Chronological sequence of element concentrations in wood of Carya spp. in the southern Appalachian Mountains

Abstract

Tree-ring analyses of hickory (Carya spp.) from the long-term ecological research site, Coweeta Hydrologic Research Laboratory, revealed that concentrations (micrograms per gram) of lead, aluminum, and zinc are increasing, that concentrations of copper, cadmium, nickel, and manganese have remained generally constant since the 1880's, and that hickory annual radial growth increments are declining. Lead, aluminum, and zinc burdens (microgram per growth interval), unlike their respective concentrations, have remained generally constant during the 1900's. The interpretation of growth and burden data indicates that hickory trees at Coweeta are in a mature phase of their life cycle and that annual growth does not seem to be reduced by pollutants.