Assessing vigor when tree marking: the importance of crown dieback


  • François Guillemette Direction de la recherche forestière du Quebec


The silvicultural approaches generally used for uneven-aged northern hardwood stands mostly involve partial cuts. To facilitate the implementation of stand improvement in these cuts, several classification systems have been developed to help tree markers visually assess tree vigour based on the presence of individual defects. However, very few studies have tried to empirically validate such systems. We assessed tree vigour using repeated measurements collected as part of long-term silvicultural trials conducted in 615 permanent plots throughout the northern hardwood forest of Quebec, Canada. Our results confirmed that crown dieback is by far the best indicator of tree vigour. They also showed that the rate that vigorous trees develop defects increased with increasing diameter. 

Author Biography

François Guillemette , Direction de la recherche forestière du Quebec

François Guillemette (PhD) is a forest engineering graduate from Laval University in Quebec City. Since 2005, he has been employed by the Direction de la recherche forestière of the Quebec government as a researcher on hardwood silviculture. His work mainly deals with the dynamics of hardwood stands after partial cutting. He is particularly interested in young hardwood stands, in different classification systems for standing hardwood trees and in growth modelling (the SaMARE model). He also studied the notion of diameter at maturity for hardwood trees.