The Study On The Optimization Of Spatial Arrangement And Development Scale Of Farmland Shelterbelts In JianHu County Based On GIS

The study on the structure of farmland shelterbelts is always the hot topic ,It decide the function and effect of the farmland shelterbelts. The establishment of farmland shelterbelts system of JiangSu province plays the important roles in realizing the slogan "green JiangSu"which advocated by JiangSu government . Based on the research on the growth rule of the existing farmland shelterbelt , taking the Geographic Information System (GIS)as tools ,The study aim at the spatial arrangement of farmland shelterbelts and its development scale, The main results are as follows : Applying software MATLAB6.5, selecting classical growth function of logistic , Richards　and　Mitscherlich, the growth model of average height, dominant height , average diameter at breast height and volume of poplar I-72of shelterbelt in JianHu county are established . The result of function curve estimation shows that the logistic function is the best function for DBH and average height , the Richards function is the best function for dominant height and volume simulation. Assessment of the site quality was carried out and the age of maturity are decided according to the result of the model, The result shows that the site type of study area can be divided into six level . The protective maturity age of shelterbelts is eight to twelve years , the economic maturity age of shelterbelts is fifteen years , the quantitative maturity age of shelterbelts is eighteen years , and the regeneration age is fifteen to twenty years. Taking volume as the function of shelterbelt age ,site index and density , based on the data of plots of shelterbelt in study area , the curve estimation of the varied-density and whole-stand volume model was established , It helps to predict the volume of study area. Basing on the analysis of theoretically optimal structure arrangement of farmland shelterbelts, take the structure parameters such as the mature height , average volume per tree at the protective maturity age, shelterbelt width ,the spacing of shelterbelt ,permeability ,average nutrition area of per tree ,tree spacing as the arrangement indicators, applying the spatial analysis and statistical functions of the GIS, the spatial arrangement of shelterbelts of study area was carried out. The arrangement of shelterbelt net was divided into three or four levels, and five arrangement scheme was taken ,the result of area and forest coverage was stated , the result shows that the forest cover percent of the five arrangement can reach 4.19%,6.79% 5.82%,5.10%,11.43% .the forest cover percent of shelterbelts is improved distinctly, and taking the tools of ARCGIS and MO into the spatial arrangement help to the statistic of arrangement area. Using MO and VB, applying the technology of second integrated development ,the Shelterbelts Spatial Arrangement Information System is established, the system has the basic function of operation ,edit, inquiry ,spatial analysis and output the graphics , it also has the special function of generation of shelter net , generation of buffers at different width and the integration of the model of volume prediction. Applying the technology of '3S', the spatial arrangement information of farmland shelterbelts and model of volume predication is integrated into one system, It can control not only the spatial distribution and area variation of farmland shelterbelts, but also the volume variation of different shelterbelt. The Shelterbelts Spatial Arrangement Information System provide the manager a new scientific management method, it can be used to other regions , it offer a new mind concerning with the precise forestry. Appling the technology of '3S'into the spatial arrangement of farmland shelterbelts is a new attempt, its function need to be improved in actual application. The paper study the development scale of farmland shelterbelts. the forest cover percent and stand volume of different arrangement scheme are analyzed, and comparing it with the aim of 'the eleventh five development plan ',the result shows that the scheme of B,C, and D can realize the aim of forest cover percent of 15%, it is feasible to realize the aim of stand volume of two millions cubic meters . at the same time ,the evaluation of agriculture effect value and woods value are carried ,the result shows that the figure of agriculture effect of study area is 1.22, the increased productivity value of crops induced by the shelterbelts is 14.60 millions yuan ,and the wood value induced by the volume growth reach 2 millions yuan. The paper discuss the existing problem of farmland shelterbelt , analysize the problem of sustainable management of farmland shelterbelts ,and bring out the index of sustainable management of farmland shelterbelts .Basing on the inventory of exist management pattern and its benefit , the existing problem is brought out and proposal is given . the forest rights is also taken into account , the forest land and forest stand value are evaluated ,the result shows the highest net value index can reach 3.86.