The installation ‘Tree Line’ is part of a series relating my impressions of the urban boreal forest. Tree lines in high latitudes are shifting. Climate warming in the boreal and Arctic region is projected to be substantially above the global average. Ecosystem changes are expected, such as tree species expanding northward past the tree line into the tundra, but dying off in the lower reaches of their range due to increased levels of prolonged droughts, wildfires and melting permafrost. Evergreen species may be out-competed by deciduous trees that can tolerate warmer climates. These bark-patterned panels, with camouflage lining on the reverse side, hang in the balance of a changing climate.