Carbon Storage Estimation Of Urban Green Lands In Yiwu

Global climate change is one of the main environmental problems. As the largest carbonsink, the forest is playing an important role in balancing global carbon budget and mitigatingglobal warming. The forest area in urban area is quite limited, but it has a significant impact onprompting the carbon cycle.In this paper, taking Yiwu as the case the carbon reserves estimation model of urban greenspace was developed based on high resolution Quick Bird images. The Urban Green space inYiwu was classified into park greenbelt, unit affiliated green land, and other green land. Eachkind of Green spaces was surveyed by using the classic plot sample survey method, and then,biomass and carbon storage were calculated based on allometric equations. Some spatial factorssuch as gray value, neighbor, tasseled cap components, principle components were adopted asindependent variables, the plot carbon storage was used as the dependent variable. Simplelinear regression and stepwise regression model were used to estimate green space carbonstorage and distribution of study area.Compared with simple linear regression，the stepwise regression model in estimating urbangreen space carbon storage performances better. The simulation accuracy of unit affiliatedgreen space and other green space that used stepwise regression estimation is higher, thecorrelation index of each model were0.781and0.675, prediction accuracy were77.51%and79.73%, the correlation of sample value and remote sensing simulation value were0.846and0.7234, respectively. Prediction accuracy of protective greenbelt is69.37%which was lowest inthe above models, the correlation index was0.552. The carbon storage of park green space was3623.80tons, and carbon intensity was27.41Mg/hm~2. Greenbelt’ s carbon storage was5245.78tons, while the carbon intensity was24.89Mg/hm~2. The carbon storage of unit affiliated greenland was5284.84tons, and carbon intensity was38.61Mg/hm~2. Other green space’s carbonstorage was5343.65tons, the carbon intensity was25.48Mg/hm~2. In totall, the carbon storagewas19498.07tons, he carbon intensity was28.29Mg/hm2. Most parks in Yiwu werecomprehensive parks, in which, the function of recreation is more than the role of carbon sink,and grass, pavilion, cabinet, waterside pavilion account for a high proportion. Tall trees shouldbe transplanted in order to promote carbon sink function. According to greenbelt, roadlandscape irrigation belt in Urban Periphery was a little more, which affected overall carbondensity, and trees can be planted in irrigation to improve carbon absorbing. Relative carbondensity of unit affiliated green space was a little high, while overall green area is not enoughand should increase green area. Other green space’s area was largest in above four kinds ofgreen space, which has great contribution to carbon sink of Yiwu.The main innovation in this study is to establish a model based on the different function ofgreen space carbon sink. The result revealed that the classification method prospect corresponded accuracy requirement，which provided a basis to forestation decision, urbanplanning and management decision, and has a good application.