Community Structure And Spatial Distribution Pattern Of Main Tree Species Of Secondary Forest In Jiande,zhejiang Province

In this paper,the secondary forest(Broad-leaved secondary forest,Pinus and broad-leaved mixed secondary forest,and Pinus secondary forest)in Jiande,Zhejiang Province was used as the research object.The method of standard large-scale land survey was used to analyze the flora composition and the important value of forest community in the ecological study.The research methods of community species diversity index,niche and spatial pattern distribution of main tree species,comparative analysis of different types of secondary forest community structure and spatial pattern characteristics of main tree species,and in-depth analysis of the existence of plants in the vegetation zone of Jiande City The rules and the use of these community characteristics and laws to guide the tending management of Jiande City's secondary forests to solve the problem of the irrational structure of the age group and the low productivity of the forests provide a scientific basis for the restoration,transformation and protection of the secondary forests in the region.The main findings are as follows:(1)There are 32 species of arbor trees in the arbor layer of Broad-leaved secondary forest,belonging to 16 families and 24 genera.The Fagaceae family has the most species,followed by Lauraceae.There are 39 species of trees in the Pinus and broad-leaved mixed secondary forest.The tree species belong to 19 families and 32 genera,and the species of the family Fagaceae are the most,followed by the family of the family Branchaceae and Theaceae.The tree layer of Pinus secondary forest has 29 species,belonging to 17 families and 27 genera,and the family Fagaceae and Polygonaceae.The number is the most.followed by Rosaceae and Rosaceae.The flora characteristics of the secondary forest community are basically the same as those of the flora of Zhejiang Province and the subtropical evergreen broad-leaved zone.There are two endemic species in the Pinus and broad-leaved mixed secondary forest and Pinus secondary forest,which are Cunninghamia lanceolata and Sassafras tzumu.(2)The main tree species of the secondary forest community are as follows:Broad-leaved secondary forest:Cyclobalanopsis glauca,Lithocarpus glaber,Castanopsis sclerophylla,Schima superba;Pinus and broad-leaved mixed secondary forest:Pinus massoniana,Castanopsis sclerophylla,Cunninghamia lanceolata,Loropetalum chinense,Lithocarpus glaber;Pinus secondary forest:Pinus massoniana,Cunninghamia lanceolata,Castanopsis sclerophylla,Platycarya strobilacea,Liquidambar formosana.There were significant differences in species diversity levels among different types of secondary forest communities.The stability of Broad-leaved secondary forest communities was the worst,and the stability of Pinus and broad-leaved mixed secondary forest communities was the highest.(3)The niche breadth values of the main tree species in the secondary forest community were large.Among the Broad-leaved secondary forest,Cyclobalanopsis glauca width index was the largest,followed by Castanopsis sclerophylla,Schima superba and Lithocarpus glaber;in the Pinus and broad-leaved mixed secondary forest,Castanopsis sclerophylla niche breadth index was the largest,followed by Pinus massoniana,Loropetalum chinense,Cunninghamia lanceolata and Lithocarpus glaber.Among the Pinus secondary forest,Pinus massoniana has the largest niche breadth index,followed by Platycarya strobilacea,sweet Liquidambar formosana,Cunninghamia lanceolata and Castanopsis sclerophylla.The degree of niche overlap among major tree species is relatively large(4)The main tree species of Broad-leaved secondary forest,Cyclobalanopsis glauca,Lithocarpus glaber,Castanopsis sclerophylla and Schima superba,showed significant aggregation distribution on the scale of 0-25 m.The relationship between Cyclobalanopsis glauca and other major tree species was basically negatively correlated.Castanopsis sclerophylla and other The correlation between the main tree species was not significant The main species of Pinus and broad-leaved mixed secondary forest,Pinus massoniana,Castanopsis sclerophylla,Cunninghamia lanceolata,Loropetalum chinense and Lithocarpus glaber were significantly aggregated on the scale of 0-25 m,and the correlation between species,and most of the sexes were not significant.Pinus massoniana was positively correlated with other tree species;the main species of Pinus secondary forest,Pinus massoniana,Cunninghamia lanceolata,Castanopsis sclerophylla,Platycarya strobilacea and Liquidambar formosana,also showed significant aggregation on the 0-25 m scale.Distribution,the relationship between Pinus massoniana and other major species is basically unrelated.Most of the main tree species are concentrated in the range of small and medium-sized diameters,and most of the same species have positive correlations.