Biomass values are predicted from the radar at various frequencies and polarizations and are compared to the actual biomass values. Predicted biomass levels are most accurate at P-band. Multiple incidence angle data also reveal that the incidence angle of the radar illumination affects the retrieval of biomass from the radar data even at HV polarizations. One consequence is that topographic information is required for mapping the biomass in areas of moderate topography. Also the inversion curve for biomass retrieval varies with season and environmental conditions.