思茅松天然林林分直径大小多样性及环境解释

以云南省普洱市45块思茅松天然林样地为研究对象,选用Shannon指数(H)、Simpson指数(D)和断面积Gini系数(G)对思茅松林分总体、思茅松和其他树种的林分直径大小多样性进行量化,并采用CCA直接梯度排序法分析林分直径大小多样性随气候因子、地形因子、土壤因子和林分因子的变化规律。研究表明:(1)样地总体和思茅松的Shannon指数(H)和Simpson指数(D)的变化比较一致,其他树种的Shannon指数(Ho)、Simpson指数(Do)和断面积Gini系数(Go)变动幅度均比其他6个指数大。(2)气候、地形、土壤和林分因子直接排序的第一排序轴分别解释58.6%、92.0%、64.4%和76.4%的信息量,较好地反映了林分直径大小多样性随环境因子的变化规律。(3)从环境因子与排序轴的相关性上看,气候因子中除年降水外的8个降水因子相关性在0.15以上,而温度因子与林分直径大小多样性的相关性不高;地形因子中海拔(Alt)与第一排序轴的相关性最高(-0.467 5);土壤因子中全磷(TP)、全钾(TK)与第一轴排序相关性均高于0.30;林分因子中林分优势高(Ht)与第一排序轴呈现-0.418 0的负相关。(4)当较高气温和中等降水,海拔和坡度中等,全磷(TP)、全氮(TN)、有机质(OM)质量分数和p H值中等时,林分优势高和林分平均高最小;林分密度指数中等时,思茅松天然林具有最大的Ht、Hs、Dt、Ds值,而其他树种的林分直径多样性指数以及3个断面积Gini系数的规律性不强。

Stand Diameter Size Diversity and Their Environmental Explanation in Pinus kesiya var.langbianensis Natural Forests

With 45 plots of Simao Pine (Pinus kesyi a var.langbianensi ) natural forests in Pu’er City of Yunnan Province, Chi-na, Shannon index (H), Simpson index (D) and Gini coefficient (G) for overall stand, Simao pine and other trees in plots were selected to quantify the stand diameter size diversity .Then, canonical correlation analysis (CCA) was used to analyze the change law of stand diameter size diversity along with climate factors , topographical factors , soil factors and stand factors.The result showed that:(1)Shannon index (H) and Simpson index (D ) of overall stand and Simao pine had more consistent changes , while the Ho , Do and Go of other trees had great fluctuation than others which reflect that Simao pine had more abundant size classes .( 2) The first ordination axis of the climate , topography , soil and stand factors reflec-ted 58.6%, 92.0%, 64.4%and 76.4%for the variation, respectively, and it had better explanation on the variation of di-ameter size diversity along with the environment factors .(3)It was vividly depicted on the correlation between environment factors and ordination axes , the correlation between eight precipitation factors ( except Annual Precipitation ) and ordination axes was more than 01.5 , and the correlation coefficient were not significant between temperature factors and ordination ax -es.The altitude ( Alt) had the highest correlation with the first axis which was -0.467 5; the correlation between total phosphorus (TP), total potassium (TK), and the first axis was more than 0.30, while the stand dominant height (Ht) was the most relevant (-0.418) stand factor.(4)Simao pine natural forest had the largest Ht, Hs, Dt and Ds when the stand was under higher temperature and moderate precipitation , moderate altitude and slope , moderate total phosphorus (TP), total nitrogen (TN), organic matter (OM) content and pH value of soil, and least stand dominant height, stand average height and medium stand density index .But the change of Ho , Do and three Gini coefficients were with irregularity .