RETRIEVAL OF FOREST STEM VOLUME USING VHF SAR

The ability to retrieve forest stem volume using CARABAS (coherent all radio band sensing) SAR images (28-60 MHz) has been investigated. The test site is a deciduous mixed forest on the island of Oland in south ern Sweden. The images have been radiometrically calibrated using an a rray of horizontal dipoles. The images exhibit a clear discrimination between the forest and open fields. The results show that the dynamic range of the backscattering coefficient among the forest stands is hig her than what has been found with conventional SAR using microwave fre quencies. The backscatter increases with increasing radar frequency. T his work shows an advantage compared to higher frequencies for stem vo lume estimation in dense forests.