择伐有利于改善林分物种多样性状况,使林分物种更为丰富。本研究结果表明采取弱度择伐的方式更有利于维持林分物种结构及物种多样性,有利于云冷杉天然林的可持续经营和发展。

Dynamic Response to Selective Cutting Intensity on Tree Species Structure and Species Diversity in a Natural Spruce-Fir Forest

Selective cutting operation under different intensities (control 0%, low intensity 20.6%, middle intensity 29.9%, and high intensity 41.6%) was established in a natural spruce-fir forest in Jingouling forest farm to quantitatively analyze the dynamic changes in species composition and diversity in the tree layer and establish intensity suitability. Results indicated that after 10 years of restoration, selective cutting had little effect on the original structure of the forest, and low and middle intensity selective cutting maintained the pre-cutting tree species structure such that the fir species were dominant, while pine and spruce were sub-dominant. High selective cutting changed the structure slightly, but not significantly. Compared with that before selective cutting, the α diversity indices of all selective cutting plots after 10 years of restoration increased and the dominance index exhibited different degrees of reduction. The increase in species richness, diversity and evenness and the decrease in the dominance index of the selective cutting plots under low intensity were greatest. This showed that low intensity selective cutting was beneficial for forest species diversity and richness. Furthermore, this study demonstrated that low intensity selective cutting was more advanta-geous to the maintenance of species structure and diversity and to the development and sustainable management of the natural spruce-fir forest.