Content of Chemical Elements in Tree Rings of Lodgepole Pine and Whitebark Pine from a Subalpine Sierra Nevada Forest

摘要

The wood of lodgepole pines and whitebark pines from a high elevation site in the east-central Sierra Nevada of California was analyzed for chemical content to determine whether there were any temporal patterns of chemical distribution in tree rings. Cores were taken from 10 trees of each species and divided into 5-year increments for chemical analysis. Correlation analysis indicated that calcium and magnesium, both of which have divalent cations, were strongly correlated for both species. The elements copper, iron, cobalt, nickel, molybdenum, chromium, tin, and arsenic were all significantly correlated with one another in lodgepole pine but not in whitebark pine. Concentrations of calcium and magnesium decreased over time for both species, while that of boron increased dramatically. None of the youngest wood, which probably reflects greater mobility of soluble forms of elements in the study are presumably free of the effects of substantial input from humans. The data provides valuable information on wood chemistry with which to evaluate disturbed or polluted stands with similar characteristics.