• An Issue Devoted To Southeastern Dendrochronology Editor's Note

      Leavitt, Steven W.; Tree-Ring Society (Tree-Ring Society, 2009-01)
    • Preface: An Introduction To Dendroarchaeology In The Southeastern United States

      Grissino-Mayer, Henri D.; Laboratory of Tree-Ring Science, Department of Geography, The University of Tennessee–Knoxville (Tree-Ring Society, 2009-01)
      Dendroarchaeology has a discontinuous history in the Southeastern United States, mostly because of misconceptions (the Southeast is too mesic), bad sampling practices (no standard protocol exists for preserving prehistoric wood samples), and a lack of reference tree-ring chronologies long enough to date wood from the abundant prehistoric sites. The majority of archaeological applications in recent years has focused on the dating of historic sites and structures to verify the documented year(s) of construction largely in response to requests from historical agencies to verify when a particular structure was built. We have found that most structures are one to two generations younger than their reported date(s) of construction, but most agencies find this information useful as tree-ring dating lends historical credibility to any site. The future of dendroarchaeology in the Southeast is encouraging but many more trained experts are needed to meet the demand of dating historical structures and sites. Furthermore, once a sampling protocol becomes standardized for retrieving wood from prehistoric sites, the potential for absolute dating of these sites is enormous given that abundant wood is archived in locations throughout the Southeast.
    • Progress In Constructing A Long Oak Chronology From The Central United States

      Stambaugh, Michael C.; Guyette, Richard P.; Missouri Tree-Ring Laboratory, Department of Forestry, University of Missouri–Columbia (Tree-Ring Society, 2009-07)
      We describe methods and progress in developing the American Long Oak Chronology (ALOC), an effort to construct an oak tree-ring chronology from the Central US that spans the Holocene. Since 2000, we have collected and measured ring widths on over 550 pieces of subfossil oak (Quercus) wood. Over 330 oak samples have been radiocarbon dated, with ages ranging up to 14,000 cal yr B.P. A 1,093- year-long tree-ring record has been constructed from live and subfossil bur oaks (Q. macrocarpa Michx.) and swamp white oaks (Q. bicolor Willd.) growing along and buried in sediments of streams that flow through northern Missouri and southern Iowa, USA. Here we describe the ALOC for the period A.D. 912–2004 to demonstrate its dendrochronological value, display the material quality, and emphasize the importance of chronology construction. We also report on progress in developing older floating chronologies. The development of more long, multi-millennium chronologies will be an important contribution to dendroclimatology. These chronologies will be particularly useful to the Central US, a region with a continental climate and limited temporal depth of annually resolved paleorecords. Perhaps more critical is its location in the middle of one of the most important agricultural regions in the world.
    • Research Communication: An International Tree-Ring Isotope Data Bank- A Proposed Repository For Tree-Ring Isotopic Data

      Csank, Adam Z.; Laboratory of Tree-Ring Research, University of Arizona (Tree-Ring Society, 2009-07)
      The International Tree-Ring Data Bank (ITRDB) is an invaluable resource, providing access to a massive and growing cache of tree-ring data. Oxygen, carbon, nitrogen and hydrogen isotope treering studies, which have provided valuable climatic and ecological information, have proliferated for decades so an ITRDB expansion to include isotopic data would likewise benefit the scientific community. An international tree-ring isotope databank (ITRIDB) would: (1) allow development of transfer functions from extended isotopic data sets, (2) provide abundant tree-ring isotopic data for meta-analysis, and (3) encourage isotopic network studies. A Europe network already exists, but the international data bank proposed here would constitute a de facto global network. Associated information to be incorporated into the database includes not only the customary ITRDB entries, but also elements peculiar to isotope chronologies. As with the current ITRDB, submission of data would be voluntary and as such it will be crucial to have the support of the tree-ring isotope community to contribute existing and forthcoming isotope series. The plan is to institute this isotope database in 2010, administered by the National Climatic Data Center.
    • Tree-Ring Dating Of Old-Growth Longleaf Pine (Pinus Palustris Mill.) Logs From An Exposed Timber Crib Dam, Hope Mills, North Carolina, U.S.A.

      Van De Gevel, Saskia L.; Hart, Justin L.; Grissino-Mayer, Henri D.; Robinson, Kenneth W.; Laboratory of Tree-Ring Science, Department of Geography, The University of Tennessee; Department of Anthropology, Wake Forest University (Tree-Ring Society, 2009-01)
      On 26 May 2003, intense rainfall from a series of thunderstorms in eastern North Carolina caused flooding that eventually destroyed the concrete dam in Hope Mills, draining Hope Mills Lake, and revealing a formerly submerged and buried structure that was identified as a timber crib dam. Inspection revealed these logs to be old-growth longleaf pines, which are now rare on the coastal plain landscape. Our primary objective was to develop a new multi-century longleaf pine tree-ring chronology by crossdating the tree rings from sections extracted from logs in the crib dam with an anchored tree-ring chronology created from nearby living longleaf pine trees. We also examined the climatic response in the longleaf pine trees to evaluate their potential for reconstructing climate. Using tree-ring measurements obtained from old-growth longleaf pines found at a nearby church, we were able to date the rings on 21 series representing 14 logs from the crib dam, spanning the years 1597 to 1825. Distorted sapwood in many of the logs prevented us from finding absolute cutting dates and lessened the strength of correlation during the period of overlap between the church series and crib dam series. Human disturbances, specifically related to the naval stores industry, likely influenced the growth-ring patterns of the crib dam pine samples, as well. Correlation analyses between the longleaf pine chronology and temperature, precipitation, Palmer Drought Severity Indices, and North Atlantic sea surface temperatures showed a significant response to cool and wet spring months.
    • Variance Stabilization Revisited: A Case For Analysis Based On Data Pooling

      Fowler, A. M.; School of Geography, Geology and Environmental Science, The University of Auckland (Tree-Ring Society, 2009-07)
      The traditional approach to standardizing tree-ring time series is to divide raw ring widths by a fitted curve. Although the derived ratios are conceptually elegant and have a more homogenous variance through time than simple differences, residual heteroscedasticity associated with variance dependence on local mean ring width may remain. Incorrect inferences about climate forcing may result if this heteroscedasticity is not corrected for, or at least recognized (with appropriate caveats). A new variance stabilization method is proposed that specifically targets this source of heteroscedasticity. It is based on stabilizing the magnitude of differences from standardization curves to a common reference local mean ring width and uses data pooled from multiple radii. Application of the method to a multi-site kauri (Agathis australis (D. Don) Lindley) data set shows that (a) the heteroscedasticity issue addressed may be generic rather than radius-specific, at least for some species, (b) variance stabilization using pooled data works well for standardization curves of variable flexibility, (c) in the case of kauri, simple ratios do not appear to be significantly affected by this cause of heteroscedasticity, and (d) centennial-scale variance trends are highly sensitive to the analytical methods used to build tree-ring chronologies.