Analysis On Spatial-Temporal Characteristics And Driving Factors Of Woodland Change In The Huanglong Mountain Based On 3S Technology

The temporal and spatial changes of different woodland in Huanglong Mountain in 1986, 1997, and 2008, were detected based on the data of remote sensing information and vegetation resources. We adopted the advanced remote sensing image processing techniques such as image fusion, band combinations, geometric corrections, and cropping to improve the spectral and spatial quality of the satellite images. Collected the data of vegetation resources in the three periods, and established the supervised classification and interpretation signs to obtain the information of woodland. Additionally, in order to examine the effect of potential topographic factors (i.e. elevation, slope, and aspect) on the variation of woodland, the Digital Elevation Model (DEM) performed in ArcGIS to analysis the temporal and spatial characteristics of vegetation in the study area. Moreover, we analyzed the role of National Forest Laws and Policies on the variation of forestlands in Mt. Huanglong. Using the regression analysis to choose te optimal social-economic factors depending on the National Economic Statistics during 1986-2008, and then establish the driving force model for the variation of forestlands in Huanglong Mountian. Our results showed that:(1) the OIF index indicated that the band combination 543 provides a plenty of information about remote sensing image, and has minimum redundant information among different bands. Moreover, the colors of the R (5) G (4) B (3) bands combination are suitable for human eyes, which is the best for distinguishing different woodland types.(2) The results showed that there was a significant fluctuation of woodland in Huanglong Mountain. The forestedland and other types of woodland were increasing constantly, while the area of shrubland and open forest land was shrinking. There were internal conversions between different kinds of wood land, and the main trend were that the shrubland and open forest land transferred to forestedland. The conversion rate of forestry resources in Huanglong Mountain was slow down from 1997 to 2008 compare to it was from 1986 to 1997.(3) Mt. Huanglong is located at Southeastern Loess Platwau of Shaanxi province, which belongs to"the upper and middle Yellow river region"in the overall layout of the National Ecological Environment Construction Planning. Thus, The Natural Forest Protection Project, Grain for Green Project, and Closing Mountain are effective measures to drive the temporal and spatial variation of forestlands in Huanglong Mountain.(4) The socio-economic driving force model demonstrated that the forestedland has high relevance to the GDP increasing and other types of forest variation, while the total investment in fixed assets and the proportion of agricultural population were respectively of high relevance with the area change of shrub forest and open forest land in Huanglong Mountain.