PROCEEDINGS: Index of Abstracts

PREDICTING THE EFFECTS OF TROPOSPHERIC OZONE ON FOREST PRODUCTIVITY IN THE NORTHEASTERN U.S.

Scott V. Ollinger-1, John D. Aber-1, and Peter B. Reich-2

1-Complex Systems Research Center, University of New Hampshire, Durham, NH 03824. 2-Department of Forest Resources, University of Minnesota, St. Paul, MN 55108.

It is widely believed that tropospheric ozone presents a significant anthropogenic stress on forest ecosystems. Although much information has been collected regarding ozone effects at the seedling and leaf level, we do not have a reliable means of estimating the effect on mature, native forests. For the present study, we incorporated leaf-level ozone response information into an ecosystem model of forest production known as PnET-II in order to make whole-forest predictions that account for factors such as light attenuation, canopy ozone gradients and water stress. We ran the model using ambient ozone data from 64 locations across New York and New England. Predictions indicate reductions in annual NPP of from 2 to 17 percent under mean ozone from 1987-1992. Reductions were greatest in southern portions of the region on soils where drought stress was absent.