Fungi for the Forests: Mushrooms and Climate Change

Our world is in crisis. Climate patterns are irregular and average temperatures are rising exponentially. Species diversity, as well as wildlife population numbers, are collapsing, and ice caps are melting, causing sea-level rising and climate instability – all at a rate of which we have never seen before. Humans as a species have developed some bad habits over the past 250 years. We discovered coal, petroleum, and natural gas, and became dependent on them for all of our everyday conveniences (electricity, heat, food and even sometimes water and transportation). Each of these luxuries can depend on, or come from, the burning of fossil fuels. This doesn’t even mention the ecological damage we are doing with massive industrial farming practices, pesticide and herbicide use, nutrient runoffs that cause subsequent algal blooms and dead zones in our oceans. In times like these, we need to consider every option as a society. Things are too close for comfort and may become desperate sooner than we have been led to believe. We need widespread, accessible, affordable options to replace fertilizers, filter excess nutrient runoff from livestock herds, replace pesticides, and take steps to undo the damage we have done to our forests by rebuilding nutrient cycles there. Mycorestoration may be the key to filling all of those roles for us as a society and helping us to take steps toward being better stewards of the earth. 

Mycorestoration is the up-and-coming science of using fungi to treat specific wounds in our ecosystem; it is spearheaded by an incredible group of mycologists from all around the world. Mycorestoration is currently being used for a variety of different goals, such as repairing logging roads to help reduce silt runoff and make it easier for local salmon populations to recover by strategically covering damaged areas in mushroom-inoculated wood chips. This helps rebuild the healthy humus layer as well as filter water running into the salmon stream. It is a beautiful, hopeful, exciting collision of the mushroom world with the world of conservation biology, which yields some amazing experiments and results. It is another light to lead us out of the dark of the looming storm that is climate change on planet Earth. 

Climate change is an ubiquitous force in every natural cycle. The atmosphere is full of greenhouse gasses such as methane and CO2. Waterways are being polluted by industrial and chemical waste, agriculture runoff, harmful pesticides and herbicides, and artificial fertilizers. Soil is being degraded at an unsustainable rate, and sea levels are rising due to melting ice caps and glaciers worldwide. Here, we will focus on two aspects of climate change: agricultural pollution and ecosystem nutrient degradation due to farming and forestry. Both solutions to these problems are made possible by a brilliant technique called a “mycofiltration,” which makes for a powerful environmental cleaning tool. There is so much potential in the power of mushrooms to help heal our ecosystems, and a lot of that potential lies in our forests. 

Our forests depend on fertile soils for their overall health – nothing is more important to an ecosystem than its soil. Without soil, say, on a newly formed volcanic island, there can be no primary producers, no plants at all, and thus no consumers. Fungi just happen to be perhaps the best soil makers on the planet. Even just the act of putting mushroom spores in chainsaw oil gives fungi “a head start on decomposing stumps and brush” which increases recovery rates in soil nutrient loss and makes for a healthier next generation (Stamets, Running, 83). Logging roads in Northern California, Oregon, and Washington have been detrimental to the overall health of their forests. The fact is that “run-off of water from rains causes massive environmental havoc in the form of erosion, removing life-sustaining top soils, causing sedimentation and siltation inflows into downstream watersheds” (Stamets, Sumerlin). In this particular study, the silt runoff was affecting local salmon populations, further hindering their ability to bring population numbers up. 

Paul Stamets and David Sumerlin and a team covered a runoff site with wood chips inoculated with a local oyster mushroom mycelium (this kind of works like mushroom seeds), mixed in some grass seed, and sandwiched it between two layers of wheat straw. They then wetted the whole thing down, and waited. In the first week, grass was “starting to sprout and mushrooms were seen fruiting from the spawn(Stamets).” In three years, the team found a “mantle of nearly contiguous mycelium at the wood chip/gravel interface, holding the sub-moraine together.” Finally, four years into the project, there was half of an inch of topsoil growth – much more than the minimal success the forest service had had in seven years with grass seed alone. In the face of climate change, with extreme and irregular rainfall, with flooding more common, this may prove a vital tool in combating soil erosion in our forests and beyond, until (and if) we can get back to the point where our soils are healthy and strong again. 

The implications of this experiment are incredible. The benefits are three-fold, at least. First, topsoil is created by the mycelium digesting the wood chips that surround it. Second, the foot-thick mycelial mat functions as a filter in this area of high runoff. Particulate-dense water runs into and through the mat, which collects particles from matter at an amazing rate. Last, this technique saves local wildlife populations that cannot live in watersheds which are too full of minerals and nutrients. A single square inch of healthy, mycelium filled topsoil can contain eight miles of mycelial hyphae. So, any water that does run into the mat comes out clean on the other side, and happy mushrooms are left behind with new things to eat (Stamets, running). This concept of a mycelial filter is a game-changing concept that is proving useful in so many unexpected areas. Particularly exciting is a solution to one of our largest pollution issues on the planet, livestock runoff. 

Livestock runoff is an extremely scary subject when it comes to the concept of climate change. When a farm is subject to heavy precipitation, which is vastly more common in the age of climate change, it causes everything on the surface to run downstream into main water sources. This means that heavy feces and other types of nitrogen and phosphorous-rich fertilizers enter the water and cause eutrophication of watersheds. This can lead to aquatic and marine die-offs (sometimes on a massive scale) and cause algal blooms like red tide – which is toxic and makes fish dangerous to eat" (EPA, NRDC). Livestock runoff can also carry “Pfiesteria, E. Coli, amoebic parasites and viruses” into local watersheds, further imperiling our aquatic species populations (Stamets, farm). 

However, this problem is easily addressed, as described in Mushroom, The Journal, by Paul Stamets, employing the use of something as simple as a berm.

A berm is built up on one end of the manure holding pond, and a microfilter, in this case one of the Garden Giant or Rugoso anulata, with sawdust, corn cobs, wood chips, and loose straw (Stamets, farm).  The goal of the berm is that it allows water to slowly flow from the pond, through the filter to be cleaned, and eventually run off as it naturally would have before it ran into that livestock farm. This allows ponds to drain faster, which means they have less chance of flooding in heavy precipitation events, and everything that is drained is filtered clean, showing a 90-95% reduction in particulate matter passed through (Taylor, implementing). This method can be used along rivers to make them cleaner, and along pastures and even fields of crops to catch haber-process nitrogen fertilizers. The applications are enormous and almost endless. The mushrooms continue to inhabit the area year after year if they are fed fresh wood chips on top annually. This is an incredible, low-cost, effective way of cleaning water as it leaves agriculture. Stamets says “the cost of spawn is probably the biggest expense, but once established and cared for, the mycelium can regenerate itself until the debris base has been reduced to soil” (Stamets, Farm). 

This doesn't even scrape the surface of the potential uses of mushrooms to revolutionize the agriculture industry. Fungi can also be extremely effective as an agent of common pest control, controlling bark beetle populations, breaking down petroleum spills, removing heavy metals from soil, and protecting bees from varroa mites and deformed-wing virus to combat colony collapse disorder. The field is practically unexplored and just utilizing the two techniques covered in this paper could revolutionize the way we manage land to improve soil health. There are about 14 thousand named species of mushroom and about 1.5 million mushrooms estimated to exist on the planet that could hold the solutions to solving the problems humans may soon face on a daily basis.  In this time of uncertainty, we should be doing everything we can to secure the future for our children and grandchildren, and mushrooms just may hold the keys to a couple of doors that lead down that road. 

Works Cited

The Sources and Solutions: Agriculture. (2020, July 30). Retrieved November 12, 2020, from https://www.epa.gov/nutrientpollution/sources-and-solutions-agriculture 

Stamets, P. (2010, February 02). A Novel Approach to Farm Waste Management. Retrieved November 12, 2020, published in Mushroom, the Journal, from https://paulstamets.com/mycorestoration/a-novel-approach-to-farm-waste-management

Stamets, P. (2005). Mycelium running: How mushrooms can help save the world. Berkeley, CA: Ten Speed Press.

Taylor, A. W., & Stamets, P. E. (2014). Implementing Fungal Cultivation in Biofiltration Systems – The Past, Present, and Future of Mycofiltration. Retrieved November 11, 2020, from https://www.fs.fed.us/rm/pubs/rmrs_p072.pdf#page=31

Taylor, A., Flatt, A., Beutel, M., Wolff, M., Brownson, K., & Stamets, P. (2014, June 17). Removal of Escherichia coli from synthetic stormwater using mycofiltration. Retrieved November 12, 2020, from https://www.sciencedirect.com/science/article/pii/S0925857414002250?casa_token=sAwzG5HSJ7gAAAAA%3A-FavOF1ouMpovvKLJxRh_iLapIA8-Xyl-s6-gueDPrLcQuHJ48johlNiWyxpmJulAUdCKVB4pA