• Address:
  705 Spear Street
  South Burlington, Vermont 05403
  United States of America
  
  Phone: (802) 391-4135
  Email: femc@uvm.edu
  Website: www.uvm.edu/femc

Calcium is an important soil nutrient in healthy forests, but interactions with acid rain cause elements, such as aluminum, to interfere with calcium uptake by plants. Calcium-to-aluminum ratio in foliage and soil has been shown to be a predictor of tree health and is used in critical loads assessments to determine impacts of air pollution. Most studies have been done on greenhouse seedlings and have questionable application to mature forests. Another element, manganese, has also been shown to interfere with nutrient uptake. NSRC researchers investigated these ratios in mature forest trees. They measured chemistry of soil, soil water, and foliage of sugar maple, yellow birch, white ash, and black cherry in 56 hardwood forest plots from Pennsylvania to New Hampshire. Researchers assessed tree health by rating tree canopies for dieback, transparency, and overall vigor. They measured stem diameter growth with increment cores.