Susan Jones: Washington's Forests - East of the Cascades...The Evolution Of CLT
CLT is an engineered wood product. By that, I mean that it is a product assembled from pieces of lumber, usually two-by-sixes, eight feet wide, 40' feet long, layered at right angles to one another, like the layering of thinly sliced veneer used to make sheets of plywood. Picture a laminated wood beam, with the layers all running one direction. Now remind yourself that, in CLT, the layers run at right angles to one another, like plywood. The product is incredibly strong for its weight, which is about one-third that of steel. Some refer to CLT “plywood on steroids.” It’s a very apt description.
13 MINUTE READ
Susan Jones is a Seattle architect with deep and remarkably instructive roots In Pacific Northwest forests.
When Ms. Jones was a small child, four decades before she founded her Seattle design firm, her grandfather, Rogan Jones, bought 141 acres of cut-over timberland on Orcas Island, a Puget Sound hideaway about 100 miles northwest of Seattle.
She was only five at the time, so her memories of the plat are vague, but she does recall that it was “kind of ugly.” It no doubt was. Most of the 57 square-mile island had been clear-cut around 1900 to help feed the Puget Sound’s already enormous lumber industry. Early harvesting records indicate parts of the island were logged again in the 1940s, probably in support of our World War II armed forces.
Wars consume enormous amounts of wood. Some 90 billion board feet were harvested from privately owned timberlands in the Pacific Northwest and Southeast during the Second World War – so much that President Franklin Roosevelt only reluctantly approved the harvest which, while necessary, undoubtedly exceeded forest growing capacity.
The tract Mr. Jones purchased was atop Mount Constitution, at 2,400 feet the highest point in the spectacular San Juan Islands chain. He planted fir, pine and spruce on the plot, no doubt believing that the land would someday yield a fine crop of harvestable timber.
But when Ms. Jones and her family revisited the site, some 45 years later, they discovered, much to their dismay, that his hard work had been overrun by opportunistic hemlock, an abundant and prolific tree species that had naturally reseeded the area so quickly that the spruce, pine and fir that her grandfather had planted was soon overtopped by competing hemlock.
“It was a great lesson for all of us,” Jones said when we visited her office in August. “Without monitoring and management, naturally reseeding hemlock, simply erased my grandfather’s hard work. His planted forest needed careful management – and sunlight - that it never got.”
At the recommendation of San Juan County, Ms. Jones’ mother hired Rain Shadow Consultants, a highly regarded Orcas Island forestry consulting firm to write a forest management plan for the property, thin and harvest the small diameter Western Hemlock, and replant Douglas fir and Western White Pine as quickly as possible.
“They were about as green as you could get,” Ms. Jones says of Rain Shadow’s foresters. “So their land management philosophy was a comfortable fit for our family. We were able to revive my grandfather’s plan.”
The replanting was a spectacular success. Of 800 Douglas-fir seedlings planted in 2014, 768 survived two winters on the often windswept island. Rogan Jones’ forest redux is well on its way, and Ms. Jones’ mother definitely got her money’s worth from Rain Shadow Consultants.
Ms. Jones has written a fascinating and well-illustrated paperback book titled “CLT Investigations,” in which she tells the story of her family’s Orcas Island Tree Farm and its unexpected convergence with her design firm’s ambitious focus on using cross-laminated timbers [CLT] in a two-story Seattle area house [her own, constructed to BUILT GREEN 5-Star standards] and a Bellevue, Washington church.
Although U.S architects are typically trained to design and build using steel and concrete, there is fast developing interest in using Austrian-developed CLT because it sequesters carbon [steel and concrete do not] and because wood products consume far less energy in their manufacture and use than do steel or concrete. CLT-framed buildings 12-14 stores tall are already in service in several European cities, giving rise to the phrase, “plywood on steroids.” Suffice it to say, Europe is far ahead of the United States in CLT-related technology and innovation.
In her ongoing CLT-related research, the Harvard-educated Ms. Jones is working with graduate students at the University of Washington’s College of Built Environments, which trains them for careers in design, planning, production and the sustainability of physical and natural environments.
In this interview, she discusses her commitment to CLT’s environmental advantages – among them the fact that it can be manufactured from small diameter trees of the kind that scientists say must be removed from overcrowded, diseased and dying central and eastern Washington forests in order to slow the advance of catastrophic wildfires that are quite literally consuming Washington’s way of life.
Evergreen: Ms. Jones, you have the distinction of having built the first house in Seattle constructed entirely from cross-laminated timbers. What inspired your initial interest in CLT?
Jones: Probably its carbon sequestration powers. Mitigating climate change is a matter of increasing concern in the architectural world, as we architects are the ones specifying materials for our buildings. Carbon emissions from buildings constitute a huge amount of our climate change issues. And CLT holds significant potential for reducing the carbon footprint associated with buildings. And, in Canada and Europe they are building them up to 18 stories tall.
Evergreen: Many architects shunned wood-frame construction for years out of a fear that timber harvesting was an unsustainable activity. What was the prevailing view when you were an architecture student at Harvard?
Jones: The very first project I worked on was a design using wood. All the rest used concrete, masonry or steel structure.
Evergreen: And yet we know that wood is the only renewable structural building material on earth, and that wood products consume far less energy in their manufacture and use than do products made from steel or concrete.
Jones: All true, but it has taken some time to break through all of the misinformation and disinformation surrounding forest practices and timber harvesting. CLT only first came on the market in Austria, Germany and Switzerland in the late 1990s.
Evergreen: Where did you first see cross-laminated timbers in use?
Jones: I worked in Vienna, Austria as a young architect. The Austrians are leading the way in CLT manufacturing, design and use. I was especially impressed by their ability to manufacture high quality CLT components from small diameter trees that are carefully thinned from forests in Austria. The Austrians are very good foresters. Their forests are very impressive.
Evergreen: They are indeed. You tell the story of your family’s introduction to forestry in a beautiful little book you recently wrote titled CLT Investigations. Would it be fair to say that the failure of your grandfather’s small forest on Orcas Island contributed in some small way to your interest in CLT?
Jones: I suppose so, though I was very young when my grandfather purchased his tract. What had more influence on me was what I learned in the course of our family’s commitment to pick up where he left off. As you suggest, his initial planting failed for lack of hands-on management. As a family, we decided to replant the tract. We hired Rain Shadow Consultants. It was that experience that really opened my eyes to forestry’s great possibilities.
Evergreen: You do a very nice job of weaving your family’s forestry experience into your CLT odyssey. First, there are your childhood memories of what you saw on Orcas Island, which take on new life when you revisit the island decades later; you grow up near Bellingham, north of Seattle, walk through woods to school every day, go off to architecture school at Harvard, come home and start your own firm; then you are introduced to CLT in Vienna, and the product so excites you that you launch your own independent investigation of its possibilities, and your investigation grows to include graduate architectural students at the University of Washington; and then, to test the results of your ongoing investigation, you build your own home using cross-laminated timbers, and it is the first CLT-permitted house in Seattle. Do we have your story about right?
Jones: That’s a pretty good chronological summation - thank you! - and as you say, our investigation continues, and no doubt will for years to come.
Evergreen: What was your reaction to CLT when you first saw it in Austria?
Jones: I thought it was beautiful. You are surrounded by wood – the floors, walls and ceilings. I remember thinking that it would be a shame to paint it. And we haven’t in our home in Seattle. The wood, with its grains, textures and tones needs nothing else to add to its beauty.
Evergreen: The title of your book suggests that your CLT investigation continues. What exactly are you investigating?
Jones: We need to be sure that our CLT carbon sequestration data is accurate; we need to be sure our designs are well-engineered and structurally sound; we need to be sure we are using CLT as efficiently as possible; and, of course, we need to know that the forests from which our wood is harvested are being sustainably managed. We also have a lot of work to do with building and fire code writers who don’t yet fully understand how CLT performs when compared to other structure building materials. I am volunteering for a two-year effort to modernize our national Building Code system to allow Tall Timber buildings, up to 18-20 stories, or possibly even higher, if the building science issues, especially Fire issues can be addressed to our satisfaction.
Evergreen: That’s a lot to do, but before we dive in head first, can you describe cross-laminated timbers for our readers?
Jones: CLT is an engineered wood product. By that, I mean that it is a product assembled from pieces of lumber, usually two-by-sixes, eight feet wide, 40’ feet long, layered at right angles to one another, like the layering of thinly sliced veneer used to make sheets of plywood. Picture a laminated wood beam, with the layers all running one direction. Now remind yourself that, in CLT, the layers run at right angles to one another, like plywood. The product is incredibly strong for its weight, which is about one-third that of steel. Some refer to CLT “plywood on steroids.” It’s a very apt description.
Evergreen: How many cross-laminated layers?
Jones: Usually three, but sometimes five, seven or nine. It depends on the intended use.
Jones: CLT panels – or billets – are 40 feet long, eight feet wide and at 3-ply, about four inches thick.
Evergreen: How are the panels fit together to make a house?
Jones: They are precut to the architect’s specifications, which must account for the placement of windows, doors, walls and vaulted ceilings as well as the pathways for plumbing and wiring. This pre-fabrication makes for very accurate building, and allows the architect to control the design deep into the fabrication and construction time.
Evergreen: Building from panels, rather than dimension lumber, speeds construction time, doesn’t it?
Jones: By about 10-50 percent, depending on what you are building. Most of the actual assembly work is done by crane operators, and foreman on site, helping to hand set the panels while the crane operator lifts them into place.
Evergreen: Let’s go back to wood consumption for a moment. You said that each 40-by eight-foot billet holds about 2,200 board feet of wood. Can you translate this amount into number of trees consumed? (Is this true? I have not done the math on this…)
Jones: I can. If we use our Seattle CLT House as an example, about 17 trees were used in the assembly of the 17 panels it took to construct the home. If you figure that the average low-density forest planting holds about 302 trees per acre, our 17 trees represent about 0.06 acre of forest.
Evergreen: That’s not much.
Jones: No, it isn’t, but here’s where the data takes on real significance. We planted 17 trees to replace those used in the construction of our home. And, we assume that for every tree harvested to make our panels, another tree was planted. Then, the CLT stores or sequesters carbon, the 2,500 square feet on which the house sits acts as a virtual carbon sink equivalent to about one-fourth of an acre of trees, an area more than three times the size of the area occupied by our 17 trees. We have to remember that for every tree harvested, only about 1/3 of it can be considered as a continual carbon sink, because our lumber is only harvested from about 1/3 of the mass of the tree. So it was important to us to plant approximately 3 trees for every tree that we used.
Evergreen: Are we correct in assuming that much of the data you are citing comes from the research you and your University of Washington graduate students are doing?
Jones: Some of it does, but there is a wealth of energy and carbon cycle research material available from a variety of sources including the Consortium for Research in Renewable Industrial Materials. Most of CORRIM’s research, is housed at the University of Washington, so it is close by. But there is also a great deal of data available in Europe, and from forestry and engineering schools in the United States, Canada and Europe. Calculating the amount of carbon from a forest, or that is sequestered within a building is a highly complex matter, and we have a number of researchers at the UW who are working on National Science Foundation and USDA grants to try and better quantify this very issue right now. I can’t wait for them to figure it out, so we can be as straightforward as possible in our discussions about CLT and Carbon.
Evergreen: Earlier, you mentioned something about CLT manufacturers using small diameter trees in their billets. How is that possible?
Jones: They finger-joint smaller pieces of wood, to make long, 40’ long boards, then lay them up at right angles, gluing them with environmentally friendly adhesives, to make super strong, lightweight 8’ wide x 40’ long panels.
Evergreen: So this is the connection between cross-laminated timber and all the urban chatter we are hearing about how the smaller diameter trees that are overcrowding the West’s forests could be used to manufacture environmentally superior wood products before they are reduced to smoke and ash by costly and environmentally devastating wildfires.
Jones: Well, yes. Sustainably managing our forests leads to all kinds of good outcomes, as they constitute approximately 18% of our country’s ability to capture and hold carbon. The forestry industry has a huge and important role to play in sequestering carbon.
Evergreen: We’ve been writing about CORRIM’s research for 25 years, but I must say I never expected to see the forest restoration story converge with the wood manufacturing story in such an innovative and exciting way. This is a marriage made in heaven, isn’t it?
Jones: There are certainly lots of systemic connections here involving carbon sequestration and the more creative and efficient use of wood which, by the way, is grown in nature by the free, non-polluting energy of the sun. No other structural building material on earth can make this claim. And yet, as an architect, I need to remain very subjective about all of this because we don’t yet have the whole carbon sequestration story nailed down.
Evergreen: What don’t we know?
Jones: CLT hasn’t been around long enough for us to have a complete life cycle analysis like the analyses we have for other wood-based building materials, especially in the recycling arena. Intuitively, I suspect it performs just as well, maybe better through the whole cycle from tree growth to recycling. But we still need the data when it is available. And, as I mentioned, we really need to have some good carbon numbers that we can all agree on.
Evergreen: And because we’ve read your book, we know that you have some interesting data that helps illustrate your point.
Jones: EPA fuel consumption and tailpipe emission measurements tell us that the average American car annually pumps 9,960 pounds of carbon dioxide into the atmosphere. Working backwards through data from the U.S. Department of Energy, we learn that one tree stores 22 pounds of carbon annually, while 51 trees grown for 25 years sequester 28,050 pounds of carbon dioxide – an amount equal to three passenger cars taken off the road for one year, or one car for three years.
Evergreen: We saw some research data a few years ago that revealed that one large California wildfire had pushed so much carbon dioxide into the atmosphere that mitigating it over a one year period would have required that every car in California be parked for that entire year.
Jones: I prefer picturing those lost trees as beautiful buildings constructed from cross-laminated timber. As architects and designers we have a responsibility to specify materials that push the world in a more responsible way, and CLT answers a lot of concerns for us. I do hope for more CLT manufacturers in the U.S., but at the moment, there are only two, the D.R. Johnson Lumber Company in Riddle, Oregon and SmartLam in Whitefish, Montana.
Evergreen: Your mention of the need to specify environmentally friendly building materials reminds me of a lively brochure sent to us 10 or 15 years ago by a wood specifier in London, England/ The heading on the front cover said, “If you’re not specifying wood, you’re killing the planet.”
Jones: That is amusing.
Evergreen: Your CLT story has a lovely local, organic angle, too, doesn’t it?
Jones: It certainly does. Urban shoppers love organic produce, especially locally grown. CLT presents the opportunity to buy an environmentally superior product that is locally grown and manufactured, right here in the Pacific Northwest. By encouraging its sustainable growth, production and consumption, we sequester huge amounts of carbon that otherwise escapes into the atmosphere when forests burn. What’s not to like here?
Evergreen: We recently read an essay by Mike Stevens, who is Washington State Director for The Nature Conservancy, in which he posited that putting a price on carbon - using market forces to drive down fossil fuel consumption - is central to the whole question of better national forest management and increased use of carbon sequestering wood products. His message dovetails nicely with yours.
Jones: The carbon issue is an extremely important issue, especially with urban dwellers and forests have a gigantic and important role to play in this discussion of solutions. I am struck by my observation that many in the timber industry don’t yet seem to grasp what an important and quickly evolving role they have to play in the addressing our carbon issues in climate change.
Evergreen: I am dumbfounded by the industry’s reluctance to aggressively market the carbon sequestering powers of wood. Properly structured, a tax on fossil fuels would create a significant revenue stream that could help pay the cost of restoring western national forests that are dying and burning in fires for which there is no historic or ecological precedent. How do we break through stubborn resistance to ideas that seem to present such clear and easily understood benefits?
Jones: By pressing forward with projects - like our CLT Investigations - that demonstrate success in achieving sought after social, economic and environmental benefits. I have been speaking all over the country since we completed our two CLT projects in 2015 - to audiences from architectural students, to architects and contractors, to foresters, to local and national politicians. I am confident that public opinion leaders here in the Pacific Northwest and elsewhere around the country, especially in Washington DC are beginning to understand the important leadership role that the sustainable management of our forests and mass timber have to play in our fight against climate change.