Much attention has been paid in recent years to forest biomass, due to the significance of forests in the context of climate change. The Committee on Earth Observation Satellites (CEOS) has been accelerating its forest biomass monitoring activities. Many spaceborne sensors suitable for aboveground forest biomass estimation, such as the Synthetic Aperture Radar (SAR) and Light Detection and Ranging (LiDAR), are currently in operation, and more are planned in coming years. As part of the CEOS biomass monitoring activities, maps of aboveground forest biomass are being generated by international research groups, many of which are using Japanese radar (SAR) satellite data as the key input dataset. Map validation constitutes an important part of this CEOS effort. In this study, we present results from the initial validation of an above-ground biomass map against two field-plots datasets in Japan. Our results indicate a general tendency of underestimation in the biomass map compared to ground-based measurements, in particular in high biomass forest areas. We therefore believe that it is crucial to establish a dedicated, accurate Japanese forest biomass mapping technology, adapted to take into account the special characteristics of the types of forest in Japan.
