Canadian Forest Service Publications

Change and evolution in the plant hardiness zones of Canada. 2014. McKenney, D.W.; Pedlar, J.H.; Lawrence, K.; Papadopol,P.; Campbell, K.; Hutchinson, M.F. BioScience 64:341-350.

Year: 2014

Available from: Great Lakes Forestry Centre

Catalog ID: 35496

Language: English

CFS Availablity: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1093/biosci/biu016

† This site may require a fee

Mark record

Abstract

We present 50-year updates for two plant hardiness models (maps), developed originally by Agriculture Canada and the US Department of Agriculture (USDA), that are widely used for plant selection decisions in Canada. The updated maps show clear northward shifts in hardiness zones across western Canada. Shifts are less dramatic in southeastern Canada, with modest increases in zone values associated with the Canadian map but modest declines associated with the USDA approach. Species-specific climate envelope models are an alternative to generalized hardiness zones. We generated climate envelopes for 62 northern tree species over the same 50-year interval and found an average northward shift of 57 kilometers. These changes signal an increase in the productivity and diversity of plants that can be grown in Canada. However, late spring frosts and other factors discussed herein may limit the extent to which this potential is realized.

Plain Language Summary

We updated Canadian plant hardiness maps that were developed 50 years ago by Agriculture Canada and the US Department of Agriculture. The maps are used widely across Canada for plant selection decisions by gardeners as well as forest managers. The updated maps show clear northward shifts in hardiness zones across western Canada and less dramatic shifts in southeastern Canada. We also created potential range maps for 62 northern tree species over the same 50-year interval (an alternative to generalized hardiness zones) and found an average northward shift of 57 kilometers. These changes signal an increase in the productivity and diversity of plants that can be grown in Canada. However, variability, late spring frosts and other factors may limit the extent to which this potential can be realized. These findings have implications for a wide range of interests (from gardeners, nurseries and, forest management policies related to the movement of seed).