Sébastien Dumont

Beech bark disease is a major concern for northern hardwood forest management that affects most of the American beech range in North America. In infected stands, mitigating effects of the disease and promoting more resistant beech populations for natural regeneration relies heavily on our ability to identify high-risk trees and adapt tree marking for partial harvesting. We monitored several individual characteristics, including external signs of disease, on 871 beech trees in recently infected northern hardwood stands at the northern range limit of American beech in Canada, to assess their ability to predict mortality over an 8-year period. At the stand level, the mortality rate over the study period was 29.3%, while the uninfected rate was 16.6%. At the tree level, the diameter, the levels of Neonectria perithecia coverage on the stem, crown dieback, and the level of canker coverage on the bark had the greatest capacity to predict individual short-term mortality. Therefore, tree markers should first select trees with a diameter > 20 cm that are affected by any sign or symptom of the disease, followed by smaller trees with >10% coverage of Neonectria perithecia or crown dieback >25%, and lastly, trees with >50% coverage of canker.