‘Wood Vaulting’ Explained: The Climate Solution You’ve Never Heard Of

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In northwestern Montana’s Swan Valley, a heap of astir 100 tiny logs, 10 feet agelong oregon so, sits neatly stacked, ringed by berry bushes, a fewer achromatic wildflowers, and towering larch trees. Surrounding the logs are respective acres of U.S. Forest Service land, which was thinned of dead, downed, and dense understory trees past twelvemonth to trim wildfire risk. The log heap that remains is excessively tiny to beryllium processed into lumber, positive the sawmill conscionable down the road precocious closed. So the wood whitethorn get sent to a pulp mill, if the terms is right. Or it whitethorn beryllium successful the wood for years. Smaller limbs whitethorn beryllium burned successful a prescribed fire. But Ning Zeng, a clime idiosyncratic astatine the University of Maryland, is sizing up the pile, too. He sees different solution: burying the logs, and each the planet-heating gases they’d different release, underground.

That’s the thought of a c sequestration method called wood vaulting. Forests passim overmuch of the occidental U.S. are overgrown, afloat of tangled trees and brushwood that’s primed to burn. The Forest Service’s wildfire situation strategy calls for removing excess vegetation connected up to 50 cardinal much acres of federal, state, tribal, and backstage lands by 2032. Scientists and clime tech companies alike accidental wood vaulting could assistance store immoderate of the c dioxide equivalent, successful the signifier of flammable vegetation, that the Forest Service indispensable woody with successful the coming years — an estimated 2.2 cardinal metric tons. That’s astir arsenic overmuch CO2 arsenic cement accumulation worldwide emitted successful 2016, and arsenic overmuch arsenic forests globally removed from the ambiance past year.

“There’s much wood successful the wood than markets for it to go,” said probe forester Nate Anderson, who studies merchandise proviso chains for the Forest Service’s Rocky Mountain Research Station successful Missoula. Valuing the c stored successful wood vaults could alteration that.

If done properly, burying the debris could assistance bounds the merchandise of greenhouse gases that lukewarm the ambiance and lend to clime change. “I don’t spot immoderate crushed wherefore it can’t beryllium really rather important and scope millions of tons of c dioxide sequestered per year, successful the U.S. alone,” said Sinéad Crotty, the manager of the nonprofit Carbon Containment Lab. Daniel Sanchez, a prof who studies CO2 removal astatine the University of California, Berkeley, agrees. “Wood vaulting is simply a recently emerging attack that we deliberation is comparatively low-cost and comparatively scalable,” helium said.

A tract successful Montana wherever 2 companies are partnering connected biomass burial aft a wildfire burned hundreds of acres of privately owned land. © Mast Reforestation

Investors, including Bill Gates, person poured millions of dollars into jumpstarting wood vaults successful caller years. A fistful of small-scale sites are successful advancement crossed the country, including successful Maryland, Nevada, Texas, and Colorado. The Department of Energy precocious awarded $50,000 for 2 companies, including Zeng’s Carbon Lockdown Project, to conception a wood vault successful Montana — 1 of galore c dioxide removal, oregon CDR, aviator projects to person funding. According to the 2023 Intergovernmental Panel connected Climate Change’s Synthesis Report, CDR exertion — which tin include nonstop aerial seizure technology, land-based c sinks, and much — is an “unavoidable” constituent of limiting warming to 1.5 oregon adjacent 2 degrees Celsius, which experts say is indispensable if we are to debar irreversible effects of clime change.

Wood vaulting is conceptually simple: Dig a spread with an excavator and bury tiny trees, woody debris, and different works materials that aren’t ample oregon invaluable capable to sell. The vaults lucifer a furniture barroom of trees, gaps filled with dirt, and much trees stacked connected top, finished disconnected with a frosting of topsoil.

Once companies get biomass, not conscionable immoderate spread volition do. The intrusion of water, oxygen, and adjacent termites could compromise a vault’s durability by encouraging decomposition. Digging vaults successful clay oregon silty soil, distant from groundwater, is thought to beryllium champion practice. (Some alternative methods really submerge the wood successful h2o entirely, but that’s little common.) Conditions wrong the vault indispensable stay unchangeable — ideally successful perpetuity, without quality involution — for projects to uphold their promises. The aforesaid kinds of sensors already utilized successful landfills tin beryllium installed to show information similar oxygen, moisture, and methane levels implicit time.

Digging holes 15 to 25-plus feet heavy tin mean disturbing soil, destroying habitat, oregon removing nutrients from the scenery — each imaginable downsides of wood vaulting — truthful companies are considering utilizing already-degraded locations, similar aged concern sites oregon mines. (Several besides person plans to rehab wood vault sites aft trees are buried, planting the ungraded with autochthonal seeds for pollinator situation oregon grazing use.) The perfect determination for a wood vault is adjacent the root of its biomass, which cuts backmost connected proscription emissions and logistics. Enough labour to transport biomass and conception vaults, positive immoderate benignant of extortion that they won’t conscionable get dug up successful a fewer decades, are different cardinal factors.

Another interest with wood vaulting is that it whitethorn incentivize much logging than necessary. But truthful far, the manufacture is focused connected burying the leftovers of wildfire hazard simplification treatments, arsenic good arsenic trees that person already burned oregon were hazard trees removed from municipality environments. Guidelines from Stripe Inc.’s Frontier fund, 1 of the starring funds that purchases c dioxide removal credits from startups, recommends the leftovers of wildfire hazard simplification projects arsenic a sustainable source.

The subject to cognize however agelong these vaults could support CO2 retired of the ambiance is inactive successful the works. “We privation to beryllium arsenic clear-minded arsenic imaginable erstwhile promising thing astir durability,” Crotty said. If done properly, Sanchez thinks vaults mightiness beryllium capable to store CO2 for hundreds to thousands of years; companies stock numbers that scope from 100-plus to 1,000-plus years.

While it’s hard to accidental precisely however agelong wood vaults whitethorn beryllium capable to store carbon, erstwhile discoveries clasp clues. A bulldozer connected Carbon Lockdown Project’s Canada tract recovered a reddish cedar log buried heavy successful the soil; Zeng inactive has it successful his bureau today. He says further investigation (yet to beryllium published successful a peer-reviewed journal) confirmed it was 3,000 years aged but had lone mislaid 5 percent of its carbon.

Another mode to analyse wood vaulting’s imaginable is by comparing however overmuch c it tin store to different much established techniques. Wood vaulting’s c output is precocious compared to that of biochar, a charcoal-esque ungraded amendment that comes from partially combusted integrated material. Biochar tin clasp astir 30 percent of its biomass’ archetypal carbon, portion wood vaulting is thought to store implicit 90 percent, according to Sanchez.

Read Next: Biochar is simply a ‘shovel-ready’ clime technology, but tin it standard up?

Wood vaulting is besides reasonably inexpensive compared to different methods. Calculations from 1 of Zeng’s trial sites recovered it outgo $105 per metric ton of CO2, mostly successful proscription costs. For comparison, the mean outgo of biochar successful California is $400 per metric ton of CO2, and nonstop c seizure technologies tin cost anyplace betwixt $600 to $1,000 per metric ton of CO2. “That’s the transformative facet of this thought compared to galore different biomass utilization strategies,” Zeng said. “It is going to travel down to economics.” 

Several companies are presently trying retired wood vaulting, mostly connected backstage land. Zeng created the Carbon Lockdown Project, which began with a probe tract extracurricular Montreal, successful 2013. He’s present moving connected a spot successful Maryland for trees removed from municipality settings that would person different been mulched.

Then there’s Mast Reforestation, a institution that seeks to replant forests aft they pain for c credits. CEO Grant Canary said he’s particularly funny successful burying the already-burned trees that make a hazard for workers and the tiny saplings they plant. The institution plans to store betwixt 5,000 and 20,000 metric tons of CO2 equivalent that travel from trees connected hundreds of acres of precocious burned backstage onshore successful cardinal Montana. Mast Reforestation is partnering with Zeng’s Carbon Lockdown Project connected the site, and Canary said operation whitethorn beryllium underway arsenic soon arsenic the extremity of 2024 oregon aboriginal 2025. As a victor of the Department of Energy’s prize, the task promises implicit 17,000 c dioxide removal credits to the national authorities by the extremity of 2028.

Also retired West, Kodama Systems is successful the permitting signifier for a wood vault to store astir 1,000 metric tons of CO2 equivalent successful occidental Nevada. Material could beryllium successful the crushed arsenic soon arsenic aboriginal this year. Arid rangelands successful this country are considered premier for wood vaults; researchers astatine the Carbon Containment Lab besides accidental the Four Corners portion of Arizona, New Mexico, Colorado, and Utah has precocious imaginable for wood vault development. Carbon Containment Lab scientists spouse with companies, including Kodama Systems, to cod their ain autarkic data.

So what’s needed to crook wood vault projects from the fistful of aviator sites that presently beryllium to a c dioxide removal exertion astatine scale? More subject to verify longevity and retention claims, much wealth to jumpstart further projects, and much buyers of c dioxide removal credits. While companies and scientists person their sights acceptable connected moving with the Forest Service someday, authorities onshore absorption agencies are notoriously dilatory to effort thing new, meaning a public-private concern connected wood vaults is inactive acold off.

For Zeng, lasting successful the mediate of the woods, seeing everything from mill infrastructure to imaginable wood vaulting sites successful Colorado, Montana, and beyond was illuminating, fusing mentation with signifier connected the ground. “I got truly encouraged connected this trip,” helium said. “The dots are getting connected.” While wood vaulting is not a single-handed solution for overgrown forests, wildfire risk, and a rapidly warming climate, it whitethorn beryllium a elemental solution to sequester immoderate c and trim wildfire risk, too.

This nonfiction primitively appeared successful Grist astatine https://grist.org/solutions/wood-vaulting-carbon-storage-solution/. Grist is simply a nonprofit, autarkic media enactment dedicated to telling stories of clime solutions and a conscionable future. Learn much astatine Grist.org