陕北黄土高原森林植被数量分类及环境解释

通过对陕北黄土高原森林群落的系统聚类分析和因子分析（FA）及其与5个土壤变量的多元统计分析。定量研究了该地区森林植被的类型及土壤特征之间的相互关系。结果表明，陕北黄土高原森林植被可分为5个群系，即油松林、辽东栎林、山杨林、白桦林和侧柏林，聚类分析结果与传统分类的结果完全一致。该地区森林植被格局可由群落土壤条件的差异来解释，土壤因子中含水量、全氮和有机质是主导性因素，各群落沿此梯度呈现出一定的分布格局，其它土壤因子的作用并不明显。

Quantitative classification and environmental interpre tation on forest communities in Loess Plateau of the north of Shaanxi Province

Basing on clustering analysis,factor analysis and multianalysis with the soil characteristics of 35 forest samples in Loess Plateau in the north of Shaanxi Province,the relationship between forest types and soil characteristics were investigated.The result showed that the forests in Loess Plateau in the north of Shaanxi Province can be divided into 5 formations:\%Platycaladus orientalis\% forests,\%Pinus tabulaeformis\% forests,\%Quercus liaotungenses\% forests,\%Populus davidiana\% forests and \%Betula platyphylla\% forests,which coincides with subjective classification under the dominance species principle.The forest pattern was determined by soil characteristics rather than climate factors.Contents of free water,total N and organic matter in soil were predominant in all of the soil factors while another soil factor was not so evident.Along this gradient,the forest communities showed certain spatial distribution pattern.