Ozone injury across the Southern United States, 2002–06
| Authors: | Anita K. Rose, John W. Coulston |
| Year: | 2009 |
| Type: | General Technical Report |
| Station: | Southern Research Station |
| DOI: | https://doi.org/10.2737/SRS-GTR-118 |
| Source: | Gen. Tech. Rep. SRS–118. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 25 p. |
Abstract
In the Eastern United States, hourly concentrations of ozone typically range from 30 to 50 parts per billion(ppb), with events that may exceed 100 ppb. Typical exposure levels can cause visible foliar injury tosome plant species and have the potential to reduce tree growth by up to 10 percent per year, dependingon species and environment. As part of the Forest Service, U.S. Department of Agriculture, ForestInventory and Analysis (FIA) Program, ozone-induced foliar injury is evaluated in the South betweenlate July and mid-August on about 350 ozone biosites. For 2002 through 2006, ozone injury occurredon between 8 (2006) and 29 percent (2003) of the sampled biosites. South Carolina had the highestpercentage of biosites with injury in 3 out of 5 years. The area at greatest risk from ozone injury occurredin northern Georgia. Both the moisture index and the combination of ozone exposure and moisture were
significantly different for biosites where injury was observed and biosites where injury was not observed.
This evidence suggests that, despite reported declines in ambient ozone concentrations over the past 10
years, some forest areas in the South were classified in the low and no risk categories due to the moisturedeficit conditions that existed during the 2002-06 time period. The correlation between ozone injury and
moisture conditions, as well as the consistent low to moderate levels of injury, occurring year after yearin some parts of the South, warrant continued monitoring and close scrutiny for potential forest healthimpacts. FIA conducts the only annual nationwide systematic survey for ozone-induced foliar injury. Thisinformation is extremely valuable to research on trends in ozone exposure and injury and the impacts tovegetation across the United States.