Because of the importance role in the land use carbon emissions of tropical forests in general, and of the Amazon forest in particular, observing systems are needed for monitoring deforestation and for estimating forest biomass. Up to now, the existing monitoring programs rely mostly on optical remote sensing. With the recent and forthcoming availability of open and systematic SAR data, there is a need to assess the contribution of SAR data in observing systems. This paper examines the use of SAR data to observe Amazon forests, e.g. Sentinel-1 data for deforestation monitoring, ALOS PALSAR data for biomass retrieval in the Cerrado, and the future BIOMASS data for measuring the high range of biomass in dense rain forests. The promising results indicate that SAR data can be integrated in current monitoring programs.