Building with Intentionally Sourced Wood on a Grand Scale
Rendering of the new main terminal by ZGF Architects
The Portland International Airport’s new main terminal opens on August 14, 2024! And with it, the region begins to see that building with sustainable, local wood is possible – even for very large projects.
The remodel of the main terminal is the largest public construction project in state history in dollars spent – and at nine acres, it’s one of the largest mass timber roofs in the nation by square footage. The building designers (ZGF Architects) and their client (Port of Portland) started asking early on: Can we build this in a way that is better for our communities, local economies, and the environment?
The answer was yes, but it requires a new way of doing business.
“The team involved in redesigning and rebuilding the Portland International Airport’s new main terminal is changing the industry by sourcing wood for the project locally and tracking where that wood came from, who produced it, and how it was harvested,” said Paul Vanderford, senior director of wood markets for Sustainable Northwest, a conservation nonprofit in Oregon and Washington. Vanderford was part of that team.
For most of the construction industry, lumber is anonymous, which makes sense when you consider that most people want a single, consistent product. But there’s power in knowing where wood comes from and how it's harvested. “At arms-length, people said it could not be done at this scale. The secret was approaching suppliers with an open mind, building relationships, and celebrating the values that emerged from the creative process,” Vanderford said.
In the airport’s ceiling lattice and roof, 3.5 million board feet of wood are being used.
The roof was built with two engineered products: mass plywood panels and glulam beams. Both can withstand heavy weights and are fire-resistant.
100% of the wood for the roof and ceiling came from local forests within 300 miles of the airport.
96% of the wood for the roof and ceiling came from sustainably managed forests, which project managers defined as either (1) certified by the independent Forest Stewardship Council, or (2) directly traced back to foresters practicing ecological forest management that go above and beyond local regulations.
“We can have healthy forests, a healthy economy, and beautiful, sustainable buildings,” Vanderford said. “Builders around the world are taking notice of this project, and more companies are starting to ask not only, can we build this with wood, but also, where does the wood come from? They are realizing that they can support climate health, community health, equity, clean water, and wildlife with their building material choices.”
FAQs about wood sourcing for the Portland International Airport remodel
Why haven’t other projects pursued this kind of sourcing and tracking before?
The reasons more projects haven’t pursued transparent sourcing and/or ecological sourcing are complex. In current sourcing practices, wood rarely goes directly from a forest to the end user. Instead, harvested wood is typically delivered to a log yard where it is mixed in with wood from a variety of forests – effectively ending its traceability. By the time the wood reaches the end user, it has gone through many hands, divorcing the product from the land in which it grew, and any connection to that landowner’s forestry practices.
Disrupting this business-as-usual process is challenging, but as we learned on the PDX main terminal, not impossible. It took an incredibly driven client in the Port of Portland, a whole lot of conversations with mills and landowners, and several years to procure wood in this manner.
We also learned from the PDX process that transparency is on a spectrum. Project teams can make one small step toward transparency relatively easily by asking where their logs are coming from, or they can hire a third-party wood advisor like Sustainable Northwest to explore similar direct sourcing pathways piloted by PDX.
Our hope is that by sharing our approach for the airport, we can inspire and make it easier for more projects to follow suit and ask where their wood comes from.
Why couldn’t we achieve 100% sustainable sourcing for the roof?
Transparent sourcing had never been achieved at this scale before, and many initially said it couldn’t be done because of how the supply chain works. While many mills source a portion of their wood from sustainably managed forests, very few have the incentives and systems for tracking it. Logs that arrive at a mill are processed quickly and rarely segregated based on landowner source. When a project needs a certain product at a certain time, they are largely limited to what is available at that moment.
It took several years, and a whole lot of conversations with mills and landowners, to procure wood in this manner for PDX. In the case of the glulam, our first purchase from Zip-O Log Mill took place before our sourcing infrastructure was fully in place. This is why 5% of the glulam is not certified or traceable. Once we had the criteria established, Zip-O Log Mill worked closely with us on meeting the sourcing criteria and we achieved 100% for remainder of purchase – 95% of the glulam or nearly 2 million board feet.
For the lattice, we were able to achieve 100% sustainable sourcing because of our project partners. And were are able to track the wood all the way from forest to frame because our lumber mill partners – Elk Creek Forest Products, Manke Lumber, and Kasters Kustom Cutting – all agreed to segregate, store and deliver the lattice wood separate from other wood product.
What is a board foot?
Board foot is a common unit of measurement in the timber industry. It represents a volume of wood that is one foot long, one foot wide, and one inch thick.
What is a mass plywood panel?
Mass plywood panel, or MPP, is a newer engineered wood product. MPP is fabricated by pressing and gluing together layers of veneer or thin sheets of wood, similar to how plywood is made but on a larger scale. It can be used in similar applications as other mass timber products.
What is Glulam?
Glulam, or glue-laminated timber, is a type of mass timber product. It is made by gluing several layers or dimensional lumber, or lamstock, together to form a single, strong wood beam of column. Lamstock is a common term for wood used to make glulam.
Where is the lattice in the ceiling from?
All 600,000 board feet of the lattice came from direct sourcing procurement methods. That means we can track from forest-to-frame for the 11 different landowners that lattice wood is sourced from. Direct sourcing approaches also allowed us to work closely with the supply chain to target specific landowner types or harvest criteria to better influence where our wood came from. This was one of the key innovations of our sourcing strategy.
How does this project support healthy forests?
Forest health can have different meanings to different people based on various management approaches and as with most things about forestry, it’s on a spectrum.
In general, if the current regulatory standards ensure a certain amount of forest health, then we can say that PDX provides additional forest health benefits because our project’s criteria goes above and beyond the regulatory threshold.
Our sourcing criteria supports forestry practices that increase forest complexity and diversity, two of the key components for maximizing healthy forests. In many cases, our direct sourcing approaches procured wood from forests at the farthest end of the spectrum—the ones practicing forest restoration or other harvest practices that prioritize forest health over economic efficiency.
What are some examples of forests that were in better condition after the harvest?
Hyla Woods: The forest management approach for Hyla Wood is focused on is moving their forests towards more ecologically complex forests, including multi-age and multi-specifies trees. Harvest includes thinning of lower grade trees to retain high quality stands and small patch harvests.
The Nature Conservatory Cle Elum/Central Cascades Forest: TNC is actively restoring these dry, mixed-conifer forests to their natural densities and spatial configurations that are more resilient to wildfire. Before TNC stepped in, these stands had been over-harvested by large private companies. This, combined with over a century of fire exclusion on the landscape, led to a very unhealthy, overcrowded forest conditions with less resilient, fire-prone tree species like Douglas fir. Post-harvest, this forest is back on track to the low intensity, frequent-fire cycle that prunes the forest, instead of killing the old growth ponderosa pines with the large-scale megafires that we’re seeing more frequently in this region. TNC is also using prescribed fire, a difficult fuels reduction strategy to implement (from both a public perception and cost perspective), but recent studies have shown that the most effective wildfire resilience treatment combines mechanical thinning with prescribed fire. Note: The Yakama forest management is very similar to this dry-side restoration approach.
Chimacum Community Park (Jefferson County landowner): This harvest focused on hazard tree removal of an overcrowded stand where large trees are being killed by Laminated Root Rot. Harvesting these overstory hazard trees has opened up the canopy to encourage understory development and stand diversity. Western red cedar and other hardwood species not susceptible to root rot are prioritized for retention, thus creating a healthier and more resilient species composition for the forest. These species will also benefit from better understory development when small openings are created through hazard tree removal.
