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Retrieval of forest above ground biomass using automatic KNN model

Forest is an important component of terrestrial ecosystems, so it is necessary to estimate the forest aboveground biomass (AGB) accurately in order to reduce the uncertainty of the carbon stock in forest ecosystem. In this study, a fast, efficient and automatic method has been proposed, called as Automatic KNN(AKNN). Using the Landsat 8 OLI data, airborne polmetric SAR (PolSAR) data, the AKNN has been applied to estimate the forest AGB and stem volume at two levels, the pixel and the subcompartment levels, respectively. The results showed that the power of AKNN in quantitative retrieval at two levels(R2=0.75, RMSE=23.43t/ha; R2=0.52 and RMSE=21.86m3/ha, respectively).