A record of estimated annual (prior August to current July) precipitation derived from a regional bur oak (Quercus macrocarpa Michx.) tree-ring chronology indicates that southern Manitoba's hydroclimate has been relatively stable over the last 200 yr. Although this stability was interrupted briefly by pronounced wet intervals in the late A.D. 1820s and 1850s, hydroclimatic conditions since permanent Euro-Canadian settlement were much less variable and persistent than those prior to A.D. 1790. The reconstruction indicates that the Red River basin experienced extremely dry conditions between A.D. 1670 and 1775, with below-normal precipitation occurring approximately 2 years out of 3. Annual precipitation was estimated at more than two standard deviations below the mean during A.D. 1477, 1485, 1556, 1595, 1612, 1644, 1661, 1743, 1900, and 1980. Comparisons with limnological records from North Dakota and Minnesota suggest that multidecadal fluctuations in regional hydroclimate have been remarkably coherent across the northeastern Great Plains during the last 600 yr. However, individual dry years in the Red River basin were usually associated with larger scale drought across much of the North American interior.
Bibliographical noteFunding Information:
For assistance in the field and/or laboratory, we wish to thank Dan Bailey, Roslyn Case, Lisa Friedrich, Jeff Gutsell, Glen MacDonald, David McLeod, and Gaywood Matile. We thank Mike Allen (City of Winnipeg Forestry Branch), Scott Parker, Tom and Jennifer Shay, and Sam Shellenburg for permission to collect tree-ring samples across southern Manitoba and Dave Sauchyn for providing the Maple Creek reconstruction. Limnological data were obtained from World Data Center for Paleoclimatology, Boulder, Colorado, USA. Patricia Anderson, Emi Ito, Emma Watson, Steve Wolfe, and an anonymous reviewer commented on an earlier version of the manuscript. The Manitoba Geological Survey, the Red River Flood Protection Program, the Canadian Climate Change Action Fund, and the Manitoba Hydro Forest Enhancement Program supported this research. This paper is GSC contribution 2001126.
- Canadian Prairies
- Quercus macrocarpa
- Tree rings