Fungi: The Forest’s Digestive System


Fungi are a Forest’s Digestive System

“It’s beautiful, isn’t it?”

The man asking this question is Lance Biechele, a man who’s been studying mushrooms for 35 years. He’s looking at a dead maple tree, and to the untrained eye, this skeletal tree is one of the last things a person would even be tempted to call beautiful. The tree is rotting, it’s almost falling apart with decay. It makes you think of Halloween, not Renoir.

To Biechele, the tree is nevertheless beautiful. To him, it’s an example of how nature’s best recyclers work. “There may be as many as 1000 different species of fungi at work in this tree,” he states. “Without them helping to decompose trees and other vegetation, we would have no forests.”

The forest needs fungi, he goes on to explain, because fungi are “the forest’s digestive system.” Fungi break down the old vegetation so that new trees have the room and nutrients to grow.

Fungi also Support an entire Ecosystem

Part of the dead tree’s beauty, in Biechele’s eyes, is that it supports an entire ecosystem. Pointing to several large holes in the tree, he says that that these make wonderful homes for raccoons, possums, and woodpeckers. But what really inspires his sense of wonder is the trillions of fungi, almost all of which are too small to see.

On the tree’s surface, you can see a few of the large, visible kinds of fungi. The most obvious are the 50 or so gray-green, turkey tail mushrooms growing at the base of the tree. They look like a series of half circles layered on the tree like shingles. They really do remind you of turkey tails.

Biechele can easily point out a dozen other kinds of mushrooms on this tree. These include the brownish deer mushrooms, the cream-colored oyster mushrooms and the tan-colored puff balls.

The Hyphae

The visible part of each mushroom on the rotting tree is sustained by miles of microscopic “roots” or filaments called hyphae. You can’t see the hyphae, partly because they’re generally inside the tree’s trunk, but mostly because they’re far too small. A thousand of these hyphae bundled together would be no thicker than a human hair.

The hyphae provide the mushrooms with the nutrients and the energy to give off astonishing numbers of reproductive cells. A typical mushroom can release millions of spores an hour for several days. The giant puffball mushroom may contain as many as a trillion spores.

One of the most surprising facts about fungi is that some of them can act like living spider webs. Their hyphae regularly trap microscopic worm-like creatures called nematodes. They do it by using the biological equivalent of Krazy Glue. The carnivorous fungi attract their prey by giving off a chemical that the nematodes seem to find alluring. Apparently, it’s the Channel Number 5 of the nematode world. When a misguided and bamboozled nematode touches a strand of hyphae, the nematode will become hopelessly stuck to it. The fungus gradually ingests its immobilized prey.

Once you know some of the complexity and importance of what’s going on inside dead trees, Biechele hopes you’ll look at them in a new way. They aren’t ugly, they’re part of an intricate and astonishing environment that becomes beautiful as you get to know it.

For a good book on the fungi that perform these wonders, Biechele recommends Mushrooms Demystified, by David Arora. It’s available through Ten Speed Press in Berkeley, California for $35 plus $3.50 postage and handling. You can call Ten Speed Press at 1 800 841 2665. They accept credit cards.


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