Sustainable Wood from Mass Timber, with Dr. Paul Mayencourt

How Sustainable Wood Helps Mitigate the Impact of Climate Change Sustainable wood refers to the use of mass timber, which involves smaller pieces of wood that are dried and glued together in a perpendicular, crosswise pattern to form large slabs. This process can incorporate a closed-loop system that repurposes wood, promoting a circular practice that minimizes wood waste and reduces landfill usage, transportation needs, and carbon emissions. Additionally, the wood retains the carbon absorbed by trees during their growth, storing it in the floors and walls of buildings. As infrastructure demands increase, sustainable wood offers an environmentally friendly solution to meet these needs. Why the Construction Industry Needs Sustainable Wood Sustainable wood, particularly through the use of mass timber, is gaining recognition as a critical climate solution in the construction industry. Traditional building materials like concrete and steel are carbon-intensive to produce, responsible for nearly 8% of global carbon emissions. In contrast, mass timber is derived from a renewable resource: trees. Through responsible forest management, trees can be harvested and replanted in a sustainable cycle, allowing forests to continue absorbing carbon dioxide. The wood used in mass timber stores this carbon long after the trees are cut down, effectively sequestering it in the walls, floors, and structures of buildings for decades or even centuries. This makes sustainable wood not only a viable building material but also a carbon sink, helping reduce the overall carbon footprint of new construction. The production of mass timber involves using smaller, fast-growing trees that are often thinned from forests to maintain ecological health. These pieces of wood are dried and glued in layers, forming large, strong panels that can be used for walls, floors, and even entire building frames. This technique reduces waste by making use of smaller trees or leftover wood that might otherwise be discarded. Additionally, mass timber is much lighter than steel and concrete, reducing the energy needed for transportation and lowering emissions from construction sites. The process can also incorporate repurposed or recycled wood in a closed-loop system, further contributing to the circular economy and minimizing waste. The climate benefits of sustainable wood go beyond carbon storage. Timber construction has a much lower embodied carbon than steel and concrete, which require energy-intensive processes to extract and manufacture. By substituting these materials with mass timber, builders can reduce carbon emissions by up to 70%. In regions where sustainable forestry practices are employed, this approach also supports local ecosystems by preventing deforestation, protecting biodiversity, and encouraging the regeneration of forests. Importantly, mass timber’s design allows for prefabrication, which reduces construction time and waste, making it not only a greener option but also an economically competitive one. As cities and communities around the world grapple with the need for affordable housing while also addressing climate change, sustainable wood provides a promising solution. By scaling up the use of mass timber in mid- and high-rise buildings, the construction sector can reduce its reliance on carbon-heavy materials, sequester large amounts of carbon, and promote sustainable forest management practices. This integration of environmental, economic, and social benefits positions sustainable wood as a key player in the transition toward a low-carbon future. The Future of Sustainable Wood: Making Construction Faster and Greener  Sustainable wood, especially when derived through the use of mass timber, offers a range of environmental, economic, and structural advantages over traditional building materials. From a structural standpoint, mass timber is both strong and lightweight, making it a highly versatile material. It has a high strength-to-weight ratio, allowing it to be used in large, multi-story buildings while reducing the overall load on foundations and minimizing transportation costs. Additionally, mass timber is more fire-resistant than many people realize; when exposed to fire, the outer layer of the wood chars and insulates the inner core, slowing down the spread of fire and maintaining the building’s integrity for longer than some steel structures. This combination of strength, fire resistance, and flexibility gives mass timber a competitive edge in construction. Economically, sustainable wood offers cost-saving opportunities through faster construction times and less material waste. Mass timber panels can be prefabricated off-site, reducing the time spent on construction and the labor costs associated with traditional methods. This efficiency not only lowers the overall cost of building but also minimizes disruption in urban areas. Furthermore, the use of repurposed or recycled wood supports a circular economy, where resources are reused rather than discarded, reducing the environmental impact and fostering a more sustainable construction industry. As demand for sustainable and affordable housing rises, mass timber presents a compelling, eco-friendly alternative to conventional building practices. One of the most significant benefits is its ability to sequester carbon. Trees naturally absorb carbon dioxide from the atmosphere as they grow, and this carbon remains stored in the wood even after it’s used in construction. By utilizing wood in buildings, the carbon is locked away for the lifespan of the structure, helping to reduce overall greenhouse gas emissions. In contrast, materials like concrete and steel release large amounts of carbon during their production, contributing to climate change. This makes mass timber a powerful tool in the fight against global warming, especially when paired with sustainable forestry practices. Sustainable Wood Skepticism Despite its many advantages, the use of sustainable wood and mass timber as a building material does have some drawbacks and criticisms. One primary concern is the reliance on sustainable forestry practices. If forests are not properly managed, large-scale timber harvesting can lead to deforestation, habitat destruction, and biodiversity loss. The success of mass timber as a climate solution depends on responsible sourcing, including replanting trees to maintain the carbon-absorbing benefits of forests. Unsustainable logging practices or overharvesting could negate the environmental benefits of mass timber by releasing more carbon into the atmosphere and harming ecosystems. Another challenge is the perception of wood’s durability and fire safety. While mass timber is engineered to be fire-resistant, some critics remain concerned about its performance in large-scale buildings. Public perception and regulatory hurdles can be barriers to adoption, as many building codes and fire safety standards are based on traditional materials like concrete and steel. These regulations may need to be updated to reflect the true performance of mass timber, but in the meantime, they can slow down its widespread use in urban construction. Additionally, there are economic concerns, particularly regarding initial costs. While mass timber can reduce construction time and labor costs, the price of sustainably sourced wood can be higher than that of conventional materials, especially if demand outstrips supply. The infrastructure for large-scale mass timber production is still developing, and until it reaches full maturity, the material may remain more expensive and less accessible than concrete or steel, limiting its adoption in some markets. Over time, these challenges may be addressed, but they highlight the need for careful planning, regulation, and investment in the mass timber industry. Who is Our Guest? Dr. Paul Mayencourt is a researcher and educator at studying low-carbon design solutions in architecture. He does much of his work in the Wood Lab at the University of California, Berkeley between the Department of Architecture and the Department of Environmental Science, Policy, and Management. Dr. Mayencourt specializes in mass timber, structural design, and structural optimization. ResourcesUC Berkeley: Forest to frame: Paul Mayencourt bridges forest management and sustainable constructionAmerican Wood Council: Mass TimberUC Berkeley: Continuing Berkeley’s legacy in forest productsVox: The hottest new thing in sustainable building is, uh, woodSeattle Business Magazine: Cross-laminated Timber: the Future of Building?Further ReadingUrban Machine: https://urbanmachine.build/Hardware to Save a Planet: Podcast with Co-Founder of Urban MachineWashington Post: Forget the log cabin. Wood buildings are climbing skyward — with pluses for the planet.Swedish Wood: A global solution for a locally active industryDalberg: A Forest Economy for the Future: Generating social and economic dividends from more sustainable, circular sources For a transcript, please visit https://climatebreak.org/sustainable-wood-from-mass-timber-with-dr-paul-mayencourt/