White pine (Pinus strobus) showing the sort of yellowing that could be caused by ground-level ozone damage

The Appalachia Forest Action Project measured changing rates in the mortality of trees in the mixed mesophytic forest. This photo of white pine needles on Joe Aliff's property shows the symptoms that led to the creation of a separate effort to monitor the effects of ultra-violet B radiation due to holes in the stratospheric ozone layer. The purpose of this project was, as ecologist Orie Loucks wrote, "to correlate the level of damage to pine needles with seasonal progression of the sun angle and days of exceptionally low levels of stratospheric ozone (high levels of ultraviolet B radiation)." While the project was able to show this relationship at a site in Tennessee, there was not enough information on sites in West Virginia and Ohio. "The effects are dramatic on white pine foliage," wrote Loucks, "but hard to prove due to confounding variables….The yellowing of the pine could be ground-level ozone damage, but on pine there is never as clear a symptomology as there is on several of the hardwoods, especially the magnolias." (E-mail to Mary Hufford, October 11, 1999)