Multi-temporal analysis of a boreal forest using ERS-1 and JERS-1 SAR data

Discusses the information content in satellite SAR images of forested areas. As methodology, the authors study temporal changes in ERS-1 (C-band) and JERS-I (L-band) images. Three ERS-1 scenes and five JERS-1 scenes are used. Experience from the MAESTRO-1 data set demonstrates a higher sensitivity of L-band to biomass attributes, while C-band images are not that sensitive to such parameters. A multi-temporal C-band analysis over a year helps however to discriminate between deciduous and coniferous stands and to detect changes in moisture conditions. The test area is located 20 km north-west of Umea, a town in northern Sweden by the Gulf of Bothnia. The forest consists mainly of naturally generated Norway spruce and Scots pine with ages up to 150 years. Birch is the only prevalent broadleaved species. Maximum values of tree heights and volumes are 25 m and 300 m³/ha respectively. Most of the area is located in flat terrain. Stand sizes vary between 3 and 25 ha. Eleven stands within the scenes have been chosen to be test sites. Four stands of Norway spruce, five stands of Scots pine, one birch stand and one clear-cut were selected. Also, one bog has been examined