Bridging technology and culture: X-ray µCT-based wood identification of Sub-Saharan African heritage

Wood identification of cultural heritage objects is vital for facilitating their international travel, providing invaluable information for conservation strategies and improving our understanding of the objects’ historical and cultural context. To date, wood identification is most commonly performed using techniques that rely on sampling, which is especially undesirable for valuable cultural objects. X-ray micro-tomography (µCT) offers a non-destructive alternative for gaining insight into the material composition of objects. It is a tool for identifying the wood species by visualizing the internal wood structure without changing the object. However, obtaining sufficiently high-resolution anatomical images that can be used for identification remains a challenge, particularly when examining diverse heritage objects.

This study applies µCT for the wood identification of 20 heritage objects from the Royal Museum for Central Africa (RMCA, Belgium), showcasing the efficacy of this non-invasive technique. Despite variations in the size, shape, and material composition of the objects, successful wood identification was achieved for all objects. Since two objects contained more than one wood species, the total number of identifications was 22, of which 18 were to the species level. For the four remaining samples, wood identification was achieved at the genus level (3 samples) or identified as a liana (1 sample).

Additionally, by obtaining a wood identification through X-ray µCT images, the physical and mechanical properties of the wood species were discussed in relation to the objects' original context and function. Specifically, lightweight wood species were found in objects with a portable function such as masks and a toy, while low-durability wood used in a funerary object could be linked to its symbolic role. Two musical instruments were identified as being made from wood species known for their acoustic qualities. These findings highlight the significant potential of advanced non-destructive imaging using µCT for wood identification, providing much-needed material and contextual insights into previously understudied museum collections.