New types of resins could open the door to the widespread use of hardwoods in cross-laminated timber in America’s Upper Midwest.
It comes as researchers are developing new products and creating supply chains that could drive decarbonisation across the country’s heartland.
The upshot is that Michigan—known for its auto industry—could develop hardwood CLT from local forests in the next few years, helping the state to achieve its new “My Healthy Climate Plan.”
Already used in tropical climates, including Southeast Asia, where hardwood CLT needs to be rot-resistant, researchers are testing ‘temperate’ hardwoods, including sugar maple, red maple, yellow poplar, yellow birch, white ash, and red oak, to determine if local timbers can help drive America’s tall timber boom in the Upper Midwest.
That is according to Mark Rudnicki, director of the Hardwood Mass Timber Institute at Michigan Teach, who is leading a team looking to turn the state’s low-value hardwoods into high-value construction products.
By the numbers, trees in Michigan’s Upper Penisula vastly outnumber people – and of more than 8.8 million acres (or 3.5 million hectares) of forested land, 70% are hardwoods. “That’s a lot of potential CLT,” Professor Rudnicki said.
“I couldn’t put a number on when it is going to be on the market,” Professor Rudnicki said, “But I don’t think it is good to characterise it as competing with softwood” – which is less expensive and easier to work with.
Instead, hardwood-based CLT is just a diversification of wood as a building material: “The point is that we want to use all of the biobased material that we can replace carbon-intensive materials like concrete and steel.”
According to George Berghorn, a construction management and sustainable wood construction professor at Michigan State University, “The issue of hardwood versus softwood CLT is getting the manufacturing process right so that we can develop a panel that can be certified as structurally sound.”
That’s why Michigan Tech researchers are working with different types of resins on different tree species, using different pressures across different timespans. “That’s what gets tested and codified into the manufacturing standard, which then gives us the ability to have a certified, stamped, structurally sound product,” Professor Berghorn said.
In March, Wood Central reported that mass timber construction could increase between 25 and 40-fold across the US, which, subject to adoption, could generate a 20% carbon benefit to the economy.
The report, published by the University of Georgia, The Potential Use of Mass Timber and Associated Carbon Benefits in the United States, found that the surge in timber builds will be fuelled by the South (43%), followed by the West (23%), the Midwest (21%), and the Northeast (13%).
However, to maximise the “carbon benefit,” local supply chains are a must, according to Sandra Lupien, the director of Mass Timber @ MSU. Ms Lupien—a member of the International Mass Timber Conference steering committee—is working to map supply chains of hardwood CLT and its implications for Michigan and the Great Lakes region.
She said that while Michigan Tech focuses on the “hard science” of hardwood CLT, Michigan State is working on bringing it and the general principles of mass timber to the industry. If successful, this would bring a “job bonanza” to northern Michigan, along with its lumber yards and managed forests, slashing transportation emissions in the process.
Wood Central understands that the push to embrace mass timber intensified after the Michigan Democrats swept the governorship and both houses during the 2022 mid-term elections. Governor Gretchen Whitmer is now targeting mass timber in the Healthy Climate Plan.
“The Michigan Democrats has pledged $500,000 over five years to enhance sustainable mass timber construction and manufacturing in the state, aiming to utilise further the $20 billion-plus forest products industry to boost the economy while also working toward achieving net-zero carbon emissions by 2050,” according to field analyst Tori Irving – who spoke to Climate News last month.
“This continued partnership will support research on potential manufacturers, finding suitable manufacturing locations, and identifying optimal products to meet Michigan’s needs.”
As for the next steps, Hardwood CLT must be approved by the North American Manufacturing Standard, a process that Professor Bergeron estimates is still several years away.
“When approval comes, I think it will be good for the economy in the states where you have hardwood in the markets,” Raju Pokharel, a professor of forest economics at MSU, said. “When there’s more demand, the prices can go up a little bit, but I don’t think it will have much of an impact [on] wood prices.”
- To find out why the US government is turning to mass timber to achieve net-zero construction, visit Wood Central’s special feature. To find out how researchers and engineers in the northeast are now turning to Eastern hemlock to make new types of cross-laminated timber, click here.
