The POLDER instrument （POLarization and Directionality of Earth Reflectances） flew during the BOREAS experiment onboard a C130 aircraft from NASA. BRDF measurements were obtained by POLDER on various supersites in the South area of the BOREAS. Large hot spot features over forest covers

and specular components over fen areas are described. The paper quantifies with airborne POLDER data the improvement of classification and discrimination of various forest covers when remotelysensed directional signatures are added to the more conventional spectral signatures. When using non supervised classifications

the terms of interclass confusion matrices are much lower （by a factor between 2 and 5） when directional information is added to the conventional spectral information. This proves that directional signatures enhance the discrimination of boreal forest covers by remote sensing.