Use of ERS SAR interferometry for monitoring clear-cutting of forests

Clear-cut monitoring is an important application for spaceborne SAR systems. With 17 ERS interferograms from the boreal forest of Sweden, obtained over a 3 year period, this paper investigates the use of coherence information for identifying clear-cuts. It is shown that coherence performs significantly better in separating clear-cuts from forest than intensity data, and can be used with a resolution about twice that possible for backscatter measurements based on a single image. The minimum area of cutting that can reasonably be detected is about 3 ha. The detection of clear-cuts tends to deteriorate with increased time between images. This is particularly significant for 13 interferograms from the rain forest of Brazil which have also been studied. These show generally lower separability than the results from Sweden