A Workshop with Cheetah Tchudi on Mycoremediation
In December 2022, the Community Alliance with Family Farmers partnered with TurkeyTail Farm to co-host a workshop and peer-to-peer learning event about using mushrooms for bioremediation (utilizing natural processes to improve/heal something) in post-wildfire applications. Several years ago, Cheetah Tchudi and his wife Samantha Zangrilli bought 40 acres of undeveloped land in Butte County. The farm sits on a hillside just up from where the western fork of the Feather River flows into Lake Oroville, and also just a few miles east from Paradise, California. Today they raise several types of livestock, tend a one acre herb garden, and produce a variety of culinary grade mushrooms.
In 2018, TurkeyTail Farms was faced with disaster. The Camp Fire was tearing down the Feather River canyon and headed straight towards the town of Paradise. Cheetah and his family were on the other side of the canyon and able to get out, but he didn’t have time or space to evacuate 15 sheep and pigs and decided to set them loose so they could fend for themselves. Under the extended evacuation orders, his worry grew that the pigs would not survive because no one was allowed to return to their properties. However, with support from local officials like police, fire, and the County Agricultural Commissioner, Cheetah was able to visit his farm while still under evacuation orders (now known as an Ag/Livestock Pass), and support the livestock with water and hay deliveries. At first, it looked like the fire would spare Turkey Tail Farms, but then on the fifth day, a shift in the winds caused the fire to burn back up the gorge and across the farm. Cheetah’s house, and even the water and power infrastructure were completely destroyed, leaving behind a variety of pollutants from melted cars, pumphouses, etc.
When Cheetah returned after the fire to assess the damage, he suspected that the soil was polluted. Pollution of the soil is concerning for anyone, but to a farmer, it’s a direct threat to their livelihood. Soils with high concentrations of heavy metals and pollutants are not ideal for agricultural production. Cheetah’s observations prompted him to start asking questions about what to do: what are the nature and quantity of the toxins on the land, and is it possible to use mushrooms to remediate those toxins? This became the inception of his nonprofit, called Butte Remediation, which helps people in the Butte County area treat polluted sites after wildfire events. Butte Remediation is especially focused on those that are low income and/or unable to receive support from the California Office of Emergency Services Wildfire Recovery Programs.
The workshop began with a presentation in Cheetah’s living room–a welcome respite from the cold December afternoon in Butte county. Cheetah covered the basics of mycology (the study of fungi), mushroom cultivation techniques, and the pollutants that can be released when structures burn. The Fungal Kingdom encompasses a variety of organisms, including yeasts, molds, and mushrooms. Some get food by living intertwined with plants or animals. These fungi are most often parasitic (stealing food, in the form of sugars, to the detriment of the host), or symbiotic (a mutually beneficial relationship of resource/food exchange). The ones that we are interested in however, are called saprophytic: these fungi are decomposers that get their energy by digesting organic matter. If you picture a generic mushroom in a forest, it’s a saprophytic one, digesting dead leaves, branches, and even entire logs. There is much more to a mushroom than what we can see. Mushrooms are the fruiting, or reproductive, bodies of fungi whose roots–called hyphae–extend all throughout the soil. Fungal bioremediation occurs when these hyphae are sequestering and transforming pollutants along with organic material. The fact that mushrooms can digest lignin (wood cellulose) is an impressive feat. But not only can they digest wood, they can also bind and digest dangerous pollutants.
When wildfire burns through urban areas, the burning of cars and houses can release dioxins, a type of Persistent Organic Pollutant (POP).
“Persistent Organic Pollutants created through the combustion of plastic products have been found in soils exposed to intense urban wildfires at levels exceeding the Environmental Protection Agency and Office of Environmental Health Hazard Assessment screening thresholds. Toxic effects include cancer, immune toxicity, developmental, and hormonal effects” (What to Know About Wildfire and Food Safety).
Heavy metals are another toxin that wildfires can release when cars and batteries burn. Aluminum, Arsenic, Copper, Lead, Cadmium, and Chromium are all either toxic to humans, bad for the environment, or both. Studies have shown that fungi can accumulate the heavy metals in their tissues, thereby removing them from the soil, and making them less available to plants. This also prevents the metals from getting washed downstream after it rains.
After the Camp Fire, Cheetah applied his mycoremediation techniques to several sites on his property. By taking soil samples before and after the treatment, he was able to see how well his mushrooms healed the soil. The overall results of heavy metals uptake were positive, but mixed. However, the mycoremediation treatments were very effective against dioxin, whose levels were reduced eightfold.
With the crash course on fungi and mycoremediation complete, it was time to get outside, see the land, and build some mushroom growing kits. The group got a tour of the mushroom growing greenhouses, herb garden, and livestock.
Finally, everyone gathered around a long table covered in sterilized straw and learned how to inoculate different substrates with fungi spawn.
Straw wattles and jute landscape fabric are two erosion control materials that are easily inoculated with fungi. The first step is to sterilize the material upon which the fungi will grow. This is an important step to ensure that other fungi, which could reduce potential for mycoremediation, don’t outcompete the one you want. Instead of heat sterilization, which is expensive, the jute mats are soaked in a Calcium hydroxide and water mixture. This chemical sterilizes the mats by raising the pH so high that any foreign spores hiding in the mats will be killed. It is also necessary to wear gloves and a clean shirt or coveralls so as not to introduce foreign contaminants to the mixing process. After the Calcium hydroxide is rinsed off, the mats can be rolled in spores or spawn to inoculate them. Keep this in a bag or greenhouse at the right temperature and humidity, and the mushrooms will grow. Once you’ve got one roll of jute mats, it is easy to propagate the mushrooms onto another mat by simply rolling the inoculated mat around the new one.
After the Camp Fire, 300,000 feet of straw wattles were deployed to mitigate erosion in the region. Had all of that also been inoculated with bioremediating fungi, the amount of environmental pollution and health hazards could have been significantly reduced.
There are, of course, limits to fungi as a solution for soil remediation. One issue with mycoremediation is that, depending on your local climate, it may become too hot in the summers or too cold in the winter, for mushrooms to grow properly. However, mycoremediation is an effective, low-cost, ecologically sustainable method of remediating soils after wildfire. It should be incorporated into any farmer’s toolkit for responding to disaster in an ever-changing climate.
Interested in learning more about farming and wildfire? Check out the Community Alliance of Family Farmers’ Wildfire Resilience Program! Also check out Cheetah Tchudi’s bioremediation non-profit, Butte Remediation and the podcast CAFF hosted with him on this topic in 2022.
Michael Berlin is a photographer, artist, and farmer in Nevada City, CA. View his portfolio at michaelberlinphoto.com
Written by Josh Harjes, CAFF’s 2023-2024 Wildfire Resilience Program Grizzly Corps fellow.