Tree ring growth and elemental concentrations in wood cores of oak species in eastern Pennsylvania: Possible influences of air pollution and acidic deposition

Abstract

Annual ring growth patterns of red oak (Quercus rubra) and white oak (Q. alba) were compared from Lehigh Valley (near neutral soils) and the Pocono (acid soils) forests in eastern Pennsylvania. The two red oak populations were parallel, although statistically different, from 1935–1950. For white oak, the two populations had the same mean for the period of 1935–1965; and from 1965–1985 the means were different. Chemical analyses of wood cores had shown increasing concentrations of several trace elements in new rings of both oak species from the Lehigh Valley and the Pocono areas. Although the results suggest certain changes in growth pattern and chemical composition in the wood cores, no clear‐cut evidence that air pollution or acid rain was affecting the health of the two forests could be detected.