Predicting log grade volumes in sugar maple and yellow birch trees in Quebec’s hardwood stands

Résumé

Models were developed for sugar maple (Acer saccharum Marshall) and yellow birch (Betula alleghaniensis Britton) to estimate log grade occurrence and volume in northern hardwood stands in southern Quebec, Canada. For each species, we used data from more than 2,000 trees that had been harvested and bucked into logs at 30 sites across Quebec’s hardwood forests since the early 2000s. Separate models were developed for each species by adding site predictors, such as climate and ecological variables, to tree-level variables, such as tree diameter at breast height and tree quality class. For both species, the best results were obtained by adding the ecological region as an explanatory variable. For sugar maple, the observed proportion of sawlog volumes in the ecological regions of the balsam fir–yellow birch bioclimatic domain was significantly lower than in the sugar maple–yellow birch bioclimatic domain (i.e., Quebec’s southernmost regions for hardwood stands). For yellow birch, sawlog volume was variable among ecological regions, although lower values were observed in eastern Quebec. Our results suggest that site and growth conditions should be considered when assessing potential products for hardwoods.