A new study revealed that acid rain's damage to America's forests may be much more widespread than previously believed. It may actually create conditions in trees similar to compromised immune systems in humans, establishing a vulnerably with grave potential implications.
"As with immune-compromised humans, plants may appear and function as if they were healthy, until exposed to even a routine stress or disease, then experience declines far more exaggerated than expected," says Donald DeHayes, Dean and Professor in the School of Natural Resources at The University of Vermont. DeHayes co-authored a study in the most recent issue of the journal "Ecosystem Health" released in June at an international conference on Ecosystem and Human Health in Washington, DC, which was attended by about 1000 environmental scientists and policy makers.
Up to now, acid rain has been associated with the decline of forests in certain specific locations. DeHayes and colleagues, UVM senior researcher Gary Hawley and USDA Forest Service scientist and UVM adjunct faculty Paul Schaberg previously documented the mechanism through which acid rain depletes calcium and weakens high elevation red spruce trees, making them more vulnerable to winter freezing injury.
Their new work shows that this mechanism is also applicable to other tree species, including balsam fir, white pine, and eastern hemlock. Because calcium is a critical ingredient in the plant's stress response system, acid rain's depletion of cellular calcium may suppress the capacity of trees to survive environmental stresses.