PARENT SESSION
Poster Session # 14: Forest Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Tropospheric ozone impacts on large, mature trees in the Great Smoky Mountains National Park.
Chappelka, Art*,, Somers, Greg1, Neufeld, Howard2, 1 School of Forestry and Wildlife Sciences, Auburn, Alabama, USA2 Department of Biology, Boone, North Carolina, USA
ABSTRACT- Great Smoky Mountains National Park (GRSM), encompassing over 206,000 hectares of area in the states of Tennessee and North Carolina, is the most visited National Park in the United States. The Park contains a wide diversity of plants and animals representative of a large region of the eastern USA. Ozone exposures are high in the Park, and have increased significantly during the decade of the 1990s, with possible detrimental effects on the vegetation, and in particular, forest trees. Yellow-poplar and black cherry trees previously cored (1994) and identified regarding ozone sensitivity were re-cored in 2001 at three sites within the Park. Twenty trees/species (10 sensitive, 10 non-sensitive)/ site were cored. Some slight differences existed between the original analysis using cores collected in 1994 compared with those collected in 2001. Based on the 1994 cores, significant differences at p=0.02 were observed for yellow-poplar regarding differences in tolerance. However, using data collected from 2001, significance was observed only at the 88% level. Reasons for these differences are unknown, but could be due to the following factors: 1) variability due to small sample size (not all trees measured in 1994 were included in the 2001 analysis for various reasons), 2) differences in analytical procedures or equipment used between laboratories, and/or 3) a disparity between individuals reading samples. Growth for both species was affected by site, but no site X sensitivity interactions were observed. Black cherry radial growth did not differ by ozone sensitivity group during any time period analyzed. Yellow-poplar varied by sensitivity group during 1990-1994 (ozone-sensitive trees exhibited less radial growth), but no differences in growth were observed from 1997-2001. Yellow-poplar grew better from 1997-2001 compared with the period 1990-1994, but black cherry grew less.
Key words: ecology, air pollution, ozone, radial growth