思茅松天然成熟林林分直径结构偏度和峰度变化及环境解释

Skewness and Kurtosis Variation and Their Environmental Explanation on Stand Diameter Structure of Pinus kesiya var. langbianensis Natural Mature Forests

以云南省普洱市45块思茅松天然成熟林样地为研究对象,选用偏度和峰度对林分总体、思茅松和其他树种的林分直径结构进行量化,并选用典范对应分析方法,对林分直径结构随林分、地形、土壤和气候因子的变化规律进行分析。结果表明,思茅松林分直径结构分布形态与标准正态分布呈现出较为一致的表现,而其他树种林分直径结构分布形态与标准正态分布的差异较为明显,说明思茅松天然成熟林林分直径结构受到其他树种的影响较大。林分、地形、土壤和气候因子第一排序轴分别解释了林分直径结构变化信息的71.7%、67.1%、60.4%和76.3%,较好的反映了林分直径结构随4种环境因子的变化规律。从4种环境因子与排序轴的相关性来看,林分因子中郁闭度与第一排序轴的相关性最高(0.2263),林分平均高、林分优势高和林分密度指数与排序轴的相关性达到0.23以上;地形因子中海拔与第一排序轴具有最大相关性(0.4602);土壤因子中土壤pH值、全磷与第一排序轴的相关性均超过0.40;气候因子中除最冷月最低温、最湿季均温、最热季均温外,其他8个温度因子与排序轴的相关性均在0.22以上,除降水最大月降水和最湿季降水外,其他6个降水因子与排序轴的相关性均在0.24以上,表明林分直径结构与14个气候因子密切相关。林内总体、思茅松林分直径结构受到环境因子的影响较为显著,与其呈现出较强的规律性,而其他树种与环境因子的规律性不强。

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 correspondence 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 environmental 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 indicated 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 respectively showed a strong regularity with environmental factors.However,the regularity of other tree species and environmental factors was not strong.