Assessing the climate suitability and potential economic impacts of Oak wilt in Canada

Abstract

We assess risks posed by oak wilt—a disease caused by the fungal pathogen Bretziella fagacearum. Though not currently found in Canada, our distribution models indicate that suitable climate conditions currently occur in southern Ontario for B. fagacearum and two of its main insect dispersal vectors, Colopterus truncatus and Carpophilus sayi. Climate habitat for these species is projected to expand northward under climate change, with much of the oak range in eastern Canada becoming climatically suitable within the next two decades. Potential costs for the removal and replacement of oak street trees ranged from CDN$266 to $420 million, with variation related to uncertainty in costs, rate of tree replacement, and city-level estimates of oak street tree density. The value of standing oak timber in eastern Canada was estimated at CDN$126 million using provincial stumpage fees and as a CDN$24 million annual contribution to national Gross Domestic Product (GDP) when calculated using a combination of economic and forestry product statistics. These values can help inform the scale of eradication and/or management efforts in the event of future oak wilt introductions.

Early detection of the oak wilt fungus (Bretziella fagacearum) using trapped nitidulid beetle vectors

“…Although oak wilt occurs more sporadically and acts differently in the Appalachian region and northeast (Juzwik et al, 2011), land managers continue to be concerned about the disease as its range expands northwards. In areas where the disease has not been found, such as Canada, oak wilt is a pathogen of regulatory concern, and modelled estimates of removal and replacement costs were hundreds of millions of Canadian dollars (Pedlar et al, 2020). Early detection is crucial to management success, as finding and removing infected trees before the fungus can reproduce allows managers to stop local spread (Juzwik et al, 2011).…”

“…Although oak wilt occurs more sporadically and acts differently in the Appalachian region and northeast (Juzwik et al, 2011), land managers continue to be concerned about the disease as its range expands northwards. In areas where the disease has not been found, such as Canada, oak wilt is a pathogen of regulatory concern, and modelled estimates of removal and replacement costs were hundreds of millions of Canadian dollars (Pedlar et al, 2020).Early detection is crucial to management success, as finding and removing infected trees before the fungus can reproduce allows managers to stop local spread (Juzwik et al, 2011).Our native oak trees contribute numerous timber, wildlife and aesthetic benefits, as well as improving the quality of our environment.…”

Genetic Lineage Distribution Modeling to Predict Epidemics of a Conifer Disease

“…Climate-driven SDMs have traditionally been used to assess habitat suitability for a given species including forest pathogens (Pandit et al, 2020;Pedlar et al, 2020). We are unaware of studies in forest pathology that have used genetic clusters as inputs into SDM, and outputs of these models for assessing the severity of forest pests or diseases.…”

Forest Biosecurity in Canada – An Integrated Multi-Agency Approach

“…The pathogen was first recorded in the United States in the early 1940s and its range has slowly expanded such that it is now present in the states that border the province of Ontario (Juzwik et al, 2011). Although the pathogen has not been recorded in Canada (CFIA, 2019a,b;Nienhuis and Wilson, 2018), climatic suitability modeling suggests that climate would not be limiting and that serious economic consequences could occur if the pathogen became established here (Pedlar et al, 2020b).…”