E-mail : veronique.tremblay2@mddep.gouv.qc.ca

A dendroecological analysis of white birch (Betula papyrifera) decline after tree harvesting in the Réserve faunique des Laurentides
Supervisor : Serge Payette


In the Réserve faunique des Laurentides, the moribund state of white birch (Betula papyrifera) left in cut areas suggests that there is a relationship between forest cuts and birch decline. The goal of this project is to identify and determine the cause of white birch decline after harvesting using dendroecological techniques. A dendrochronological analysis combined with a qualitative evaluation of decline symptoms from tree individuals coming from 10 cut areas and 10 witness sites confirmed the decline of white birch after forest cutting. Growth curves for white birch, white spruce (Picea glauca), and balsam fir (Abies balsamea) indicate that severe insect epidemics occurred over the last two centuries. However, the white birch decline is not directly related to these epidemics. Unfavorable climatic conditions, such as excessive July precipitation, combined with poor drainage conditions, appear to be the principal factors affecting the residual birch. This study demonstrates the multicausal phenomenon of white birch decline.