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.