A simple Bayesian approach to tree‐ring dating

Abstract

Tree-ring dating involves matching sequences of ring widths from undated timbers to dated sequences known as 'master' chronologies. Conventionally, the undated timbers (from a building or woodland) are sequentially matched against one another, using t-tests to identify the relative offsets with the 'best' match, thus producing a 'site' chronology. A date estimate is obtained when this is matched to a local master chronology of known calendar age. Many tree-ring sequences in the UK produce rather low t-values and are thus declared not to have a 'best' match to a master chronology. Motivated by this and the routine use of Bayesian statistical methods to provide a probabilistic approach to radiocarbon dating, this paper investigates the practicality of Bayesian dendrochronology. We explore a previously published model for the relationship between ring widths and the underlying climatic signal, implementing it within the Bayesian framework via a simulation-based approach. Probabilities for a match at each offset are produced, removing the need to identify a single 'best' match. The Bayesian model proves successful at matching in both simulated and real examples.