Effects of ozone on the productivity of natural vegetation in a high meadow of the Shenandoah National Park of Virginia

A 3-year study of the effect of ambient ozone (O/sub 3/) on biomass production of native vegetation in the Big Meadow area of the Shenandoah National Park used an air filtration chamber system to make comparisons of plots with charcoal-filtered air and those with open-top chambers. The results show that biomass was greatest in the filtered plots. The study found a significant interaction between harvest date and year. Although the O/sub 3/ dose in 1981 was 65% of the monitored in 1979 and 1980, it was still sufficient to reduce biomass production. A second experiment during 1980 examined three-meter microplots and found that the total above-ground biomass of native vegetation was largest in the filtered air in three out of six measuring periods. 31 references, 4 tables.