The Thinning Intensity Research Of Natural Secondary Forest Based On Intermediate Cutting Index

As the main body of terrestrial ecosystem, Forest is a kind of geomorphic factors closely linked with life and the material basis of national economy and social development; It plays an irreplaceable role in improving the ecological environment, maintaining ecological balance, and dealing with global climate change. Since the21st century, with the rapid development of our social economy, the rising population, the expansion of the scope in human activities, and the increase gradually with the developing and cutting strength in the primeval forest, forest area is decreasing, while the secondary forest area is gradually increasing. According to statistics, natural forest is the main body of forest resources, accounting for about70%of the total area,90%of the total accumulation, but it mostly contains the secondary forest. Therefor, the secondary forest management has become the most important part of forest management, and also the most important topics of forestry development in China.As the main body of forest resources in our country, natural secondary forest is the important base. But natural secondary forest has poor growth, early recession, its stand structure is not stable, tree species composition is not ideal, density is too large, distribution state is crowded, the shape is uneven and material is poor in overall growth. So it is the first problem to be solved that we should take the measures of scientific and reasonable management cultivation to establish a stable forest community structure and increase the productivity of secondary forest.Forest-thinning is the important technical measures in the process of forest cultivation, plays a vital role in the forest management, and the premise of forest sustainable development. In the traditional thinning intensity studies, it sets the test sample to compare stand growth and development within the given time (diameter growth and tree height growth or volume growth, etc.). The paper takes the thought that is using the hypothesis first, then studying and analyzing, finally summarizes to explore and establish new methods and new ideas of thinning intensity in the natural secondary forest, by the typical natural secondary forest in bluestone, forest farm of Hunan province. By building stand spatial structure unit, determine the uniform angle index of the main stand to adjust the target, and use trees competition index to choose intermediate cutting trees firstly, then use intermediate cutting index to determine intermediate cutting trees, run forest-thinning simulation and analyze effect of stand structure optimization or not, finally, summarize new methods and new ideas of thinning intensity in the natural secondary forest. And to perfect the system of natural secondary forest-thinning, in some sense, to achieve selected intermediate cutting trees and determined thinning intensity basis in quantification of stand spatial structure index, so as to realize the sustainable development of the secondary forest would be significant.