The Research Of Monitoring Natural Forest Protection Project Base On Remote Sensing In Western Sichuan

Natural forest protection project is the major project of state forestry construction and ecological environment construction. Natural forest is the main part of natural forest resources of China. The region of Western Sichuan is the second largest body of natural forest area of China, and it is an important ecological security barrier of water conservation in the upper reaches of the Yangtze River. It is also the pilot area of national natural forest protection project of China. Since the implementation of natural forest protection project for 12 years in West Sichuan, the effect of project is widely concerned in the whole country. In this study, Jiasikong Forest Farm which is state-owned was take as research area. The satellite images (1989TM,1999 TM and 2007 SPOT) were used as the main data source. With the help of software systems ENVI4.2, the image was pre-processed, interpreted, classified with supervision. and extraction of vegetation index was also processed. Then using ArcGIS9.2 for vector operations and statistical analysis, the changes of forest structure before and after the natural forest protection project of the Jiasikong Forest Farm were analyzed. The structural factors analyzed were mainly forest land type, vegetation cover, forest cover, and forest stock volume and soil erosion intensity changes. Is mainly supported by the following findings:(1)Using remote sensing technology to realize the natural forest protection project. The use of subdivision and zoning classification wears combination can improve the accuracy of supervised classification. At the same time, combined with manual modification of the classification methods, can be used in Western Sichuan region an achieve forest monitoring classification accuracy, which is a typical image interpretation difficult mountain valley areas.(2)Take ArcGIS software as platform produce digital elevation model (DEM), through the DEM extracted the elevation, slope, aspect and other topography factors to study the rules of natural forest resources' topography differentiation.(3)The change of nature forest structure study showns that thrub land increased slowly from 1989 to 2007, an increase of 650.88 hm2, due to the destruction of the original habitat degradation to shrub forest.In addition, after the natural forest protection; project, some agricultural land and grassland forest vegetation has restoration to thrub; Coniferous forest sharp declined 2835.72'hm2 before the natural forest protection project from 1989 to 1999, the proportion in entire forest area decreased from 22.70% to 18.51, decreased rapidly by 4.19%, after the natural forest protection project, he coniferous forest area increased 335.70hm2, the proportion increase from 18.51% to 19.00%, increase by 0.49%, But compared to the reduction of the area,the increased slowly; Clear-cutting land increased from 0.52% to 3.26% between 1989 and 1999.1n the Natural Forest Protection Project, the cutting sites were effective afforestation updated. To 2007 it has been basically eliminated.(4)Before the implementation of natural forest protection project, forest cover in research area decline from 71.39% to 67.87%, decreased by 3.52%; after implementation of the project, increased to 72.02%. (5)Before the implementation of natural forest protection project, vegetation coverage of research area decreased by large-scale, thereinto, the proportion of vegetation coverage during (40%-80%) had decreased from 16.79% to 15.07%. Because of the effective protection of natural forest resources, logging slash be updated, the study area's vegetation coverage has been a gradual recovery.(6) sample survey results show that between 2003-2007 of four years, a Sri Lankan forest of stand volume hole increases 331115.4098 m3, an increase of 7.23% It shows that during the Natural Forest Protection Project, stand volume rise significantly. (7)By extracting influential factors of soil erosion:the rainfall, vegetation cover, terrain slope, gully density, slope length, land-use types and soil texture 7 factors' information, and generates raster image, then apply the method of sum the every factors according to their weight, had researched the change of research area soil erosion intensity. The results showed that:before the implementation of the natural forest protection project, the soil erosion had deteriorating trend; under the natural forest protection works, soil erosion situation has improved.