Reliability and Repeatability in Dendrochronological Analysis: Tests Using the Fletcher Archive of Panel‐painting Data

Abstract

Research into the dates of timber used for art‐historical objects has provided a large data set on which to test standard dendrochronological techniques. Some 177 sets of tree‐ring measurements, originally analysed by the late Dr J. M. Fletcher at Oxford University, have been re‐examined independently in the tree‐ring laboratories at the University of Sheffield and the Museum of London Archaeology Service. The results show a high level of agreement between the laboratories. In contrast, many of the dates produced by Dr Fletcher for the paintings are not confirmed. The two different approaches described here also resulted in remarkably similar internal groupings of the dated material. These groupings probably reflect the provenance of the timbers and suggest that two different areas of the eastern Baltic supplied the bulk of the material with smaller quantities of panels originating in Britain and central Europe.

Provenancing Baltic timber from art historical objects: success and limitations

“…Nearly 80% (430 out of 540) of all the tree-ring series from this art historical database could be dated against standard Baltic master chronologies Baltic1 and Baltic2 [21], and East-Pomerania [19]. Averaging tree-ring series from the same tree, displaying high inter-correlation and excellent visual agreement, reduced the original data set down to 390 series.…”

“…Well known Baltic master chronologies, computed from tree-ring series of art historical objects, were built by Bauch [2] and Eckstein et al [18]. Using tree-ring series measured on panel paintings Hillam and Tyers [21] established the Baltic1 and Baltic2 chronologies. For dating purposes these master chronologies have proved to be extremely useful.…”

Late Gothic Altarpieces as Sources of Information on Medieval Wood Use: A Dendrochronological and Art Historical Survey

“…Correlation matrix (t BP -values) of all trees that were used to carve at least two sculptures (see Table 1). Each tree is also compared with the "Baltic1" reference chronology (Hillam & Tyers 1995) and the "Altarpieces" chronology, which is computed from all tree-ring series that could be dated against the Baltic references.…”

“…The majority of the recorded treering patterns (71 out of 84 dated sculptures) display high correlations with the standard Baltic reference chronologies. For instance, the trees that provided the wood for several related sculptures (see Table 1) are compared with the Baltic 1 reference chronology (Hillam & Tyers 1995) and a new chronology (Altarpieces) that is computed as the average series of all recorded tree-ring series that could be dated against Baltic reference chronologies. The corresponding t BP -values for both reference chronologies are listed in Table 2 and are in most cases higher than 6.0.…”

“…The object chronologies and all individual sequences were then compared to European reference chronologies. Chronologies composed of tree-ring series from southern Belgium (Hoff-summer 1995), Germany (Hollstein 1980;Becker 1981) and France (Bernard 1998) as well as Baltic/Polish reference chronologies (Wazny 1990a;Hillam & Tyers 1995) were consulted. For the Baltics, a dense network of local and site chronologies (for definitions see Kaennel & Schweingruber 1995) has recently been assembled .…”