American beech (Fagus grandifolia) in the eastern United States and Canada has experienced more than a century of mortality under a steady expansion of disease agents collectively causing beech bark disease (BBD). In North America, BBD consists of insect (e.g., Cryptococcus fagisuga [beech scale] and Xylococculus betulae) and phytopathogenic fungal (Neonectria faginata and N. ditissima) components that can variously interact with host and environment to cause extensive aboveground mortality of beech (i.e., killing front stage). This heavy mortality causes cascading impacts on forest ecosystems, resulting in altered biotic and abiotic conditions in which BBD-inducted mortality persists at reduced levels (i.e., aftermath stage). New evidence