Study On Forest Biomass Estimation Based On RS And GIS

Forest is the principal part of the land ecological systems,it contains about eighty percents of global terrestrial above-ground carbon stocks and the fifty percents of the below-ground carbon stocks,which plays an important role in the carbon cycle.Using satellite images to analyse ecological biomass is a key way for the regional ecological patterns study,remote sening techonology provide a very efficient way for our fast and efficient forest biomass estimation.As the fifteenth transect ,NSTEC(North-South Transect of Eastern China) covers large areas and wide range of forest vegetation types,which provides a very good platform for our study on forest biomass.In this paper, NSTEC forest is our research object.The data sources include the plot biomass,the climate data,Digital Elevation Model data,remote sensing image-bands and the vegetation indexes data,By using the remote sensing technology,geographic information technology,mathematical statistics and spatial analysis technique,we analize the correlation relationship of the ground plot biomass with the remote sensing factors,geo-factors and the meteorological factors,explore the forest biomass estimation method based on remote sensing,establish the multiple linear regression model of forest biomass.The study process and conclusion are following.(1)We collect and process the remote sensing images in the context of the NSTEC,including GLS1990(Global Land Survey) datasets,TM datasets between 2006 and 2007 and the Modis datasets at the same time period,with these datas,the vegetation indexes can be get.By the plot datas,GLS1990 TM datas,DEM,climate and other datas we got,the multiple linear regression model of forest biomass is build.(2)We use the TM datasets between 2006 and 2007 and the Modis datasets at the same time period to build the linear transformation models for each red band and the near-infrared band.By using the forest biomass model we build above,we can get the NSTEC regional distribution map of the forest biomass .(3)We select several profile lines to analyze forest biomass changes along each line,also use the gradient analysis methods to get the biomass distribution change along the precipitation gradient, temperature gradient and the vegetation index.The results showed that in a regional context: forest biomass decreases with the latitude increase from south to north ,increases with the longitude increase from west to east. For the biomass, the coniferous forest is also significantly less than broad-leaved forest.