The high-latitude forest-tundra transitional zone is a region which is highly vulnerable to the current Arctic warming. The local changes accompanying expected northward migration of the treeline requires systematic monitoring. We focus on an area in the east of the Mackenzie Delta in Northwest Territories, Canada, which is characterised by patches of black spruce forest. We investigate the capability of TerraSAR-X / TanDEM-X bistatic constellation for the characterisation of these forest patches. Interferometric phase and coherence from seven image pairs were used to estimate tree height and density. We compare the SAR products with standard vegetation metrics from airborne LiDAR, such as vegetation height percentiles and vegetation ratio. The preliminary analysis shows a high agreement between SAR and LiDAR data.