Abstract: To explore the community characteristics of Carpinus turczaninowii and their relationships with soil environmental factors on Dalu Island in the northern Yellow Sea, we carried out plot survey with nine C. turczaninowii communities on Dalu Island. We analyzed community characteristics by flora composition, species importance value, species diversity, and diameter structure, and determined the soil influencing factors by using twoway indicator species analysis (TWINSPAN) and redundancy analysis (RDA). The results showed that: (1) A total of 110 vascular plant species belonging to 46 families and 84 genera were recorded in the C. turczaninowii communities, including 107 species in 82 genera of 44 families of seed plants and 3 species in 2 families of 2 genera of ferns. Most of the seed flora composition had temperate distribution properties. The dominant species in the tree, shrub, and herb layers were C. turczaninowii, Zanthoxylum schinifolium, and Carex callitrichos var. nana, with importance values of 52.84%, 34.49%, and 21.54%, respectively. Species composition of tree layer was relatively poor, while species of shrub and herb layers were more abundant. The community did not reach the climax stage of succession. The diameter size structure of C. turczaninowii populations reflected that the community was composed of growing population. (2) The cluster analysis classified the C. turczaninowii  communities into four types of clusters. The ordination analysis results verified the rationality of the aforementioned cluster analysis results, and showed that soil thickness, soil total phosphorus content, and pH were the main factors affecting species distribution in C. turczaninowii communities.

Key words: Carpinus turczaninowii community, forest community characteristics, cluster analysis, ordination.