The Importance of Analysing Waterlogged Wooden Artefacts and Environmental Conditions when Considering their In Situ Preservation

The importance of analysing the state of preservation of waterlogged wooden artefacts as part of the in situ monitoring programme at the Iron Age site of Nydam is discussed. Determination of density, wood cell wall components (cellulose and lignin), coupled with macroscopic and microscopic analysis showed that artefacts were completely degraded, and that it was only the lignin rich compound middle lamella and water in the cell wall and lumen which retained the shape of the artefacts.Erosion bacteria (cellulose degraders) were identified as the main cause of deterioration of the wood. With no cellulose remaining, and under the prevailing conditions, it is unlikely that the wood can act as a substrate for further microbial deterioration. One of the major threats to the future preservation of wooden artefacts is drainage. Experiments to simulate the effect of desiccation on artefacts showed that there was the possibility of fungal deterioration by white rot species, yet more seriously, artefacts would suffer immediate collapse with loss of archaeological information.