Study On Optimal Strategy Of Carbon Reduction And Sink Increase For Residential Greenbelt In Xi’an

The rapid development of urbanization has led to the continuous expansion of urban area and many problems in urban living environment.With the goal of"carbon peak and carbon neutrality"proposed in China,issues such as strengthening the high-quality construction of urban green space and reducing and offsetting carbon dioxide in the atmosphere have attracted extensive attention from scholars in the fields of climate,ecological environment and urban planning.Residential green space is the most frequent and direct green space system associated with the life of urban residents.Studying the impact of residential green space on carbon reduction and sink increase can provide great help for the improvement of urban environment.However,the current research on the carbon sink benefit of residential green space lacks quantitative results and systematic research.At the same time,the research on the carbon sink benefit of urban residential green space has certain regional characteristics.Different cities have different geographical locations,climate and terrain conditions,leading to the impact of the arrangement of residential green space,the difference of green space area and species.According to the local characteristics and the actual situation,the result of adapting to local conditions is obtained.At present,the research on carbon reduction,sink increase and transformation optimization of Xi’an residential greenbelt has not been carried out.Therefore,this paper takes the residential green space in the main urban area of Xi’an as the research object,supported by 3S technology and based on the background of environmental science,landscape ecology and urban planning,analyzes the CO₂emission of Xi’an through remote sensing and non-remote sensing data as the basis for the selection of simulation objects.Through literature review method,SPSS analysis method,establishment of evaluation index system,i-tree model simulation method and carbon sequestration calculation,the research was carried out to analyze the correlation between green space and carbon sequestration capacity,evaluate and select simulated objects,and calculate the most economical allocation ratio of trees and shrubs.In addition,the ecological benefits such as carbon sequestration and oxygen release of the two types of green space in Xi’an residential area were quantitatively evaluated.Through the transformation cases,the change degree of green space carbon sink before and after the transformation was quantified and compared,the overall improvement of green space in Xi’an residential area was deduced,and the optimal design and transformation strategy for the construction and transformation of residential green space based on carbon reduction and carbon sink increase were proposed.The main results of this paper are as follows:（1）The correlation degree between each part of green space in residential areas and carbon sink capacity is quantitatively analyzed.The results showed that there was a complete positive linear correlation between green space and carbon sequestration in residential areas.Among all types,the correlation degree between green space near houses and carbon sequestration was the most significant 0.887,the correlation degree between central green space and carbon sequestration was 0.716,and the correlation degree between cluster green space and carbon sequestration was 0.169,showing a weak correlation degree.（2）Based on the principle of science and rationality,from the four aspects of stability,biodiversity,safety and functionality,12 three-level indicators including green land rate,per capita green area,three-dimensional green amount,plant species diversity,number of trees per unit area,proportion of native tree species,pollutant absorption,noise reduction effect,dust retention effect,green landscape accessibility,recreation and vertical greening were selected.To establish an evaluation index for the benefit of carbon sink in Xi’an residential greenbelt.（3）Based on the simulation of i-tree model and calculation of carbon sequestration amount,this paper studies the proportion of trees and shrubs with the best comprehensive benefits,summarizes the ranking of carbon sequestration amount of common trees in residential areas of Xi’an,and estimates the carbon sequestration increase of research samples and residential areas after renovation in the main urban area of Xi’an through simulation experiments.The results showed that:（1）The comprehensive benefit was the highest when the ratio of shrub to tree was 40%+shrub60%,tree 50%+shrub 50%and tree 60%+shrub 40%.（2）The average ranking of carbon sequestration of a single common tree（25-35cm DBH）in Xi’an is as follows:Poplar>Magnolia>Maple>Willow>Camphor tree>Sakura>Sophora tree>Pine>Red leaf plum>Apricot tree>Mulberry tree>Riguet>Loquat Tree>Toon tree>Walnut>Pear tree>Buckeye tree>Cypress tree>Conifer tree>Gingko tree>Palm tree>Persimmon tree,and the larger the tree diameter of the same species,the higher the carbon storage of a single plant.（3）The carbon sink capacity of No.128 Courtyard of Xiaozhai East Road was increased by 1362.2 kg/year（9.5 yuan/year）after the optimization,and the carbon sink capacity of Longfu North County was increased by824.4 kg/year（5.75 yuan/year）after the optimization.It is predicted that the carbon sequestration amount can be increased by 8432.62 tons/year（58,800 yuan/year）after the residential green space transformation in the residential district in the main urban area of Xi’an.