Study On Spatial Structure Of Coniferous And Broad-leaved Mixed Forests In Weihe River,jilin Province

Understanding the composition and structure of forest communities is the basis for studying community ecology;the spatial structure of forest can reflect the spatial relationship of species within forest communities.This paper mainly studies the species composition,important values,and diameter-level structural indexes of the forest plots in Jiao He,Jilin province,and studies the characteristics of the community structure.The method of spatial structure unit is used to describe the forest by using Mingling,Dominance and Uniform angle index.The tree-species relationships,tree differentiation,and tree-level distribution patterns were used.The Ripley’s K function was used to analyze the spatial distribution of single species and the interspecific distribution of major tree species.The main results are as follows:(1)The conifer and broad-leaved mixed forest shows obvious flora characteristics in species composition.There are many tree species in the mixed forest,and individual differences are larger.The top eight tree species with important value are respectively the Juglans mandshurica,the Acer mono,the Fraxinus mandschurica,the Ulmus japonica,the Acer mandshuricum,the Ulmus macrocarpa,the Ulmus laciniata and the Pinus koraiensis;the diameter-distribution structure of all individuals showed an inverted "J" pattern,indicating that the community has a better regeneration condition.(2)The average mixed degree of the whole forest stands is 0.84,this relatively high average mixed degree,indicates that the natural forest has good natural management and protection;in the size configuration,Juglans mansii has the most advantage;the mean angular dimension is 0.53.The horizontal distribution pattern of trees in this plot is agglomeration.In the course of business,attention can be paid to tree species collocation in order to improve the stability of forest stands;adjusting the size ratio of the target tree species to create a good ecological living space for the target tree species;and cutting down the target tree with a smaller angle scale to reduce one-way aggregation.Make the forest stand randomly distributed.(3)The vast majority of tree species are spatially aggregated and their degree of aggregation is closely related to the spatial scale.Most of the eight dominant tree species are clustered on the 0-100m scale.The 28 interspecies relationships of 8 tree species indicated that there were strong competition relationships among the species with similar niche in the community,the largest number of individual individuals in the Juglans mandshurica,the distribution in the entire plot,the most concentrated distribution,and the strongest adaptability.There is a positive spatial correlation between the Fraxinus mandschurica and most tree species on the 0-50m spatial scale,which is a good companion species.