MONTREAL, Dec. 5, 2012 /CNW Telbec/ - According to a new study on the website of the Proceedings of the National Academy of Sciences (PNAS), larger spring fires can be expected in boreal regions in the coming years.
These wildfires threaten the carbon sink of forest ecosystems and could, by extension, contribute to increased global warming.
Among the ten researchers who participated in this study are several members and collaborators of the NSERC-UQAT-UQAM Industrial Chair in Sustainable Forest Management and the Centre for Forest Research, including Yves Bergeron, professor in the Department of Biological Sciences, Université du Québec à Montréal; Adam A. Ali and Christelle Hely, professors at the l'Université Montpellier 2; Martin P. Girardin and Sylvie Gauthier, researchers at Natural Resources Canada; Aurélie Terrier, a doctoral student in environmental science at UQAM; and Aurélie Genries and Olivier Blarquez, postdoctoral fellows.
Evolution of forest fires:
By focusing on the evolution of forest fires since the last glaciation, the researchers found a correlation between climatic warming and forest fires. To do this, they studied the carbon present in the bottom sediments of lakes in the coniferous boreal forest of eastern North America.
The study allowed the researchers to draw a regional history of fire frequency, biomass burned and the average size of fires in the study area. They compared their results with numerical simulations from a climate model for an understanding of the processes involved.
A basic trend
In the coniferous boreal forest of eastern North America, the number of fires and the biomass burned have actually decreased over the last 3,000 years. Simulations of fire hazards indicate a trend to increased moisture in this region during the same period.
The researchers concluded that the downward trend of forest fire activity was ultimately caused by the continual reduction of summer insolation - energy received on a given surface in a given time - related to orbital changes.
But larger fires
In contrast, the area covered by the fires has increased. To explain this phenomenon, the researchers demonstrated that fire size correlates with average spring temperatures.
These temperatures are about 1°C higher than they were 5,000 years ago, because of increased spring insolation. According to the researchers, this slight increase in temperature is still sufficient to increase the average size of spring wildfires by a factor of three.
With anticipated global warming, an increase in the area burned would affect the planning of forestry activities and the costs of fire suppression by fire-fighting agencies. In addition, a greater number of communities could be affected.
The article, published on the PNAS website on December 3, 2012, is entitled Control of the multi-millennial wildfire size in boreal North America by spring climatic conditions.
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