Study On Structure Optimization Technology Based On Spatial Structure Of Homogeneous Characteristics Of Quercus Aliena Var. Accuteserrata Forest

This paper mainly studies on Quercus aliena var.accuteserrata forests in Xiaolongshan. Based on large sample plot survey, utilizing mingling degree et al. six spatial structure parameters homogeneity and comprehensive index constructed by multi-objective planning——trees homogeneity index, this paper evaluated patial structural condition, and analyzed the trend of indexes under different selective cutting intensity. Final results is the ideal system of homogeneity index and reasonable structure optimization technology. The overall aim is to improve existing spatial structure of Quercus aliena var.accuteserrata forests and the grade of heterogeneity evaluation, while providing scientific foundation and theoretical basis of sustainable management of forest in this region. The main results showed that:(1) The degree of mingling intensity of Quercus aliena var.accuteserrata forests belong to the intensity of the mixed, and distribution frequency increases with increasing mingling, the lowest value was mingling intensity of Quercus aliena var.accuteserrata. The degree of neighborhood comparison is in the middle, and frequency distribution was nearly averaged. The most obvious advantage species of degree were Quercus aliena var.accuteserrata and Quercus wutaishanica. Distribution of mean uniform angle was slightly aggregated and frequency distribution belong to normal distribution. Condition of spatial density index was moderately congested, as well as the main tree species. All the storey indexes were low, and frequency distribution concentrated in 0.5 or less. Storey species mostly appear 1 or 2 in the main tree species.(2) Mean competion index of Quercus aliena var.accuteserrata forest was 3.47, and frequency distribution of competion index concentrated in the range between 0 and 4. The intraspecific competition intensity was greater than the interspecific competition intensity in Quercus aliena var.accuteserrata. The competition intensity gradually reduced with the increase of diameter scale. The trees homogeneity indexes were low, and index frequency distribution concentrated in the range between 0.2 and 1.The almost 2 grade of heterogeneity evaluation showed that parts of the spatial structure homogeneity indexes were not meet the standard.(3) The most obvious increase of mean mingling degree of stand happened in the low intensity selective cutting. Selective cutting did not change the neighborhood comparison of Quercus aliena var.accuteserrata forest. With high selective cutting, the average uniform angle index of stand showed slight aggregation, while with low or middle selective cutting, it would distribute randomly. After selective cutting, average spatial density index changed from moderately crowded to mildcrowed,with low selective cutting taking more percentage in it. The average storey index decreased most under high selective cutting, while middle or mild selective cutting had advantages when it is higher than 0.75. Selective cutting measures can effectively reduce competition between individuals.(4) Selective cutting can be increased heterogeneity evaluation index of stand, so that homogeneous evaluation grade of parts of plots was upgraded. The change of heterogeneity evaluation indexes before and after selective cutting showed that overall performance of 20% selective cutting which is mild selective cutting of Quercus aliena var.accuteserrata forest in Xiaolongshan is most appropriate, contributing to improvement of spatial structure and sustainable forest management.(5) Ideal homogeneous structure of Quercus aliena var.accuteserrata natural forest in Xiaolongshan is:(a)Mingling degree: intensitively mixed;(b)Neighborhood comparison: dominant species;(c)Uniform angle index: random distribution;(d)Spatial density index: moderately crowded state of 0.5;(e)Storey index: complex degree of more than 0.75;(f) Competion index: dominant trees.(6) According to priority Sequence of decision factors: Mingling degree> Spatial density index> Storey index> Uniform angle index> Competion index> Neighborhood comparison, the cutting wood were determined by decision technology process according negative influence with homogeneity index, and ecological harvesting technology which were single tree selective cutting, 20% selective cutting intensity and reserved closure more than 0.6, can optimize spatial structure Quercus aliena var.accuteserrata forest in Xiaolongshan and ensure its stability and the continuity of function.