James, P., 2002b. “The Dendrochronology Debate”, Minerva: International Review of Ancient Art and Archaeology 13:4, 18 (original) (raw)

Every archaeologist's dream is a dating technique which can date finds to a precise year, and of all available methods dendrochronology comes nearest. In an ideal case bark will still be preserved and dendrochronology can tell us the exact year when the wood was felled. But while this might work well for prehistoric posts or firewood, matters are not so easy for artefacts where carpenters and sculptors have shaved off an unknown number of tree-rings. For this reason dendrochronology usually only offers a terminus post quem, a date after which the artefact was made. All the same, the fact that dendrochronology deals in real, exact calendar years makes it more 'tangible' than radiocarbon, which can only express dates as a broad range in terms of statistical probability. To know that the last tree-ring in an artefact dates to 899 BC is far more rewarding than learning that it grew sometime between 1020 BC and 830 BC (at 95.4% probability). One reason for the vagueness in radiocarbon dating is that the amount of carbon 14 produced in the atmosphere (and hence absorbed by living organisms) has not remained constant. It is dendrochronology that has provided the key to this puzzle: by measuring amounts of C14 in well-dated tree-rings we can calibrate radiocarbon results. Hence the double importance of a sound dendrochronology.