A stepwise multidisciplinary approach to determine the date and provenance of historical wooden objects

We present a stepwise multidisciplinary approach combining woodworking expertise, dendrochronology, DNA genotyping and radiocarbon dating to determine when, where and how historical wooden objects were made. The effective implementation of this approach is demonstrated with a set of wooden stocks from the Rijksmuseum collections in Amsterdam (the Netherlands). In 2019, preceding an exhibition about slavery, stocks made of oak (Quercus sp.) were donated to the Rijksmuseum. The history of the object was unknown, and a stepwise approach was devised to determine the date and potential place of its manufacture, and whether they were made in the context of Dutch colonial slavery. Pencil marks and tool traces found on the surface of the wood are characteristic of traditional woodworking techniques and indicated that the stocks were processed after 1800 C.E., from fresh wood, shortly after the felling of the tree, and in one go. The tree-ring analysis revealed that the beams originate from the same tree, and that the tree grew in a dense forest. However, it failed to return an exact date for the wood and, consequently, also to determine its provenance. Therefore, we decided to employ DNA-genotyping and radiocarbon dating. The retrieval of DNA was successful, and the results placed the provenance of the wood in an area covering a broad latitudinal transect in central Europe. Radiocarbon wiggle matching, modelled with sapwood statistics for central Europe, revealed that the tree was likely cut between 1791 and 1824 C.E. These results combined suggest that the stocks were produced in the first quarter of the 19th century, using local wood, at a small rural town somewhere in Italy, the Pyrenees, eastern France, Belgium, the Netherlands, Germany or even further north (Denmark, Sweden). While their association with slavery in colonised territories seems unlikely, their production in the context of the Dutch colonial system cannot be ruled out. Therefore, they are valuable historical objects worth being curated and exhibited at a national museum. The stepwise approach here presented can be applied to other large objects at museum collections. We encourage curators, conservators and restorers to consider its implementation to maximise knowledge acquisition and appreciation of wooden cultural heritage.