Urban Biochar: From Pilot to Pathway in Debris Management
- Sarah Hon Gaskin
- Nov 28, 2025
- 5 min read
Updated: Dec 18, 2025
Original article published in the TCIA Magazine
As professionals in tree care, the challenges of wood chip management is nothing new. While traditional methods such as mulching and dumping have been the norm, a groundbreaking approach has been emerging: biochar production through pyrolysis, right in the heart of our cities.
This story delves into my recent experience, as the project leader at A Plus Tree, in launching one of the first advanced biochar pyrolysis units of its kind cleared for use in an urban setting, what others are doing, and explores what it could mean for our industry.
The Genesis of Our Biochar Journey
Like most endeavors, it began with a problem: too many woodchips with nowhere to go but the dumps. Like many of you, we try to offload to other avenues —asking clients to keep them, using ChipDrop, and even attempting a mulch division. However, there’s still too much excess AND we wanted a more innovative and sustainable approach that could also help solve a broader problem.
Maybe you've heard of Biochar, maybe you haven't. But it's a carbon-rich material created from woody biomass, and used as soil amendment. We’ve been using it in our Plant Health Care programs for years. Incorporating it into our practices was a no-brainer for soil health, water retention, and even pest and disease resistance. It also locks in carbon for centuries, making it a valuable tool in combating climate change. (As oppose to mulch, which releases all the carbon back into the atmosphere.) Not that woodchips-to-biochar is a new idea, or that others aren’t doing it, but no one we knew were doing it on a larger scale within the confines of a metropolitan area.
Which led me to the thought: “How hard could it be?”
And with those naively ambitious words, in 2019, I got the green light from our CEO, Cyrus DeVere, to embark on a pursuit to bring this idea to reality. Little did we know, it would take 4 years and a myriad of seemingly never-ending obstacles.
Fueling the Vision
Visions don’t fund themselves, no matter how great they are. We knew this project was going to cost a lot of money; money we didn’t have. So I googled all the Biochar experts in California and found a guy. Raymond Baltar, someone whose vision matched ours perfectly, happened to live nearby, and was enthusiastic about helping us figure it all out. We welcomed him as our Biochar specialist and partnered with his organization, the Sonoma Ecology Center, a nonprofit with significant experience in managing large grants. Together, we secured a state grant from CalFIRE’s Urban and Community Forestry program, which was instrumental in getting this project off the ground. The goal was to prove the model that woody waste materials produced by the urban tree care industry can be successfully upcycled into biochar.
The funding not only covered equipment and site preparation, it also covered permitting costs, air quality reports, tree planting, and community outreach. We were also expected to invest some of our own money as well, about 20% of the awarded amount.
A year after grant submission, we were awarded $1.2 million. It was more than just dollars; it was an endorsement of what this could become.
Choosing Technology Wisely
When it came to choosing the right pyrolysis technology, we needed something that could handle urban realities: compact footprint, low emissions, and scalability. After researching multiple systems, we landed on ARTi’s unit. It checked all the boxes– within our price range, scalable, fully containerized, mobile, emissions-controlled, and capable of processing urban wood waste with minimal pre-processing.
With this unit, we felt confident that we could prove our model at a practical scale, meet air district requirements, and demonstrate that clean biochar production can happen within city limits. The unit requires only a small amount of natural gas to start up, but once it’s running, it sustains itself by recirculating its own gases. Emissions are remarkably low, making it a truly clean and viable solution for cities looking to manage wood waste sustainably.
Navigating the Regulatory Landscape & Opening Day
The permitting process to launching our pyrolysis unit was far from straightforward and hurdle after hurdle, especially in the heart of the Bay Area in Northern California. As with most bureaucratic agencies, new ideas are often met with hesitancy as they grapple with unfamiliar concepts and fear deviating from the norm.
We encountered significant regulatory challenges with the Bay Area Air Quality Management Board (BAAQMD) and then a major setback when the U.S. EPA classified the ARTi unit as a "solid waste incinerator". This classification effectively deemed its operation illegal in urban environments, since wood chips were viewed as use in Municipal Solid Waste (MSW).
In August 2024, after another 10 months of meetings, appeals, and detailed letters explaining the technology, the EPA reversed its decision, exempting our unit from that classification.
On May 3rd, 2025, we officially launched one of California’s first advanced biochar pyrolysis units cleared for use in an urban setting, with a ribbon cutting ceremony and all!
This was a HUGE WIN, not just for us, but for the broader biochar industry, potentially paving the way for others to follow.
This unit is now producing 2 Tons of biochar daily from 10 Tons of woodchips.
The Power of Partnerships
The project also wouldn’t have been possible without the right partners. Sonoma Ecology Center, our non-profit partner, was instrumental in securing and administering the grant. ARTi, our technology partner, collaborated closely with us to adapt their pyrolysis unit specifically for the arborist wood chips generated in urban tree care. Finally, Napa Recycling & Compost Services provided us with something truly rare in urban settings: ample space. Their existing site not only offered the land to operate but also already held some of the necessary zoning and permits.
We could never have accomplished this alone; such collaborations are truly what make innovative projects possible.
Future Considerations & A Call to Action
Okay, let's be real: most tree care companies just aren't going to buy a massive pyrolysis unit. The sticker shock alone is enough, not to mention the permitting nightmares and the sheer headache of running the thing. But that doesn't mean smaller companies can't get in on the biochar revolution.
One solid option is to look for partnerships with local recycling centers. These places often already have their permits sorted and plenty of room to produce biochar. By working together, tree care companies can use existing facilities and share the operational expenses. It's a smart move that benefits everyone.
Getting our urban biochar unit off the ground was tough, but honestly, it's been just as rewarding. We hope our story inspires other tree care companies to find new ways to handle all that tree debris.
Ideally, everyone would shift towards using biochar instead of just mulch. Tree care companies and Arborists need to collaborate to promote the use of biochar in urban soils. Our urban soils are in such poor condition and desperately require amendments like biochar and compost to ensure our trees, shrubs, and turf thrive.
The path we've taken at A Plus Tree demonstrates that with determination, collaboration, and innovation, it's possible to turn urban wood waste into a valuable resource. We encourage other tree care companies to consider biochar as a sustainable solution to debris management. Whether through investing in pyrolysis units or forming strategic partnerships, there's a role for everyone in this transformative journey.
Sarah Gaskin is the VP of Strategic Initiatives with A Plus Tree, LLC, who spearheaded the project and led it with Raymond Baltar with Sonoma Ecology Center. The project was funded by CalFire and now operates at the Napa Recycling & Compost facility.
Partners:
Sonoma Ecology Center - Non-profit grant partner and co-project leader
ARTi (Advanced Renewable Technologies) - Manufacturer of the Pyrolysis Unit
Napa Recycling - Actual location of operations
CalFIRE Urban and Community Forestry Grant - Source of main funding
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