For the Russian Service Case of GSE FM ENVISAT ASAR APP data (HH/HV, swath 7) were used during the first two years. For optimal SAR based forest cover mapping a well suited SAR data set is required. Thus emphasis is put on the analysis of ASAR time series throughout the seasons. The investigation comprises for each image of the time series the analysis of the signatures of the relevant land cover classes and their separability. For forthcoming GSE FM service production PALSAR L-band data will be introduced. L-band data can be assumed to complement the data input and afford an improved forest cover mapping whilst the costly manual classification refinement effort is minimised. Various PALSAR products will be analysed regarding their suitability for forest map production. Regarding the separability of forest and non-forest, different PALSAR acquisition modes as well as winter coherence images have been investigated.