Since 2000, mountain pine beetle (MPB) has spread relatively rapidly east across the Rocky Mountains, through northeastern British Columbia, across much of Alberta, and northward towards Yukon and the Northwest Territories. The risk of farther northward spread is low in the near future due to poor climatic suitability and the subsiding of large populations in northern British
Columbia. However, an area of highly susceptible pine in southeastern Yukon is expected to be at risk by 2050 due to the anticipated effects of climate change. Spread into the boreal forest is comparatively slower than spread across western and central Alberta. Slower spread rates are likely due to (i) aggressive control efforts in eastern and central Alberta; (ii) lower pine volumes in eastern Alberta compared to farther west; and (iii) a lack of massive long-distance immigration events into eastern Alberta. The current climate of Canada’s southern boreal forest can likely support MPB, and there is an opportunity to improve climatic suitability indices to assess future risk.