Combined ERS SAR and optical satellite data for the estimation of forest structural attributes

ERS-1 acquisitions of the Black Forest test site in Germany from 1991 to 1993 were selected to cover a variety of seasonal and phenological stages. Multisensor analysis (ERS-1, SPOT) was performed using a forestry GIS data base from the regular forest taxation. It turned out that the C-VV band of ERS-1 is sensitive to age in young deciduous and coniferous forest stands of temperate zones. A synergetic relationship between optical and microwave data has been established. The combined data set provided a combination that allowed better differentiation of forest age classes, as compared to results obtained with the individual sensors.