Monday, November 13, 2006
111-8
Soil and Foliar Elements, d15N, and N Dynamics in Mixed Hemlock-hardwood Stands in the Allegheny National Forest, Pennsylvania.
Kathryn Piatek, West Virginia Univ, Forestry Dept, PO Box 6125, Morgantown, WV 26506
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 in the expectation of the impending arrival in the Allegheny National Forest (northwestern Pennsylvania) of the insect. Reference soil and foliar elemental analysis was performed in three insect-free mixed hemlock-hardwood stands to help elucidate the cause/effect relationships. Soil and foliar concentrations of N, P, Ca, K, Mg, and δ15N, soil in-situ and potential net N mineralization, and forest floor mass and N availability were determined. Variation in these variables is discussed in relation to the potential effects on soil and tree nutrition of an adelgid infestation.