Relationships among beech bark disease, climate, radial growth response and mortality of American beech in northern Maine, USA

摘要: A majority of beech forests across Maine first experienced bark disease (BBD) from 1935 to 1960 when sap feeding by an introduced scale insect, Cryptococcus fagisuga, allowed lethal fungal infections primarily Neonectria ditissima and/or faginata. Beech stands along the Maine–Quebec border in northern were excluded this initial killing phase presumably due cold winter temperatures that inhibited survival. However, a sharp increase mortality after 2002 occurred previously uninfected and long affected BBD. averaged 50% during 2003–2006. To identify plausible stresses could explain mortality, dendropathological study was conducted 2005 2006 quantified temporal spatial relationships between possible stressors with growth decline. Nineteen sets high‐ low‐mortality plots located randomly four bioregions. Increment cores taken both trees (n = 565) associated tree species (n = 450). change index increments used evaluate responses biotic climatic stresses. prolonged period relatively mild winters without insect (<−34°C) 2000 2004 coupled low August–October precipitation 2003 may have provided ideal conditions initiating widespread epidemic. major drought 1999 coincided decline significant all regions included study. found infecting weakened region. Drought, are explanations for episode high Maine. This is report within BBD ‘aftermath’ forests.