Sustainable solutions

Butte College instructor touts biochar production as a forest management tool

Stephen Feher sees untapped potential to reduce greenhouse gases in overgrown forests at risk for fire.

Stephen Feher sees untapped potential to reduce greenhouse gases in overgrown forests at risk for fire.

Photo by Evan Tuchinsky

Learn more:
Visit for information about Stephen Feher and the Sustainable Community Development Institute.
Go to (search “FAC”) for Butte County’s Forest Advisory Committee, which has a vacancy.

California forests have a tree problem.

Due to overgrowth density—coupled with die-offs due to bark beetles and the relative dearth of back-country fires over previous decades—huge areas of mountain acreage sit littered with twigs and dry husks, tinderboxes ready to spark. That message was delivered at the latest Butte County Forest Advisory Committee meeting, held Dec. 18 in Paradise.

Stephen Feher has a solution.

Feher champions biochar production: the making of soil-enriching charcoal through low-emission burning. A retired aerospace engineer who teaches at Butte College and heads a sustainability group, Feher sees biochar production not only as a means to reduce wildfire fuels but also to reduce greenhouse-gas discharge.

At the invitation of Peggy Moak, the county treasurer-tax collector who’s part of the Forest Advisory Committee, Feher made a half-hour presentation on the practice. He explained the science, processes he’s developed with his students and broader applications of biochar.

Moak, who’d seen him speak to the Yankee Hill Fire Safe Council, said she felt “it would be a worthwhile presentation for our board to hear.”

The Forest Advisory Council reports both to the Board of Supervisors and the Federal/State Land Use Coordinating Committee; Moak sits on the latter and serves as liaison between the two committees. She sees Feher’s idea as “still in some of the infancy stages” but ripe for further consideration by the county’s Tree Mortality Task Force.

“They’re looking for ways to utilize the trees and the woody debris that we have in the county, related to the bug-kill problem and the drought,” Moak said. “So there may be some way that his project could be utilized effectively.”

In a presentation separate from and preceding Feher’s, the region’s forest and fire adviser out of UC Davis documented forest overgrowth. Dr. Kate Wilkin showed photos of an Upper Ridge ranger station shot nearly a century apart; the thicker concentration of large pines in modern times was glaring. She also showed photos of woodlands naturally contoured by lightning-strike fires and those laden with vegetation and deadwood.

Responding to the forest crisis, Gov. Jerry Brown authorized increased logging, targeting the timber for biomass fuel; and Cal Fire this year increased its use of controlled burns.

Feher sees his form of controlled burns as a more efficient, more ecological answer.

Why send logs to mills—via diesel-powered trucks—for biomass instead of creating biochar on the spot?

“It’s hopeless to remove all that wood from the forest,” he told the committee. While the U.S. Forest Service currently has machines to reduce the emissions of combustion, the most mobile units cost $50,000 each and the largest, three times that much.

Feher’s biochar production technique utilizes top-down burning. Instead of placing the kindling and ignition source at the bottom of the pile, as most people do when lighting a fire, Feher’s flames start at the apex. The result is a fire with less smoke and carbon dioxide, plus residue richer in carbon and soil amendments.

How does this work?

The scientific term is pyrolysis. As the flames move down and the ashes collapse upon the unburnt wood, the fire becomes starved of oxygen. It’s still burning hot, around 1,000 degrees Fahrenheit, so it doesn’t extinguish.

“Most of the heat of the fire breaks up the carbohydrates of the wood and burns off more easily as flammable hydrogen,” he explained.

Hydrogen and oxygen combine to form H20 (water). Top-down fires tend to emit more water vapor—and the smoke they do give off has a characteristic blue tinge—and less carbon dioxide than other fires.

Feher and students at Butte College have experimented with top-down burning in rice-cookers from Asia, in metal dumpsters and on the ground. They validated the process while finding they produce a yield of biochar ranging between 25 percent and 30 percent of the preburn mass.

Since 2011, Feher has received two grants from the U.S. Environmental Protection Agency for the work at Butte College. He’s pursuing another. Feher also travels internationally with his wife, Elisabeth, for the work they do through the nonprofit they run out of their Paradise home, the Sustainable Community Development Institute.

Feher became interested in biochar as an offshoot of an earlier fascination: disposing of agricultural field matter in an eco-friendly way. (In fact, his tests with top-down fires in cookers used rice hulls.) He’d moved to Paradise in 2001 after marrying Elisabeth, a fellow native of Hungary, following an extensive engineering career that took him to Seattle, San Diego and points overseas.

With his “retirement project”—biochar production—he told the CN&R that his “primary intent is to spread the word that we need to take care of the forest waste, the biomass that is accumulating alarmingly in the underbrush in the forest; and the best way I see, just like with agricultural waste, is to turn it into biochar by some economically viable means, which means without big machines and transportation.”

After speaking to the Forest Advisory Committee, he said he felt “encouraged that there’s some movement going on that will eventually help the situation.”