Mushrooms on a Tree Trunk Means Your Tree is Dying

Mushrooms on a Tree Trunk Means Your Tree is Dying

Mushrooms growing on tree trunks from heart rot and root rot

Do you have mushroom conks growing out of your tree trunk? Don’t mistake these fungi as a regular thing, they are a grim sign that your tree is dying or already dead. gathered information on why mushrooms grow on tree trunks and the immense danger they represent.

Mushrooms Growing on a Tree

Mushrooms are a common sight in fertile garden soil, healthy landscapes, on outdoor woodpiles, and fallen trees. This may contribute to the misplaced sense of normalcy when you see them growing on tree trunks or root flares.

You should be alarmed when you see mushroom conks on a tree:

• Mushroom conks are the reproductive part of fungi.
• Fungi require rotting organic material to thrive.
• When mushroom conks grow on the trunk of a tree, it is a sign of rot within the tree.
• When mushrooms grow from a tree’s root flare or on surface roots, it is a sign of root rot.

Mushrooms growing on tree root flare indicate root rot

By the time mushroom conks appear on a tree trunk or root flare, the responsible fungus has already caused severe damage to the host tree.

Signs of a Fungal Tree Disease

Your tree may be succumbing to a fungal disease without the immediate appearance of mushroom conks. The following signs of disease may precede the presence of these reproductive bodies:

• Dieback occurring on one side or throughout the crown.
• Early leaf drop.
• Stunted leaf growth
• Severe wilting or drooping of the tree’s foliage.
• Chlorosis (leaves lose their vibrant green color) of the tree’s foliage.
• Branches and twigs die and become brittle.
• Cankers appear on branches and the trunk.
• The tree may begin to lean.
• Carpenter ants nesting in the trunk or limbs.
• Boring insects successfully attacking and infesting the tree.

Wilted tree foliage indicating severe fungal infection

If one or a combination of these symptoms are present in your tree, hire an arborist to evaluate the tree and recommend a course of action.

Tree Fungus Types and Identification

Many types of fungi grow on trees. Some of those fungi are harmless to a mature tree, while others signal certain decline and eventual death. Take the following fungi, for example:

Lichens – A lichen is a symbiotic relationship between algae and a fungus, and poses little to no threat to a tree. Lichens come in many shapes, sizes, and colors but appear most commonly as a low, flat, crusty, greenish substance branching out like a doily.

Lichens growing on tree trunk exterior

Lichens do not penetrate tree bark; they attach themselves and spread along the surface. This organism may grow on trees, cement pathways, park benches, brick structures, windows, etc.

Powdery mildew – This fungal disease affects the foliage of various trees and plants. Powdery mildew diseases can be caused by many different fungal species from the order Erysiphales. These fungi appears as a white powdery covering of foliage and stems. It is rarely fatal to mature trees unless widespread infection weakens the tree, allowing subsequent infections and insect infestations.

Powdery mildew growing on tree leaves

Polyporus Alveolaris – This is a species of fungus in the genus Polyporus, and poses a significant risk to trees. It causes white rot in dead and decaying hardwoods. Commonly growing on decaying logs and rotting trees, conks of this species have a yellowish to orange scaly cap and hexagonal or diamond-shaped pores. This species of fungus is widespread across North America.

Ganoderma Applanatum – Rot caused by this fungus may take several years to kill a tree but makes the tree very susceptible to secondary infections, infestations, and wind-throw. The shelf-like fruiting structure forms at or near the soil line. It appears brown to reddish-brown on top with a white-colored margin. The underside of the shelf contains millions of pores in which spores are formed.

Mushrooms on tree trunks ganoderma applanatum fruiting structure

Ganoderma Lucidum – This species causes root rot and forms a shelf-like structure on the wood similar to that of Ganoderma Applanatum. Fruiting structures occur singly or in clusters and have a varnished appearance.

Armillaria – Fungi from this genus cause Armillaria root rot on many species of conifers and hardwoods. The mushroom is a fleshy, firm, honey-colored conk growing in clusters of up to 100 or more. The cap of the mushroom can reach from 1.5 to 6 inches in diameter with a depressed center.

Mushrooms on tree trunks armillaria mellea

Laetiporus Sulfureus – Signs of this fungus include massive clusters of bright, yellow to salmon or bright orange shelf-like conks that turn white with and fall off as they age. The underside of the conk has millions of pores in which spores are formed. These conks appear long after the damage has occurred. Infected trees are prone to wind breakage long before the fungus forms its fruiting structures and should be removed when an infection is confirmed.

Laetiporus sulphureus mushrooms on dying tree trunk

How a Tree Fungus Spreads

Fungi are spread easily from tree to tree by the following means:

Spores – Millions of spores can be produced and released by a single fruiting structure or conk. These spores can be spread by:

• Wind
• Splashing Water
• Rain

Mushroom fruiting structure and spores on tree trunks

Human Activity – Handling diseased plants and trees with gardening tools and pruning equipment, then using those “infected” tools on healthy plants and trees.

Tree Fungus Treatment

The most recommended method of treatment for trees against fungal infections is prevention. By promoting the healthy growth and proper seasonal pruning of your trees, they can resist infections and infestations that can lead to disease.

However, once a fungus infects a tree, the tree cannot be fully cured. Treatments that stop the progression of the disease, allowing the tree to compartmentalize it, can be applied to restore your tree’s health.

Steps you can take to prevent fungal infections include:

• Ensuring proper drainage of the soil around your trees.
• Avoid overwatering your trees.
• Mulch your trees to maintain optimal levels of moisture and ground temperature.
• Apply fungicides like neem oil to tree bark and surface roots.
• Sanitize pruning and gardening tools between trees.
• Fertilize your trees in late winter or early spring as they enter the growing season.
• Have your trees and landscape inspected annually by an arborist.

Sanitized pruning equipment to avoid disease contamination

To avoid widespread infections or catastrophic tree falls, have your trees inspected at the first sign of trouble. The earlier you address fungal infections, the easier it is to treat them.

Tree Fungi and Conks on Trees

When mushroom conks grow on your tree trunk or root flare, there is a grave problem within your tree that must be addressed. Otherwise, a potentially catastrophic tree fall may occur.

In this article, you discovered the signs of fungal tree diseases, types, and identification of fungi, how they propagate and spread, and how to treat them.

Your slow reaction to the signs of fungal infections on your tree may result in the loss of the tree. The tree may eventually fall on your vehicle, home, or causing severe physical injury to people.


Todd’s Marietta Tree Services

200 Cobb Pkwy N Ste 428 Marietta, GA 30062
(678) 505-0266

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