• The Decomposition of Tree-Ring Series for Environmental Studies

      Cook, Edward R.; Tree Ring Laboratory, Lamont-Doherty Geological Observatory, Palisades, New York (Tree-Ring Society, 1987)
      Signal extraction in tree-ring research is considered as a general time series decomposition problem. A linear aggregate model for a hypothetical ring-width series is proposed, which allows the problem to be reduced to the estimation and extraction of five discrete classes of signals. These classes represent the signals due to trend, climate, endogenous disturbance, exogenous disturbance, and random error. For each class of signal, some mathematical/statistical techniques of estimation are described and reviewed. Except for the exogenous disturbance signal, the techniques only require information contained within the ring-width series, themselves. A unified mathematical framework for solving this decomposition problem has not yet been explicitly formulated. However, the general applicability of ARMA time series models to this problem and the power and flexibility of state space modelling suggest that these techniques will provide the closest thing to a unified framework in the future.
    • A Dendrochronological Study of Cryptomeria Japonica in Japan

      Kojo, Yasushi; Department of Anthropology, University of Arizona, Tucson, Arizona (Tree-Ring Society, 1987)
      Living specimens of Cryptomeria japonica D.Don var. radicans Nakai collected in western Japan were analyzed to evaluate the research potential of this tree species for future development of dendrochronology and dendroclimatology in Japan. A sufficiently strong correlation of tree growth with climatic factors was obtained in the residual chronology in which the variance due to autocorrelation was removed. It was also revealed that regional average climatic data are strongly correlated with tree growth. Thus, Cryptomeria japonica appears to have a promising potential for chronology- building and climatic reconstruction in Japan.
    • The Summary Response Function of Cedrus Atlantica (Endl.) Carriere in Morocco

      Till, Claudine; Catholic University of Louvain, Laboratory of Palynology and Tree-Ring Research, Belgium (Tree-Ring Society, 1987)
      This paper presents the synthesis of all the response functions computed on Cedrus atlantica (Endl.) Carrière in Morocco. More than a thousand tree-ring width series collected in 40 sites have been used. At every site, a distinction has been made between young adult trees and old adult trees. Response functions have been calculated on the mean raw ring widths by using the multiple linear regression model of Guiot (Guiot et al. 1982). Among the variables selected to determine the response of Cedrus to climate, the precipitation of autumn and winter and the temperature of January, April, August and September play the leading part in explaining the ring-width variations.
    • Trackways and Tree Trunks - Dating Neolithic Oaks in the British Isles

      Morgan, R. A.; Litton, C. D.; Salisbury, C. R.; Dendrochronology Laboratory, Department of Archaeology and Prehistory, The University, Sheffield, England; Tree Ring Dating Laboratory, Department of Mathematics, The University, University Park, Nottingham, England (Tree-Ring Society, 1987)
      The Midlands and South-west of England are represented by a long oak tree-ring chronology spanning approximately 4500-3900 BC (calibrated radiocarbon dates). The wood on which it is based originates in a technologically advanced trackway crossing the low-lying Somerset Levels, in a coastal submerged forest probably killed by rising sea-level, and in flood-plain oaks washed down the River Trent. Cross-matching between the growth patterns of the three groups of trees is of good quality, yet so far the chronology has failed to cross-date with the long Irish and German dated chronologies. The reasons for this, and the implications of eventual dating, are discussed.