Retrieval of stem volume in coniferous forest from low VHF-band SAR

Retrieval of forest stem volume using SAR in the lower VHF-band holds great promise. The basic idea is that coniferous trees behave as Rayleigh scatterers with a backscatter proportional to stem volume. In the paper, measurements using the CARABAS SAR at five different test sites are compared. The authors conclude that backscatter on horizontal ground indeed has a simple linear relation with stem volume. No signs of saturation is found up to 1000 m/sup 3//ha. The proportionality factor is however slightly dependent on ground reflection coefficient. The paper also evaluates temporal stability using repeat-tracks. High repeatability is found after 1 hour (R/sup 2/=99%) and 20 months (R/sup 2/=91%) implying good system and scene stability.