[LUM#7] Wood for Tomorrow
The oldest material in the world is now considered one of the most modern. As a renewable natural resource, wood offers extraordinary mechanical properties. And it is by far the most eco-friendly of all materials…
Furniture, transportation, construction, civil engineering, aerospace, and even robotics: whether visible or hidden, rustic or high-tech, solid or processed, it’s everywhere! Is this the great comeback of wood? It’s only just beginning, promises Bernard Thibaut, a researcher at the Laboratory of Mechanics and Civil Engineering (LMGC). And for good reason:“Like metal and polymers, it’s one of those universal materials with which you can make just about anything you want,” says , a researcher who has been studying the biomechanics of trees and the properties of wood for 40 years (Wood Machining with a Focus on French Research Over the Past 50 Years, in Annales des sciences forestières, 2016).
Reference material
This material, as old as humanity itself, has nevertheless fallen out of favor in recent times. Humans have long embraced an “all-wood” lifestyle: since our arrival on Earth, almost everything around us has, for a long time, come from the bounty of trees. Until it reached its peak in the18th century: a golden age when wood, having become a universal material, permeated the human sphere more than ever before.
Then came the Industrial Revolution, and the triumph of its rivals: the19th century was the age of steel, the20th that of concrete and plastic. And the21st century? It is the era of a renaissance for wood, asserts Bernard Thibaut.“Wood took its time, but it has finally made the transition to modernity. This timeless material is now being rediscovered thanks to the technological advances it has benefited from.”
New industrial applications
“While wood is making a strong comeback, it’s in new forms,” confirms Cédric Montero.“Historically, we’ve used raw wood for a very long time,” summarizes this researcher specializing in structural timber at the LMGC. “The current boom in wood, particularly in construction, is largely due to new processing methods: plywood, glued laminated timber, cross-laminated timber, and products that make use of wood chips or sawdust , such as particleboard or fiberboard…”(Feasibility of Glulam Beams Using Tropical Hardwoods, B. Thibaud, 2013)
A revolution. By breaking free from the limitations imposed by its original form, wood has transitioned from craftsmanship to the industrial age. It can now be used for virtually any purpose. This engineered wood is, in fact,“comparable to a fiber composite,” the researcher continues: a standardized, reproducible material. Used today even in high-tech applications, it offers excellent mechanical performance: it is every bit as good as its artificial cousins—fiberglass, carbon fiber, or Kevlar—over which it holds a major advantage: its lightness, due to its microscopic honeycomb structure.
The current trend is to combine wood with these same materials—or with others, such as steel—in composites whose structure depends on the desired results. The end result is performance far superior to that of any single component.“This is a field with vast potential: we are only at the beginning, and many technological innovations are yet to come.”
Sturdy, lightweight… and fire-resistant!
Man’s oldest ally is thus proving to be a promising material, capable of turning any industrialist into a staunch advocate of wood.“Recent innovations have sparked a real shift in mindset,” notes Bernard Thibaut. Building quickly using prefabricated modular structures? Wood’s lightness makes it possible. Building massive towers? It’s possible! The race to the sky is on: new industrial wood-based materials support buildings exceeding 20 stories. And they offer performance ideally suited to seismic loads…
Wood construction, which until now has been relatively uncommon in France for cultural reasons, is therefore gaining ground.“Perceptions of this material have changed, particularly regarding fire risks: just a few decades ago, it was unimaginable to build large-scale structures out of wood. Its fire resistance is now being reevaluated.” Less heat-conductive than steel or concrete, wood burns slowly without warping or releasing toxic substances.
Eco-friendly fiber
Wood’s greatest strength lies elsewhere: this gift of the forest is inherently eco-friendly. Abundant and underutilized—particularly in France, which nonetheless has thefourth-largest forest area in the European Union—wood is a renewable and inexpensive resource that requires little energy to process. And while the production of steel, concrete, aluminum, or plastic generates greenhouse gases, wood can actually help reduce them: trees naturally capture and store carbon dioxide (CO2)—a gas responsible for global warming—at a rate of one ton per cubic meter. CO2 directly removed from the atmosphere… and all that remains is to store it, in the form of wooden furniture or buildings. If wood is making a major comeback, it is therefore against the backdrop of sustainable development: using it as a material means fighting the greenhouse effect. It’s a must.
30,000 different varieties
“There are at least as many types of wood as there are tree species—more than 30,000 species worldwide! Each has its own properties, which can vary by a factor of 1 to 100 depending on the specific variety,” explains Bernard Thibaut. The key is to combine different species for the best results. This practice is particularly relevant in construction. Even in its raw form, wood—a versatile material—thus offers an extraordinary range of possibilities. As for its mechanical properties, they are “naturally” of great interest (Physical and Mechanical Properties of Reaction Wood, in The Biology of Reaction Wood, 2013):“Let’s not forget that wood built a tree—that is, a particularly daring structure: few architects would dare attempt such a feat!”
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