The Dendrochronology Lab of the Royal Institute for Cultural Heritage specialises in research into and dating of movable and immovable wood. Its team offer three complementary services: dendrochronology, the identification of wood species and dendroarchaeology, i.e. the archaeology of wood.
Specialists in wood dating
Museums, local authorities, churchwardens, private collectors: anyone can call upon the lab's expertise, namely, dating wood in movable and immovable heritage items from 500 BC to the present day.
Dr Christophe Maggi, dendrochronologist: "Sampling is done on-site, at the restoration location, in the museum or private homes. Even wood structures that are difficult to reach, such as roof structures, pose no problem, as we work with safety ropes."
The dendrochronology team comprises art historians, archaeologists and archaeological scientists. The mix of profiles guarantees a solid scientific foundation for our findings. We also work closely with other experts within our institution, such as the Radiocarbon Dating Lab, the Monuments and Monument Decoration Lab, the art historians and the conservation-restoration studios.
Our knowledge and skills also take us abroad for research or to exchange experiences and expertise with other dendrochronologists, art historians and archaeologists.
Dendrochronology is a wood-dating technique that uses the growth rate of annual tree rings. The experts can determine when a tree was felled for use in wooden sculptures, panel paintings, buildings, carpentry or violin making, for example. In optimal conditions, this dating process is accurate to within half a year.
Dr Pascale Fraiture: "A dendrochronological analysis provides more than just dating information. It can also reveal the wood's geographical origin, enabling us to reconstruct trade networks, for example, and provides information on forestry (the type of wood used and its use in the structure or artwork)."
How we proceed depends on the type of object and its condition. A typical dendrochronological study includes:
- prior expertise
- sampling: via coring, sawing or with digital macro photos (a non-invasive method used for artworks, among others)
- preparation of the samples and measurement of the year rings
- synchronisation of the dendrochronological series
- interpretation of the results and contextualisation
- an illustrated report with the complete protocol of the analysis, the results of the research and the dendrochronological data.
Dendrochronology can be applied to a variety of objects:
- movable heritage: panel paintings, sculptures, musical instruments, manuscripts, furniture, industrial machines, etc.
- architectural heritage: roof trusses, floors, panelling, stairs, carpentry, etc.
- archaeological heritage: remains of buildings, artefacts, wells, boats, etc.
Identification of wood species
Most wood species have their distinctive anatomical structure. Some can be identified based on a macroscopic examination, without sampling, such as oak, elm and beech. Other species require microscopic examination in our laboratory.
"This is done using a sample with a width of about 1 centimetre", says Armelle Weitz. "If sampling is done by our experts and combined with a macroscopic analysis of the object, a sample of a few millimetres is sometimes enough to identify the wood."
The Royal Institute for Cultural Heritage specialises in identifying European wood species in archaeological objects (dry wood, wet wood and charcoal) and works of art (sculptures and painted panels).
An archaeological study can complement a dendrochronological study. This research is carried out by analysing the wood traces and studying the metal elements present.
Sarah Cremer: "We look for traces and markings on and in the wood. This gives us a better insight into how the object was produced."
- the various phases of the design and the execution
- the tools and techniques used
- the management and use of the wood resources on the construction site or in the workshop (e.g. the number of logs used or reused)
- the history of the structure or the object (repairs, interruptions in work)
The research can also be based on metal elements, such as fixtures and nails. These often provide additional information we cannot obtain based on the wood alone. An example: later adaptations to a building structure, in which the original wood was reused. In doing so, we go beyond pure dating and succeed in reconstructing the techniques and know-how of the past.