Foliar injury and shoot growth in response to prolonged acidic misting of Pinus strobus seedlings

During a 24-week period coinciding with the growing season, two-year old Pinus strobus seedling sheets were exposed to acidic mists in the 2.6-5.6 pH range nightly. Foliar necrosis was evident in all plants exposed to acidity levels below pH 5.6. Injury magnitude and quantity was pH-dependent, ranging from no injury of the pH 5.6 needles to more than 50% injury of needle tissue from the pH 2.6 group. No significant differences were detected in the macroscopic growth of seedlings between the different treatment groups. Needle elongation progressed in a normal, unaffected manner despite needle injury.