Monitoring for Ozone Injury in West Coast (Oregon, Washington, California) Forests in 1998

Abstract

In 1998, forest vegetation was monitored for ozone injury on permanent plots in two Sierra Nevada national forests in California, at three locations in Mount Rainier National Park in Washington, and at 68 forest health monitoring (FHM) locations throughout Washington, Oregon, and California. This was the first year that extensive monitoring of forest vegetation for ozone injury was carried out in Oregon and Washington. Injury was detected on ponderosa and Jeffrey pine in the Sierra Nevada permanent plots and on red elderberry at one FHM location in southwest Washington. No injury was detected at the Mount Rainier sites. We also report on results of a trial where red alder, huckle-berry, blue elderberry, and chokecherry were exposed to ozone under controlled conditions. Abstract This page has been left blank intentionally. Document continues on next page. 1 There is widespread concern about the potential impact of air contaminants on the long-term sustainability of our Nation's forests (Chappelka and Chevone 1992, Smith 1985, USDA Forest Service 1997, US EPA 1996b). Air pollutants, such as ground-level ozone, are known to interact with forest ecosystems and cause visible injury and other less obvious, but significant, effects (Hakkarienen 1987, Krupa and Manning1988, Smith 1990). Ozone is the only regional gaseous air pollutant that has been measured at known phytotoxic levels at numerous remote locations across the continental United The scientific evidence collected so far indicates that the response of western tree species to ozone pollution differs widely depending on species and genotype within speciestain major forest species, such as ponderosa pine (Pinus ponderosa Dougl. ex Laws.), are sensitive to ozone at concentrations that normally occur over wide areas of the western landscape (Miller 1996, Peterson et al. 1991, US EPA 1996b). Because of the long life span of trees, there is ample opportunity for a long-term, cumulative effect on tree growth. Ozone has been implicated in the growth decline of pollution-sensitive eastern white pine genotypes in the Ozone also may have a broad effect on forested landscapes, potentially altering species composition and influencing pest interactions, soil moisture, and fire regimes Significant visible injury or effects on tree health have not been observed, however, in forests in these areas (Duriscoe and Temple 1996). Ozone monitoring has consisted of either measuring the amount of ozone in the air (ambient ozone) with air quality monitors or visually evaluating the extent and severity of ozone-induced foliar injury to sensitive plants …