The impact of three large coal-burning power plants (electric generating stations with tall stacks) on vegetation in southwestern Pennsylvania USA was examined from 1964, prior to operation, to the present. Sulfur levels in foliage close to and downwind from the power plants increased during the early years of the study, then leveled off. Foliar symptoms caused by SO2 were observed at two locations within 10 km of one of the large power plant, after initiation of operation; symptoms were also noted on an extremely small percentage of the Scots pines within 25 km of the power plants. Foliar SO2 symptoms also were observed in the vicinity of local sources such as burning coal-spoil piles, a small existing power plant, and coke ovens. Reductions in tree growth, as measured annually with a diameter tape, were associated with adverse weather conditions and insect defoliation, but not with distance or direction from the power plants. Increment core analysis will be conducted in 1984-1985. By far, the most severe air pollution injury was caused by O3; O3 injury was common, widespread, and often severe, even prior to the initiation of operation of the power plants.
All Science Journal Classification (ASJC) codes
- Plant Science