Mad River Mass Timber (MRMT) has become California’s first commercial producer of dowel-laminated timber (DLT), a type of mass timber developed with guidance from Assistant Professor Paul Mayencourt and the UC Berkeley Wood Lab. The company is using this technology to transform waste wood from local forests into construction-ready building panels.
DLT differs from traditional lumber in that it can be made from a wide variety of wood species, including those typically unsuitable for construction, such as red fir, hemlock, and Ponderosa pine. It also allows for the use of fire-damaged timber, providing a new commercial outlet for material that previously had little value.
Mayencourt explained the environmental significance: “It’s essential that we reimagine how we build.” He noted that DLT avoids chemical adhesives by using wooden dowels as connectors, making it completely recyclable. Unlike steel and concrete, mass timber is a renewable resource that stores carbon within buildings for their lifespan.
The adoption of mass timber products like DLT could help shift the construction industry away from materials with high greenhouse gas emissions. According to research published in Building and Environment, mass timber buildings have been found to reduce global warming potential by an estimated 39–51% compared to similar concrete structures and 28–34% compared to steel-based buildings. However, another study indicated that the average embodied energy in mass timber buildings is 23% higher than in reinforced concrete alternatives.
Previously, California builders sourced most mass timber products from out-of-state suppliers in Washington or Canada. This reliance on long-distance transport increased the carbon footprint associated with these materials. With MRMT now producing DLT locally using wood sourced from California forests, there is potential to reduce these transportation emissions and support low-carbon construction methods within the state.
George Schmidbauer, MRMT President and fifth-generation sawmill operator, described his motivation: “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 pointed out that traditional cross-laminated timber production would require significant investment and adaptation of local sawmills due to differences in available lumber types. After visiting UC Berkeley Wood Lab and observing small-scale DLT fabrication led by Mayencourt’s team, Schmidbauer identified DLT as better suited for California’s resources.
Through collaboration between academia and industry—including design input from Mayencourt’s team—MRMT developed its own equipment for large-scale production of prefabricated floors, roofs, walls, and beams made with DLT. These efforts included referencing existing building codes when writing design guides for their products.
Sourcing wood through forest health projects also helps reduce wildfire risk by removing biomass that could otherwise fuel fires while creating economic incentives for ongoing forest management efforts. “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.”
In addition to supporting sustainable forestry practices, MRMT is collaborating on prefabricated kits aimed at rapid affordable housing development—a move intended both to address California’s housing crisis and support rural economies through job creation where timber is harvested.
“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.”
