JERS-1/SAR backscatter and its relationship with biomass of regenerating forests

It has been hypothesized that regenerating tropical forests are large atmospheric carbon sinks. Accurate estimates of the location, extent and biomass of regenerating tropical forests are needed in order to quantify their contribution to global carbon budgets. Synthetic Aperture Radar (SAR) data are independent of near-constant tropical cloud cover and have proved useful for locating and mapping the extent of regenerating tropical forests. To estimate the biomass of regenerating tropical forests we need to determine the nature and strength of the relationship between radar backscatter and biomass for different types of regenerating forest. To further investigate this, two extreme forms of regenerating forest were considered; they were block-logged (clear-cut) forest in the Tapajós area of Pará State, Brazil and selectively-logged forest in Southern Cameroon. Biomass was estimated alometrically for 15 plots in Tapajós and 34 plots in Cameroon and was related to L-band backscatter derived from the JERS-1 SAR. The relationship between backscatter and biomass was strong for the Tapajós study area and weak for the Cameroonian study area. It was concluded that there is potential for the use of JERS-1/SAR to locate, map and estimate biomass for young regenerating forests following block-logging rather than selective-logging.