Biochar benefits studied in the Blackfoot Valley

By Jean Pocha, Pathfinder Correspondent

GOLD CREEK Emerging technology and forest product utilization was the focus of the forest tour in the Gold Creek area Oct. 25. 

More than two dozen people observed the Tigercat Carbonator 6050 make biochar out of slash piles as part of forest thinning and fuels reduction work done on land managed by The Nature Conservancy (TNC), Bureau of Land Management (BLM), U.S. Forest Service and private landowners.

Land managers discussed biochar production in the Blackfoot and challenges of implementation.  

"The ultimate goal of the biochar project was to reduce the burning of slash piles," said Jennifer Hensick, former Missoula District Forest Service Ranger. "After walking through a project where there were thousands and thousands of slash piles and I could touch a pile with either hand as I walked along, I thought that there had to be a better way than sending all this material into the atmosphere."

Biochar is a material that's produced by burning biomass in a low-oxygen environment long enough to produce charcoal, but not so long that the feedstock turns to ash. The finished biochar is used as a soil amendment to increase water holding capacity and the soil microbe environment. In addition, soil application puts carbon back into the earth for long-term storage.

The benefits of biochar were first realized by looking at the Terra Preta "Dark earth" soils in South America, where indigenous people had amazing yields on sandy soil in areas around their firepits. Research by Cornell University has shown that the "Dark Earth" soils there have five times the carbon content of other local soils.

"The area where the biochar was produced was part of a forest thinning and fuels reduction project. Normally these projects create a huge amount of slash that just gets burned, releasing smoke particulates and carbon into the atmosphere," said Michael Albritton BLM Fuels Specialist. "We(BLM and TNC) thought we would use this as an opportunity to try out biochar production, so we brought in the largest machine you can get into the woods to utilize the slash."

"The biochar project is an attempt to develop some value from the low value by-products of forest restoration and fuels reduction," said Mike Schadel, The Nature Conservancy (TNC) Forester. "Burning slash piles creates smoke and its associated air quality issues, plus releases carbon into the atmosphere. Making biochar is potentially a solution for both of these things since the closed system causes particulate matter to be reburned, reducing emissions and smoke."

Biochar is made by a closed container system, where a wind curtain blows across the top of the forty foot long Tigercat container. Logging slash is dumped in the top with an excavator. The fire below reaches 3000 degrees farenheit and reduces the slash into two to three inch chunks in a matter of 10 – 15 minutes. The chunks fall through a screen onto water cooled augers which move the completed biochar out of the container.

The Tigercat Carbonator 6050 weighs 92,000 pounds. The wind curtain system is powered by an on board generator. The whole machine is mounted to heavy duty track frames for remote controlled maneuverability on the job or to reach areas off road. It uses 5,000 gallons of water a day to run the system for cooling the biochar and the base of the burning compartment. Overall the machine uses less than 100 gallons of fuel a day while reducing the volume of material by 90%.

Through a cooperative effort between the Forest Service, Bureau of Land Management, The Nature Conservancy, the University of Montana and the Department of Natural Resources the Tigercat carbonator was brought from Portland, Oregon for the field trial. The Tigercat is one out of seven units of this size produced that are in use throughout the United States.

"A piece of biochar can be visualized like a pine cone," said soil scientist Barry Dutton. "All those surfaces are places that nutrients in the soil stick to, water is retained, and all of those little pockets are habitat for micro-organisms that convert minerals and organic matter into forms that plants can use. So biochar has an incredible opportunity to increase the moisture and nutrient holding capacity of soils."

TNC connected with the Blackfoot Challenge in order to integrate the biochar project with local landowners. Blackfoot Challenge developed a field trial with members of their Soil Health workgroup. Eight landowners from Potomac to Helmville will be applying the Gold Creek biochar to quarter acre test plots in plowed, and unplowed situations, in irrigated and unirrigated fields and grazed and ungrazed fields at rates of five tons/acre, 10 tons/acre and zero tons/acre as a control. The biochar will be mixed equally with compost donated by Missoula Compost to introduce more soil microbes. Monitoring will happen for a few years and soil tests will be done if plant growth changes are observed.

"I noticed that the completed biochar has some pine needles in it," said Denny Iverson, landowner and Blackfoot Challenge Board member. "This is potentially dangerous for applying to pastures where cattle graze because pine needle consumption can cause cattle to abort."

It is not known if the biochar process affects the toxicity of pine needles for cattle.

In the biochar trial 25 tons of biochar was produced from approximately 250 tons of slash.

"That is like reducing about 10 semi-trucks full of slash down to one big dump truck of biochar," said Quinn Carver, Lolo Forest District Ranger, Seeley Lake.

The multidimensional project to study the economy of biochar and the potential impact on forest slash utilization will be known over the years to come. In the future if economic efficiency can be established, biochar production could be a useful tool for management for forest thinning and fuels reduction work, said the presenters.

"I'm only coming out of retirement to be involved in this because it has such incredible potential. And I also have a forestry degree and it's nice to see the forest and the agricultural community get together and produce something to benefit folks," said Dutton. "Planting trees is a popular system of carbon sequestration. But in time the trees get cut down, or burned up. Biochar use stores the carbon in the soil, where it stays for 1000's of years. Biochar has, to me the greatest potential for carbon sequestration of any method yet devised." Local ranchers Denny Iverson and Brad Hall discuss applying biochar to their fields with Brad Weltzein, Blackfoot Challenge Land Steward.