For landowners, it’s devastating to lose acres of forest to a wildfire — and then there’s the challenge of what comes next.
Mast Reforestation has an answer that helps restore the charred landscape and prevents the release of additional planet-warming carbon while also generating revenue: it’s called biomass burial.
The Seattle startup has engineered a solution that permanently disposes of the burned trees, locking away their carbon and methane that could otherwise be released into the atmosphere. The company announced today that its first tree burial has performed as designed and it has sold 80% of the carbon credits that were produced as a result.
Under normal conditions, “the remediation of that land is really expensive,” Maria Huyer, Mast’s head of product, told GeekWire. “And this is just such a simple solution to carbon dioxide removal that has the ability to fund such a huge challenge.”
Burying biomass
After a wilderness burns, landowners have limited strategies for clearing the torched vegetation and replanting. They can finish burning the dead trees, sell them for firewood, seek a mill that will take the damaged timber, or turn it into environmentally friendly biochar — but that requires special machinery and is difficult to do with mobile units.
Because of its remote location, landowners of a destroyed forest in southern Montana only had the option of burning the remaining wood. Then came the partnership with Mast.
The project yielded more than 4,500 metric tons of biomass that was buried in a clay-lined vault that prevents the wood from getting wet, decomposing and releasing gases. The pit is carefully capped with a layer of clay, a geoengineered textile, gravel and organic matter. Native grasses are planted on top.
Sensors inside the vault monitor for changes in temperature and humidity that indicate decomposition, allowing the team to take action and stop the process. Above-ground sensors operate continually and can detect elevated levels of carbon dioxide and methane that are remotely tracked.
The startup has committed resources to continue the monitoring for 100 years.
Some of the revenue generated from the sale of the carbon credits are paying for the reforestation of the Montana forestland, which was scorched in the 2021 Poverty Flats Fire. That work will begin this spring.
Companies, organizations and institutions purchase carbon credits to offset their own climate impacts. Buyers of the Montana-based credits include the Royal Bank of Canada, the carbon credit marketplace CNaught, and Muir AI, a Seattle startup addressing supply chain costs.
The project generated 4,277 carbon removal credits that were independently verified and registered with an organization called Puro.earth. Huyer didn’t disclose what they cost, but said they were more expensive than nature-based credits created through forest conservation and roughly on par with biochar costs.
Growing strategy for carbon removal
There are other biomass burial efforts, including Graphyte, which turns crop and timber waste into bricks that are disposed in lined pits, and Maryland-based Carbon Lockdown, which uses a strategy akin to Mast’s, among others.
The use of wood vaults for capturing carbon is gaining interest, according to experts. But there are concerns about ensuring it’s the best use of woody debris. Depending on the situation, biomass can be used for the production of sustainable aviation fuels and other applications. Huyer said the company takes these alternatives into consideration when evaluating a project.
Mast initially launched in 2015 as Droneseed, which used drones to map and replant burned areas. It has expanded and shifted focus since then. It now owns Silvaseed, the largest private seed supplier west of Colorado; seedling provider Cal Forest Nurseries; and seed supplier and processor Siskiyou Seed.
The company, which most recently raised $25 million from investors a year ago, still performs drone-assisted reforestation, but does the planting by hand for improved tree survival.
Mast’s goal is to scale up its burnt-tree burials to contain about 20,000 metric tons of biomass. It aims to build a pipeline of projects that total 150,000 tons each year. There’s no shortage or material to dispose of.
“In Montana alone there’s 2.8 million tons of burned biomass,” Huyer said. “And so this is a challenge that is wide and extensive.”
