Warm Climate Opens Boreal Forest to Pine Beetles Temperatures in
boreal forests extending across Canada will soon be warm enough
to accommodate mountain pine beetles. Until recently, cold
winters confined the bark beetles to attacking trees west of the
Rocky Mountains and south of the boreal forest. In British
Columbia, the tiny insect recently killed over nine million
hectares of mature lodgepole pine, and the devastating epidemic
continues. Since 1970, the amount of habitat in BC with optimal
temperatures for the bark beetle has expanded by over 75% in
response to a roughly 1 °C increase in average annual
temperature. This has permitted the beetles to move higher up
mountainsides and northward, where they’ve found plenty of prime
pine. Experience in BC shows that the beetles rapidly move into
new areas once winter weather allows their survival. Under the
most conservative of climate change forecasts, beetle survival
in the boreal forest will no longer be thwarted by cold winters.
The forecast is based on a