A Re-evaluation of the Use of Maximum Moisture Content Data for Assessing the Condition of Waterlogged Archaeological Wood

Maximum moisture content (Umax) “profiles” were producedthroughout cut cross-sections of waterlogged archaeologicaloak, poplar and pine timbers, and the distribution ofvalues compared to visible degradation patterns. Attemptswere then made to classify the degree of degradation ineach timber. Where appropriate, comparisons were madewith the established classification scheme of de Jong(1977), for waterlogged archaeological oak. Numerical classificationschemes were investigated after statisticallyanalysing Umax data ranges for each of the three species.Moisture content profiles from all timber sections reflectedvisible degradation patterns, supporting the use of Umaxdata as an indicator of preservation state. Incorporatingnumerical data in to a classification system presentedpotential problems, as large ranges of values were commonwithin individual timbers. Numerical schemes were suggestedhowever, by incorporating two ranges of Umax values,which separate well preserved and degraded regionsrespectively. Umax ranges were unique to the individual speciesstudied and a generalised scheme was not possible. Ageneric classification system based on visual appearanceor physical examination is proposed, by modifying de Jong’sscheme for European oak, which compares relative proportionsof well preserved versus degraded material.Collectively, results provide reference data for assessingsimilar timbers, where large destructive samples cannot betaken.