Research On The Structure Of Urban Forest Planning Of Wuhan

Urban is an environment massed by people, the environmental problem is getting serious day by day with urbanization. Voice of "introducing forest into urban" and building urban forest ecology network is getting regarded recently, in particular. For various reasons, in the city's overall planning and construction, China's urban forest lack reasonable and holistic structure, In construction, a number of existing urban green and urban forest were requisitioned and destroyed, as a result of the phenomena,it brought difficulties to the construction of urban forest planning which had formed integer scale, and resulted in the structure loose of local urban forest. Therefore, how to analyse and evaluate and planning guidance the structure of urban forest by a perspective of landscape ecology, has now become the construction of urban forest issues requiring urgent solution.This study was based on Wuhan city in april 2007 TM remote sensing image as the main data source, adopted GIS and landscape pattern analysis, guided by ecology principles to modern forestry and urban green planning theory, analysed and synthetically evaluated the overall arrangement and landscape structure of urban forest of Wuhan city, according to theory of urban forest construction, landscape ecology and landscape planning theory to propose a fully functional, the layout of the building a reasonable model of urban forest, and finally explored to achieve this ideal model of urban forest layout, what planning adjustments needed based on the layout of urban forest status. Main research results include four aspects:1. The patch-level and landscape-level index's analysis & estimating were made on the study region landscapes elements, the results showed that:The development of landscape types is unbalanced, a small number of landscape types such as agricultural land and water built up the landscape pattern is the entire City. Other landscape types had small size, poor connectivity, and a high degree of fragmentation. The total of urban forest is small, city accounted for only 11.96% of land area, of which 85.41% of them was on the outer suburbs of the mountain and hilly region; affected by human activities such as urban construction, the impact of strong interference, urban forest in main urban areas of the distribution is only 2.97%, and that, proportion of small patch was significant, large-area urban forests with interior habitat were lack, patch density was great and fragmentized seriously. At the landscape level, landscape diversity index was high in the entire city, evenness index was common, the outskirts of the city in which diversity index and evenness index were the largest, followed by the main urban areas, the outer were the minimum. The distribution of urban forest was uneven generally, the connectivity of interspaces is also absence which went against species intercommunion. Those were not good enough to improving Wuhan city environments as a whole.Falling within the scope of different research on grain size distribution of patches as follows: outer distribution of the total number of small patches 84.10%, middle patches 83.73%, big patches of 85.99%, 66.15% of the huge patch. The number of urban forest patches are less than 10% of all grain size in main urban areas, and less than 20% in peri-urban areas; the main landscape type of urban forest were shelter forest and production forest, the total area of them attained 75% of the whole urban forest area; the landscape forest and the special use forest , the proportion of their own were less than 10%. At present, the distribution of patches and landscape structure was unreasonable, it was not conducive to urban forest ecosystem function.2. Based on urban forest evaluating indicator system established by this research, urban forest comprehensive evaluation indices of Wuhan score for 0.3247, lay in beta IV level, belong to urban forest structure unreasonable and layout poor degree.3. The author held urban ecological patterns and needs of urban forest construction and forest-water network integration for the planning concept, through green Point, green Line, green face a combination of, designed "two axises, two rings, three net and a number of core" as the overall layout of urban forest, to form the effect of "water and forest combined, ecological Wuhan". Upon completion of the planning, the whole city's urban forest coverage will be attained 25%, green coverage of built-up area attained 40%, green channel rate attained 85%, waterfront greening rate attained 85%,nature reserve coverage attained 5%, forest of the rate of farmland attained 80%, urban ecological land will be increased and wetland coverage will be increased 2%.4. When planning completed, the author made the layout of the existing urban forest adjustments, combined with the creation of national forests in Wuhan urban overall planning requirements, and the adjustment measures will be integrated into the main forestry projects. Including the three town of Green island construction project, nine provinces thoroughfare landscape ecological forest construction project, hundreds of lakes wetland ecological construction project, two main river with four coastal scenery and construction of embankments shelter belt and green mountain rehabilitation and reconstruction of ecological landscape, to complete the adjustment the layout and structure of urban forest by constructing these key projects.