Forest change detection from Sentinel-1 and ALOS-2 satellite images

This research presents the performance of the recently launched C-band Sentinel-1 and L-band ALOS-2 satellite missions for detecting forest clear-cuts and thinning in the winter season in coniferous and deciduous forests within Estonia. SAR data were acquired from September 2014 to April 2015 to analyze the cross-polarized backscatter dynamics over 76 stands before and after the logging event. Both clear-cuts and thinning treatments were considered with stand size ranging from 0.11-6.44 ha and compared to the in situ reference data. The results show that the accuracy of logging detection is influenced by the weather conditions as well as the size of the stand. Both Sentinel-1 and ALOS-2 provide reliable forest clear-cut monitoring and are suitable for an operational change detection service for forest stands larger than 0.5 ha.