One　of　the　objectives　of　Forest　Dragon　2　project　is　the　generation　of　a　forest　cover　change　map　between　1990s　and　2000s　for　Northeast　China　based　on　ERS-1/2　tandem　data　and　ENVISAT　ASAR　data.　For　the　1990s＇　map,　an　automatic　and　seasonal-adaptive　retrieval　of　forest　biomass　method　was　used　to　produce　a　forest　biomass　map　based　on　the　ERS　tandem　interferometric　coherence.　The　biomass　map　was　integrated　into　two　categories　(forest　and　nonforest).　For　the　2000s＇　map,　an　object-based　classification　method　was　developed　for　ASAR　HH/HV　images　acquired　on　a　single　date.　Post-classification　comparison　method　for　change　detection　was　adopted　based　on　the　two　forest/nonforest　maps.