| This paper analyzed the function of the CITYgreen software and its localization. By applying the software into the analysis of the green space system in build-up areas in Beijing, and based on the study of the ecological benefits spatial distribution and comparative analysis, recommendations were then given upon the city green space system planning and species selection.CITYgreen software is an extension to the ESRI's ArcView3.x. It conducts complex analyses of ecological benefits of the city forest, including air pollution removal, carbon storage and sequestration, water and soil conservation and energy savings. CITYgreen software also calculates all these benefits in visual monetary terms.(1)Based on the field inspection of the city green space system in build-up areas in Beijing, mapping of the green infrastructure was conducted using GIS software, then the green space Management Information System was set up. The Management Information System was at the same time been published onto the Google Earth platform for public query and updates.(2)The paper studied the suitability, limitations and adjustment of the species database and other parameters (like Atmospheric parameters) of the CITYgreen model for China, specifically Beijing City. About one hundred common species in Beijing were updated into the model database, so the results can better represents the real situation in Northern China. Ecological benefits per unit area for 60 common species were calculated.(3)Based on different types of green spaces (residential green space, attached green space, public park, green space attached to urban road and square), ecological benefits were analyzed, including quantity of air pollution removals such as SO2, NO2, CO Comparative analysis were also conducted in this procedure.(4)Comparative analysis of ecological benefits from green spaces in different areas (location, along ring road, urban and rural area) was carried out based on the spatial distribution of green spaces in build-up areas in Beijing. The results demonstrated that: ecological benefit incurred from the northern part of the city is higher than from the south. From the inner ring road to the outer ring road, related to the distance from the city center, ecological benefits revealed gradient changes. Ecological benefit fell as it moves away the city center towards southeast, east and southwest, whilst moving towards northwest, ecological benefit increased gradually. There are some fluctuations in other directions too, but only within small ranges.(5)According to the spatial distribution and brightness temperature distribution maps of the ecological benefits of the city green spaces, we arrived at a conclusion that: ecological benefits of green spaces are negatively correlated to the surface temperatures. Compare to vegetation, water bodies in the city green spaces system incurred larger contribution in relieving Urban Heat Island Effect. Among all the parameters in the CITYgreen model, other than DBH or tree height, canopy area exerts the largest contribution in reducing the urban surface temperature. Canopy area, to some extend, represents green biomass(GB).The regional parameters characteristics of the CITYgreen model however are the primary constraints. The setting of parameters and standards in the ecological benefits calculation formula had taken geographic location, climate and other factors into consideration. Although we can adjust relative parameters when studying vegetation ecological benefits in different region, there are still a few default parameters unchangeable, which limit the popularization of the CITYgreen model. |
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