Date of Award

12-6-2019

Semester of Degree

December

Document Type

Open Access Thesis

Degree Name

M.S. in Forest and Natural Resources Management

Department

Forest and Natural Resources Management

Major Professor

Ruth Yanai

Steering Committee Member

Thomas Horton

Steering Committee Member

Mariann Johnston

Abstract

Beech bark disease (BBD) invaded North America over a century ago but is still not completely understood. This disease occurs when an invasive scale insect, Cryptococcus fagisugaLind., feeds on the inner bark and cambium of American beech (Fagus grandifolia, Ehrh.) making trees susceptible to fatal infections by Neonectria fungi. These causal agents were examined in the context of experimental additions of N and P across six northern hardwood stands in New Hampshire. Scale cover varied significantly with tree diameter (p = 0.02) but was nearly identical (0.6%) at two heights on the bole (0.5 m and 1.5 m). Nearly all Neonectria samples collected were identified as N. faginata; 3% that were N. ditissima. New lesions developed on 58% of trees, with 96% developing at or below 0.5 m. Trees receiving P additions developed 2 times as many lesions as those not receiving P (p = 0.04). These results differ from previous research reporting higher BBD severity where P was low relative to N

Share

COinS