Incidence of Annual Canker of Sugar Maple Studied with the Aid of a Geographic Information System
Abstract Sugar maples (Acer saccharum Marsh) ≥ 2.0 in. dbh were evaluated for incidence of annual canker caused by Fusarium spp. A total of 1,880 trees were evaluated from 73 plots located on 635 ac of privately owned northern hardwood forest in north central Vermont. About 12% of the trees were dead and one-fourth of both living and dead trees had annual canker. A logistic regression model was used to assess the role of soil-site characteristics related to the incidence of annual cankering. Probability estimates from the estimated regression equation were used to generate a map of annual canker risk. The generality of the results obtained here are untested and need to be applied to a more extensive area for validation. However, the technique for forest disease risk assessment could have wide application. We found annual canker was more common on sites that maintained a high number of stems per acre, on sites that were shallow to bedrock, and on sites that were dominated by sugar maple. We believe these findings suggest that sites that have shallow soils that include sugar maple probably should not be managed to encourage sugar maple. Sugar maple probably should be managed in stands that contain ample stocking of other northern hardwood species, and cultural practices that encourage maple over other species probably should be avoided.