This paper proposes to quantitatively estimate the potential of 3D SAR imaging for tropical forest characterization using airborne and spaceborne system configuration. A robust forest characterization technique, relying a low-dimensionality model is proposed and is compared with a well-established polarimetric and tomographic approach. The investigated forest descriptors are the underlying ground topography (DTM) and the forest height (CHM). A quantitative performance evaluation reveals that the presented parametric technique achieves high-precision results at both high-resolution (airborne) and low resolution (BIOMASS) modes, whereas existing approaches meet limitations, due the coarse resolution of spaceborne SAR data.