Mycelium Running

The most dramatic chapters of the book are about what Stamets calls mycoremediation — using fungi to clean contaminated land. His reasoning is disarmingly simple. Fungi evolved to dismantle the tough, complex molecules in wood, especially lignin, using powerful enzymes. Many industrial pollutants happen to be built from similar molecular bonds. A fungus that can digest a fallen fir has no particular trouble digesting petroleum, and Stamets set out to prove it.

In one experiment he recounts, piles of soil soaked in diesel and oil were treated in different ways — some with bacteria, some with enzymes, one inoculated with oyster mushroom mycelium. Weeks later the untreated piles were still dark and dead. The one seeded with oyster fungus was covered in mushrooms, and as those mushrooms decayed they drew insects, then birds, then seeds, until the toxic mound had turned into a small green island. The hydrocarbons had been broken down to a fraction of their original level. The fungus had not just removed the poison; it had restarted an ecosystem.

If fungi can heal soil, Stamets argues, it should not surprise us that they carry compounds able to help heal bodies. Humans have leaned on mushrooms medicinally for a very long time — the five-thousand-year-old iceman found in the Alps was carrying a birch polypore fungus, likely for its antibacterial and antiparasitic properties. Stamets treats that as a clue rather than a curiosity: fungi live in a fierce chemical war with the bacteria and viruses around them, and the molecules they evolved to survive that war are often useful to us.

The clearest example is one we rarely credit to fungi at all. Penicillin, the antibiotic that reshaped modern medicine, is a fungal product. Stamets points out that the same evolutionary pressure that produced penicillin is still running in countless species we have never screened, and that the fungal kingdom may hold a pharmacy we have barely opened. He is especially interested in polypores and other wood-decay mushrooms, several of which have shown activity against viruses in early testing.

Step back from the individual applications and a larger argument comes into focus. Stamets is not really cataloguing tricks that fungi can do for us. He is proposing a change in relationship. For most of our history we have treated the living world as either a threat to be managed or a stockpile to be drawn down. Mycelium, in his telling, invites a third posture: partnership with an organism that was building and repairing ecosystems for hundreds of millions of years before we arrived, and that may be better at it than we will ever be.

The reframing matters because of what fungi represent structurally. A mycelial network senses damage, redistributes resources, and routes around dead spots — behaviors we associate with intelligence, arising in something with no brain. Stamets suggests we have a great deal to learn simply from the design: decentralized, regenerative, running on waste and sunlight's leftovers rather than on extraction. Where our systems tend to break down complexity into landfill, fungal systems turn breakdown into fertility. That is closer to a philosophy than a technique.

Kick over that rotting log again and the threads look different now. What seemed like decay is a working system — dismantling, feeding, sensing, repairing — and it has been doing this job since long before forests as we know them existed. Stamets's achievement in Mycelium Running is to make that invisible layer legible, and then to argue, application by application, that its capacities line up almost eerily with the problems we most need solved: poisoned soil, failing crops, stubborn disease, an economy that produces more waste than it can absorb.