STATE FORESTS’ FUTURE COULD BE HELPED BY FUNGI
Mushrooms are healing the Earth, starting with Colorado’s forests
Can mushrooms help save our Colorado forests? Jeff Ravage knows they can. Ravage is a big fan of mushrooms. He’s also the North Fork watershed coordinator for the Coalition for the Upper South Platte, an organization that has been working to protect the ecological health and water quality of the 1.6 million-acre watershed southwest of Denver since 1998.
In early June, Ravage and a team of volunteers inoculated a massive pile of wood chips at Denver Botanic Gardens Chatfield Farms with mushroom spawn. The goal? To highlight how quickly and efficiently fungi can convert a pile of waste and debris into beneficial compost, using completely natural processes.
Ravage’s team has spent the last six years experimenting with and proving out this concept. Now, they want to demonstrate that this fungal degradation process works on an industrial scale in the hopes that foresters and land managers across the country — and even private companies — begin to replicate it.
“The goal is to create enough information to allow people to do this with their local mushrooms where they’re at,” Ravage said. “It could be done by people who run sawmills who have to deal with waste. It could be done by municipal waste management, who end up with a lot of tree trimmings from residents. It can definitely be done by forest managers.”
The mushroom project was initially inspired by Colorado’s wildfires. The idea arose when staff members at the Coalition for the Upper South
Platte began brainstorming ways to deal with wood waste left behind when crews thin forests for fire mitigation.
It helps to back up here — way back. Before human settlement in Colorado and other wooded areas, wildfires had free reign. Fire roamed through the forests, burning weak and old trees while leaving the strongest standing; it also burned up forest debris. This created a mosaic-style pattern, with trees growing in heterogeneous clumps surrounded by open space. Forests were healthy and di
verse, with wildfires helping to keep the balance.
Colorado’s modern forests are vastly different from their prehistoric ancestors. Today, our forests are much denser and more homogenous, due in large part to our understandable aversion to wildfires.
Now, we squash wildfires as soon as they start. Because of this, land managers and foresters try to mimic wildfires by manually removing up to 60% of trees in an overgrown area. This creates tons of woody debris, which is expensive and inefficient to haul out. If used for firewood, this debris also releases carbon into the atmosphere. If chopped up and left in the forest, these wood chips create a thick blanket that kills off grass and wildflowers while also changing the soil’s natural pH levels. It can take 40 to 50 years for these wood chips to rot naturally, Ravage said.
Here’s where the mushrooms come in. In just a few years, native wood-rotting mushrooms can convert a pile of wood chips into nutrient-rich compost. Ravage calls this process “cold fire,” since fungal degradation achieves the same outcome as wildfires without any of the heat or potential for destruction of homes and business. His team has been exploring this concept since 2014 by observing the changes at two test sites they inoculated with native mushroom spawn.
Not only do the initial mushrooms convert the wood chips into compost, but they also encourage secondary organisms and fungi to show up and get to work. The mushrooms are also a tasty snack for squirrels, bears, deer, elk and other wildlife, which further spur the degradation process along by shuffling through the wood chips looking for food.
“If we can leave more of this wood on-site and deal with it in a manner that’s not to the detriment of the environment, then we’re going to save money, reduce the amount of fuel that’s used to haul it off, and also reduce the amount of carbon released,” Ravage said.
Native mushrooms may also help restore an area that’s been decimated by wildfire. The fungi will likely help speed up the resurgence of all the beneficial bacteria, fungi and bugs destroyed by the fire. Without intervention, a burned-out forest can take up to 1,000 years to regenerate. Ravage suspects mushrooms can speed up the process by hundreds of years, a theory he hopes to investigate with future research.
The mushroom regeneration process is labor-intensive on the front end, starting with tracking down, then cultivating, lots of native mushrooms found within a 30- to 100-mile radius of the targeted area. But after that, it’s essentially a set-it-and-forget-it approach to forest regeneration.
“Nature knows how to do this stuff. We just need to learn how to kickstart it,” Ravage said. “The realization that restoring the environment is perhaps the easiest way to fix our climate problems is growing.”
The Denver Botanic Gardens is home to one of the largest collections of mushrooms of the North American Rocky Mountains, housed within the Sam Mitchel Herbarium of Fungi. When researchers there learned about Ravage’s mushroom project, they invited him to become an adjunct researcher and take advantage of the gardens’ mycological resources.
Similarly, researchers at the gardens are partnering with Ravage to study various fungi questions in the field. Andy Wilson, assistant curator of mycology for Denver Botanic Gardens, is studying the parade of mushrooms that follow the original wood-rotters into the wood chip piles.
“How do the fungal communities within these decomposition plots work? How does that turnover happen?” Wilson said. “One species might be active on certain kinds of wood debris, whereas other fungi might come along later and feed on different kinds of residues or leftover materials.”
The team at Chatfield Farms offered Ravage a site to prove the mushroom degradation concept at an industrial scale. The gardens also benefit from having a living research study on their grounds.
“It’s also an educational display that Chatfield can engage in to show there are lots of ways to promote and engage in conservation,” Wilson said.
The Chatfield pile contains approximately 100 metric tons of wood chips. Over the next several years, Ravage and his team will observe and track the mushrooms’ progress, watching to see how quickly the pile shrinks and turns into compost.
They’re also planning a second industrial-sized test plot at the base of Pikes Peak later this month. Since there’s no pre-established instruction manual for this type of project, the group is experimenting with different mushroom strains and other elements, including how much and where they apply the spawn.
Through it all, one fact remains clear to Ravage, Wilson and other fungi fans: Mushrooms are one of our biggest allies if we hope to have any chance of healing the Earth.
“We all know that woody debris can be decomposed by lots of different organisms,” Wilson said, “but there are no organisms on the planet that do it with the level of effectiveness and efficiency of fungi.”