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Effects of Atmospheric Deposition on Sulfur and Nitrogen Content of Four Urban Tree Species

One-yr-old containerized seedlings of black locust, black cherry, Siberian elm, and yellow-poplar were fumigated with either SO2, NO2 or with a combination of both pollutants 7 hr daily for 8 weeks under controlled conditions. Tissue samples were analyzed for sulfur and total nitrogen content at the end of the experiment. Sulfur content of black locust and yellow-poplar seedlings fumigated with SO2 was always greater than comparable seedlings without SO2. However, nitrogen content of seedlings exposed to NO2 was no greater than similar plants grown in the absence of NO2. It appears that fumigation with a combination of both pollutants inhibited sulfur uptake of black locust and black cherry seedlings, and increased nitrogen accumulation in Siberian elm and black cherry seedlings.