中条山东段森林乔木树种分布的环境梯度分析与种组划分

利用CCA排序和TWINSPAN分类，探讨了中条山东段森林植被中乔木树种分布与环境梯度的关系，并根据树种在排序图上的相对位置，同时参考相关文献资料，进行了种组划分。结果表明，海拔梯度是影响乔木树种分布的最重要的环境因子，土壤肥力和土壤湿度指数也具有较大的作用。72个树种（含变种）归纳划分为6个种组，即低海拔暖湿型、中低海拔暖燥型、中低海拔温润型、中海拔湿沃型、中高海拔燥瘠型和高海拔冷湿型。每个种组内的树种在生态习性特别是在分布特征上显示出较大的相似性，介绍了各种组分布的生境特征。TWINSPAN分类结果与种组划分吻合较好。

Environmental gradient analysis and species group division of tree species distribution in eastern Zhongtiao Mountain

In this paper,the relationships between tree species distribution and environmental gradient in eastern Zhongtiao Mountain were studied by TWINSPAN and CCA ordination,and the species group division was made according to the relative positions of the tree species on the ordination diagram and referring to the dendrological documents.The results indicated that altitude was the most important environmental factor affecting the distribution pattern of tree species,while soil fertility and soil moisture index TRMI also played important roles.The 72 tree species(varieties) in the mountain were divided into 6 species groups,i.e.,low altitude + warm and moist,low-mid altitude + warm and dry,low-mid altitude + lukewarm and humid,mid altitude + moist + fertile soil,mid-high altitude + cool and dry + infertile soil,and high altitude + cold and humid-moist.Based on the greater similarities in the ecological features and distribution characteristics of the tree species in each group,the habitat characters of each species group were introduced in brief.The TWINSPAN results tallied well with the species group division.