Iron Age wood usage at an enclosure in northern Germany

The first known Iron Age enclosure in the northern German state of Schleswig-Holstein was discovered in 2010. Archaeological excavation revealed a trench, a palisade and an occupation layer. The function of the wall and trench system remains unknown but there are several possibilities: It could have been used for protection, as a type of symbolic separation or to demarcate a cult site. The enclosure was constructed around the year zero. Charcoal samples were taken in a spatially detailed manner during excavation, as well as a new pollen core from a small spring mire directly next to the site. Anthracological analysis showed that Quercus (oak) was the main type of wood used in the construction of this enclosure. Thirteen additional wood taxa were identified, of which the next best represented is Corylus (hazel) and surprisingly a significant amount of Ilex (holly) was found. The samples did not contain Fagus (beech) or Carpinus (hornbeam), which are both common in the area today. According to pollen data, Fagus had begun to establish in the local woodland during the time of the enclosure, but did not gain importance before the migration period. By diameter analysis of the charcoals the size of the used wood (branch or trunk) was reconstructed. In addition, mean annual tree ring widths of the used wood - especially Quercus - show that the wood comes from young stems and/or branches of older trees and probably not from coppiced wood. The study shows that even small-scale archaeological excavations can yield important new data on wood utilization with a high spatial precision, which contributes to the reconstruction of local woodland composition.