CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Fortin, D.; and Lamoureux, S.F.
Date : 2004.
Title : Summer drought recurrence at the southern margin of the boreal forest, Abitbi, Québec.
Publication : 100th Annual Meeting of the Association of American Geographers. 14-19 March 2004, Philadelphia, Pennsylvania.
Issue :
Page(s) :
Abstract
In studying multi-decadal climate variability, we are near the limit of what inferences the instrumental climate record can provide. A combined approach comparing instrumental and proxy records is therefore highly desirable. Preliminary analyses of the growth index of two northern white cedar (Thuja occidentalis) populations from the Abitibi region of Québec reveal a distinct oscillatory mode of variability with an approximate period of 65 years that is persistent during the last 500 yrs. The first record, which covers 260 years, has been developed from 45 living individuals located along the xeric margins (rocky outcrops) of Lake Kinojevis. The second record is 700 years long and was developed by Archambault & Bergeron (1992) from trees and snags found mostly on xeric sites at Lake Duparquet, 60 km north-west of Lake Kinojevis. At both sites, white cedar radial growth responded negatively to August temperature and is positively correlated to the regional summer discharge of the previous year. When the high frequency variability is removed, both series shows a similar dominant oscillatory mode of 65 years which is confirmed by spectral analyses. Long term climate oscillations associated with summer drought recurrence rather than natural perturbations seem to best explain this regional variability. Similar oscillations in the global climate system have also been found in climate simulations (Delworth and Mann, 2000) and instrumental records (Schlesinger and Ramakutty, 1994; Minabe, 1997).
Bibliography of Canadian Geomorphology