Community Characteristics And Factors Affecting Understory Species Diversity Of Pistacia Chinensis Bunge In Shanxi Province

The utilization and development of energy is the main issue which will be faced in the twenty-first century. The progress on biomass energy brings Gospel to the solution of the problem. According to the experiments of American and European,the bottleneck of biomass energy development is the resources supplies. In China, Pistacia Chinensis Bunge has been the perfect one to develop biomass energy for its widespread distribution, high oil content and high level of resistance. In research Yangcheng, Yuan qu of Province Shanxi, with a concentrating distribution of Pistacia Chinensis Bunge, were chosen to do more researches on the above-mentioned items. The results shows that:1. There are more mixed forest of Pistacia Chinensis Bunge than pure forest. The main species mixed with Pistacia Chinensis Bunge is Quercus variabilis, Ulmus macrocarpa, Albizzia julibrissin, Koelreuteria paniculata with a few of Pyrus betulifolia, Carpinus cor data and Tilia tuan.2.The height growth of Pistacia Chinensis Bunge is slow in the first five year, then fast until the year of15. The mean annual increment of height reaches the maximum in the year of15(0.45m), after the year of15it decreases. The mean annual increment of diameter presents increasing trend, and its declination is late. The fast growing period of volume is between the year of32-50, the mean annual increment reaches the maximum around the year of42(0.0014m3) and later it declines.3.The species diversity of pure stand is lower than mixed forest. The species richness (S), the Pielou evenness index (E) and Shannon-Wiener diversity index (H) of shrub layer are different between pure and mixed forest. The three indexes of herb layer are also different between pure and mixed forest. In the mixed forest, the three indexes of shrub layer and herb layer has no significant difference whether Pistacia Chinensis Bunge is the dominant species or not.4.The research on the influence factors of undergrowth species diversity shows:the environmental factors which have significant explanation to the variety of species diversity of shrub layer is altitude, aspect, density, and humus layer thickness; And the factors which have significant explanation to the variation of species diversity of herb layer is density, Forest Floors thickness and Gravel content.5. Natural forest of Pistacia Chinensis Bunge regenerate mainly through sprouting rather than seedling bank. We studied the influence of environment factors to natural regeneration by using general linear model, the result shows that:aspect and diversity of shrub and herb layer have significant explanation to the variation of the number of natural regenerate, while Forest Floors have significant explanation to the variation of mean branch diameter and mean height.