Is it Really Time to Reconsider Wood Houses?

The fire consumed the hillside, charring trees and bushes and homes on its way to devastating 70,000 acres in northern California. But Sean Jennings’ house did not burn. Its reddish stucco walls and green roof looked startlingly clean perched on the hillside amidst the burnt cars and white ash left in the fire’s wake. Inside, Legos and Christmas decorations were unmelted, and a propane tank behind the house was ¾ full.

Jennings says his house survived the Valley Fire of 2015 because it was not made of wood. When he’d built it five years earlier, Jennings instead used something called RSG 3-D panels—blocks of foam insulation held inside a steel grid, fastened together, and covered with concrete. The structure is sturdier, less susceptible to termites, and less flammable than wood, he says. “Wood houses are just so vulnerable and leaky,” says Jennings, who is building a second house using RSG panels for his mother in Sonoma County, near where the LNU Lightning Complex Fires in 2020 burned 363,000 acres over the course of six weeks.

As the U.S. West approaches the 2021 fire season with even drier conditions than those that kicked off last year’s record-breaking blazes, breaking up with wood makes sense, but the U.S. remains stubbornly attached to timber. It’s one of the few places in the world where wood is the dominant material used in new-home construction—90% of homes built in 2019 were wood-framed, according to the National Association of Home Builders. Even as scientists emphasize the importance of trees in capturing carbon and slowing climate change, the U.S. uses more forest products than any other country, not just for construction but for furniture, flooring and paper. Wood plays a role in American folklore, housing Abe Lincoln and employing Paul Bunyan.

Now there are growing economic reasons to find alternatives. The cost of wood has skyrocketed as more people across the country remodel or build new homes following a pandemic-year construction collapse, causing a lumber shortage that adds more than $35,000 to the cost of a new single-family home.

“Wood is ubiquitous, but it’s time to evolve,” says Matt Watson, the president of Gateway Builders, a Northern California contracting company that has been building homes since 1997. Watson started building with non-wood materials last year and now, as he works with clients who lost homes in the 2020 fires, 19 out of 21 rebuilds are using non-wood materials. His workers have traded in hammers and nails for pneumatic tools that fasten together steel panels. Still, it may take awhile, he says—old habits die hard. “It’s the same as getting people off fossil fuels.”

The world’s reliance on timber has a role in the fires that scorched Jennings’ hillside and that burned 8.9 million acres across the American West last year. Dry conditions are worsened by climate change; keeping trees, which absorb carbon dioxide and reduce human emissions, in the ground is one of the most cost-effective ways to slow it. When Elon Musk tweeted in January that he was donating $100 million toward a prize for the best carbon capture technology, one user replied, ‘Congratulations to whoever invents forests.’

But about 15 billion trees are cut down each year, and the global tree count has fallen 46% since the beginning of human civilization, according to a 2015 study published in Nature. While much of that logging today occurs in developing countries like Brazil to make room for farmland, the U.S. harvests the largest volume of trees in the world, cutting down millions annually and on shorter harvest cycles than ever.

“There was a time where they cut down trees on 60- or 80-year rotations,” says Mike Roddy, a builder who has been preaching the down sides of wood for years, ever since flying over clear cut forests in the Pacific Northwest when he was a river guide. “And then they decided that a 40-year rotation is better,” Roddy says from his living room in Alameda, Calif., while flipping through a book showing vast landscapes of forests shorn of trees.

Private landowners account for the vast majority of trees felled in the United States. About 7.8 million acres of forest—an area the size of Maryland—were harvested in 2019, according to the National Alliance of Forest Owners, and land owners re-plant to keep their forests thriving. But the shortened harvest cycle—a few decades ago it was as high as 120 years— has big climate impacts, because mature and old forests accumulate more carbon than young ones.

“Even when they’re doing sustainable forestry, they’re sustaining it at a level below the maximum that would naturally occur in those forests if they were allowed to grow,” says Beverly Law, a professor in the Department of Forest Ecosystems and Society at Oregon State University and one of the country’s leading carbon researchers. (Only a fraction of the world’s working forests are certified as sustainable.)

Old-growth trees are still being cut down in what Law calls the “gold coast,” an area of the Pacific Northwest where trees store more carbon, per unit area, than tropical forests. The Trump administration removed protections from Alaska’s Tongass National Forest, one of the largest intact temperate rainforests in the world, as one of his last acts before leaving office.

Steel can also be a driver of emissions, but 90% of the steel manufactured today is recycled, and it can be recycled endlessly in a way that wood cannot. The majority of steel plants are now also electric arc furnaces, which are less energy intensive.

Roddy, who has built more than 700 steel-framed houses around the world, including for the actor and environmentalist Ed Begley, Jr., says concerns about carbon emissions aren’t the only thing driving him to push for less reliance on wood. Because of the shorter harvest seasons, many trees being cut down are not strong enough to make the type of long-lasting beams that were once used to build homes. Instead, builders engineered wood or oriented strand board (OSB), which is made by gluing together peeled wood products. This material contains chemicals including formaldehyde, which has been shown to significantly worsen indoor air quality.

And homes made from steel and concrete don’t warp from humidity or water damage, and they don’t attract termites, he says—a reason that 72% of single-family homes built in Hawaii have steel-frame structures, according to the Steel Framing Industry Association.

Forest owners argue that a large-scale move away from wood will actually hurt the environment; without a market for trees, they say landowners have little incentive to grow them and may instead turn their land into farmland or houses. Around 1 billion trees are planted each year in the United States, according to the National Alliance of Forest Owners. Besides, says Kate Gatto, a NAFO spokesperson, wood still stores carbon when used in houses. (There’s debate as to how much carbon is actually stored in trees once they’ve been cut down to use for homes; Law estimates that just about 20% of wood harvested over the last century is still in long-term products, the rest has gone into the atmosphere.)