As California’s San Joaquin Valley completes the final phase of its agricultural burn ban, growers are confronting a mounting woody waste dilemma with few easy answers. The Jan. 1, 2025, phaseout of open burning has forced orchard operators to abandon a long-standing disposal method and turn instead to costlier, logistically complex alternatives, from chipping and soil incorporation to emerging bioenergy and biochar pathways—just as biomass infrastructure continues to shrink and orchard removals accelerate across the region.The shift has arrived as California grapples with declining biomass infrastructure, rising orchard removals driven by water and market pressures and mounting volumes of woody material with nowhere obvious to go. “The district has seen a tremendous reduction in agricultural open burning in recent years through the ongoing phase-out, including the most recent and final component that kicked in at the beginning of this year,” says Jaime Holt, chief communications officer for the San Joaquin Valley Air Pollution Control District.The San Joaquin Valley’s restrictions are unique in that it’s currently the only region in California and the nation with stringent requirements to phase out agricultural open burning.Phase-Out Impacts&nbsp; The phase-out’s roots trace back almost two decades to Senate Bill 705 and the District’s Rule 4103. The most recent milestone came in 2021, when the district, in collaboration with the California Air Resources Board, adopted a final phase-out strategy that eliminated most remaining agricultural burning by the end of 2024. Through the implementation of the final phase-out strategy, the amount of agricultural material being open burned through the district’s smoke management system process has continued to decrease.“The impact has been dramatic,” Holt says. “Agricultural material open-burned in the [San Joaquin] Valley dropped to approximately 30,000 tons in 2025, down from 99,000 tons in 2024, representing more than a 95% reduction compared to over 1 million tons burned per year historically. The reductions in agricultural open burning and use of alternatives mark record levels for the Valley since the institution of agricultural burning restrictions, highlighting the success of the district’s agricultural open burning emission reduction strategy.”Gabriele Ludwig, director for sustainability and environmental affairs for the Almond Board of California, notes while the burn ban is specific to the San Joaquin Valley, other growers around the state are keeping a close eye on what’s happening because of past events. She explains that as burning restrictions tightened, growers increasingly relied on alternatives that have since narrowed.&nbsp;“For tree removals, growers used to send material to cogeneration facilities, which helped offset removal costs because the plants paid for the biomass,” Ludwig says. “When those facilities shut down, growers lost the primary alternative and burning pressures increased again.”Today, only one biomass power plant remains in operation in the San Joaquin Valley and its capacity is limited. “We used to be able to ship that material to biomass plants or landfills,” says Roger Isom, president and CEO of the Western Tree Nut Association. “Now, there’s only one operating biomass plant left in the Valley, and it can take very limited volumes.”As a result, most growers have defaulted to chipping and soil incorporation. “For most growers, the only option left is to chip the material and incorporate it back into the soil,” Isom says. “In some places that works well, but in others it’s extremely difficult—especially if the material isn’t broken down finely enough to decompose in a reasonable timeframe.”Because of that, costs have increased considerably. Chipping an almond orchard runs about $1,600 to $1,700 per acre, walnuts can be closer to $2,200 per acre and incorporation can add another $600 to $700 per acre, according to Isom. “This problem has been compounded by several things happening at once,” he says. “SGMA [Sustainable Groundwater Management Act] implementation, low walnut prices pushing orchards out of production, and a wave of vineyards being removed. At the same time, the biomass plants disappeared, and the burn ban took effect.”The result, he says, is visible across the Valley. “There are piles of material sitting in fields because growers either don’t want to incorporate it or simply have nowhere to take it,” Isom says.Opportunity Landscape&nbsp; Biochar solutions may be one answer. For instance, there’s a project in Tulare County that many are watching which could serve as a potential template for the future. The Sitos Group, working with Treehouse California Almonds, is developing a biochar production facility centered on almond shells, considered an abundant but historically undervalued coproduct of almond processing. “Our primary feedstock for the project is almond shell, which comes directly from Treehouse California Almonds’ harvesting and shelling operations,” says Jessica Bronner, director of business operations for the Sitos Group. “Historically, those shells were sold into secondary markets like livestock bedding or other uses, but now they’re being diverted as the main feedstock for our biochar production.”The $9 million project is centered on slow pyrolysis, a thermal process distinct from combustion, and will feature three side-by-side slow pyrolysis units operating as one, along with a fully integrated drying system with emissions and dust control, and Organic Rankine Cycle generators to repurpose heat energy from the pyrolysis units into clean electricity that will support the local power grid. “At full scale, the facility is designed to process about 24,000 tons of almond shell per year, producing roughly 8,000 tons of biochar annually,” Bronner says.Another plus is that the conversion ratio results in reduced trucking with fewer loads on the road compared to hauling raw shell material.“Right now, phase one is about proving the biochar market,” Bronner says. “The energy component is phase two, where we plan to capture and redirect that energy either back into the grid or into onsite operations.”The good news is that the biochar offtake is already secured, sequestered in agricultural settings. “One of our primary offtake partners is Monterey Pacific, a vineyard management company that has been using biochar in its soils for nearly a decade and has seen strong yield improvements and a return on investment within a few years,” Bronner says. “From an agronomic standpoint, biochar delivers multiple benefits. It improves soil health, increases water retention and locks carbon into the soil. For growers, adding stable carbon to the soil is almost always a net positive.”Lessons Learned&nbsp; Treehouse was interested in the collaboration as a way to create durable value from a material long treated as an afterthought. “When you harvest almonds, you really end up with four products,” says Joe Gardiner, vice president of business development with Treehouse California Almonds. “Everyone knows the kernel, but you also have hulls, inedible almonds and shells. Historically, the shell has been the forgotten coproduct.”This project stands apart because it aims to function without relying solely on public subsidies. “Grants and subsidies are helpful, but they’re ultimately Band-aids,” Gardiner says. “This is about building a sustainable, profitable marketplace for agricultural biomass.”While ultimately successful, the project has not been without its challenges. To date, permitting has been one of the most difficult hurdles. &nbsp;“We spent two years operating a pilot facility and working closely with air districts to explain how pyrolysis differs from combustion,” Bronner says. “Biochar is not ash or charcoal—the feedstock never touches the flame.”Finding the best locations have also been an issue. “One of the biggest lessons we’ve learned is that biochar projects need to be located where the feedstock is,” Bronner says. “Transporting biomass long distances increases costs and emissions. Ideally, the feedstock, processing facility and offtake should all be as close together as possible.”What’s more, she notes, is that it’s not enough to just make biochar; you need a reliable feedstock supply and a secure offtake. &nbsp;“Flooding the market without demand can create serious problems,” Bronner says.Barriers and Bottlenecks&nbsp; Despite promising examples, scaling has remained difficult. While there’s interest in bioenergy and biochar, there’s also a lot of skepticism. “We’ve seen promising projects collapse after running into permitting challenges or strong opposition from environmental groups,” Isom says. “Our organization has met with more than 60 companies proposing alternatives—everything from biochar and pyrolysis to renewable natural gas, hydrogen and cellulosic ethanol. Only one or two are actually operating, and they’re taking very small amounts of material.”Ludwig noted air quality remains a defining constraint. “Even if an alternative produces far fewer emissions than open burning, if it adds NOX or PM2.5 in the San Joaquin Valley, it can be extremely difficult to permit,” she says.&nbsp;Economics also matter since growers often push back on business models that assume biomass should be free. “If there’s value created, some of that value needs to come back to the grower,” Ludwig says.Looking Ahead&nbsp; The Valley’s transition has been supported by strong incentives. Holt notes the Ag Burn Alternatives Grant Program has executed more than $226 million in grants, supporting alternatives across more than 310,000 acres. “Nearly 92% of material is incorporated into the soil,” she says. “Smaller shares are going to off-site reuse and air curtain incineration.”Still, funding is limited. Holt notes program funds are expected to be exhausted by mid-2026, and about $75 million per year will be needed over the next five years to maintain progress while building new infrastructure.The hope is that the Sitos-Treehouse project will be replicated, something it was designed to create. “This Treehouse project is really our showroom,” Bronner says. “We already have additional projects being evaluated, including one using hazardous forest biomass and another with a large Central Valley sheller. Even though Treehouse represents a small share of the almond industry, we’ve seen time and again that when something works at a small scale, it can be adopted widely.”For Isom, the stakes are clear. “We don’t need a single silver bullet—we need multiple solutions,” he says. “But we do need projects to actually reach the finish line.”Author: Keith Loria&nbsp; Contributing Writer, Biomass Magazine&nbsp;

2026-01-06 - From Burn Piles to Biochar (Biomass Magazine)

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Biochar and localized biomass solutions offer a new way forward for managing orchard and other ag residues in the wake of California open burning bans. 

From Burn Piles to Biochar

From Burn Piles to Biochar

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