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Carbonizing in California

An innovative California-based rancher and forestry professional employs Tigercat’s mobile carbonization technology to improve forest and soil health, mitigate wildfire risk and sequester carbon.

— Paul Iarocci

Dan Falk, owner of Falk Forestry.
Dan Falk, owner of Falk Forestry.
Daniel Falk grew up in northwest Sonoma County, California. He is part of the fifth generation of a California family that has been long involved in timber harvesting and cattle ranching. “I grew up on Richardson Ranch, owned by my great uncle, Harold Richardson. He was my logging and ranching mentor, and he pushed me to get a forestry degree,” says Dan.

Before graduating from Humboldt State University with a degree in Forest Production, Dan and some fellow classmates wrote a timber harvest plan with a registered professional forester as a class project. “When I graduated, we implemented the plan on the Richardson Ranch and from there I got into logging.” Dan leased a sawmill that his great uncle and father owned and founded Falk Forestry. Today the company is active in logging, environmental studies, fire restoration, and fire mitigation services such as forest mastication, fuel load reduction, and establishment and maintenance of fire breaks.

Dan explains that there has always been a wood waste problem on the ranch, and also in the local community. “It was too costly to chip and haul it. I saw an issue that needed to be dealt with. We harvest timber, but we’re environmentalists as well.” As a solution, Dan envisioned a forest-to-range program where his company could take care of the waste wood and fuel load issues while at the same time improving forests and rangeland.

He researched and subsequently purchased the first ROI 500 carbonizer in late 2018, nearly a year prior to Tigercat acquiring the company and its carbonizer technology. (The ROI prototype was subsequently updated in 2019 and rebranded as a Tigercat 6050). “The 6050 had the ability to process all sizes of material with varying moisture content. That’s when I first met Matt O’Connor, who was with ROI at the time.”

Matt joined Tigercat when the acquisition was completed in September 2019, taking on a number of duties related to the carbonizer program. As a product specialist, he worked closely with engineering on the extensive redesign that resulted in the release of the new 6040 carbonizer. Matt is highly involved and very knowledgeable in permitting processes. He leads government outreach, testing and data collection and manages technical and operational support, collaborating with dealers and end users.
The prototype 6040 carbonizer was purchased by Falk Forestry in 2024. The machine has a number of improvements over the 6050 design.
Dan initially put the 6050 to work on the ranch, distributing the carbon-based output back into rangeland. “We test the soil type for deficiencies. Then we can either disc charged or uncharged biochar into the soil, and replant with different types of nitrogen fixing cover crops. We like to use native species.”

Biochar acts like a sponge. It absorbs and stores moisture and nutrients and slowly releases both into the soil. “You can charge the biochar by mixing it with compost,” Dan explains. “We mixed it with our mill residuals, some of our small grind, cow manure, mushroom compost, chicken manure and organic overburden – from either our forestry roads or gravel pits. Then we applied about ten tons of the mixture per acre.”

Dan has seen improvements. “I like to say the grass stays greener for longer. We’ve seen an increase in water retention in the soil to help with the grasses that we feed our cattle.” Dan’s grass fed, grass finished cattle produce high quality beef that is marketed in the local area. For Dan, the biochar production is part of the whole process – earth to table.

Early on, Dan also held many 6050 demonstrations on projects from Sonoma County all the way up to Fort Jones in northern California. Dan credits the time spent on the tours and demonstrations as an important investment that stimulated interest from the right parties and subsequently helped him to secure contracts. “I got the jobs that I have today because of the 6050. For example, East Bay Regional Park District recognized the need for an alternative method to deal with biomass and reduce the cost and environmental footprint of transporting large volumes of material through communities.”

At the turn of the twentieth century, eucalyptus plantations were established throughout California. “It is a dominating species and a challenge to manage,” Dan explains. “The park district wanted to thin these plantations, reduce fire risk and reestablish native species throughout the region such as oak, madrone, redwood and Douglas fir.”

Dan collaborated with Earth Foundries to create a formal proposal and bid to present to the East Bay Regional Park District. Founded by Dede and Roger Smullen, the overall mission of Earth Foundries is to put an end to California’s catastrophic wildfires. The company works with public and private land managers to restore the health of California forests. Partnering with Falk Forestry is helping the company incentivize the removal of forest waste from the landscape by sequestering carbon and creating carbon-negative markets for woody biomass. In fact, the goal is to stop thinking about woody biomass as waste and start thinking about it as a base material with potential for multiple value-added product streams.
Two 6040 carbonizers working side-by-side in California
Earth Foundries’ pair of 6040 carbonizers. Dan is managing this 5,000 ton contract in Grass Valley, California. The conveyer system, newly designed for the 6040, pivots side to side.
Dede was formerly Board President of the Santa Clara County Fire Safe Council. “They did a lot of really amazing forest thinning projects and shaded fuel breaks,” says Dan. Dede and Roger are well connected and very well versed in creating proposals and managing stakeholder engagement. “They collaborate very well with the different counties, the air pollution control board, Cal Fire and state archaeology officials. They are very familiar with Cal Fire processes,” Dan emphasizes. All project collaborations between Earth Foundries and Falk Forestry work within the well-established Incident Command System (ICS) framework that Cal Fire uses in its own operations.

“The officials that run these programs like the structure and security that we can provide by utilizing the ICS and in the people that we have involved such as retired battalion chiefs that run our safety protocols.”

Strict adherence to protocol, planning, and frequent meetings help ensure every project is set up for success. “The companies and the state agencies that we work with tell us we cannot fail. We must have a plan for success.” It is the deep operational knowledge of Falk Forestry combined with Earth Foundries’ project management and administrative expertise that allows the carbonizers to operate safely and efficiently.

Falk Forestry has treated nearly 700 acres of East Bay eucalyptus forest with thinning and mastication prescriptions. Logs from three inch (75 mm) diameter and up are converted onsite to biochar. “They are using the biochar on parklands and putting it back into rangeland and agricultural fields,” says Dan who describes it as a big circle encompassing harvesting, fire mitigation and fire resiliency, sequestering the carbon and then putting it back into the land.
6040 combustion chamber
The 6040 converts 15-20 tons per hour of unprocessed woody material into a high-quality organic carbon product.
So essentially Dan started off using the Richardson Ranch as a springboard and proof of concept for the entire carbonizing process. Today, armed with extensive operational experience, regulatory knowledge and a deep understanding of commercial scale sustainable carbon dioxide removal technology, the partnership of Earth Foundries and Falk Forestry is going after contracts in the municipal and utilities sectors. “It’s growing into a very promising business,” says Dan who purchased the protype 6040 carbonizer in 2024. Between the two companies, they own four carbonizers.

We visited a worksite in Grass Valley at a Nevada County municipal yard where Dan was managing a contract involving the two Earth Foundries owned 6040 carbonizers. The machines were tasked to convert approximately 5,000 tons of material primarily consisting of hazardous trees removed from powerline right-of-way, as well as additional material coming from small landowners around Grass Valley. “We are utilizing the dead material from the fire scarred landscapes and trees that need to be cleared around power lines. Material is also coming from local landowners who also have wood waste problems. The county is developing a community pick-up where they bring all the material to this site. We’re doing a test run of 1,000 tons to see how the community, the county, and the contractor can work collectively to clean up dead and non-merchantable material and turn it into a product that stores carbon and reduces our carbon footprint.”

Getting rid of this material reduces fuel load and aids in fireproofing the community. I asked Dan about public perception. “They like to see that something is getting done for the forest. People are extremely worried about their houses burning down with all the fires in California. They like the fact that it’s carbon friendly. It makes people feel good about how the material is being processed.”
Organic carbon, bagged and ready to be deployed to a broad range of markets and uses.
The conversion process itself emits very little harmful emissions, reduces volume by 90% and creates an organic carbon-based material with many beneficial uses including soil enhancement, filtration and storm water mitigation. It sequesters approximately 25% of the total carbon, keeping it out of the atmosphere for hundreds and possibly thousands of years. And it creates the potential to participate in the carbon credit market. Dan measures production by the conversion rate (the amount of infeed that is converted to biochar in an hour.) Many factors affect this including moisture content, piece size, the type of feedstock and the species. In Dan’s experience, dry material at about 30% moisture content sized from three to twelve inches in diameter provides optimal conversion rates. Dan’s machines average fifteen to twenty tons per hour. Dan feels that aging the material four to six months is optimal both for feed rate and biochar quality – long enough to dry out, not so long that the material starts to lose carbon content. Biochar output by weight is generally about ten percent of the input.

During the 6040 design process, Dan was a valuable resource for the Tigercat engineering team to help separate out which aspects of the 6050 worked and which aspects did not. Dan has 1,800 hours on the prototype 6040. He notes that the new internal ceramic system looks good and that the newly designed and beefier grates are wearing very well. He says that the ability to rotate the grates to balance wear, a feature that he pushed for, is going to further improve longevity.
6040 conveyer system
The organic carbon product retains about 25% of the available carbon from the infeed material and sequesters it for hundreds, possibly thousands of years. Commonly known as biochar, it has many beneficial uses.
“Working with Tigercat has been exceptional,” he says. “Matt O’Connor has been very helpful. He always answers his phone. He’s out to the jobsite working with me on how we can improve the operation and production of the machine. That has been a great experience.”

Dan is impressed with the new water bath and quenching system. The quenching water is contained internally on the 6040, eliminating spillage. Water use is controlled. Because the biochar is entirely quenched, when it falls off the conveyer, it is cool enough to touch.

Dan says that the conveyor, with its ability to swing 105 degrees is also a big deal. The conveyor is fixed to the rear of the machine, folding up into the machine envelope for transport. “It works out well because you could be dumping into a bin and when that bin fills up, you can swing off to another one. That’s been really efficient.” Dan notes that the exterior sprinkler system off the sides of the machines is a great idea. “It’s a really good way to wet down the ember cast zone.” The 6040 is 7 700 kg (17,000 lb) lighter than the 6050 for easier and more cost-effective transport.

Dan is careful to mention the importance of this collaboration. “Working with Tigercat on product updates, anything that needed to be resolved with the machine has been great. They have been right there to take care of it.” As he puts it, “We are at the tip of the spear. We need this kind of involvement to innovate and improve both the machine and the operations. So that’s been very helpful.”

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