The　objective　of　this　research　is　to　investigate　the　effectiveness　of　the　radar　vegetation　index　(RVI)　derived　from　ALOS　PALSAR　full　polarimetric　data　for　forest　area　mapping.　Comparison　was　made　between　RVI　and　NDVI　of　Landsat　TM　data.　After　examining　of　the　index　maps　and　the　corresponding　histograms,　forest/non-forest　segmentation　was　performed　by　unsupervised　classification　and　by　threshold　method.　The　results　show　that　RVI　is　much　better　in　this　kind　of　application.　Considering　the　data　acquisition　capability,　full　polarimetric　SAR　data　are　quite　promising　for　forest　monitoring.　©2009　IEEE.