Effects of climate on occurrence and size of large fires in a northern hardwood landscape: historical trends, forecasts, and implications for climate change in Témiscamingue, Québec.
Ronald Charles Drever, Yves Bergeron, Mark Drever, Micheal Flannigan, Travis Logan, Christian Messier.
Questions: What climate variables best explain fire occurrence and area burned
in the Great Lakes-St Lawrence forest of Canada? How will climate change influence
these climate variables and thereby affect the occurrence of fire and area
burned in a deciduous forest landscape in Témiscamingue, Québec,
Location: West central Québec and the Great Lakes-St Lawrence forest
Methods: We first used an information-theoretic framework to evaluate the
relative role of different weather variables in explaining occurrence and area
burned of large fires (>200 ha, 1959-1999) across the Great Lakes-St
Lawrence forest region. Second, we examined how these weather variables varied
historically in Témiscamingue and, third, how they may change between
the present and 2100 according to different scenarios of climate change based
on two Global Circulation Models.
Results: Mean monthly temperature maxima during the fire season (Apr-Oct)
and weighted sequences of dry spells best explained fire occurrence and area
burned. Between 1910 and 2004, mean monthly temperature maxima in Témiscamingue
showed no apparent temporal trend, while dry spell sequences decreased in frequency
and length. All future scenarios show an increase in mean monthly temperature
maxima, and one model scenario forecasts an increase in dry spell sequences,
resulting in a slight increase in forecasted annual area burned.
Conclusion: Despite the forecasted increase in fire activity, effects of climate
change on fire will not likely affect forest structure and composition as much
as natural succession or harvesting and other disturbances, principally because
of the large relative difference in area affected by these processes.