Canadian Forest Service Publications
Incidence of beech bark disease resistance in the eastern Acadian forest of North America. Taylor, A.R.; McPhee, D.A.; Loo, J.A. 2013. The Forestry Chronicle 89(5): 690-695.
Issued by: Atlantic Forestry Centre
Catalog ID: 39126
Availability: PDF (download)
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Beech bark disease (BBD) is a fatal affliction of American beech (Fagus grandifolia Ehrh.) in North America. Although natural resistance to BBD has been observed, reports vary with respect to incidence of resistance, with 1% being most commonly acknowledged. In this paper, we provide the first formal, empirical estimate of BBD resistance over a wide geographical area where BBD has been prevalent for longest in North America. We conducted our study in the Acadian Forest region of eastern Canada. Thirty-five beech-dominated stands (>5 ha each) were surveyed across the provinces of New Brunswick, Nova Scotia, and Prince Edward Island, spanning a time since infection (TSI) period between 1890 and 1975. Stands were surveyed for incidence of disease-free beech trees, which was used as a proxy for BBD resistance. Across our study area, the average percentage of disease-free trees observed was 3.3%; however, the occurrence of disease-free trees varied significantly geographically, with the oldest, most southerly TSI zone indicating 2.2% and the youngest, most northerly TSI zone showing 5.7%. Although geographic variation of disease-free beech trees may reflect disease exposure time, we speculate that lower minimum winter temperatures, combined with less intensive land-use history are the underlying mechanisms that explain the higher observed percentage of disease-free trees in the most northerly TSI zones.
Plain Language Summary
This study investigates the prevalence of resistant beech (Fagus grandifolia) trees to beech bark disease in the Acadian Forest of eastern Canada. Using a sample of 35 beech-dominated stands from across the three Maritime Canadian provinces (Nova Scotia, New Brunswick, and Prince Edward Island), this study found that approximately 3.3% of beech trees sampled showed no signs of beech bark disease, indicating resistance; however, rate of infection varied according to location, which may be reflect disease exposure time, climate, and land-use history.