A review of analytical methods for assessing preservation in waterlogged archaeological wood and their application in practice

Waterlogged archaeological wood can present management challenges due to its vulnerability to chemical and biological decay, both during burial and post-excavation. Decay processes also often leave it severely weakened and therefore susceptible to mechanical damage. Quantifying preservation and understanding active decay mechanisms is therefore critical in informing the management of this unique cultural resource. It is critical that assessments of preservation are robust, and sensitive enough to allow changes over time to be detected. A wide range of analytical methods can be applied to assess the state of preservation of waterlogged archaeological wood, and determining which of these is most appropriate to the circumstances can be challenging. This review summarises some of the most commonly reported methods suitable for the analysis of waterlogged archaeological wood, ranging from widely used ‘low-tech’ methods, to assessment using advanced analytical instrumentation. Methods are evaluated in terms of the information gained weighed up against their cost, logistical considerations, and time investments, with the aim of supporting the development of an analytical strategy. We conclude that although an analytical strategy must be informed by the aims of assessment as well as any external restrictions, the best available analytical techniques should be employed in order to supply an accurate baseline against which future change can be measured. Critically, a multi-analytical approach is vital in obtaining a clear picture of the present state of decay, as no single technique gives the best assessment.