Mad River Mass Timber (MRMT), a company based in Humboldt County, has become the first in California to commercially produce dowel-laminated timber (DLT), drawing on research from the UC Berkeley Wood Lab led by Assistant Professor Paul Mayencourt. The company uses waste wood from forests to manufacture construction-ready panels, marking a shift toward more sustainable building practices in the state.
DLT panels differ from traditional lumber as they can be made from various wood species, including smaller or weaker trees like red fir, hemlock, and Ponderosa pine. These trees are typically unsuitable for standard construction but can be combined to create strong DLT panels. Additionally, fire-damaged timber, which previously had little commercial value, can now be used in these products.
This approach is expected to foster a new manufacturing sector in California that supports forest health and climate goals while also addressing economic concerns. By enabling faster and more efficient construction methods, DLT may help alleviate California’s ongoing housing shortage.
“It’s essential that we reimagine how we build,” said Mayencourt. He noted that mass timber products such as DLT lock away carbon for the lifespan of buildings and avoid chemical adhesives by using wooden dowels as connectors. This makes DLT completely recyclable.
The use of mass timber is seen as an alternative to concrete and steel—materials responsible for significant global greenhouse gas emissions. According to studies published in Building and Environment, mass timber buildings can reduce global warming potential by 39–51% compared to similar concrete structures and by 28–34% compared to steel structures. However, one study also found that mass timber buildings have an average embodied energy 23% higher than reinforced concrete alternatives.
Previously, builders had to source mass timber from outside California, increasing environmental costs due to transportation. MRMT’s local production reduces this impact and could play a key role in promoting low-carbon construction within the state.
George Schmidbauer, MRMT President and a fifth-generation sawmill operator, said: “When I learned about mass timber in college, I knew it was something I wanted to pursue. The market was gaining momentum and there was increasing demand for locally sourced materials to address California’s wildfire and forest health issues.”
Schmidbauer observed that traditional facilities for producing cross-laminated timber (CLT) require substantial investment and do not suit most California lumber without costly modifications. After seeing small-scale DLT experiments at UC Berkeley Wood Lab, he decided DLT would best meet his goals of forest stewardship and low-carbon construction at scale.
He began collaborating with Mayencourt on scaling up DLT production for local markets. “Initially, I acted in a consulting capacity, working to help develop the DLT process,” said Mayencourt. “George and I would have weekly calls, sharing ideas and troubleshooting.” They received support through a grant from the Joint Institute for Wood Products Innovation.
To meet demand efficiently, MRMT built its own machine for making DLT using standard components. The company now produces prefabricated floors, roofs, walls, and beams suitable for various types of construction projects.
Sourcing wood for these products involves removing biomass from forests—including national forests and tribal lands—as part of wildfire mitigation efforts. This process turns what was once an expense into revenue while reducing wildfire risks across California’s landscapes.
“With DLT, we can put lower-value wood into panels and engineer around that species’ reduced structural capacity,” said Schmidbauer. “This means we can connect forest restoration and wildfire mitigation to the low-carbon construction economy in more ways than previously possible.”
Schmidbauer’s background in affordable housing development has led him—alongside Mayencourt—to work on prefabricated kits aimed at speeding up multifamily housing projects using sustainable materials like DLT. Their early projects are underway as MRMT seeks additional partners focused on sustainable development.
The company expects its growth will stimulate job creation within Humboldt County communities where both harvesting and processing occur locally. “The entire process is optimized for local economic and environmental benefit,” Schmidbauer added.
“Seeing MRMT scale up the manufacture of DLT is exciting,” said Mayencourt. “With one relatively low-tech innovation, we can tackle forest health, wildfire risk, the housing crisis, and struggling rural economies. We can start to fulfill our commitment to reduce greenhouse gas emissions for the future of our planet.”
