Fungi As Decomposers


Yes, growing gourmet mushrooms is fun and easy, and they are delicious to eat, but these factors are only the tip of the fungal iceberg when considering fungi’s role in nature. There are about 100,000 species of fungi, and of these, only about 10% have been named! Obviously, there is still much to be learned from and about these amazing organisms. Read on for a glimpse into the important role fungi play on our planet.

In a nutshell, fungi are the primary molecular disassemblers of dead organic matter such as trees, plants, grasses, and animals. To better understand this process, let’s use the example of a maple tree’s life cycle, or more specifically, its post-life cycle.

Broken spruce with fungiAfter a long happy life of 100 years or so, the massive tree is blown to the ground during a storm. In a matter of weeks dozens of fungal species, which lay dormant in the ground beneath the maple, begin to move on to the newly fallen tree via the long thin root systems of the fungi know as mycelium. The mycelium quickly grows on and through the tree, all the while excreting powerful enzymes that break apart the strong chemical bonds that make up the long molecules of lignin. Lignin is the tough substance that gives the tree and other plants their rigidity. As the mycelium spreads, it eventually wraps itself into a tight net, penetrating the cell walls of the lignin. The net is so dense that a square inch of it contains approximately 70 miles of mycelia strands! Once the enzymes in the mycelium have disassembled the lignin and cellulose, the door has been opened for billions of bacteria and other microbes to rapidly continue the next steps of decomposition of the maple, turning it back into soil.

Because the mycelium lives, grows, and coexists in a highly competitive environment with these myriad bacteria, competing fungi, and microbes, it has developed an amazing immune system to protect itself from being consumed. Interestingly, the antibacterial, antiviral, and antifungal compounds that exist in the mycelium and the fruit body (the mushroom) get passed on to the humans who ingest them, hence the ever growing list of curative and preventative effects of mushrooms that benefit the immune systems of humans. One theory of why the mushrooms’ immune-enhancing compounds are so effective in humans is that from a genetic standpoint, the fungal and animal kingdoms are more closely related than the fungal and plant kingdoms. In other words, fungus is genetically more like a human than it is like a plant.

Once the mycelium of a certain species has reached a certain level of density, or “colonization” inside the tree, and moisture, temperature, and light are conducive outside the tree, the mycelium will be triggered into reproduction. This reproductive cycle occurs with the production of what we know as the mushroom — also called the fruit body. The mycelium will amass and produce a small bump called primordial. Within a matter of days, the primordial will grow into a mature mushroom and begin to release it seeds (spores) by the millions from its gills or pores beneath the cap. These spores quickly germinate, turning into new mushroom mycelium and growing on to organic matter above or below ground… and the cycle continues.

After a few years, where the tall maple once stood then fell, there now exists thousands of pounds of healthy, decomposed organic matter teaming with billions of beneficial soil microbes ready to support the next generation of plants, animals, and humans- all initiated by the fungi.