A new approach to post-wildfire recovery: how the magic of mushrooms decontaminate burn-site debris flow
Santa Cruz — Like most mystery sounds at 3 A.M., I thought the noise was a break-in. A stomach-dropping conclusion with a relatively easy fix. A missing laptop, a police report, a couple of therapy sessions, and I thought I’d wipe my hands clean of the whole fiasco. If only the events that took place on that seemingly normal Sunday night could have been that simple, perhaps I would not be sitting here today writing about it over a year later.
The air caught in my throat. I lurched forward, drenched in a disorientating fog known only to the sharp blade of cacophony puncturing a defenceless REM cycle. Thump. Thump. Thump. Half-awake, I stumbled out into the hallway gripping my clunky metal water bottle as a weapon of choice. With the self-assured confidence of a horror film teen walking blindly into the clutches of their captor, I investigated. Thump. Thump. Thump. My grasp tightened around the lid as I mustered every ounce of dormant courage and prepared for the worst.
To my surprise, the culprit was not a ski-masked bandit rummaging for a quick buck, but rather an invisible intruder with gusto for mayhem. A violent wind tore into the back entranceway, nearly blowing the back door right off its hinges. As the blinds wildly battered against the neat white trim of the door frame, I stepped outside into a surreal backdrop enveloping the night.
Lightning bolts jagged into the mid-August heat. Like a swarm of hungry paparazzi at a movie premiere, a flurry of angry flashes veined into the sky. Suddenly, I felt as though I was getting robbed all over again. The familiar all-consuming fear resurged within me, prickling up my spine. As a young adult coming of age in the era of climate change, I knew what inevitable truth lurked around the corner from a freak dry summer lighting storm.
The phrase ‘CZU (Santa Cruz-San Mateo Unit) Lighting Complex Fire’ became a new household name by the next afternoon. The bolts sparked a series of fires that raged on for 38 days, torching over 86,000 acres in their wake. Within days, my personal slice of California paradise was cloaked in an orange apocalyptic haze fit for Mars.
The fires transformed beloved forests and homes into blackened residue, claiming nearly 1,500 structures. It felt as though the whole town paused to support victims of the blaze for a brief moment. Donations flooded in, dousing the devastation with a newfound sense of community.
Weeks were dedicated to gathering supplies and volunteering at evacuee shelters. Everyone chipped in. Signs hung over highway overpasses that read “the love in the air is thicker than the smoke”, a sentiment that rang true until the last ember extinguished.
Cal Fire declared the CZU Complex fire 100% contained by mid-September. The state of urgency vanished with the smoke as blue skies returned. Though a slow fade into normalcy overtook the town, the fight against the calamitous flames was far from over.
Post-fire debris flow poses threats to chemical contamination of major waterways, according to a recent study. Homes contain many synthetic household items that are chock full of harmful chemicals. Toss things like kitchen appliances into a blustering wildfire and pollutants such as mercury, chromium, benzene and arsenic are bound to come out the other side.
These toxins can be extremely difficult to remove once they enter waterways. In Butte County, heavy metals and other harmful substances were detected in drinking water for well over six months after the historic Camp Fire ravaged nearly 19,000 structures.
As of now, the most common way to dispose of hazardous household waste such as paint, pesticides and electronics is to physically remove the debris via protocols set by the Environmental Protection Agency. This solution may fastrack property owners to regain access to their land, but risks disrupting important microbial ecosystems that live beneath the soil.
While many continue to uphold the status quo, others believe there is much room for improvement within the world of post-fire recovery. Maya Eslon, Director of ecosystem restoration nonprofit Corenewal, is spearheading a more holistic approach to mitigating contaminants with an unlikely assistant: fungi.
“Shoveling dirt is very effective at removing toxins from the situation. However there are a lot of limitations there,” Eslon said. “ You are scraping all of this precious topsoil that has so much potential. And then it becomes somebody else’s problem. It’s not like it magically disappears when they remove it.”
The CZU is a great example of a place that has really steep slopes above highly sensitive waterways. When the United States Geological Survey predicted that the CZU had a 90 to 100 per cent chance of debris flow, Eslon and her team of mycologists knew that it would be the perfect opportunity to apply their research on Oyster Mushrooms’ natural ability to filter and breakdown toxins.
“A lot of this research has been done in the lab and not in this applied context before,” Eslon said. “We know that they can biodegrade all this important stuff that we have in these burned down homes and we know that they can hyper-accumulate heavy metals into their fruiting bodies. We are interested in whether or not we can work with these fungi to remove the heavy metals and bring them to a hazardous waste facility.”
You have probably spotted the fungi on your dinner plate or against a rotting log. They have a classic mushroom look. Large white spongy caps with ribbed stems that cascade into natural asymmetric shelving across rough bark. Though the decomposer is commonplace, their biological makeup possesses unusual capabilities that research has only scratched the surface.
Corenewal is utilizing natural phenomenons that occur within mycelium, a network of fine filament networks akin to a tree’s root system. Biofiltration and biosorption are processes that allow the mycelium to absorb different elements and biodegrade certain chemicals. Imagine a living hyper absorbent sponge that soaks up harsh metals while simultaneously eradicating toxins.
The oyster mushroom mycelium is then inoculated into long straw tubing called wattles. Wattles are often found near burn sites to prevent erosion and contain toxic runoff into waterways. Introducing mycelium into these organic structures increases the capture of heavy metals and the breakdown of chemicals.
“As the water moves through the wattle, the mycelium acts as a network and it creates an additional barrier to just the straw. It creates a physical barrier as well as a biological barrier that can catch the contaminants and hold onto them,” Eslon said.
This method aids nature’s ability to heal itself. Allowing mycelium networks and topsoil to remain untouched enhances the soil’s ability to hold onto itself, significantly reducing the risks of erosion. Though oyster mushrooms are the predominant vehicle of operations, a wide variety of species possess the same capabilities. Incorporating an array of fungi in the effort to restore environments after wildfires will only strengthen burnsites’ abilities to recover.
Though mycoremediation, or fungi-based decontamination, remains in the minority, Eslon is hopeful future fire recovery efforts will integrate more ecological approaches.
“We are really interested in a whole community approach,” Eslon said. “I am super hopeful. I don’t think we have a choice. We are going to keep having fires and they are going to get worse.”
A year later, I look up to the charred mountainside sloping into Waddell Creek with Eslon’s warning of an exasperated fire season on my mind. Though blackened brush shows scars of the CZU, green sprouts begin to poke through the weathered soil.
As I watch a ranger reluctantly turn away handfuls of eager hikers from the debris, I cannot help but think of the silent decomposers hard at work to regenerate a salvaged land. A new flame of hope rekindles while researchers continue to probe for a sustainable world.
“We have to figure this out because the future depends on it,” Eslon said.
