• The Bootstrapped Response Function

      Guiot, J.; Laboratoire de Botanique Historique & Palynologie, UA CNRS (Tree-Ring Society, 1991)
      The bootstrap procedure provides a way to test the significance of the regression coefficients and the stability of the estimates in response functions generated by regression on principal components. A subroutine RESBO, which calculates a bootstrapped response function, has been added to Fritts' program PRECON.
    • Dendrochronology of Abies Religiosa in Michoacan, Mexico

      Huante, Pilar; Rincón, Emmanuel; Swetnam, Thomas W.; Centro de Ecología, UNAM, Ciudad Universitaria, México; Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona (Tree-Ring Society, 1991)
      An exploratory investigation of tree growth and climate relationships in Abies religiosa from Michoacan, Mexico, produced the first crossdated and standardized tree-ring chronology from the North American tropics. Pearson correlation coefficients and principal components response function analysis were employed. Results indicate that ring-width series from this species have moderately high signal-to-noise ratio (S/N = 13.42). A substantial percentage of the ring-width signal can be explained by instrumented monthly climate data, particularly spring precipitation and winter temperature. Although correlation between climate data and the tree-ring measurements indicate that growth of Abies religiosa is highly influenced by year-to-year climate variation, longer climate records and tree-ring chronologies are needed from this tropical region to improve understanding of climate -tree growth relationships, and for dendroclimatic reconstruction.