Dendroclimatic analysis and river reconstructions from northern white cedar (Thuya occidentalis) and black spruce (Picea mariana) from the central Gaspésie, Quebéc, Canada
Abstract
Detection of the regional effects of anthropogenic climate change is only possible with climatic data of at least a century, from which baseline conditions can be established. Such long baseline data is needed to be able to distinguish between low-frequency centennial and multi-decadal natural variability and anthropogenic global change. Climate data at the centennial scale does not exist for the majority of the province of Quebéc in Canada. Continuous instrumental climate data for the interior of the Gaspé Peninsula is particularly short, only starting in 1970 for Murdochville, Quebéc. Given this problem, the only feasible way to acquire annual and sub-annual climate data for this region is by tree-ring based climate reconstructions. Mountainous areas are sensitive and react quickly to anthropogenic climate change. The Chic-Choc and McGerrigle Mountains in the Gaspé interior have been little studied by dendroclimatologists. We present preliminary results from 5 northern white cedar (Thuya occidentalis) sites and 2 black spruce (Picea mariana) krumholtz sites from the Parc national de la Gaspésie, which were sampled in the summers of 2017 and 2018. The earliest chronology extends back to AD 1560, with potential to extend the chronologies back further in time using deadwood. The tree ring widths are positively correlated to summer precipitation, allowing hydroclimate reconstructions. A preliminary nested reconstruction of Sainte Anne River flow for 1833-2014 had significant predictive power with R2 > 0.45 for all nested stages. Its first nested stage spanned 1924-2014 with R2 = 0.56, R2adj = 0.48 and RE = 0.36. The reconstruction contained a period of sustained low flows for 1937-1943 unlike any captured in the short instrumental record spanning 1974-2016. Such reconstructions could contribute to wildlife conservation projects in the Parc national de la Gaspésie, particularly that of Canada's southernmost caribou herd, a highly threatened species in this location, and the economically valuable Sainte Anne River recreational salmon fishery.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP43C1938S
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGEDE: 4928 Global climate models;
- PALEOCEANOGRAPHY