Skewness and Kurtosis Variation and Their Environmental Explanation on Stand Diameter Structure of Pinus kesiya var.langbianensis Natural Mature Forests
Taking 45 plots of Simao Pine (Pinus kesiya var.langbianensis) natural mature forests in Pu'er City,Yunan Province,as the study object,skewness and kurtosis were selected to quantify the stand diameter structure on totality,Simao pine and other tree species in the forests and then,canonical corre spondence analysis was used to analyze the change law of stand diameter structure along with stand,topography,soil and climate factors.The results showed that:The stand diameter structure distribution of Simao pine and standard normal distribution had presented more consistent performance,but the stand diameter structure distribution of other tree species and standard normal distribution had presented more obvious difference.It turned out that the stand diameter structure of Simao Pine nature mature forests was more affected by other tree species.The first ordination axis of the stand,topography,soil and climate factors respectively explained 71.7％,67.1％,60.4％ and 76.3％ of the change information of stand diameter structure,so it had better explanation on the variation of stand diameter structure along with four environmen tal factors.It vividly depicted on the correlation between four environmental factors and ordination axes,and the crown density had the highest correlation with the first ordination axis which was 0.2263,the correlation between stand average height,stand dominant height,stand density index and ordination axis was more than 0.23;the altitude had the highest correlation with the first ordination axis,and the correlation coefficient was 0.4602;the correlation between soil pH,total phosphorus and the first ordination axis was more than 0.40;in addition to the lowest temperature of coldest month,the mean temperature of wettest quarter,the mean temperature of hottest quarter,the correlation between other eight temperature factors and ordination axes was more than 0.22,and apart from the precipitation of wettest month,the precipitation of wettest quarter,the correlation between other six precipitation factors was more than 0.24,which in dicated stand diameter structure was closely related to the fourteen climate factors.The stand diameter structure on totality and Simao pine were significantly affected by environmental factors,both of which re spectively showed a strong regularity with environmental factors.However,the regularity of other tree species and environmental factors was not strong.
stand diameter structureskewnesskurtosisenvironmental factorsPinus kesiya var.langbianensis
NETL
NSTL
万方数据
维普
