Research On The Evolution And Optimization Of Urban Green Space System In Changsha City

With the improving requirements of the environment quality, an upsurge of constructing garden city, ecological city and livable city appear in the global. Though the world does not have a fixed evaluation standard, urban green space is one of the important indexes to evaluate these three types city. Thus, urban green space system plays an important role in city development. To some extent, urban green space can alleviate a series of environmental problems which were brought by urbanization, creating a condition for city sustainable development, and reasonable urban green space system patterns can optimize the urban landscape pattern.Basing on the summary of domestic and abroad urban green space system research, this paper takes the green space data of Changsha in1999and2010to analysis the urban green space pattern evolution of Changsha in the10years by comparing the urban green space area and green patch types in the two years. In order to provide some reference for Changsha green space construction in the future, this paper takes Changsha regional feature and the level of economy development as basis to discuss the optimizing strategies. The main conclusions of this paper are as follows:(1) The spatial structure of urban green space system in Changsha metropolitan area is unreasonable. The main city is a region, which has dense population and developed economy. However, the green area is the least in this study area and the only green space is some sporadic small garden green space, lacking of effective connection between each other. While large green space mainly concentrates in the surrounding area of Changsha downtown, such as Yuelu district, Muyun town, Tiaoma town, Dingzi town.(2)The fragmentation trend of urban green space is obvious in Changsha metropolitan area. From1999to2010the urban green space becomes more and more fragmentation. The proportion of medium-sized patches is1.32%in1999, while it was rising to3.16%in2010. On the contrary, the proportion of large green space has decreased from89.43%to79.34%. By2010, city center area basically has no super large green space patches, while the original large greenbelt was divided and encroached gradually.(3) Pay more attention to construct urban park green space, while ignoring the natural green space protection. Relevant statistical data shows that:the area of urban park green space of Changsha from4319hectares in1999to8598hectares in2010, which was increasing in the10years. But the green space data extracted from remote sensing images displays that the total area of Changsha urban green space was reducing from1999to2010. Although the absolute accuracy interpretation of remote sensing can not be guaranteed, to a certain extent, it could be illustrated that Changsha urban green space system construction stress on urban park green space construction while neglect the natural green space protection.(4) Establishing efficient urban green space management system is emergence. In the face of unreasonable urban green space distribution, type diversity, in addition to coordinate planning department, land department and garden department to manage and maintain green space, also need to build a green space specialized management institution, which cover the Chang-Zhu-Tan city cluster, using Geographic Information System, Global Position System, Remote Sensing and computer technology to monitor and manage urban green space system professionally.