I. Introduction
The aboveground biomass (AGB) of terrestrial ecosystems is an important constraint of dynamic global vegetation models to assess carbon stocks and feedbacks of vegetation with the global carbon cycle [1]. Further, quantitative maps of AGB are an important input to support forest and landscape management [2], [3], to understand deforestation impact on carbon release and global warming [4], to assess productivity of forested areas in relation to forest composition [5], and in view of specific forest management practices [1], [6]. Since AGB is an indicator for quantity and quality of forage, it is considered relevant information to study animal ecology, i.e., herbivore behaviors [7] and grazing intensities [8], [9]. Further, grassland biomass has a high potential to become flammable during an extended dry season [10], and therefore accurate AGB estimates are relevant input for fire risk assessment [11] and carbon cycle modeling.