Forest Feature: Fungi
Our Forest Feature for September is this “fun guy” – the fungi! Fungi are incredibly diverse, making up an entire kingdom of organisms. We have fungus among us, everywhere we go.
But our favorite fungi live in the Pacific Northwest’s national forests.
If you shopping at a grocery store, you might buy mushrooms that were grown on a farm. But you can also buy wild mushrooms, and some of these are collected from National Forests!
Have you heard of the humongous fungus? How big do you think it might be? As big as a basketball? As big as a car? It’s even bigger!
A genet is a genetically distinct organism. Some genets of the Armillaria ostoyae, also called the “shoe-string fungus,” grow very, very large. Several of these fungi genets are living in the northeastern part of the Malheur National Forest in eastern Oregon, and one of them has been named the “humongous fungus” because it’s the largest known single fungus organism in the world.
It’s as large as 1,665 football fields combined — that’s 3.4 square miles in size! It’s believed to be 2400 years old.
This “humongous fungus” is not good for the trees it colonizes. It kills and decays the root systems of certain conifer trees, resulting in Armillaria root disease.
If a tree is infected, you might see a scalloped ring of mushrooms emerge from its base after the first fall rainfall. Or, you might see clusters of smaller, round mushroom caps. At other times, you may see a thin layer of white fungus, like paint, on the tree when mushrooms aren’t present. If you look at the roots of a fallen tree that has hosted the fungus, you might see black “shoe strings,” or rhizomorphs, which the fungus uses to spread from tree to tree below ground.
If you see signs of Armillaria root infection, be careful – some trees around might be dead or dying, and could fall at any time.
Has anyone ever warned you not to eat mushrooms that you find outside? Mushrooms are produced by some fungi to help them reproduce by opening up to spread spores. And one reason fungi sometimes have a bad reputation is some mushrooms are toxic – it takes a lot of training to know which are poisonous and which are safe to eat.
Lots of people enjoy collecting wild edible mushrooms and other fungi as a hobby.
In Pacific Northwest forests, morels, matsutakes, chanterells, are some mushrooms people like to collect to use as food.
Another type of fungi, the truffle, grows in the ground, but is also popular with foragers.
If you want to try collecting mushrooms or truffles, contact a local mycological society to find out what mushrooms grow in your area, and how to get started. Some species are endangered and should not be disturbed. You may also need a permit to collect mushrooms at certain times of year on National Forest land – contact your local Ranger District office for more information.
While some can cause problems, fungi actually play a very important role in forest ecosystems. By decaying vegetable materials like wood and leaves, they help make nutrients more accessible to insect larvae, worms and plants. This decay is also neccessary for removing debris from the forest floor, and creating healthy soil that new plants and trees will need to grow. And, like people, many animals enjoy foraging for and eating wild mushrooms and truffles that grow in our forests!
If you’re an educator who would like to explore Pacific Northwest fungi with your students, you can find more information, activities and lesson plans at the below links.
- North American Mycological Association (Lesson plans, activities and materials can be found under the “Educators” tab):
- Fungus Guide (USDA Forest Service – Pacific Northwest Research Station):
- Science Findings publication on fungi (USDA Forest Service – Pacific Northwest Research Station):
- The Malheur National Forest – Location of the World’s Largest
Living Organism, the “Humongous Fungus” (USDA Forest Service – Pacific Northwest Region):
Source information: Forest Features highlight a new Pacific northwest species (or sometimes family, order, kingdom, or genus) each month as part of the USDA Forest Service – Pacific Northwest Region’s regional youth engagement strategy. If you’re an educator who would like more information about this topic, or other ways the Forest Service can incorporate Pacific Northwest environmental and forest science in your classroom, email us at R6Update@fs.fed.us.