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News & Notes

Expect Noise. San Mateo County Parks to Use Air Burner as Part of Quarry Park Fire Fuel Reduction to Dispose of Trees and Woody Debris

On Wednesday, May 1, 2024 San Mateo County Parks will use a new tool to reduce fire fuel in Quarry Park and lessen wildfire risk in the area. In coordination with Cal Fire and the Bay Area Air Quality Management District, the department will use an air curtain burner to dispose of trees and other woody debris from earlier fuel work in the park and downed trees from winter storms.

The contractor operating the air curtain burner will be on site making preparations beginning next week. Park visitors and neighbors should expect noise from large equipment.

When the air curtain burner is in operation on Wednesday, May 1, Mirada Surf East will be closed and other closure dates are forthcoming.

An air curtain burner provides numerous environmental and logistical benefits. The burner’s large container uses an “air curtain” design to capture and re-burn particulate matter, thus greatly reducing smoke, harmful fine particles, and carbon dioxide, the primary greenhouse gas that contributes to climate change. The amount of smoke emitted is comparable to that of a chimney. The burner can process five to nine tons of material per hour and produces far less charred material, which, once cooled, will be dispersed in the area to provide nutrients for the soil. Air curtain burners have been thoroughly tested by environmental agencies, including the Environmental Protection Agency.

Because eucalyptus is a non-millable wood, thus having no mainstream market value, there is currently a surplus of eucalyptus wood in landfills and traditional dump sites, which has made it expensive to dispose. This makes the air curtain burner a valuable tool in the Department’s effort to reduce wildfire risk with minimal environmental impact and at an effective cost.

PRESS RELEASE From San Mateo County Parks: A New Tool to Reduce Fire Fuel in Quarry Park; Site preparations begin the week of April 22, 2024 and will generate noise” on April 17, 2024

Watch How BurnBoss Works

Meet the CharBoss at EXPO Richmond 2024

Air Burners is pleased to present the CharBoss, the world’s first mobile biochar production system, at EXPO Richmond 2024 on April 12 + 13. America’s leading trade show for the forest products industry is the ideal venue to introduce CharBoss, our most recent patented machine, designed under a Cooperative Research And Development Agreement (CRADA) between Air Burners and the U.S. Forest Service.

One system does it all.

CharBoss combines the best of both worlds: biomass waste reduction and earth-friendly biochar production. The trailerable FireBox system burns up to 2 tons per hour, leaving behind 20% biochar, a valuable carbon-rich ash you can sell or mix into the soil.

Cleanly. Efficiently. Economically.

Visit our booth see the CharBoss. It’s a hands-on experience second to none. Talk with our experts to discover how the revolutionary machine can help make your cleanup operations more green-friendly for the environment and your bottom line.

The ins and outs.

CharBoss streamlines forest and agricultural cleanup operations in more ways than one. The self-contained FireBox is trailable and maneuverable. It is ideal for accessing remote forests to mitigate wildfires, navigating obstacles in relief cleanup efforts, and maintaining vineyards and orchards.

CharBoss is made exclusively by Air Burners.

The above-ground refractory-lined FireBox uses a pollution-control system that cleanly and economically turns biomass debris into carbon rich biochar. The air curtain firebox is an end-solution to the world’s growing biomass waste problem. Seventy million tons are collected annually, but only 48% are recycled. As a planet, we can do better. AirEXPO Richmond / CharBoss: News Section burners is here to help. Drop by our booth and learn what CharBoss can do for you.


Please join the U.S. Forest Service and Air Burners at EXPO Richmond 2024 on April 12 + 13 at Meadow Event Park in Caroline County, VA, just 40 miles north of Richmond.

For more ticket info, visit


CharBoss heads to the 2024 North American Biochar Conference.

The CharBoss is a revolutionary machine developed under a Cooperative Research and Development Agreement between the US Forest Service and Air Burners, Inc. The CharBoss utilizes Air Burners’ patented air curtain pollution control technology to eliminate forest slash, make Biochar and protect the environment. This machine will be on display at the 2024 North American Biochar Conference in Sacramento, CA from February 12 to 15. This year’s theme is “Climate Action with Biochar for Economic and Ecosystem Resilience.”

Take a deep dive with guest speaker Mike Schmitt of Air Burners into the CharBoss, the world’s first portable biochar production system that creates biochar out of wood piles. But that’s just the beginning. CharBoss eliminates up to 1 ton of vegetation per hour. The efficient burn rate delivers productive and economic efficiency, leaving behind 25% biochar to sell or return to the soil. The carbon-rich natural byproduct is one of many reasons the air curtain firebox is an end-solution for the world’s growing unwanted wood waste problem. The pollution-control system generates less harmful particulate matter, like black carbon smoke, which improves the air we breathe.

Jointly developed by the US Forest Service and Air Burners, the machine is produced exclusively by Air Burners. The CharBoss uses an innovative patented process to separate charcoal from woody biomass during the burn. The biochar cools quickly after entering the patented quenching system which is designed to minimize water usage. The air curtain firebox is an end-solution for the world’s growing biomass waste problem.

Seeing is believing.

Experience the revolutionary CharBoss at the show. Visit the Air Burners booth to learn more about the world’s first mobile biochar production.

We hope you’ll join us at the 2024 North American Biochar Conference.

Air Burners Launches BioCharger Collab With Rolls-Royce & Volvo CE

By Kathy Wells

Air Burners, a manufacturer of air curtain burner systems worldwide, collaborated with Rolls-Royce and Volvo Construction Equipment (CE) to develop and test the BioCharger, an innovative, portable machine that turns biomass waste into energy.

The BioCharger is the first machine of its kind, combining three innovative steps to provide off-grid power from vegetative waste management. First, it eliminates vegetative waste using air curtain technology to minimize the harmful particulate matter entering the atmosphere. Then, it converts the residual heat energy into electric energy and stores it in a connected Battery Storage Module. Finally, with the accompanying charging mechanism, the BioCharger allows for off-grid electric vehicle and machinery charging.

“While electric machinery becomes increasingly popular in the fight against climate change, when it comes to forest management, we must have practical solutions for charging electric machinery away from traditional power sources,” said Brian O’Connor, president of Air Burners. “The Air Burners’ BioCharger provides that solution and manages wood waste, all done in an economical and environmentally conscious way.”

Vegetative waste is a significant and growing problem — seventy million tons of wood waste are collected annually in the USA, but only 48% of that waste is recycled, leaving the rest to open burns or decomposition, which releases particulate matter and greenhouse gases into the atmosphere. The BioCharger permanently eliminates up to 20 tons of vegetative waste per hour without emitting harmful greenhouse emissions like methane and black carbon — the second biggest contributor to climate change after carbon dioxide.

Air Burners consulted with Rolls-Royce in developing the Battery Storage Module within the BioCharger, a 450-kWh charging station that can recharge multiple battery-electric machines and tools, from chainsaws to excavators. The BioCharger creates and stores enough energy daily to recharge three to six battery-powered machines. In addition, the BioCharger retains enough energy to start itself and continue the cycle the next day.

“The BioCharger is a unique application for our mtu EnergyPack battery energy storage system that I think shows just how versatile energy storage can be,” said Kevin McKinney, Sales Director at Rolls-Royce Solutions America. “The BioCharger’s ability to reduce emissions and generate energy through responsible handling of vegetative waste perfectly aligns with our targets to support our customers with innovative solutions for the transition to clean power generation.”

Volvo CE teamed with Air Burners to prove out the charging capabilities of the BioCharger with its new 23-ton crawler excavator, the EC230 Electric. The EC230 Electric is currently in pilot testing across North America ahead of its commercial launch next year.

“This collaboration with Air Burners for the BioCharger allows us to demonstrate one of the more nonconventional sources to fast-charge our equipment in off-grid locations,” said Dr. Ray Gallant, vice president of sustainability and productivity services, Volvo CE.

Unlike biomass power plants, the BioCharger is a fully portable machine that can be relocated to a new site and be operational in approximately six hours. The machine accepts whole logs, root balls, pallets, crates, and any other clean wood or vegetative waste without sorting, crushing, or grinding. Air curtain burners also do not require any secondary fuel sources like natural gas, reducing costs and easing installation.

Loveland Fire, Big Thompson Watershed Coalition holds training, demonstrations of slash burning machine

By  |

The Loveland Fire Rescue Authority and Big Thompson Watershed Coalition spent several days this week training and teaching local agencies and elected officials the importance of a machine the department acquired earlier this year aimed at wildfire prevention.

On Tuesday, Wednesday and Thursday, the department brought out its Air Curtain Burner unit, an AirBurners BurnBoss machine, to show how it could be used to improve wildfire mitigation and stop the spread of potential fires.

“Anytime we are trying to dispose of waste, the biggest concern is what are the repercussions if it goes haywire,” said Fire Chief Tim Sendelbach. “This device introduces the safety component and the efficiency of being able to do a massive quantity in short order.”

The 10,000-pound green machine can be hitched to a truck and driven on-site to take care of slash, or debris left after logging, pruning, thinning or brush cutting; this can include logs, chips, bark, branches, stumps and broken understory trees and brush.

The unit, once set up at whatever location it is brought to, drops a rectangular box to the ground where slash can be thrown in to safely burn, reducing it to wood ash and biochar, according to a handout from AirBurners.

Sendelbach said the $77,000 unit was secured through a grant awarded to the Big Thompson Watershed Coalition and is now under the possession of the LFRA. He added the department will oversee the deployment of the unit to qualified agencies throughout the Big Thompson and Poudre watersheds.

While the department was able to hold train-the-trainer programs on Tuesday and Wednesday, meant to teach members of different Larimer County agencies in a more detailed format how to use the machine, it was unable to hold an official burn on Thursday for its planned live demonstration due to high winds in the area.

However, the department was still able to share the importance of the machine with those gathered when it comes to wildfire prevention. For those involved at the Thursday event, the education, even without a live demonstration, was a great way to strengthen collaborations between departments in the area.

Sheriff John Feyen said prevention like this is like eating vegetables or going for a run so you can take care of something before it becomes a problem. He went on to describe the unit as another tool in the toolbox for wildfire mitigation.

“Do the prevention we can before the fire gets going,” he said.

Larimer County Commissioner Jody Shadduck-McNally, who also happens to be a member of the Colorado Forest Health council, said handling slash in the county is a big deal and opportunities like this help to connect agencies to resources.

“There is an urgency to deal with this need now,” she said. “This is something that could be catastrophic for Colorado again. It’s not if but when we have the next natural disaster, so we need to do the work immediately with the workforce and tools all coming together in partnership.”

“The only way we can be successful as a response component is if we have something like this underway,” Sendelbach said. “The reality is wildfire response is basically a community based effort. We have to have everyone working together to give the firefighters a chance. And from the preventative side, reducing that fuel is a critical component.”

Loveland Fire Rescue Authority Fire Chief Tim Sendelbach talks with Larimer County Commissioner Jody Shadduck-McNally about the department’s Air Curtain Burner at the Loveland Recycling Center Dec. 7, 2023. While the department was unable to conduct a live burn on Dec. 7 because of high winds, those present said getting to learn about the machine was still very important. (Austin Fleskes / Loveland Reporter-Herald)

Efficient Power Generation from Vegetative Waste

As companies transition to sustainable energy sources, the choice of clean power becomes vital. Green energy sources like wind, solar, and biomass are preferred. An economical and eco-friendly approach is to use wood and clean vegetative waste as fuel. Foresters, farmers, land clearing experts, and disaster recovery teams can now harness power from waste, simultaneously addressing the carbon pollution problem. The Air Burners PGFirebox® offers a compelling solution, contributing to climate change mitigation.

Waste Woes: The Challenge and Consequences

Approximately 20% of global waste consists of wood and vegetative matter, and recycling rates are low due to a lack of demand and environmentally questionable processing methods. Landfilling is no longer a viable option in many regions, leading to higher costs and emissions associated with waste transport and open burning, releasing black carbon, a significant climate change contributor. The PGFirebox® addresses this issue effectively.

Turning Waste into Power: The PGFireBox® Solution

The PGFireBox® is a game-changer for waste elimination and power generation. It’s easily portable, self-contained, and doesn’t rely on secondary fuels like natural gas. Unlike traditional grinding methods, it reduces waste mass by approximately 98%, leaving only a small amount of ash and nutrient-rich biochar. It captures waste heat to generate electricity and doesn’t require extensive pre-processing. With a capacity of up to 20 tons per hour, it produces emission-free energy, which can be sent to the grid or stored in a battery module. The PGFireBox® is an economically and environmentally sound solution for waste reduction and clean energy generation.

Benefits of the PGFireBox®

1. Reduces waste by 98%, leaving clean ash and biochar.

2. Generates electricity, potentially exceeding equipment requirements.

3. Supports a more secure electrical grid through distributed power.

4. Reduces black carbon emissions and greenhouse gases.

5. Easily relocated, eliminating waste travel zones.

6. Provides cost savings and environmental benefits.

Global Impact

AirBurners, with 25 years of experience, continues to meet the growing demand for waste elimination and pollution control solutions. The PGFireBox® extends our commitment to providing greener solutions for businesses and industries worldwide.

Behind The Curtain

On an early June morning in Minnesota, the sun is barely visible through a blurry haze that shrouds the landscape from the ground up. 1,300 miles to the east, New York City’s skyscrapers are engulfed in an eerie curtain of smoke, and even those who aren’t particularly sensitive to air quality are cautioned of the outdoors. Such has been the case for weeks, likely with much more in store. The cause, in this case, is not one derived within the states themselves — or even the country — as the rampant, uncontrolled wildfires all across Canada are wreaking havoc on the air across a significant portion of the U.S. From the Midwest to the Northeast and Mid-Atlantic, some states are recording their worst-ever air quality.

But the U.S. is no stranger to unprecedented wildfires. The western part of the country continues to break records with each consecutive wildfire season, heightening the concerns of those in the area, as well as foresters, firefighters, environmentalists and other stakeholders. While there is no silver bullet, aside from climate change mitigation strategies, forest management — thinning and disposal of high-hazard material wherever possible — is a leading solution. To Brian O’Connor, president of Palm City, Florida-based Air Burners Inc., it is perception — or rather, misperception — that is perhaps the biggest challenge in the increasing deployment of the company’s technology — air curtain burners. In particular, the impression that they are polluting incinerators.

Nevertheless, the units, which have been studied and tested at length by the U.S. EPA, are steadily gaining traction — for example, many of his units have been purchased and are used by Cal Fire, which is using them for hazardous fuel reduction activities. “Wildfire mitigation today is a big deal,” O’Connor says. “Our machines get sold to many fire agencies in additional to Cal Fire — in high fire danger areas in Nevada, Arizona and other places in the western U.S., and even Australia. It’s a matter of cleaning the brush out and eliminating it in the machine. And because it’s clean wood waste, you’re left with pure carbon ash and biochar that’s turned back into the soil. There is no hauling or grinding. You can put root balls in there, logs, branches — if it fits, it goes.”


Trial, Error and Success
Backing up to the beginning, as for how O’Connor came to own Air Burners — and ultimately leading it to success — it was very much a case of curiosity and passion. “Air Burners was doing welding for a company I owned at the time, about 35 years ago, and I learned they had a really cool environmental idea, but just couldn’t sell any of the machines. The inventor had just gotten things rolling with a rental fleet, but unfortunately passed away. The company then bumbled along mostly doing fabrication jobs, but eventually went bankrupt. The largest creditor hung onto the company for several years, but didn’t know what to do with it, and as I got to know them through some subcontract manufacturing, I began to understand what the machine was, and why they couldn’t sell it.”

O’Connor describes himself as somewhat of an environmentalist, and the purpose of the Air Burner technology — reducing smoke and particulate matter from burning — hit home, as a person with asthma. An engineer by trade, O’Connor began to do research on the air curtain concept. “I found it very interesting, and I offered to buy the company,” he explains. “It was mostly tooling, welding and fabrication equipment, but I put on my engineer hat to understand this whole concept and how it works. I spent about a year building test machines and doing a variety of tests, trying to get this concept down.”

The first full machine that O’Connor built — it didn’t work very well, he admits. “But I got a better understanding of the air curtain and what it’s supposed to do — how it’s supposed to trap particulate matter — so ultimately, I came up with a design that did work, and really well. In fact, that very first machine that was modified several times, it has been 26 years and it’s still in use today.”

The principle of the air curtain is relatively simple. Clean wood waste such as logs or slash is loaded into a firebox and an accelerant is used to ignite the wood. As the smoke rises off and the wood burns naturally, smoke particles rise up on the hot gasses and encounter the air curtain, which acts like a lid, trapping the smoke and causing it to reburn. “Once the particles are small enough in the reburning process, they can escape through the air curtain and off into the environment,” O’Connor says. “But now, it’s reduced so much that it doesn’t bother anybody. That’s the whole purpose of an air curtain — to create a secondary burn chamber and eliminate the smoke, and it does it very well.”

The better the machine is operated, the better the control is for the air curtain, and the further emissions are reduced, according to O’Connor. He says the machines burn wood waste about 40 times faster than opening burning. “From an economic standpoint, it’s the fastest way to get rid of your wood waste,” he says. “Most of what we do are the fireboxes, which are self-contained. To run it incorrectly is to overload it, or pile wood waste above the manifold that’s creating the air curtain, because then it gets dispersed in many different directions and doesn’t do its job. An operator will soon learn it burns much slower then.”

While there are misconceptions of the systems being a form of incineration, O’Connor emphasizes that they are not. “There are no gas jets, no secondary hydrocarbon fuels that support combustion — we only use clean wood waste, and it has to burn naturally,” he says. “You light it as you would an open burn with a drip torch, and then once it’s burning, you just add wood. As it burns down you add more, and at the end of the day, you rake out the ash and the biochar, and life is grand.”

O’Connor says the machines have been tested extensively all across the world, including by the U.S. EPA. “We were really honored to be asked to join them in a cooperative research and development agreement, or a CRADA, and we were a partner for seven years. We did a lot of testing with them and a lot of interesting projects.”

Air Burners has a machine on every continent aside from Antarctica, and resultingly has a library of data.


In-Woods Innovation
Currently, wildfire mitigation is one of Air Burners’ biggest markets. “We have a variety of machines, and all are self-contained and portable,” O’Connor says. “They arrive on-site and ready to do the job. You can drag them around, and they’re easy to take care of.”

One major advantage of the machines is that they don’t require any chipping, grinding or preprocessing of the biomass, so long as it fits.

There are many different Air Burner machines under five lines — the Power Series, FireBox, Roll-Off FireBox, Boss Series and Trench Burner — with the same core concept. The CharBoss, a smaller model in the BossSeries line, was designed in partnership with the U.S. Forest Service. Based on the Air Burners BurnBoss design, this machine was further developed with an internal system to automatically produce biochar from the waste materials. “Their [Forest Service] goal was to recycle the biochar back to the forest floor, but we do have some customers that use the bigger machines and manually rake out the biochar and sell it,” O’Connor says, adding that a customer in Florida had been selling biochar for approximately $125 per cubic yard, producing around 10 cubic yards per day. “So, he was making over $1,000 a day on biochar, and on top of that, getting paid to eliminate the waste.”

The FireBox and BossSeries lines are popular, but the right fit all depends on the customer’s intentions. “We have customers in California that have a fleet of the BurnBosses and TrackBosses, and they deploy them across the mountain ranges,” O’Connor says. “They have workforces that come out and handload the machines. The BurnBoss is ideal to move from pile to pile to eliminate them, rather than move all the piles to one particular site.”

The standard FireBox allows customers options in terms of capacity, requiring as little as three to four tons per hour, but can process up to 13 or 14 tons an hour. “It’s tough sometimes when people look at our elimination numbers — they’re used to grinders — and they might say their grinder does 50 tons an hour,” O’Connor says. “But they’re putting 10 tons in and getting 10 tons out. If you put 10 tons into our machines, you get a couple pounds of ash out. We’re eliminating it, and that’s a big difference.”

As for what Air Burners is most excited about, O’Connor says its Power Series is it. As its name suggests, the machines do just that — generate electricity. “From the beginning, I have always thought that we need to make power — there’s just too much potential energy than to simply burn the material,” he says.

But that idea turned out to be rather complicated. “It wasn’t a simple problem,” O’Connor says, mostly because when looking at portability, there were no good options for generators in the 100- to 300-kilowatt range. After a number of years, Air Burners connected with Atlanta, Georgia-based ElectraTherm, which is owned by BITZER. The company manufacturers an organic Rankine cycle generator that Air Burners uses exclusively. “They have the most installed power of anybody in ORCs, and they’re focused on the smaller sizes,” O’Connor says.

But another issue was that these ORCs weren’t able to work offgrid. “That was another technical problem, but they can now, as we have developed a little microgrid,” O’Connor says. “Our BioCharger has four components — a cooling module, a firebox module, a power module and a battery storage module.”

Air Burners has also partnered with Volvo, which is assisting with knowledge and technical expertise on battery-powered machinery, and Rolls Royce, which builds the chargeable batteries for the system. “All day long, you run your battery-powered excavators, forklifts, loaders, etcetera, eliminating waste,” O’Connor explains. “In doing this, you’re making electricity and storing it in the battery storage module. At night, you plug in your battery-operated machinery, and they recharge.”

He adds that this system is particularly helpful in places like California, which, as of next year, is banning the sale of new small gas engines — even chainsaws. “So here is the opportunity to eliminate this waste, which there is no use for, turn it into energy on-site, and put the energy into powering the machines. It’s a really cool thing.”


Building Out
On a final note, O’Connor says he believes the air curtain burners are turning the notion that biomass energy is expensive on its head. “You’re getting paid to eliminate waste and generate electricity that can be used on-site with the BioCharger, or sent into the grid, with our on-grid PGFireBox System,” he says. While it seems like a no-brainer, he believes the technology is still fairly misunderstood. “People look at us and think that since we’re burning things, it can’t be good,” he adds. “I think the biggest issue is understanding what our machines actually do — they are a pollution control device. And to the skeptics, we say come look at it.”


Author: Anna Simet

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Air Curtain Burners: An Innovative Alternative to Chip & Till Prescriptions for Woody Biomass Reduction

Executive Summary
There are air quality regulators in the western US encouraging agricultural land managers to reduce wood waste by chipping and incorporating wood chips into orchard or farm soils, rather than burning the wood. To reduce air quality concerns, this may seem like a reasonable and fast disposal method (out of sight out of mind) but this prescriptive method may hold unintended consequences to nutrient availability that may impact soil productivity.

Just because the wood is no longer visible does not mean it has no further effects to the farm. When a material with a high carbon to nitrogen ratio (C:N) is introduced into the soil, it can limit plant available nutrients and thus affect crops. Introducing wood directly into the soil is detrimental because:

  • Wood decomposition can limit soil nutrients available to the planted crop.
  • Limiting nutrients can reduce growth and crop value.

To determine if Chip & Till will limit crop yields, farmers with excess wood may benefit by evaluating effects to soil productivity. Consultation with Natural Resource Conservation Service (USDA-NRCS) or the Agricultural Research Services (USDA-ARS), for site-specific soil recommendations is suggested.

The CharBoss (Air Burners Inc.) offers an alternate methodology that converts wood to charcoal (Biochar), reducing regulatory concerns of smoke and other emissions while also creating a product that improves soil productivity. This work is eligible to be funded through USDA programs (CSP 384A – Biochar Production from Woody Residue) as the benefits of biochar are recognized by both federal and state agencies.

The CharBoss offers an innovative solution to wood disposal that can reduce greenhouses gases while improving soil productivity. The CharBoss can:

  • Reduce regulatory concerns of smoke and other emissions while also providing the opportunity for carbon credits to farmers.
  • Create biochar that enhances:
    • Soil organic matter
    • Soil/water holding capacities
    • Soil nutrient exchange
  • Potentially be funded through USDA programs


There are air quality regulators in the western US encouraging agricultural land managers to reduce wood waste by chipping and incorporating wood chips into orchard or farm soils rather than burning the wood. For those with the immediate concern of avoiding emissions (PM2.5 & gases), this may seem like a reasonable and fast disposal prescription (out of sight out of mind). Unfortunately, this prescriptive method may hold unintended consequences to soil nutrient availability, leading to cumulative effects that may reduce farm yields. When an organic material with a high carbon to nitrogen ratio (C:N) is introduced into the soil, it can limit plant available nutrients and thus affect crop yields.

In the absence of a full Life Cycle Assessment (LCA), this brief report attempts to explain how and why this may not be an appropriate method of disposal and offers an adaptation to existing burning which may meet the goals of all involved.


Biomass can steadily accumulate in fruit and nut orchards as result of the yearly pruning required for tree health and vigor or accumulate quickly if a change in the desired crop requires the extraction of the orchard. Often demand in the consumer market or water regulation can drive such decisions (Hester, 2021, Kushman, 2022 and Bland 2023), in addition to the effects of Climate Change.

All organic matter is ultimately potential soil and woody material is not the exception to that rule, however, of all of the ingredients to make soil, wood takes the longest to decompose. Wood left whole and on the surface of the soil can take 50-100 years to decompose, depending upon factors like species of the wood, its density and the woods exposure to the decomposing elements like temperature and moisture (Gough, 2007). Regardless of the reason for the accumulation of wood, because it is slow to decompose often a faster disposal method is needed once the amount reaches a tipping point. Not many farmers have acres of land not in production to store wood, since they rely on the entirety of their available farmland to remain financially solvent. Few farmers have the operational space to wait out decomposition of wood or compost it, before using it as a soil amendment; nor are they willing to risk the liability of having piles of wood vulnerable to wildfire.

Typically, wood piles are burned but regulators are concerned with smoke and emissions, hence their desire for chip and till as a fast and smokeless means of disposal.

Reducing the size of wood by chipping speeds up the decomposition process. Once chipped, there is a greater surface area exposed to the elements and decomposers (bugs and fungi) accelerating the decomposition. Similar to composting, if the wood is then placed in a consistently moist environment (Gough et al., 2007); the combination of increased surface area, water and biologic activity from decomposers accelerates the production of soil. This is where the Chip & Till prescription falters, while it is out of sight and mind, it can still have unintended consequences.

Since their objective of smokeless disposal has been achieved, air regulators seem to end the prescriptive effects assessment at this point and fail to analyze the effects of wood chips on soil health. The prescription’s problem is the assumption that the wood will add to the soil’s productivity immediately and not have a potentially short-term detrimental effect. Unfortunately, it is also the part of the prescription that has the greatest potential consequence to a farmer surviving from year to year on crop yields that can rise and fall based on the plants ability to access nutrients.

As previously mentioned, wood has the highest carbon to nitrogen ratio of all plant matter. Organic soil amendments such as compost, typically have a recommended C:N ratio of 30:1 (Cornell University). When wood chips with a potential C:N ratio of 500:1 is added to the soil, available nutrients may be reduced as the soil biota works to overcome the new high carbon food source The size of the wood chip also plays an integral role in the process. The larger the wood chip, the longer it will limit plant available nutrients. So, if wood chips are utilized as a soil amendment, the finer the wood chip is in size, the less amount of time it will limit plant available nutrients. An economic factor to consider is that smaller wood chips cost more to produce. While it may be possible for farmers to add wood chips to the soil in active fields with minimal to no effects to acre yield, it would require intensive soil testing and likely the application of fertilizers to overcome the effects of the wood chip additions.


Air Curtain Burners - An Innovative Alternative
When wood decomposes, the carbon collected during its life cycle is released forming the gases; carbon dioxide (CO2) and methane (CH4) (Kipping et al. 2022). Biomass can be consumed by either flora and fauna living in the soil, or during controlled or uncontrolled burning. Burning also can produce a fine particulate (PM2.5) which is taken aloft in the rising smoke. The production of smoke and PM2.5 are the issues of concern for the air quality agencies.

As an alternative to the Chip and Till prescription, Air Curtain Incinerators (ACIs), can be utilized. ACI equipment is a low-smoke disposal option, that can capture carbon through the formation of charcoal; reducing Greenhouse Gas (GHG) emissions in agriculture. When an ACI like the BurnBoss or CharBoss are used; the volatile gases released from wood are largely consumed with the creation of the charcoal, an agriculturally viable product. These two mobile ACIs have the ability to minimize carbon loss by keeping it in the form of charcoal, thereby preventing carbon from compounding with oxygen to form CO2. While tilling in the chipped wood typically delays the release of carbon in the form of CO2 as it takes time for decomposers break down the material. As the decomposers respire in the soil, they also release methane CH4; which is a far more potent Greenhouse Gas (EPA 2023). By converting the wood to charcoal with an ACI, carbon stored in wood is stabilized.

Testing by the USFS Rocky Mountain Research Station has determined that the resultant charcoal is greater than 80% carbon. The brittle charcoal may weather (freeze/thaw or crushing) into smaller particles, but it has a low likelihood of being taken up by plants, which gain carbon in the form of CO2 gas. When added to soils limited by available water and plant-available nutrients, this sequestered carbon can bring improved productivity to some farm soils. Therefore, we can assume the conversion process of stabilizing carbon as a charcoal, then using it as a soil amendment; is a form of carbon capture. To summarize the process, woody farm plants acquire the carbon from the atmosphere, the ACI coverts the plant material into stabilized carbon in the form of charcoal before it can be lost to wildfire or decomposition. It can then be utilized to increase soil productivity. Both ACI’s operate at temperatures sufficient to kill all plant diseases and pests. ACIs provide a long-term benefit to farms.

The BurnBoss produces charcoal in batches and was originally designed to burn material to ashes. The BurnBoss can produce only small batches of charcoal. In contrast, the CharBoss continually produces charcoal as new wood is placed into the equipment. In recent testing, the CharBoss was estimated to have a conversion rate of 30% producing 600 pounds of charcoal per ton of wood. While the BurnBoss and the CharBoss both are efficient at reducing biomass, the CharBoss has the added benefit of producing charcoal in quantities sufficient to be marketed to farmers or others.

Within the burn chamber of the ACIs, the heated wood forms charcoal on the wood surface and volatile compounds are released. As charcoal forms on the surface of the wood and the exothermic reaction moves into the wood, charcoal is exfoliated further exposing the heated wood to form more charcoal. The difference between the ACIs is that the CharBoss accelerates the process by adding agitation to the burning wood, so brittle charcoal is rubbed free and drops out of the burn chamber to be extinguished in a water bath. This quenched charcoal is stable and no longer able to bond with either oxygen or hydrogen to form CO2 or CH4.

The charcoal (biochar) made from the ACI units has been seen to increase both water and nutrient holding capacities in the soil. It can be added to other organic amendments or used alone as an amendment. Applications of unamended biochar can be timed to crop dormancy or blended with other organic amendments (mulches, manures…) to offer the greatest benefits to a given soil type.


With the potential for the Chip & Till to limit crop yields, it may be prudent for farmers with excess wood to consult on soil productivity risks as well as obtain information on alternative methodologies. Consultation with NRCS (USDA-NRCS) or the Agricultural Research Services (USDA-ARS); for site-specific soil recommendations is suggested. These government agencies also have new programs that may help farmers to pay for the conversion of wood to charcoal for soil amendments. This work is eligible to be funded through USDA programs (CSP 384A – Biochar Production from Woody Residue) as the benefits of biochar are recognized by both federal and state agencies.

The CharBoss offers a methodology that could reduce regulatory concerns of smoke and other emissions while also meeting the soil health objectives through funded USDA programs.


Alister Bland 2023. Mangoes and agave in the Central Valley: California farmers try new crops to cope with climate change.

Jessica Leigh Hester 2021. What are Almond Growers Uprooting Their Orchards?

Rick Kushman. 2022. California Almond Acreage Drops in 2022 – First Time in Decades.  California Almond Acreage Drops in 2022 – First Time in Decades (

C.M. Gough, Vogel C.S., Kazanski C., Nagel L., Flower C.E., Curtis P.S.  2007.  Coarse woody debris and the carbon balance of a north temperate forest.  Forest Ecology and Management 244 (2007) 60–67.

J.R. Butnor, Johnsen, K.H., Sanchez, F.G., and Nelson C.D.  Impacts of pine species, stump removal, cultivation, and fertilization on soil properties half a century after planting.

Cornell University, Cornell Composting.,%3A1)%20in%20your%20compost.

Kipping, l., Gossner M.M., Koschorreck M., Muszynski S., Maurer F., Weisser W.W., Hehmlich N., and M. Noll.  2022.  Emissions of CO2 and CH4 from 13 Deadwood Tree Species is Linked to Tree Species Identity and Management in Forest and Grassland Habitats.  Global Biogeochemical Cycles Vol 36, Issue 5.

EPA.  2023.  Global Methane Initiative.  The importance of Methane.

USDA-NRCS, CSP 384A.  Biochar Production of Woody Residues 2019.

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Charboss, the World’s First Mobile Biochar Production System, Was Put to the Test—and Passed with Flying Colors.

On Tuesday, April 4, 2023, the ongoing battle against climate change took a turn for the better. At a biochar production demonstration in Harrisonburg, VA., Air Burners demonstrated the power and cost-efficiency of how the new CharBoss turns unwanted wood waste into biochar, a nutrient-rich byproduct you can sell or use to restore damaged soil.

The patented, advanced technology is similar to the Air Burners trailer-mounted BurnBoss, a towable FireBox that cleanly and cost- effectively eliminates wood waste, including whole trees, stumps, and logs. Like the CharBoss, the BurnBoss is also ideal for forest management, wildfire mitigation, and land clearing operations. The Boss series of machines use air curtain pollution control to eliminate Biomass debris 40x faster than open burns, reduce harmful smoke and particulate matter, and create nutrient-rich carbon biochar that can improve the health of the soil and your bottom line. In addition, each Boss series machine has the mobility to access remote, hard-to-reach areas and the maneuverability makes it easy to avoid obstacles in smaller spaces.

The above-ground, fully-assembled CharBoss and BurnBoss require no grinding, hauling, or permanent facilities. While both eliminate wood waste and create biochar, CharBoss does it with a twist—and adds a shaker table to the burn box that drops material to a conveyor belt where it gets cooled and converted into biochar.

What makes biochar so valuable?

Biochar is a nutrient-rich carbon residue that can amend and restore soil to increase fruit and vegetable crop yields and help restore forests. Biochar also removes impurities and toxins during water filtration, making it ideal for storm water management, mine land reclamation, waste water treatment, odor absorption, agricultural BMPs, and as a replacement for activated carbon.

Thank you.

Air Burners, Inc. is grateful to the following organizations for sponsoring the Biochar Production Demo:

Virginia Department of Forestry

City of Harrisonburg Public Works Department USDA Forest Service Wood Innovations


New Forest Technology Offers Alternative to Burning Slash Piles

By KATE HESTON | Daily Inter Lake

Forest management activities are a major part of life in Northwest Montana; they create valuable products like lumber and employ many across the region.

But in the process, timber harvests also generate woody waste that has little economic value and act as fuel for wildfires, known as slash piles. Burning slash piles releases most of the wood’s beneficial carbon into the air through thick smoke and particulate matter; what’s left is ash.

That’s where the CharBoss comes in, and it just came to Montana.

The Forest Service, working with a private company in Naples, Florida – Air Burner, Inc. – created the mobile machine that converts the woody waste into biochar, a nutrient-rich product with restoration and enhancement potential, specifically in the soil.

Debbie Page-Dumroese, a researcher with the USDA Forest Service Rocky Mountain Research Station, is a leading expert in soil enrichment and the use of biochar. She helped develop and patent the CharBoss technology.

“This allows us to put a pulse of organic matter back into the soil so the soil can do everything we expect it to do,” Page-Dumroese said in an interview last week.

The Rocky Mountain Research Station and the Flathead National Forest showcased the machinery Feb. 16 during a presentation near Coram. Page-Dumroese was present at the event, among many other industry professionals and interested patrons.

A CharBoss will be used in the Lake Five and Coram area, and the data will be collected during the forestry work.

“The work that the Flathead will be doing here will be some of the first scientific data we have,” Page-Dumroese said at the event.

Scott Snelson, a district ranger in the Spotted Bear Ranger District of the Flathead National Forest, wanted the CharBoss to come to the Flathead because it helps with the adverse effects logging has on the climate and air quality.

“We have a lot of piles that we are essentially lighting and sending the majority of the carbon dioxide back into the atmosphere,” Snelson said. “This is a way for us to capture that material and turn it into stabilized carbon for our benefit.”

The event showed how the CharBoss – a dumpster sized machine that actually converts the slash into biochar – operates without an overuse of smoke, in turn creating nutrient rich, charcoal like material.

Biochar, according to the Rocky Mountain Research Station, can boost soil water holding capacity, promote vegetation growth, build landscape resistance and increase carbon sequestration potential in soil. They identified four main purposes for the product: agriculture, forest restoration, mine reclamation and tree nurseries.

The woody biomass that goes into the machine is leftover product from forest operations, like stems, limbs, leaves and other parts of trees. There is a motor across the top of the bin that creates an air curtain, preventing the smoke and particulates from escaping. An arm in the machine moves back and forth while the wood burns to move the overly burnt wood out of the way, preventing the creation of ash.

Page-Dumroese said the machines are helpful in wildfire mitigation work, especially in places where structures are nearby. The machines could be used by forestry departments, forestry contractors, or even compost facilities and landfills.

She also said that the machine can be replicated to a smaller version, such as a kiln or a small controlled fire pit.

The event in Coram showcased one of these kilns burning slash into biochar, a smaller option of the technology. While the kiln does not have an air curtain to avoid excess smoke, lighting it from the top down and off of the ground creates a flame cap that helps to keep more nutrients in and prevent the wood from burning down to ash.

“I started doing this a couple years ago and I have never had as many green beans as I do now using biochar,” Page-Dumroese said, talking about putting biochar into her garden soil.

There is some hesitation with the new product. Keith Hammer, who attended the event, said that there is worry that the biochar, by removing slash piles, will impact habitat and not help the forest in the greater context of carbon sequestration.

Hammer, Chair of the Swan View Coalition in Kalispell, an environmental group, worries that the new biochar binds up water and nutrients that plants need, in turn preventing those plants from getting those nutrients right away. He cites a paper written by Page-Dumroese from 2017, which can imply that in certain cases, leaving slash spread on the ground compares favorably to putting biochar on the soil.

Hammer noted that he recognized the machine is targeted toward slash caused by logging, but worried about the future and expense of removing all slash piles.

“Leave the forest alive and standing,” Hammer said. “... nature has been at this for a long time.”

Page-Dumroese recognized the concern, agreeing that slash piles can be habitat for animals like rabbits and gophers. But she assured that foresters are not going to burn all slash piles, mainly just the massive ones at log landings, specifically to help native vegetation grow faster on the sites.

According to Snelson, the CharBoss and biochar technology will improve the ecological base in Montana forests. He also noted that if we were to embrace the technology, “we could be a real climate leader.”

Rather than releasing the carbon dioxide back into the atmosphere, this technology lets people trap the material and turn it into stabilized carbon – improving the atmosphere and the soil, Snelson said.

Tim McEntire, a Northwest Region Representative with the Montana Logging Association, attended the event in Coram as well. He said that Montana loggers look forward to the continued push to diversify the lumber business.

“This is just another tool we can use,” McEntire said.

Reporter Kate Heston can be reached at or at 758-4459.

The CharBoss, a machine that converts woody material into biochar, is seen on Feb. 16, 2023 at a showcase event near Coram. (Kate Heston/Daily Inter Lake)

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