Tuesday, November 6, 2007
217-4

Soil and Foliar Nutrients in Mixed Hemlock-Hardwood Stands in the Allegheny National Forest, Pennsylvania, U.S.a.

Kathryn Piatek, PO Box 6125, West Virginia Univ., West Virginia University, Division Of Forestry, Morgantown, WV 26506-6125

Higher foliar levels of some nutrients in eastern hemlock (Tsuga canadensis) trees and increased soil N turnover rates in hemlock stands have been found in association with feeding by the hemlock wooly adelgid (Adelges tsugae). Whether these nutrient relationships are a predisposing factor for or a consequence of insect feeding is not clear. This study was undertaken to establish reference soil and foliar nutrient levels in hemlock trees prior to the arrival of the insect to help elucidate the cause/effect relationships. The study was established at the Allegheny National Forest in northwestern Pennsylvania in three mixed hemlock-hardwood stands. A control and a thinning treatment were included to better understand the effects of increased resource levels to the remaining trees on insect preference for individual trees. Soil, foliar, and forest floor concentrations of N, P, Ca, K, Mg, soil potential net N mineralization, and forest floor mass were determined. Variation in these variables is discussed in relation to the potential effects on soil and tree nutrition of an adelgid infestation.