Some observations on the three subalpine biogeoclimatic zones in British Columbia, Yukon and Mackenzie District
Krajina, V. J.
In summary, three subalpine biogeoclimatic zones are distinguished in British Columbia, the Yukon, and the Mackenzie District of the Northwest Territories: the coastal mountain hemlock (MH) zone and the Engelmann spruce-subalpine fir (ESSF) zone occur only in British Columbia, whereas the third zone, the spruce-willow-birch (SWB) subalpine zone occurs only in the most northern parts of British Columbia and mainly in the Yukon and the Mackenzie District. Its upper shrub subzone, characterized by willows (mainly Salix pulchra and S. glauca) and especially by resin birch (Betula glandulosa), occurs down to the coast of the Beaufort Sea where it used to be called as the Low Arctic Zone. The Canadian High Arctic Zone is rather similar to the alpine tundra biogeoclimatic zone of the Canadian subarctic regions.