The wood products industry is massively undercounting its impact on the climate, a new study has found.
Through its production of paper, pulp, pellets and lumber, the industry releases at least 3.5 billion tons of carbon dioxide every year, according to a study published last week in Nature.
That is a large number in its own right: more than three times the annual emissions from aviation and nearly twice the carbon burned off by fossil fuel-dependent Russia.
But it is particularly dramatic when compared to the carbon cost claimed by the wood products industry itself — which is often calculated to be less than zero.
“For the most part, people treat wood harvests as though they’re not causing emissions,” said study coauthor Timothy Searchinger, who splits his time between Princeton and the World Resources Institute.
The findings in Nature, however, show that wood harvests exert “a really, really big carbon cost,” he said.
“And we’re not paying attention to it,” he added.
On the surface, the idea that wood harvests release carbon dioxide is intuitive, Searchinger said. Wood is mostly made of carbon, and every aspect of the process of harvesting it, whether for pulp, housing or furniture, dumps carbon into the atmosphere.
The biggest portion of wood’s carbon emissions comes from simply burning it. About half of the volume of wood that enters saw, pellet and paper mills — like bark and small branches — is stripped off and burned up to power the factories.
Much of what remains is sold as firewood — to be burned in homes — or wood pellets, which largely go to power plants.
While this energy is renewable — the wood can grow back — it isn’t carbon-free, unlike potential replacements like solar or wind power, Searchinger noted.
And yet for decades, the industry has operated under the assumption that wood harvests offer only benefits in the fight to slow climate change.
The reason: It assumes any trees that are chopped down to create wood products will be replaced by the new trees that grow in their place, replacing the carbon that was lost in the products’ creation.
This logic is commonplace. “Harvested wood products … represent a common widespread and cost-efficient opportunity for negative emissions,” according to a 2018 study in Carbon Balance and Management.
And a study by the U.S. government agency charged with promoting timber products found “notable carbon emissions savings when wood products are used in constructing buildings in place of nonwood alternatives.”
The idea that wood products are carbon negative by definition reached its apogee in the 2022 climate stimulus bill, which argued that this holds true even if those products are burned up in biomass or “wood-to-energy” plans — in which pelletized wood is burned in place of fuels like coal, with similar amounts of carbon released into the atmosphere.
(Some studies have found that wood pellets release more carbon dioxide than even coal.)
In a move championed by forest-state lawmakers like Sen. Susan Collins (R-Maine), federal law now requires federal agencies to design policies that “reflect the carbon neutrality of forest bioenergy and recognize biomass as a renewable energy source.”
A spokesperson for Collins told E&E News that such a conclusion “not only aligns with the science, but also encourages investments in working forests, harvesting operations, bioenergy, wood products, and paper manufacturing.”
Based on this logic, wood industry lobbyists argue that logging is ultimately good for the forests it draws on — because, as the thinking goes, a healthy market in wood products keeps them from being cleared and replaced with agriculture.
“If forest markets are unable to provide sufficient financial incentive to landowners, forest land would be converted to higher income-generating agriculture or development,” writes Virginia-based biomass giant Enviva.
That idea that wood harvests are inherently sustainable — even if they’re used to create products that are ultimately burned — has over the last decade provided justification for a massive uptick in wood harvests in vital creekside bottomlands along the U.S. East and Gulf coasts.
Additionally, the wood industry argues that a freshly logged and rapidly regrowing plantation forest grows far faster — and therefore stores more carbon — than the more sedate carbon sequestration offered by an older one.
This argument is correct, Searchinger argued — at least, up to a point.
On a global scale, the fast growth rate of formerly cleared forests means Northern Hemisphere forestry can benefit from an extremely rapid rate of carbon sequestration — because Europe, the U.S. and Canada so thoroughly deforested their territory in the 19th and 20th centuries that the current rate of forest regrowth is very high.
In terms of the carbon storage of its forests, Searchinger said, “the Northern Hemisphere was born on third base and thought it hit a triple. It’s basically, ‘We’re great because we’re not as bad as we were in the past.’”
But the rest of the arguments for wood’s inherent carbon-neutrality don’t hold up, he said.
The industry, Searchinger said, “has also managed to convince people that the reason that forests exist is because of our demand to cut them down. And there’s almost no evidence for that.”
While wood industry proponents often argue that demand for wood products — and therefore logging — keeps forests standing, Searchinger argued that this misunderstands the major factors driving American land use: the qualities of the land itself.
Most commercial wood is grown in plantations more akin to oversized corn fields than biodiverse forests. States like Maine grow these trees in place of corn because such crops grow badly there.
And while old growth stores less carbon over time than new growth, that’s because it is holding down that carbon in the bodies of trees and in the structure of the soil — carbon that is lost once those trees are cleared, and that (in the best case) will take decades to reaccumulate.
Searchinger compared the process of forest growth and regrowth to that of a worker getting paid.
“If I take your paycheck — well, I can say, you get a paycheck next month, right? It’s renewable, but that doesn’t mean if I take your paycheck you’re not worse off.”
He likened the loss of stored carbon when forests are cleared to a still more significant theft.
Assume someone steals your identity and raids your pension fund, he said — “But they don’t take out more than you added that year. So I say ‘Hey, you haven’t lost anything, right?’”
In the paper, meanwhile, the authors compare claims that wood is carbon negative to the idea that driving a small gas-powered car over a large one is. While less carbon may be burned, they say in no real sense is it being saved.
The study’s findings come with a substantial silver lining, Searchinger said: While the costs of the wood industry are huge, they mean humanity has an additional policy dial we can turn to slow climate change.
For example, carbon emissions could be reduced by burning far less wood for fuel; packing more wood production into dense plantation forests, instead of pulling it from natural ones; and practicing less destructive forms of logging, which lead to less disruption of forests, and therefore less planet-heating carbon in the atmosphere.
The Nature authors give several distinct policy prescriptions for how to cut the carbon cost of wood in a fact sheet published through the World Resources Institute.
Getting lower-income countries to use more renewable electricity in place of wood stoves — and getting the higher-income world to turn away from burning biomass in its power plants and paper mills — could cut global emissions by 500 million tons per year, the authors say.
Increasing tree plantation yields by 50 percent could cut another 600 million tons; and harvesting wood from tropical forests more carefully could cut another 200 million, they add.
Performing these actions alone would net 1.3 billion tons of carbon savings, according to the fact sheet — equivalent to decarbonizing Japan and nearly equivalent to decarbonizing leading fossil fuel exporter Russia
But solving the high carbon cost of wood begins with admitting it exists, Searchinger said.
It still surprises him that this is controversial, he told The Hill.
“I just had a piece in Nature based on the fact that ‘land is not free,’” he said. “It’s kind of embarrassing, right? It’s like, ‘Really? You get to publish all these scientific papers just because you realized that land is not free?’”
“Well,” he laughed, “I’m willing to admit that this should be ridiculous. I should not have a scientific career.”