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TitleExtracting a paleotemperature record from Picea engelmannii tree-line sites in the central Canadian Rockies
AuthorSt. George, SORCID logo; Luckman, B H
SourceCanadian Journal of Forest Research vol. 31, no. 3, 2001 p. 457-470, Open Access logo Open Access
Alt SeriesGeological Survey of Canada, Contribution Series 2000031
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf
NTS82J/13; 82J/14; 82K/16; 82M/16; 82N/01; 82N/02; 82N/05; 82N/06; 82N/07; 82N/08; 82N/10; 82N/11; 82N/12; 82N/13; 82N/14; 82N/15; 83C/03; 83C/04; 83C/05; 83D/01; 83D/02; 83D/06; 83D/07; 83D/08
AreaRocky Mountains
Lat/Long WENS-120.0000 -115.0000 52.5000 50.7500
Subjectsgeochronology; paleoclimatology; paleoenvironment; dendrochronology; temperature; correlations; Trees
Illustrationstables; sketch maps; graphs
AbstractA new network of 21 Picea engelmannii Parry ex Engelm. ring-width chronologies was developed from tree-line sites in the Canadian Rockies. These chronologies range in length from 297 to 648 years (mean 423 years) and have mean sensitivities between 0.16 and 0.20 (mean 0.18), first-order autocorrelations between 0.73 and 0.88 (mean 0.83), and subsample signal strengths >0.85 for 246-494 years (mean 324 years). Mean intersite correlations (A.D. 1700-1982) for chronologies with expressed population signals >0.85 are 0.46 and 0.63 for standard and residual chronologies, respectively. Standard ring-width chronologies are, in general, positively correlated with summer temperatures and negatively correlated with spring and previous summer temperatures. A regional June-September temperature reconstruction for the Banff-Jasper region (BJR; A.D. 1715-1982) was developed using multiple regression of three significant principal components from 14 standard ring-width chronologies. The first principal component contains 55% of the total chronology variance. The model reconstructs 38% of summer temperature variance during the calibration period (1888-1982). The BJR is the first regional temperature reconstruction for this area based on ring-width data from a network of sites. The reconstructed temperature patterns are broadly similar to other regional estimates of past temperatures. Above-average summer temperatures occurred in the mid-20th century and the late 1700s - early 1800s. Most of the 19th century was unusually cold, with the coldest conditions in the late 19th century. Detailed differences between BJR and previously developed reconstructions lie well within 2 sigma confidence limits and may reflect differences in tree species, modelling techniques, spatial coverage, and the seasonal temperature parameter reconstructed.

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