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

Abstract

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.

Microstructural and Chemical Characteristics of Archaeological White Elm (Ulmus laevis P.) and Poplar (Populus spp.)

“…The deposition of inorganic elements in the wood structures during the service life and storage periods might be an additional reason. These findings are almost in agreement with the previous studies on the chemical compositions of archaeological oak and elm wood samples [43][44][45][46]. Values labelled with the small letters show the statistical differences between recently cut and archaeological specimens (ANOVA, Fisher's LSD test, p < 0.05).…”

“…The band at 1733 cm −1 , which is assigned to the stretching vibrations of the unconjugated C=O group and specific moieties, such as esters, had disappeared in the archaeological elm and poplar. This could be related to the strong degradation of hemicelluloses after the ageing process [41,45,48]. Both archaeological elm and poplar samples exhibited considerably higher absorption in the region between 1235 and 1646 cm −1 .…”

Heavy metals content in ashes of wood pellets and the health risk assessment related to their presence in the environment

“…Generally, the ash content for wood is often less than 2% 42 . However, under incomplete combustion due to unburnt organic material, high values of ash content could be obtained, etc.…”

Essential Oils as Alternative Biocides for the Preservation of Waterlogged Archaeological Wood

“…Through the action of extracellular enzymes that depolymerase the wood cell walls’ polymers (lignin, cellulose, and hemicelluloses), these microorganisms produce different decay forms that can be grouped in three main categories soft, brown, and white rot [ 1 , 2 , 3 , 4 , 9 , 10 ]. Microbial degradation patterns and cell wall polymers degradation have been widely studied and characterized through microscopic, chemical, and physical analyses [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”