As wood is now used in an increasingly wide range of constructions, it is essential to know the precise qualities of this material. Jean-Bernard Litzler
Uncovering all the secrets of wood without actually touching it—that is the ambition behind this technology developed by the French-Swiss company CBS-CBT. Named Sylvatest, it acts as a true X-ray of wood, determining its physical and mechanical properties without causing damage. The test can be carried out in the forest, at a sawmill, or on existing buildings. This solution was created and refined over nearly 15 years by French-Swiss engineer Jean-Luc Sandoz, a former researcher and professor at the Swiss Federal Institute of Technology in Lausanne (EPFL) before founding several wood-related companies.
From the beginning, the device has relied on ultrasounds transmitted through the tested piece of wood, measuring and analysing their propagation speed. Combined with extensive research in materials engineering, these data make it possible to establish a precise identity card of the mechanical properties of the examined element. Correlated with the density and stiffness of the wood, this ultrasonic travel time enables an estimation of the material’s mechanical resistance and its modulus of elasticity (its stiffness against deformation).
This technology has attracted highly diverse users across the world. It is particularly valued for heritage restoration projects. For the reconstruction of Notre-Dame de Paris, the selection of the best oak trees for the spire’s timber frame was carried out at the sawmill using Sylvatest. The same process was applied at Beijing’s Forbidden City, where numerous columns and beams were examined. The method is also used on high-value wooden objects: aircraft manufactured by the French company Robin Aircraft, spruce baseball bats, and even in violin making, such as with the centuries-old spruces from the Risoux forest, renowned for their acoustic qualities.
The company continues to innovate, now equipping its flagship device with Bluetooth for easier handling and even more comprehensive diagnostics. In promising markets, the technology is used on large-scale projects to examine wooden utility poles, railway sleepers, and more recently for securing copper-mine galleries in Chile, sorting wooden poles in Africa, and selecting structural timber in Northern Europe. According to CBS-CBT, examining wood upstream allows optimal grading and, in the best cases, could double the lifespan of selected pieces compared with ungraded materials.
The latest development: deployment of the test in Malaysia. This market is particularly attractive, given that the country has nearly 3,000 different wood species, compared to just over 120 in Europe. This diversity opens up major opportunities for enhancing tropical woods as close as possible to their mechanical and structural potential. A new field of exploration enabling Jean-Luc Sandoz and his company to put their motto into action: listening to the material without ever harming it.
