Plant Community Of Qianwangling Parkin Lin'an Based On I-tree Model Research On Structure And Ecological Benefits

In recent years,quantitative evaluation of urban green space ecological service function and its ecological benefit value has become a research hotspot of garden ecology and landscape architecture.Based on the field survey,this paper analyzes the composition and diversity of the 32 plant communities in Qianwangling Park,Lin'an,Hangzhou.The i-Tree model is used to save energy,absorb carbon dioxide,improve air quality,intercept rainwater,and aesthetics of the investigated communities The ecological benefits of 5 aspects were quantitatively evaluated.At the same time,the evaluation results of the i-Tree model aesthetic benefits and the SBE beauty assessment results were compared and analyzed,and the park plant community was optimized based on the research results.The purpose of this study is to use i-Tree model to explore the ecological benefits of plant communities in urban parks,and to provide a certain reference for the construction of high ecological benefits green space in Hangzhou.The findings are as follows:(1)A total of 1,613 trees and shrubs were investigated,belonging to 74 families,39 genera and 62 genera.DBH is mainly distributed at 7.60-30.50 cm,accounting for 67.08%;tree height is mainly distributed at 250-1250 cm,accounting for 69.87%.Evergreen and deciduous trees accounted for80.90% and 19.10%,respectively;broad-leaved trees and coniferous trees accounted for 79.11% and12.46%,palms accounted for 8.43%,and the park as a whole was dominated by evergreen broad-leaved trees.The overall health status of the trees was 65.59%,32.11%,2.23%,and 0.06%,respectively;the tree species with RPI(relative performance index)> 1 totaled 42 species,accounting for 55.08% of the total tree species surveyed.The spatial structure of the plant communities under investigation is mainly mixed and "qiao-irrigate-grass" multi-layered models;it is divided into needle-broad mixed type,evergreen deciduous broad-leaved mixed type,evergreen broad-leaved type,bamboo broad Of the four types of mixed type,the number of needle-broad mixed type communities is the largest,accounting for40.62%.The Margalef richness index,Simpson index,Shannon-Wiener index,and Pielou evenness index of the investigated communities were 9.628,0.911,4.427,and 1.035,respectively.Among them,the Margalef index,Simpson index,Shannon-Wiener index,and Pielou of the needle-broad mixed community The indices were the highest,at 3.109,0.843,3.171,and 1.229,respectively.(2)Using the i-Tree model to evaluate,the total value of annual ecological benefits of the 32 plant communities investigated was 450081.28 yuan.The values of energy conservation,carbon dioxide absorption,rainwater retention,air quality improvement and aesthetic benefits are 48111.36 yuan,98334.72 yuan,57805.44 yuan,4005.76 yuan and 2412384.00 yuan,accounting for 10.69%,21.85%,12.84%,0.89% and 53.73 respectively.%.These five types of benefits are ranked according to their value: aesthetic benefits> CO2 absorption benefits> Rainwater retention benefits> Energy conservation benefits> Improved air quality benefits.(3)From the perspective of different types of communities,coniferous and broad-leaved mixed communities have obvious advantages in terms of energy saving,carbon dioxide absorption,and rainwater retention;evergreen broad-leaved and coniferous-leaved mixed communities have advantages in improving air quality;evergreen deciduous broad-leaved communities The mixed leaf community has significant advantages in aesthetics.From the perspective of growth type,coniferous and deciduous broad-leaved trees have higher ecological benefits.The ecological benefit of the community was positively related to the average benefit of the individual plant in the community and the proportion of the number of trees.However,due to the different types of trees in the community,there was no correlation with the overall average DBH of the community.(4)SBE beauty evaluation method and i-Tree model for the aesthetic evaluation of plant community landscape did not show consistency in community ranking order,community type and different functional areas,that is,the value of aesthetic aesthetic benefits of communities with good visual effects may not be high.vice versa.(5)Based on the research results of the evaluation of plant community structure,ecological benefits,and beauty,by adjusting the composition of the tree species,average DBH,and hierarchical structure of the community,the ecological benefits of the four typical communities are ensured under the premise of meeting the type and structure of the inherent community in a specific functional area Based on the original increase of 33.44%,13.14%,46.24%,173.11%.Among all the ecological benefits,the value of aesthetic benefits increased the most.