I currently coordinate a diverse collaborative group of scientists from the USDA Forest Service, The University of Vermont and other institutions that evaluate the influence of human-associated stress (e.g., pollution additions, climate change, etc.) on forest health and productivity. This research concentrates on the impacts of anthropogenic stress on aspects of tree physiology, including tissue cold tolerance, carbohydrate and nutrient relations, foliar pigments and antioxidant enzymes. Current issues that I am working on include: red spruce winter injury and other aspects of conifer cold tolerance, sugar maple decline, the impacts of calcium depletion on tree health, the biological basis of red pigment expression in the fall, and cold tolerance as a limitation to American chestnut restoration in the north.