Characteristics of a 13th century oak (Quercus sp.) foundation sill from the archaeological excavations in the Old Town of Elbląg

This article is the first and so far only research on the properties of the 13th century oak wood from the Elbląg old town. The extraction of this scarce material made it possible to carry out complex research into the properties of oak wood used for construction purposes. Experiments were conducted to determine the chemical composition and structural, physical, and mechanical properties of archaeological oak wood. The small average ring width indicates that wood came from trees growing in natural forests. The anaerobic conditions and a high groundwater level in which the wood had remained had modified its properties. The chemical composition has changed slightly, mainly due to the extraction of water-soluble substances. The wood has a high density due to the penetration of inorganic substances, confirmed by the high ash content, and a high shrinkage. Most of the properties studied are statistically significantly correlated with wood density.