Botany provides a tool for defeating art fraud

Some of the most well-known classical musicians are violinists, and they can be many times younger than the violins they play. Some of the best violins in the world are antiques and, if a violin is authentic, it can be worth millions. But that attracts counterfeiters. ABC News reports that: “Interpol says art theft is a crime exceeded in dollar value only by drug trafficking, money laundering and arms dealing. Estimates have put the losses at $4 to 6 billion worldwide.” There are ways of authenticating artefacts, but these often involve taking a sample and destroying it in a controlled manner. It takes a certain kind of curiosity to find out that your Stradivarius was worth $15 million. A few recent publications have highlighted how botanists, specifically dendrochronologists who examine tree rings, can help with authenticating a violin. It’s not entirely straightforward, as Paolo Cherubini reports in Science.

The basis of the method is down to how trees grow. As children learn, trees add a growth ring each year, but not all rings are the same. Some years are better than others. That means that the rings can grow a bit like a barcode with a series of good, bad or average years. If you have enough trees, you can build something like a very long barcode recording the climate into the past. For a wooden artefact, like a violin, if you can find the outermost ring, you can say the artefact cannot be older than that date.

As Cherubini points out, that’s not quite the same as dating a violin. Once the wood is chopped down, it could be years before it’s made into something. However, if you’re being sold a seventeenth-century violin, and the tree rings say the wood was growing in the eighteenth century, you can be sure it’s a fake.

This happened in 1999 when Stewart Pollens dated the youngest ring on the Messiah Stradivarius to 1738. This date was controversial as the date for the violin was thought to be 1716. This date was later retracted, though Cherubini says it’s not clear why. Later analyses set a date of 1682 for the wood, so a 1716 date may be feasible for the violin. However, it’s still open for debate. In May 2021, in Mediterranean Archaeology and Archaeometry, Michael Schwartz has said the best match is 1700. The problem, he says in his article, is that the Messiah may have been made during a period when the tree rings were not that distinctive.

It’s not just Stradivari that dendrochronologists can help with.

Mauro Bernabei recently reported on how dendrochronology can not just date an instrument in the journal Heritage Science. It can also locate where the wood came from and help identify who made it. He found an uncatalogued violin and identified who made it and where, from images sent via WhatsApp. The violin’s owner was fortunate as their violin was a twin of another violin produced by Giuseppe Guarneri filius Andreae.

If you’re sceptical of authentication by social media, Bernabei can show how working from digital images allowed him to use the same computerised analytical tools that he could have, just as if he had the violin in front of him.

In the Journal of Cultural Heritage from March-April this year, Lauw and colleagues report on a dendrochronological study of Portuguese violins and cellos. The study is possibly complicated because Portuguese luthiers (makers of stringed instruments like violins or guitars) used imported wood. Their study found that many instruments in the collection were correctly attributed, but two seventeenth-century violins were made of eighteenth-century timber. They also found some violins made of wood a couple of centuries older than their assumed date. However, that doesn’t automatically mean that they’re forgeries. They state that the luthier(s) could have chosen older wood deliberately for its qualities.

This gap between felling and construction is a factor that Cherubini highlights in his Science article. “It is important for musicians and art collectors to know how much confidence they can place in the dendrochronological authentication of fine violins. Dendrochronological dating does not provide an absolute date for the creation of a work of art. Indeed, dendrochronology cannot provide information about how many years passed between the time the tree was felled and when it was crafted into an instrument, nor can it indicate how much of the outermost wood was lost when the wood was crafted. Wood may also be stored and used later. Dendrochronological dating can only identify the date before which the instrument was certainly not made.”

While it’s not a silver bullet for defeating fraudsters, the data encoded in a violin case is another security measure that can help support or reject a date for a violin – if you can read the tree rings like a dendrochronologist.