Dendrochronology of Black Oak (Quercus velutina Lam.), White Oak (Quercus alba L.), and Shortleaf Pine (Pinus echinata Mill.) in the Central Mississippi Valley

Tree—ring samples (increment cores) from living trees at 61 different forest sites were analyzed by using skeleton plots and several computer routines to determine the effect of climatic influences upon the growth of black oak, white oak, and shortleaf pine. All cores were cross—dated within each species and between species by skeleton plots, and a specific calendar year was assigned to each annual ring. Black oak was easier to cross—date than white oak or pine. Computer—calculated negative mean sensitivity values verified cross—dating by skeleton plots. Comparisons of site chronologies derived from both the skeleton plots and the index routine for each species showed that a number of narrow rings consistently occurred in certain years throughout the Central Mississippi Valley. Within any species the degree of similarity in narrow rings decreased as the distance between sites increased. Major changes in soil types also influenced the number of narrow rings; thus ecological differences may occur within the same species as well as between species. Information about the past history of the stand and its present ecology may be obtained from the increment cores and the ring—width listing routine. Bivariate distribution tables indicated that for each species annual ring widths correlated highest with certain periods of precipitation. Analyses of variance permitted the evaluation of relative similarities and differences of tree—growth response and indicated past stand disturbances as well as the effects of climatic and edaphic influences. Pine has greater tree—to—tree variability on clay soils than on cherty soils. Oaks have more tree—to—tree variability on cherty soils. Analyses of variance also indicated that black oak generally responded more to climatic influences than to other factors of the environment.