How an integrated diagnostic approach can help in a correct evaluation of the state of preservation of waterlogged archaeological wooden artefacts

Artefacts made of wood coming from archaeological excavations provide insights into human cultural behaviour of the past. They show how man utilised natural resources and how the development of woodworking techniques and artistic endeavour were developed. Within archaeological contexts, waterlogged anaerobic conditions generally preserve the appearance of artefacts, although wood is subject to severe decay processes. The said conditions can transform the original material into a new one, thus demonstrating specific differences from those of the "fresh" wood of the same species. In order to assess these new properties correctly, an integrated diagnostic approach is needed, one which includes a multidisciplinary (micromorphological, physical and chemical) evaluation of the state of preservation. This paper reports several diagnostic results regarding wood artefacts coming from a series of archaeological excavations carried out in Italy. Different types of artefacts - ships, furniture, foundation piles, etc. - that date to different eras (Roman times, the Middle Ages, the Renaissance) have been included in this study. In addition, several species of wood at different levels of decay were analysed. Our study provides evidence of how a multidisciplinary approach, based on anatomical (micromorphological), physical and chemical analyses, avoids goes beyond the limits of each single type of analysis, thus contributing to a complete and reliable evaluation of the state of preservation of these archaeological artefacts.