14 VIRGINIA FORESTS Emerging and Established Threats Impacting American Beech By Carrie J. Fearer Characteristic crinkled and banded symptoms associated with beech leaf disease. American beech (Fagus grandifolia) is a foundational tree species in the eastern deciduous forests of the United States with its range extending across 30 states from Maine to Florida. Along with sugar maple (Acer saccharum), American beech comprises the canopy of beech-maple forests, one of the dominant forest ecosystems in the northeastern United States. In the Southern Appalachians, it is an important tree species in high-elevation, northern hardwood forests and comprises the dominant “beech gap” forest type. Beech gaps harbor a highly rich and diverse community of understory plants that are endemic to these high elevation forests. They produce beechnuts, which are an important food source for mammals and birds, especially black bears and turkeys. In addition to forests, American beech trees are often planted in parks and landscape settings as shade trees where they are admired for their smooth, gray bark and gold, autumn foliage. American beech is generally renowned as a longlived species, and its height and diameter can span over 50 feet. However, old-growth American beech forests may soon face the same fate as other native tree species like the American chestnut and American elm due to threat of nonnative, invasive pests and pathogens. Beech bark disease American beech has long been affected by beech bark disease, a complex forest disease caused by both native and nonnative insect and fungal species. The disease was first discovered impacting American beech in the United States in Maine in 1935. Since its discovery, it has spread as far south as North Carolina and as far west as Wisconsin, leaving a trail of dead overstory beech in its path. Beech bark disease generally progresses through a forest in three recognizable stages: advance front, killing front, and aftermath. In the advance front, there are no visible symptoms of beech bark disease, but there is a build-up and spread of the Colonization of the beech scale insect (identified by the red arrow) on an American beech tree infected with beech bark disease.
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