Once or twice, you may have asked yourself, “What’s growing on that tree?” while taking a walk in your neighborhood, the park, or the middle of nowhere. If you’ve ever wondered about an odd-looking growth on a trunk, stump, or branch, you’re not alone. A lot of us would love to be great at spotting tree fungus, which is why we made this helpful guide!
Remember that fungus on a tree usually means that the tree is dying or decaying. Fungi are often a sure sign that a tree is almost dead because they eat dead organic matter. Tree fungi come in diverse arrays of shapes and sizes. There are a few growth forms of fungus that are easily identifiable. We’ll go over some of the main types of tree fungus and how to identify them.
Most of the time, the shape and feel of a tree fungus are enough to tell it apart. What you’re seeing is the fruiting body of a fungus, and that’s only the very top. The hidden mycelium makes up the rest of the organism. Like a plant’s roots, it helps the fungus get food. The most important part of a fungus in order to identify it, however, is the visible part. Here are 3 common types of tree fungus and examples to look for:
This type of fungus is named after the easily identifiable shape they create. They look like little shelves that protrude from the trunk or branches of a tree. Although they all exhibit the same general shape, they can be all sorts of colors and textures.
Finding a fungus sprouting from a tree stump in your yard can be puzzling and concerning. Fungi thrive on decaying organic matter so a tree stump is prime real estate. But are fungi harmful and how can you get rid of them? This guide covers the common causes, identification, and removal methods for fungi on tree stumps.
Why Does Fungus Grow on Tree Stumps?
When a tree is cut down the remaining stump still contains organic compounds like lignin and cellulose. Fungi release enzymes that break down the tough woody material in the stump. The fungi use the dead stump as a food source extracting nutrients as they decompose the wood.
A few key factors lead to fungi colonizing and feeding on a tree stump:
-
Moisture – Fungi thrive in damp, humid conditions. Stumps retain moisture which fungi need.
-
Shade – Less sun exposure keeps stumps from drying out, creating the perfect damp environment.
-
Nutrients – The wood contains proteins, sugars, and starches that fungi consume.
-
Damage – Wounds and cuts in the stump provide entry points for spores.
-
Time – Fungi may take weeks or years to establish on a stump as it slowly decays.
If you have a tree stump in your yard, chances are fungi will eventually colonize it as they break down the woody material.
Identifying Fungi on Tree Stumps
Many types of fungi can be found growing on tree stumps. Here are some of the most common:
-
Turkey tail – Colorful bands of brown, gray, and orange; leaf-like and thin.
-
Reishi – Large with a reddish-orange fan shape and woody texture.
-
Artist’s conk – A bracket fungus with brown top and white underside you can draw on.
-
Oyster mushroom – Clustered together in overlapping caps that are white to gray.
-
Chicken of the woods – Bright orange or yellow shelves in clusters on oak stumps.
-
Wood ear – Jelly-like fungus that is brown, ear-shaped, and gelatinous.
-
Coral fungus – Resembles aquatic coral with branching arms, often bright colors.
Use shape, texture, color, and stump location to accurately identify the fungus. Many are harmless, but some may indicate disease.
Are Fungi Growing on Tree Stumps Harmful?
In most cases, fungi naturally sprouting on tree stumps are not harmful:
-
They help decompose wood and recycle nutrients back into the soil.
-
Many edible varieties like oyster mushrooms grow on stumps.
-
They indicate the stump is decaying and gradually breaking down.
-
Tree defenses stop fungi from spreading to living trees.
However, certain fungi may be cause for concern:
-
Shelf fungi could mean root rot infecting your trees’ health.
-
Large spread indicates advanced decay which may destabilize trees.
-
Mushrooms in your lawn could sicken pets if ingested.
Monitor for changes and contact an arborist if you notice neighboring trees declining. Prompt stump removal helps limit fungal spread.
How to Safely Remove Fungus from a Tree Stump
If fungi are taking over a tree stump in your landscape, here are some removal methods:
-
Physical removal – Use a trowel, putty knife, or wire brush to scrape mushroom caps and brackets off the stump.
-
Saltwater spray – Mix 1 cup salt per gallon of water and spray the stump to dry out fungus. Reapply after rain.
-
Vinegar spray – Use full strength household vinegar to help kill fungus and retard growth.
-
Bleach solution – An 8:1 water/bleach mixture can kill fungal spores on contact. Rinse off after 20 minutes.
-
Borax powder – Sprinkle this natural antifungal on the stump and just inside holes. Reapply after rain.
-
Remove the stump – Eliminate the food source by grinding down the stump or digging it out.
For severe fungal growth, stump removal is the most effective long-term solution. Otherwise, commit to reapplying chemical sprays or trying different remedies.
How to Prevent Fungus on Tree Stumps
To proactively prevent fungi from growing on tree stumps:
-
Cut tree stumps as low to the ground as possible since fungi grow slower on lower stumps.
-
Apply a wood sealant like lacquer immediately after cutting to help repel moisture and prevent spore germination.
-
Cover the fresh stump with a plastic tarp to block spores and retain moisture in the first weeks after cutting.
-
Remove the stump within 3-6 months before extensive decay and fungal networks establish.
-
Treat surrounding trees with fungicides if trying to prevent spread from an infected stump.
Removing stumps completely is the best prevention since it eliminates the food source. But for stumps that remain, early protection is key before fungi take hold.
When to Worry About Fungi on Tree Stumps
Consult an arborist if you notice:
-
Large clusters of mushrooms at the stump base or on roots.
-
Evidence of fungal infection in surrounding trees like mushrooms at their bases or oozing lesions on the bark.
-
A halo of thinning grass around the stump, indicating possible soil contamination.
-
Mushrooms sprouting up far from the stump itself, signaling extensive underground mycelium.
-
Any varieties you cannot positively identify as harmless species.
Rapid stump removal and fungicide application helps contains harmful spread to your landscape plants and lawn. Don’t delay treatment if disease symptoms arise.
While fungi decomposing a tree stump are part of the natural decay process, keep an eye out for any indications of disease or danger to your yard. With prompt removal and preventative spraying, most fungi are harmless. But catching issues early prevents extensive damage if more harmful fungal varieties take hold on your property’s precious trees and plants.
Turkey Tail Fungus (Trametes versicolor)
One of the more common species of shelf fungus is the turkey tail fungus. You can find this one all over the world. It’s easy to spot because of its psychedelic colors.
A classic cap mushroom shape is the first thing that comes to mind when someone thinks of a mushroom. You can still see this kind of fungus on a tree trunk, even though it grows on the ground more often than on trees.
Oyster Mushroom (Pleurotus ostreatus)
An incredibly common cap fungus is the oyster mushroom. These are eaten worldwide, and are the target of many a mushroom forager. They grow in clusters and are a creamy white color. Oyster mushrooms can be found nearly everywhere in the temperate regions of the world, growing on the trunks of broad-leaf trees.
DEADLY FUNGUS (for the tree)
What fungi grow on trees?
Shelf fungus: Also known as bracket fungi or shelf mushrooms, these tree-dwelling fungi have flat, often circular, or shelf-like caps. These conspicuous growths attach firmly to tree trunks or branches. Types of shelf mushrooms growing on trees are chicken-of-the-woods, turkey tail, beefsteak fungus, and maitake mushrooms.
Can fungi grow on dead trees?
Go for a walk in the woods and you’ll see plenty of fungi growing on trees. Any old stump or deadfall is a potential home for a crop of them, whether it’s mushrooms or plate-like bracket fungus. The many fungi that appear on dead wood are an essential part of nature, helping to process old trees back into the food chain.
How do Fungi affect trees?
Infected tree roots transform, becoming slimy and mushy, hindering their ability to absorb water, oxygen, and nutrients. Various fungi contribute to root rot, including: Armillaria (Shoestring Fungus) They affect various plants, including palms, succulents, and trees. Initial signs include dropping leaves, yellowing, and upper limb dieback.
Can you see cap fungus on a tree trunk?
Although this type of fungus is more common growing on the ground than on a tree, it’s still possible to see them on a tree trunk. An incredibly common cap fungus is the oyster mushroom. These are eaten worldwide, and are the target of many a mushroom forager. They grow in clusters and are a creamy white color.