Beech Bark Disease–The Aftermath Forests are Structured for a New Outbreak

Abstract

Abstract Stands of American beech in Maine–severely damaged by the beech bark disease in the 1930s and 1940s–were surveyed in 1973-74. Both disease agents (the scale Cryptococcus fagi and the fungus Nectria coccinea var. faginata) are now endemic, but few trees are dying. Another scale (Xylococculus betulae) is also abundant on all size classes of trees. Beech has become more numerous since the disease because death of large trees released sprout thickets. Serious defect is now present from previous cankering by Nectria spp. and infestation by X. betulae. As they grow, young trees will be more susceptible to the disease. The stage seems to be set for a new severe outbreak.