Tree trunks fill demand for climate-friendly wood products
Open-air structures like this bandshell in Lacrosse, WI showcase the appeal of unmilled timbers.
By Lee Burnett
All photos courtesy WholeTrees Structures
A company that processes whole tree trunks into structural elements for open-air buildings is the latest entrant in the growing field of climate-friendly wood building products.
WHOLETREES® STRUCTURES in Wisconsin has secured $1.7 million in grants over the past few years to help establish a manufacturing plant in Ashland, Maine. The new company could start production by the end of 2024, according to company co-founder Amelia Baxter.
The company’s unique aesthetic is certainly eye-catching, but the company is about more than just a woodsy look. Lab tests have documented that the continuous fibers of unmilled trees are significantly stronger than those of comparably sized dimensional lumber. The company’s portfolio includes a highend bakery, an industrial commercial building, a carport at a coffee roaster and an outdoor pavilion. The company also prefabricates truss kits that come with fitted steel connectors.
“We do things that no one else can do,” says Baxter, a former urban farmer, community organizer and sustainable development advocate.
The company’s DNA lies closer to yurts than to timber frame houses. Thirty years ago, forester-architect Roald Gundersen began building simple structures with saplings harvested from his own off-grid property in the Driftless region of Wisconsin. First, he built an A-frame to live in with his family, then a greenhouse, then other greenhouses for farmers in the area. He was fascinated with the strength of saplings and by the lateral strength of branching limbs, which he also incorporated into his structures.
“Curves are stronger than straight lines,” he explained to a New York Times reporter in 2009. “A single arch supporting a roof can laterally brace the building in all directions.”
Gunderson and Baxter teamed up to form WholeTrees Structures in 2007 and secured official verification of Gunderson’s foundational insight. Forest Products Laboratory in Madison, run by the USDA, found that a whole, unmilled tree can support 50% more weight than the largest piece of lumber milled from the same tree.
“I fell in love with the structural brilliance of unmilled trees,” Baxter says. “That something so tall and slender would not only not fall over and break but could literally hold up buildings.”
This solar carport in Waterbury, VT is one of a few WholeTrees Structures buildings in New England.
Easy as shopping from an L.L.Bean catalog
The genius of WholeTrees Structures is in how it transposes idiosyncratic structures into the geometric, risk-averse construction world. First, tree sections are hoisted by crane and scanned using lidar technology, then the forms are digitally modeled so they can be imported into computer-aided design programs. WholeTrees has developed a database of more than 400 basic tree forms in 13 species, with 10 additional variables for size, branch spread, number of branches and so on. WholeTrees makes it as easy to specify a tree section as to shop from an L.L. Bean catalog.
Tree sections are also graded for load-bearing limits, after trunks are debarked, x-rayed and visually inspected. Sections are not grade stamped as dimensional lumber is, but column-strength values can be derived from earlier testing done by the utility-pole industry. Other strength values are derived with testing by U.S. Forest Products Lab.
A Vermont structural engineer who has worked with WholeTrees says working with tree sections “takes more thinking,” but is not too much different from what engineers already do when they account for anomalies in materials. Russ Miller-Johnson of Engineering Ventures, PC in Burlington has worked on WholeTrees projects at Franklin Park Zoo in Boston and a nature center in Vermont. Materials “aren’t always straight and true and uniform in size,” he says. “They’re out of plumb or twisted. There are issues that come up every so often. So, in a way, it’s nothing new.”
Upcycling cull trees
WholeTrees targets these less desirable trees that are thinned from the forest to allow higher-value trees to grow faster, according to the Maine company that will be supplying trunks to the mill. Typical thinning harvests generate low-value products such as chips, firewood, pulp or pallet logs, says Dan LaMontagne, president and CEO of Seven Islands Land Company. “This allows us to sell at a much higher price. It’s low-volume, but high-value.” Eleven tree species native to northern Maine are suitable: hardwoods beech, sugar maple, red maple, aspen and yellow birch, and softwoods red spruce, white pine, hemlock, tamarack, eastern white cedar and balsam fir.
This upcycling of cull trees from a sustainably managed forest is central to the company’s economic development model. Seven Islands is one of Maine’s premier forestland owners, with roots in the mid-1800s. The company was one of the first in the nation to champion third-party certification of sustainable forest practices in the 1990s and has stayed the course with certification while others have dropped it. Seven Islands now manages more than 820,000 acres in Maine, certified by both the Forest Stewardship Council (FSC) and the Sustainable Forestry Initiative (SFI). Seven Islands also owns a 66,000-square-foot building in Ashland, site of the former MooseWood Millworks hardwood flooring business, that Original Mass Timber Maine plans to lease. At capacity, the company would employ 23.
“It’s extremely exciting that we could be changing the economics of rural areas,” says Baxter. “That speaks to me.”
It’s an especially appealing message in Aroostook County, which has seen a 40% population decline over the past 60 years. As it continues its startup fundraising, WholeTrees has been lining up customers. One of those customers is MMG Insurance in Presque Isle, which hopes to incorporate both structural and aesthetic timbers in a planned expansion. The company likes “bringing the outside in,” says Stacy Shaw, senior vice president and chief information officer at MMG. “It’s absolutely beautiful.” The company also wants to align itself with the homegrown economic development model, he says. “I think it’s a wonderful approach. I like all of their branding.”
Mass timber market
The new company’s name, Original Mass Timber Maine (OMTM), is aimed at the growing market for mass timber. This is a little bit of a stretch because mass timber has traditionally referred to wall-sized panels prefabricated under factory conditions using crisscrossing layers of dimensional lumber, adhesives and pressure. Speed of assembly at the job site and very low embodied carbon footprints are selling points of mass timber. WholeTrees’ pitch is that its products have even smaller carbon footprints than do glulam and cross-laminated timber because the trees are minimally processed. The company has published an environmental product declaration, a third-party-verified accounting of a product’s environmental impact, essential information to performance builders.
OMTM’s startup costs of $2.8 to $3.2 million make it an easier launch than the $50 to $100 million capitalization costs of the traditional mass timber manufacturing Maine has been seeking to lure to the state for many years. The company has already lined up $5.3 million worth of contracts, according to a market feasibility study conducted by economic development consultants Camoin Associates. Camoin estimated that at full capacity Original Mass Timber Maine could achieve sales of $10 million a year.
One construction engineer active in Maine’s mass timber movement wonders about widespread acceptance since whole trunks are not grade stamped for strength as dimensional lumber is; instead, they involve individual calculations. “It has very specific applicability and a very specific look,” said Matt Tonello, vice president at Consigli Construction, which recently installed non-structural trunks as entrance columns on new dorms at Colby College in Waterville.
The future may lie in the residential market, where the pre-engineered truss systems may find acceptance among builders. WholeTrees has already begun discussions with Katahdin Cedar Log Homes, a company which manufactures log and timber frame kits and sells directly to authorized builders. A partnership would allow the log home company to prefabricate more of the truss systems under factory conditions, according to Gabe Gordon, vice president for sales and marketing at Katahdin. “We’re still in the exploratory phase,” Gordon says. “I see this as an upgrade for our customers.”
The most recently awarded grant will enable the company to hire a recruiter for the timber initiative, who will work to fill four leadership positions for the new business. “A big challenge will be how to develop a work force that will stay that far north,” says Baxter. “The biggest issue is getting leadership in place.”
These tree trunks are contemporary versions of the unmilled timbers that support many of Maine’s historic mill buildings.
This article appeared in the Spring 2023 edition of Green & Healthy Maine HOMES. Subscribe today!
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