Relative Sensitivity of Red, Jack, and White Pine Seedlings to Ozone and Sulfur Dioxide

Abstract

Groups of red pine (Pinus resinosa), jack pine (P. banksiana), and white pine (P. strobus) seedlings at ages 3, 5, and 7 weeks were exposed to individual dosages of ozone and sulfur dioxide. Exposures to each gas were 2 hours at 25.0 or 50.0 parts per hundred million (ppHM). Jack pine was the most sensitivie to ozone. None of the species was sensitive to sulfur dioxide at the 25.0 ppHM level. Red pine, however, was more tolerant to sulfur dioxide at the 50.0 ppHM level. Ozone was more injurious to all three species than was sulfur dioxide.