PARENT SESSION
Poster Session #17: Resource Management and Risk Assessment.
Tuesday, August 7, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Simulation of ozone effects on eight tree species at Shenandoah National Park, Virginia, USA.

Laurence, John¹, Lee, E.¹, Hogsett, William¹, ¹

ABSTRACT- As part of an assessment of potential effects of air pollutants on the vegetation of Shenandoah National Park (SHEN), we simulated the growth of eight important tree species using TREGRO, a mechanistic model of individual tree growth. Published TREGRO parameters for black cherry, red maple, red oak, sugar maple, and yellow poplar were adjusted to account for meteorology and phenology at SHEN. Parameters for basswood, chestnut oak, and white ash were based on literature reports of physiology and growth. Ozone response functions were developed from reports in the literature, when available, or estimated by comparison of stomatal conductance to that in similar species with a known response to ozone. Simulations were for 1997-1999. Ozone scenarios were constructed from measured ambient ozone at SHEN and included a rollback of 20 percent and increases of 10, 30, and 50 percent in hourly concentrations (about 50 to 450 ppm⋅hr SUM06 over 3 years). Predicted changes in total growth due to ozone ranged from almost 0 percent in sugar maple to about −2.75 percent over the 3 year simulation in white ash. In all cases, the greatest effects on growth were simulated in roots, similar to responses reported in the literature. For the final assessment, these results will be incorporated into ZELIG parameters to simulate the potential effects of ozone on growth under competition and subsequent stand composition and productivity.

KEY WORDS: ozone, assessment, modeling