August 23, 2024

3 Top Questions Answered about Specifying Sustainable Wood in the U.S.

 “Start with the rising sun and work toward the setting sun, but take only the mature trees, the sick trees, and the trees that have fallen. When you reach the end of the reservation, turn and cut from the setting sun to the rising sun, and the trees will last forever.” 

—Chief Oshkosh, the Menominee 

01 How Is Wood Sourced?

In the early 20th century, U.S. forests were hurting. Extensive logging, lack of effective management practices, and widespread clearing for agriculture had decimated many of our mixed forestlands and threatened the wildlife that depended on them. The modern conservation movement was launched because Americans recognized that these practices were unsustainable. However, it wasn’t until the 1980s that the age-old wisdom of Indigenous communities was recognized as a highly effective model for achieving the goals of the U.S. Forest Service: maintaining ecosystem health, preserving habitat diversity, preventing large-scale wildfires, maximizing yield to satisfy demand, and ensuring healthy forests for future generations.
Widely considered one of the best-managed forests in the world, the Menominee woodlands in northern Wisconsin have thrived since they were incorporated in 1854. The tribe’s management philosophy is based on a prescription written by Chief Oshkosh 170 years ago:

“Start with the rising sun and work toward the setting sun, but take only the mature trees, the sick trees, and the trees that have fallen. When you reach the end of the reservation, turn and cut from the setting sun to the rising sun, and the trees will last forever.”

And so they have. The Menominee forest has more wood now than in 1854, is still rich in biodiversity, and provides an important economic engine for the tribe. 

Chief Oshkosh’s 1854 prescription was not a breakthrough. He merely wrote down what the Menominee, and many other communities, had been doing since before recorded history. This is the difference between living on the land and living with the land. 

The Menominee Tribal Enterprises practice selective harvesting, where loggers choose specific trees to remove, maintaining the overall structure and function of the forest while being careful not to harvest more than the forest can generate. 

One type of selective harvesting is single-tree. “This is where we’re thinning out individual trees to open up the canopy to allow the sunlight to hit the seedlings and saplings,” procurement forester Steve Pilgrim told me last fall. We were in a forest in northern Wisconsin being managed by wood-products company NWH, not far from the Menominee lands. “Without full sunlight, trees can never mature healthily.” 

“A shelter-wood cut is a little different,” Pilgrim continued. “We’re allowing the young trees to grow in the shelter of mature trees. As the new growth takes hold, more of the mature trees can be taken.” 

Procurement foresters like Pilgrim work mostly with private landowners to help them manage their forests for their specific goals. Even though few landowners invest in FSC (Forest Stewardship Council) or SFI (Sustainable Forestry Initiative) certification, the same management standards and practices apply. By some estimates 99 percent of all wood harvested in the U.S. is from forests managed to these standards. 

It’s important here to address a common misperception. Many designers say that when they hear “managed forestry,” images of tropical deforestation come first to mind. Forest management in North America is literally the opposite of deforestation—it aims to sustain forests indefinitely; deforestation involves the permanent clearing of natural forests for development, mining, bamboo plantations, or conversion to agriculture or grazing.

Clear-cutting is a managed forestry practice that involves removing entire stands of trees at once and is most effective for the long-term health of areas with species that thrive on full sunlight, like aspen, birch, lodgepole pine, some types of spruce, and Douglas fir. This is how most plantation wood is harvested. Plantation forests get a bad rap, but they take a lot of stress off natural forests in meeting the demand for products like toilet paper, newsprint, packaging, sawlogs for construction and furniture frames, veneers for plywood, mass timber, and fiber for engineered panels like particleboard and MDF. These fast-growing forests still inhale carbon dioxide and store it until the wood is burned or decomposes. Unless a natural forest or other sensitive ecosystems have been purposely cleared for plantation trees, plantation forests are still considered a positive for the environment, and for the wood-products value chain. 

Every forest ecosystem has its own natural rhythm of disturbance and renewal and the best harvesting methods mimic that rhythm. Single-tree selection and shelterwood harvests mirror disturbances like disease, insect damage, and localized windstorms like tornadoes and derechos. Prescribed burns, another staple forest management tool perfected by Indigenous peoples around the world, aren’t a harvesting method, but they are an important part of managed forestry. They’re used to strategically reduce fuel loads, boost nutrient content, manage invasive plants and insects, open up areas for larger game animals, and, of course, spark forest regeneration.

02 What about Reclaimed Wood and Wood Composites?

Solid wood isn’t the only kind of forestry product that can be used in buildings. 

There’s growing interest in sourcing wood from urban areas in two ways: by recovering felled trees for lumber and veneers, or by salvaging wooden beams, joists, posts, and decking from the demolition of factories, warehouses, and other large buildings to be re-machined into structural or decorative elements, stairs, railings, ceilings, wall paneling, and even furniture. 

Urban Evolutions in Appleton, Wisconsin, has been working with reclaimed wood for over a quarter century. Co-owner and creative director Robin Janson says these time-capsule materials often inspire the design of an entire project. “Our process is to flip the script on material aesthetics. Rather than designing the look of a building and then hunting far and wide for materials that meet that aesthetic, we start with identifying the materials at hand and let them 

shape the building’s look and feel,” she says. “A key principle in circular design is to circulate products and material at their highest value for as long as possible. There’s no better way to achieve this than using reclaimed wood.” 

The other avenue for forestry products is composite wood materials like particleboard and MDF, which, in a testament to the frugality of the wood-products industry, can sometimes be manufactured entirely from postindustrial waste wood. Before these materials were invented in the 1940s and 1960s, respectively, 50 percent of the fiber from trees harvested for furniture and construction—sawmill scraps and shavings—was destined for landfills and incinerators. Now utilization of that fiber tops 99 percent. 

This waste is processed, combined with resins and waxes, and pressed into panels engineered for a variety of furniture and millwork applications. They offer dimensional comtability and consistency at a lower price than most other wood-based materials and are compatible with highly automated manufacturing technology. The key sustainability consideration with these materials, of course, is the health impacts and emissions of any additives used in their manufacturing.

“We’ve developed lighter products with outstanding physical properties that reduce our carbon footprint and help reduce emissions in production and transport,” says Don Raymond, vice president of marketing for panel producer Uniboard Canada. “All our regular particleboard and MDF products meet CARB Phase 2 and TSCA TITLE VI emissions standards, the most stringent environmental guidelines in North America.”

03 How Does Wood Help with Decarbonization? 

Temperate and boreal forests, where we source most of the wood for construction and furniture, together cover about 1.9 billion hectares globally and account for about 46 percent of the world’s forest carbon storage, underscoring the importance of these forest types in mitigating climate change. 

Trees inhale carbon dioxide from the air, release oxygen, and convert carbon into glucose, which provides energy and building blocks for growth. We learned about this process—photosynthesis—in school, and that’s how a tree makes cellulose, the primary component of wood and the most abundant organic compound on Earth. 

The chemical makeup of wood is 50 percent captured carbon by dry weight. This carbon is not released back into the atmosphere until that wood decomposes or burns, which means significant amounts of carbon are stored in solid and composite wood products for decades, even centuries. 

Managed forests, where selective logging, replanting, and thinning are practiced, can sequester carbon more effectively than unmanaged forests because of enhanced growth rates from younger, healthier trees. 

Owing to product category rules for wood products, life cycle assessments (LCAs) for these offerings cover cradle-to-gate impacts. In composite wood, the LCAs find that the materials are storing about 40 percent more captured carbon than is released in the harvest and conversion into panels, rendering them truly climate positive. 

Putting numbers to it, according to the Construction Material Pyramid developed at the Royal Danish Academy’s Center for Industrialized Architecture, one cubic meter (or about 35 cubic feet) of MDF has a carbon footprint of –783 kilograms of CO2; glulam is –664 kilograms; construction timber, –680 kilograms. Aluminum, on the other hand, has a carbon footprint of positive 28,890 kilograms; glass, 4,580 kilograms; and vinyl flooring, 3,802 kilograms. 

Any topic as important and emotional as forests and their role in carbon capture and sequestration will generate controversy. Recently some academic articles have questioned the positives of forest carbon. According to Brent Sohngen, professor of environmental and resource economics at The Ohio State University: “There are some studies that measure only the carbon impacts of harvesting trees, but you have to recognize that the only way wood is available to harvest is because it grew.”