Canadian Forest Service Publications

The tree-ring record of drought on the Canadian Prairies. 2009. St. George, S.; Meko, D.M.; Girardin, M.-P.; MacDonald, G.M.; Nielsen, E.; Pedersen, G.T.; Sauchyn, D.J.; Tardif, J.C.; Watson, E. J. Clim. 22: 689-710.

Year: 2009

Available from: Laurentian Forestry Centre

Catalog ID: 29481

Language: English

CFS Availability: PDF (request by e-mail)

Abstract

Ring-width data from 138 sites in the Canadian Prairie Provinces and adjacent regions are used to estimate summer drought severity during teh past serveral hundred years. The netword was divided into five regional groups based on geography, tree species, and length of record: the eastern Rockies, northern Saskatchewan, central Manitoba, southern Manitoba, and northwestern Ontario. Regional tree-ring records are primarily related to summer moisture and drought conditions, are less responsive to droughts caused by deficits in winter precipitation. These summer-sensitive data are not linearly related to major modes of climate variability, including ENSO and the Pacific decadal oscillation (PDO), which primarily affect the climate of western Canada during winter. Extended drought records inferred form tree rings indicate that drought on the Canadian Prairies has exhibited considerable spatial heterogeneity over the last several centuries. For northern Saskatchewan and northwestern Ontario, intervals of persistently low tree growth during the twentieth century were just as long as or longer than low-growth intervals in the eighteenth or nineteenth centuries. Longer records from southern Alberta suggest that the most intense dry spell in that area during the last 500 yr occurred during the 1720's. At the eastern side of the prairies, the longest dry event is centered around 1700 and may coincide with low lake stands in Manitoba, Minnesota, and North Dakota. Although the Canadian Prairies were dry at times during the 1500's, there is no regional analog to the sixteenth-century "megadroughts" that affected much of the western United States and northern Mexico.

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