Studies On The Green Corridors Based On The Vegetation Quantity In Wuhan City

Green Corridors have played an important role in landscape structure, achieving optimization of the spatial structure and reasonable layout on urban green space in limited land resources, which can make the ecological,social and economic benefits of the green corridor more fully and efficiently. This study with the support of the National Natural Science Foundation of China "Studies on Structure of urban vegetation quantity based on of the leaf area index inversion (LAI)" (Grant No.:30972413) utilizes the method of measuring ground LAI inversion of tridimensional vegetation quantity basing on community in 3S technology platform which initially builds the system of green corridors in Wuhan City, discusses the landscape pattern of the green corridor with the situation of the network connection and circle expansion, and carries on the synthetical、multi-level、systematic analysis on the spatial structure of urban green corridors.The main research contents and conclusions are as follows:(1) Cluster analysis on LAI value of the community in Wuhan sample point shows that, there are significant differences on leaf area index among natural complex communities, artificially simple communities and single structure communities. The order of leaf area index is:natural complex communities> artificially simple communities> single structure communities. Using Spot images of Wuhan city in 2010 as the data source of urban vegetation "the vegetation quantity", the overall inversion effect of leaf area index’s is superior to that of classification inversion. The better fitting degree of the samples communities’ the overall inversion is the exponential model equations of MSAVI vegetation index.(2) Extracting the vegetation quantity allocation plan in downtown Wuhan city from RS and ArcGIS platform, and abstracting the graphic information of urban green corridors according to the indices such as green space scale, shapes, and the vegetation quantity distribution,etc. Based on which to divide different grades and establish Wuhan city green corridor system. (3) Using the function of statistical data on ArcGIS to analyze the overall landscape pattern and the grading landscape pattern of the green corridor, it shows that a higher level of green corridor has more important roles on the control of the whole spatial pattern, as it has high specific gravity, high gathering degree, strong connectivity, significant edge effect and outstanding contributions to the vegetation quantity, rich community structure and significant eco-efficiency(4) The correlation analysis on the combination degree of the green corridor and the roads and waters network in Wuhan city shows the large and medium-sized lakes and wetland which has the highest blue-green combination degree, but the buffer area of rivers and medium-sized lakes and wetlands has lower vegetation quantity. Gray-green combination degree of the main city roads is higher, which has the most closely linkage with green corridor, while the green belt distribution of expressways and railways on both sides was scattered, and vegetation quantity is lower.(5) The study on the green corridor in the circling expanding found that space structure of Wuhan city green corridor was restricted by landscape pattern and the lack of circle green belts, and its envelops feature was less visible. From the city centre to the outer ring, each level of green corridor quantity and vegetation quantity is gradually increasing, the average vegetation quantity appears "higher-low-highest", while that of the scattered green land is "more-much-less". Furthermore, the study found that the urban spatial expansion has formed quite obvious axial direction, and the six green wedge clearance zones also presented development trends of the sectors-connecting. The study analyzed the contact degree of green corridor and green wedge in different differentiation patterns.(6) Aiming at the main problems consisted in green corridor in downtown Wuhan city, this duty presented the ways to optimize the green corridor system from different aspects, and also proposed the relevant strategies of green corridor layout, combined with urban and rural development, water system, traffic structure, local context and the current greenway planning.