Résumé - CAFD

Reconstruction of fire history (1680–2003) in Gaspesian mixedwood boreal forests of eastern Canada.

Eve Lauzon, Daniel Kneeshaw, Yves Bergeron.

We describe the fire regime in the Gaspesian mixedwood boreal forest in order to improve our knowledge of the maritime fire regime through time and the role of climate on changes in fire cycle. We also investigated the importance of coarse scale spatial factors, such as topography, altitude, soil-type and vegetation-type. Fire history was reconstructed for a 6480-km² area using Quebec Ministry of Natural Resource archival data and aerial photographs combined with dendrochronological data, collected using a random sampling strategy. Physiographic features were not found to significantly influence the fire cycle, but an increase in the cycle (from 89 to 176 years p  0.0001) was observed since the end of Little Ice Age (LIA) (1850). Relative agreement between the archival data (1920–2003) and the semi-parametric survival analysis approach for the 1850– 2003 period provides greater confidence in our determination of a fire cycle situated between 170 and 250 years. An analysis of fluctuations in the Canadian forest fire Weather Index system, calculated for the period 1920–2003, showed a statistically significant decrease in extreme values. Given such a long fire cycle and in the context of forest management based on natural disturbance, even-aged management under short rotations should be questioned in these mixedwood boreal forests. © 2007 Elsevier B.V. All rights reserved.