What makes a Stradivarius violin so special? Scientists traced it to one forest in Italy.
A new tree-ring study solves the mystery of where the famed instrument-maker Anton Stradivari sourced timber for his violins during his “golden age.”
Stradivarius violins are famous for their craftsmanship and sound. Made by Italian violinmaker Antonio Stradivari during the 18th century, their renown means these instruments change hands for large sums, too. The “Baron Knoop”, created during Stradivari’s ‘golden age’ between around 1700 and 1725, sold for $23 million last year.
One feature of these violins that makes their sound so famous is the instruments’ soundboard, sometimes called a top plate, which vibrates and amplifies the sound as strings are played. The density, stiffness, and consistency of the wood all affect the quality of the sound, shaping its richness, brilliance, and dynamic range. Yet the source of the resonant wood used for Stradivari’s soundboards has been a mystery.
In one popular tale, a violinmaker approaches a man building a hut high in the forests of the Italian mountains. The luthier has found the perfect tree for crafting his instruments, but it’s destined for use elsewhere. After some bartering, the hut-builder sells the wood for a hefty sum, and it becomes part of musical history. Where exactly this supposed interaction took place is unclear, though, as strikingly similar tales have emerged from the forests of Slovenia and Switzerland.
A new analysis of tree rings from hundreds of violins indicates the Italian tale may bear some truth. The study, published last February in the journal Dendrochronologia, suggests the violins Stradivari made during his "golden age" came almost exclusively from Norway spruce (Picea abies) growing in Italy’s Val di Fiemme forest in the Dolomite Mountains.
“This is comprehensive, and especially in terms of dating and the origin of the wood, very clear,” says Valerie Trouet, a dendrochronologist from the University of Arizona who was not involved in the study. “I do think that’s put one chapter on this Stradivari controversy to bed.”
History written in tree rings
Through the scientific analysis of tree rings, known as dendrochronology, scientists can see where, when, and how a tree grew.
As trees grow, they leave behind one ring per season. The width of the rings varies each year, however, due to factors such as soil, climate, and altitude. Rings can tell scientists about the climate a tree has grown in and how closely trees grew to each other. While each tree is unique, neighboring trees tend to show similar patterns over time.
In the new study, researchers investigated 314 tree-ring patterns from 284 Stradivari violins, measured by the late British dendrochronologist John Topham over several decades.
Through a statistical analysis, they compared the violin tree rings to each other to see whether any of the instruments had been constructed from the same tree. To estimate the altitude the trees grew in, they compared the ring patterns to references in the International Tree-Ring Data Bank, a large repository with records from over 6,000 sites around the world. They then used an algorithm to cluster the violin ring patterns into similar groups.
To find the origins of the wood, the study authors then compared these groups to nearly 200 master chronologies of trees growing across Europe.
Because there are not many tree records from the period Stradivari was making his violins, the researchers had to rely on chronologies built from wood found in historical buildings and archaeological digs. This adds some uncertainty, the authors note, because the wood used for these ancient buildings may have been imported from elsewhere.
“If it's a local farmhouse from the 17th century, you can assume that it didn't come from very far, especially if it's in a forested region, but you don't know that for sure,” says Trouet. “Despite those limitations, they still found this very precise provenance.”
The findings revealed the origins of the violin soundboard woods and traced the shape of Stradivari’s craftsmanship over time.
Roughly a third of the samples fell into a group thought to be crafted before 1706, during Stradivari’s early years. The wood in these violins appears to have come from a mix of sources and forests across the Alps.
“At the beginning, he was experimenting,” thinks Mauro Bernabei, a researcher from the Italian National Research Council and lead author of the study.
Only later during his golden age, the analysis showed, did Stradivari begin sourcing wood from the Italian Dolomites.
Another transition occurs after around 1720, when Stradivari's production began to dwindle. Here, the data suggest other trees, including silver fir (Abies alba) may have been used from unclear locations.
Signs of a colder climate
Stradivari violins are notable for their many, narrow rings, suggesting the trees grew in colder conditions at high altitude. Intriguingly, the results suggest that some of the Norway spruce Stradivari used grew at higher altitudes than any do today.
This, the authors suggest, aligns with a hypothesis that the trees Stradivari’s sourced for his violins grew during an abnormally cold spell on Earth known as the Maunder Minimum. Stunted growth under cold conditions may have changed the wood’s tonal quality.
“If your tree rings are small, the wood tends to be more dense,” says Bernabei. But it could also create wood that is more homogeneous, without fiber deviation or defects, such as knots, he says.
Many of the samples also appear to have been sourced from the same trunk, too, suggesting optimal wood was kept in storage for many years. Closely matching patterns were found in instruments that, according to their labels, were created up to 20 years apart.
“The characteristics of the spruce top are crucial,” says Sam Zygmuntowicz, a violin maker from New York. “Having wood from a good and consistent source is very helpful,” he adds.
In future work, Bernabei would like to explore how the Maunder Minimum affected tree ring formations elsewhere. Future dendrochronological research on other violins from the same period could also reveal whether Stradivarius violins were uniquely made from this Italian-growing spruce or if other craftsmen used the same wood.
“It would be interesting to see this kind of comprehensive work for other violin builders, either from this time or another,” says Trouet, “to see whether they were as smart as Stradivari to zone in on one area.”
