太白山红桦林的排序

THE ORDINATION OF BETULA ALBO SINENSIS FOREST IN THE TAIBAI MOUNTAIN

运用主分量分析（ＰＣＡ）法，将太白山红桦林分为７个类型：Ⅰ．红桦＋辽东栎林；Ⅱ．红桦＋辽东栎＋华山松林；Ⅲ．红桦＋华山松林；Ⅳ．红桦纯林；Ⅴ．红桦＋华山松＋牛皮桦林；Ⅵ．红桦＋牛皮桦＋巴山冷杉林；Ⅶ．红桦＋牛皮桦林。这不仅与分类结果一致，而且反映了各样地间的空间分布格局。影响排序的主导因子是红桦、辽东栎和牛皮桦。

By means of principal con1ponent analysis(PCA),the 20 plots of Betula albo sinensis for-est are classified into 7 types:1.Betula albo sinensis andQuercus liaotungensis forest;2.B.albo sinensis and Q.liaotungensis and Pinus armandii forest; 3.B.albo sinensis and P.armandiiforest;4.B.albo sinensis forest: 5.B.albo sinensis and P.armandii and B.albo sinensisvar.septentrionalis forest;6.B.albo sinensis and B.albo sinensis var.septentrionalis and Abiesfargesis forest;7.B.albo sinensis and B.albo sinensis var.septentrionalis forest.The resultof the ordination accords with the classification result,and shows clearly the pattern of spatialdistribution of communities.The ordination is influenced significantly by Betula albo sinensis,Quercus liaotungensis and Betula albo sinensis var.septentrionalis.