Grulke reports Air Pollution increases Forest Susceptibility to Wild Fires in California

By Yulanda Hwang and Tracey O’Malley

Dr. Nancy Grulke, a Plant Ecophysiologist with the USDA Forest Service, presented her research on Air Pollution and Increased Forest Susceptibility to Wild Fires at SUNY-ESF on Tuesday, March 28, 2006 as part of SUNY ESF’s Women in Scientific and Environmental Professions Spring Seminar Series. This event was sponsored by ESF’s Faculty of Environmental and Forest Biology, Graduate Student Association, and the ESF Women's Caucus.

Dr. Grulke discussed the effects of air pollutants on forested ecosystems and their link to wildfire. Dr. Grulke first discussed how the rapid increase in human population and the change in land use from forest utilization to a management practice of fire suppression had originally led to the ecosystem’s susceptibility to wildfires.

Attention was then focused on regional ozone concentration and its relation to drought stress and on tree responses. Environmental stressors alter temporal and spatial variations in plant resources, acquisition, allocation, and partitioning. Strong tropospheric oxides cause plants to retain needles for much shorter periods of time and thus reduce root biomass. Dr. Grulke’s research proves that ozone exposure reduces photosynthesis, increases drought stress, and therefore results in a loss of roots and biomass. Whether under short, medium, or long-term ozone exposure, metrics were persistent in predicting sluggish stomatal behavior.  She concluded that sluggish stomatal response was caused by an increasing vapor pressure deficient (VPD) with ozone exposure.

Dr. Grulke suggests that air pollution increases drought stress, drought stress increases tree susceptibility to beetle attacks, and these attacks make the trees more susceptible to fires.

Dr. Grulke received her B.Sc. in Botany from Duke University in 1978, and her Ph.D. in Botany from the University of Washington in 1983. She is currently a plant ecophysiologist and Project Leader, Atmospheric Deposition on Western Ecosystems, at the Pacific Southwest Research Station, USDA Forest Service, in Riverside, California. She specializes in effects of air pollutants, especially ozone concentration, on tree responses and drought stress in forests of California.