Resource Characteristics and Spatial Distribution Pattern Analysis for Large Old Trees in Sanmen County,Zhejiang Province
To further grasp the current compositional characteristics of large old trees(LOTs)resources in Sanmen county,Taizhou city,Zhejiang province,and explore their spatial distribution patterns.This study an-alyzed the dominant tree species,species diversity,and structural characteristics of LOTs in Sanmen county,based on the basic data from the 2019 tree survey.Utilizing ArcGIS spatial analysis methods,the research sys-tematically investigated the spatial distribution pattern of LOTs in the county.The results showed that(1)San-men county has a total of 681 LOTs belonging to 24 families,30 genera,and 35 species,including 7 conifer-ous species,28 broad-leaved species,15 evergreen species,and 20 deciduous species.Dominant species like Camphora officinarum,Liquidambar formosana,Aphananthe aspera,Celtis sinensis,and 9 other species,ac-counting for 85.46% of the total tree count,forming the core resources of LOTs.The distribution of LOTs is as follows:first-level trees account for 12%,second-level for 21%,and third-level for 67% .(2)Analysis of species diversity and grey relational analysis(GRA)reveals that Haiyou Street exhibits the highest level of spe-cies diversity,with comprehensive indices of H'=2.265,D=0.854,J=0.507,and relational degree=0.978.In contrast,Shepan Township demonstrates the lowest ranking.(3)In terms of structural characteris-tics,the age of LOTs primarily falls within the range of 100-150 years,with the diameter at breast height(DBH)concentrated around 110-160 cm,the tree height is typically ranging from 15-20 m,and the crown width concentrated between 15-20 m.A notable linear relationship exists between the DBH and the crown width,represented by the equation y=0.614 37x-0.375(R2=0.455,P<0.01).(4)Significant variations are observed in the kernel density distribution of LOTs across different townships and streets,with dense clusters predominantly situated in the northwest(including Haiyou street,Hairun street,and Jiantiao township)and the central region(Hengdu town)of the county.The nearest neighbor analysis(NNA)reveals that the overall LOTs(NNI=2.968,Z=42.929,P<0.000)and second-level LOTs(NNI=2.968,Z=42.916,P<0.000)exhibit a significant dispersed distribution,while first,third-level LOTs,along with major single species,are notably clustered.The above research findings hold significance for the preservation and management of LOTs's resources and biodiversity in Sanmen county.
Sanmen countylarge old trees(LOTs)spatial distribution patternnearest neighbor anal-ysis(NNA)kernel density estimation(KED)
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