Multiresolution Spot-5 Data for Boreal Forest Monitoring

The improved spatial resolution of SPOT-5 data opens for improved forestry applications, such as improved cutting delineation, identification of soil scarification activities and for monitoring of the establishment of new forest stands. The large scene size combined with very high resolution is an operational strength when compared to VHR satellite data, although there are operational limitations for very large area coverage. Since 1999, the Swedish National Board of Forestry (NBF) has extensively used satellite data from Landsat TM, ETM+ and SPOT in its operational work. Satellite data is used for change detection analysis, primarily to map and monitor forest cuttings as required in the Swedish Forestry Act and for mapping areas of different forestry activity needs. User adapted methods for change detection and analysis were developed and implemented by Metria in the ENFORMA tool, now used operationally at the 100 forestry districts of Sweden. Yearly national satellite data coverages of Sweden, from SPOT-4 and Landsat-7 ETM are acquired by NBF and operationally used in the daily work. In 2003, a national coverage with SPOT-5 10 m multispectral data was ordered with 150 SPOT-5 and 50 SPOT-4 delivered. This study has focused on evaluating the improved data quality from SPOT-5 in comparison and in combination with SPOT-4 and Landsat-7 data, for information concerning forest cuttings and factors of importance for the establishment of new forest stands by using multiresolution satellite data. Methods for enhanced change detection with combined use of the different resolutions of SPOT-5 multispectral bands were tested. Multiresolution, single band change detection between image pairs with pixel size differences of 2.5 – 30 m was evaluated. A method for multiresolution merging of panchromatic with all multispectral bands including SWIR applicable for boreal forestry was tested for this purpose. Examples from the use of SPOT-5 data for operational and recurrent national (Sweden) coverage are given.