• Tree-Rings and Sunspot Numbers

      LaMarche, Valmore C., Jr.; Fritts, Harold C.; Laboratory of Tree-Ring Research, The University of Arizona (Tree-Ring Society, 1972)
      Tree-ring series that record climatic variation have long been of interest for study of possible effects of solar variability on terrestrial phenomena. Spectral analysis, harmonic dial analysis, digital filtering, cross-correlation and principal component analysis were used separately and in combination in an attempt to detect relationships between the annual Wolf sunspot numbers and ring-width indices, primarily from western North America. The results show no evidence of significant, consistent relationships between tree-ring data and sunspot numbers.
    • Tree-Ring Research in Europe

      Eckstein, D.; Institute for Wood Biology, The University of Hamburg (Tree-Ring Society, 1972)
      In the last ten years tree-ring analysis in Europe and its application has been extended considerably. By varied methods, a number of chronologies have been established for conifers and deciduous trees from different climatic regions that partly reach back to periods before the birth of Christ. The focus of dendrochronological research is usually dating and climatological studies are carried on only sporadically.