Mushrooms Growing on Trees: Everything You Should Know Insects & Diseases If you’ve recently spotted mushrooms on a tree in your yard, you’re not alone—and you’re right to take notice. While some fungi are harmless, others may point to deeper issues affecting the tree’s health and structure. Understanding the type of mushrooms growing on your tree and what they indicate can help you decide what to do next. In many cases, consulting a professional tree service is the best first step toward protecting your landscape and ensuring long-term tree vitality. Why Are Mushrooms Growing on My Tree? Mushrooms are the visible fruiting bodies of fungi. These fungi exist below the surface, often as thread-like structures called hyphae, which grow inside the tree and feed on organic material. When the conditions are right—moisture, shade, and decaying wood—they form mushrooms as a way to reproduce and release spores. When mushrooms grow on the trunk or base of a living tree, it can be a red flag. This often signals internal decay, stress, or disease. The fungi are likely feeding on decaying wood, which means the structural integrity of the tree may already be compromised. It’s important to distinguish between mushrooms growing around the tree in the soil—often feeding on dead roots or mulch—and mushrooms emerging directly from the tree trunk or branches. The latter usually indicates a more serious fungal infection inside the tree. What Do Mushrooms on Trees Indicate? Seeing mushrooms appear is just the beginning. What they actually reveal about your tree’s condition is far more important and often more serious. Signs of Internal Decay Many fungi that produce mushrooms on trees are decay fungi, which means they break down wood tissue over time. These fungi can remain hidden for years, silently decomposing the inner wood before mushrooms appear. There are several types of rot that fungi cause: White rot: Breaks down both lignin and cellulose, leaving behind a spongy, bleached wood. Brown rot: Primarily targets cellulose, leaving wood brittle and crumbly with a darker hue. Soft rot: A slower-decaying fungus typically seen in wetter environments. Regardless of the type, these rots weaken the tree’s core, increasing the risk of branch failure or full collapse. Potential Tree Health Risks Internal decay from fungi can lead to: Loss of structural strength Dangerous limb drop or total tree failure Greater susceptibility to insects or tree disease treatment needs Because fungi often enter through wounds or damaged bark, trees that have experienced mechanical injuries, improper pruning, or root stress may be especially vulnerable. When Are Mushrooms Harmless? Not all mushrooms spell trouble. Some fungi are saprophytic, meaning they feed only on dead material. Mushrooms growing on a tree stump, in mulch, or in soil may not pose any threat to nearby trees. Another harmless example: lichen. These are fascinating organisms composed of fungus and algae living symbiotically. While they might resemble mold or fungal growth, lichens are completely harmless and don’t penetrate the tree’s tissues. That said, proper identification is critical. Many mushrooms around trees look alike, and misidentifying a parasitic species as benign can delay necessary treatment. Common Types of Tree-Growing Mushrooms Tree fungus comes in many shapes, sizes, and colors, but a few species are particularly common and important to recognize. Chicken of the Woods (Laetiporus sulphureus) Bright yellow to orange fan-shaped caps, often stacked in layers, make this mushroom easy to spot. It typically grows on oaks and is a known indicator of Heart Rot, especially in older trees. Chicken of the woods is not to be confused with hen of the woods, a different species of mushroom with distinct characteristics. Shelf Fungi / Conks (Ganoderma, Artist’s Conk, etc.) These hard, shelf-like growths protrude from trunks and branches. Also called conks, they’re linked with internal decay and are often signs of brown rot. Once they appear, the tree may already be structurally compromised. The degree of compromise should be assessed using tools like a mallet test, resistance drilling, or sonic tomography - long story short, the appearance of conks isn’t always a death sentence. Honey Fungus (Armillaria spp.) These mushrooms grow in clusters around the base of a tree and glow faintly in the dark. The real damage, however, is underground—Armillaria hyphae invade through the roots and travel between living trees via root-to-root contact, eventually killing their hosts. Honey fungus often affects trees that are already under stress or have compromised root systems and isn’t always the main cause of decline. Turkey Tail (Trametes versicolor) This fungus resembles a wild turkey’s tail with its concentric rings in shades of brown, white, and gray. While it’s typically found on dead wood, its presence on a living tree may signal decay or decomposing areas. Birch Polypore (Piptoporus betulinus) Commonly seen on beech and birch trees, these white, smooth-capped mushrooms are another sign the tree is in poor health or already dying. Morels and Edible Mushrooms Some mushrooms—like morels or oyster mushrooms—are considered edible mushrooms and prized by foragers. While these may appear near or around tree roots, caution is advised. Their presence doesn’t always indicate a healthy tree, and unless you're trained, it's risky to eat any wild mushroom without expert identification. What to Do If You See Mushrooms on Your Tree Pictured: Hen of the Woods Spotting mushrooms is a signal to take action, but not without a clear understanding of what’s going on beneath the surface. Here’s how to respond effectively and protect your tree. Don’t Remove Them Without Understanding the Cause It might be tempting to knock off a visible mushroom on a tree trunk, but doing so won’t solve the underlying issue. Remember: the mushroom is just the fruiting body. The fungal network inside the tree remains, often hidden and widespread. Understanding what type of fungus is present and what that means for the tree’s internal structure is the first step toward responsible action. Monitor for Other Warning Signs Mushrooms should be treated as a potential warning sign, especially if they’re accompanied by: Hollow sounds when the trunk is tapped Visible cavities, cracks, or loose bark Unusual leaning Sparse canopy or early leaf drop These could all point to a declining tree. Combined with fungal growth, they warrant closer inspection. Call a Certified Arborist for Assessment Only a trained professional can properly assess the situation. A certified arborist will: Identify the fungal species Determine how far the decay has progressed In some cases, specialized diagnostic tools like sonic tomography or resistance drilling may be used. Use varies by location and situation. Recommend appropriate next steps Whether you’re looking to save a tree or determine whether it should be removed, an ISA certified arborist from SavATree can provide the guidance you need. Can Mushrooms Be Treated or Prevented? While not all fungal issues can be reversed, there are proactive steps you can take to protect your trees and limit the spread of decay. Let’s look at what works—and what doesn’t. Prevention Starts with Tree Health While some fungal infections are unavoidable, many can be minimized through proactive tree care: Avoid damaging the bark with lawn equipment. Mulch rings are an easy way to prevent this type of damage. Schedule regular pruning to reduce moisture retention and stress Maintain healthy soil and proper irrigation Practice good tree fertilization to strengthen natural defenses SavATree’s Arbor Patrol Program, combines regular inspections with cultural, biological, and technical interventions tailored to protect tree health while minimizing environmental impact. No DIY Cure Once Internal Decay Has Begun There’s no quick fix for a fungus that’s penetrated the heartwood. While there are some treatment options, they’re rarely effective once decay has taken hold inside a tree. Any attempt to manage internal rot must account for: Tree species The size and location of the infection Proximity to buildings, roads, or people Presence of other trees that may serve as future hosts A knowledgeable arborist can walk you through the best-case and worst-case scenarios, including whether preservation is viable. Preventive and suppressive treatments like root collar excavations may help reduce additional stress and improve resilience in early-stage infections. When Removal Is the Safest Option Sometimes, the best way to protect your home and other plants is to remove the affected tree. This is especially true when: The structure is unsalvageable Mushrooms signal extensive rot Nearby trees of the same species are at risk of infection Tree removal may also be recommended when the infected tree is near power lines, walkways, or playgrounds where failure could be dangerous. In these cases, removal not only protects your property but also helps prevent fungi from spreading across your landscape. Protecting Your Trees from Fungal Threats: Key Takeaways Mushrooms growing on your trees might look picturesque, but they often hint at deeper problems—fungal infections, internal decay, or stress that compromises your tree’s structural integrity. Whether you’re dealing with a mushroom on the tree trunk or clusters growing around the base, acting quickly is key. Consulting a certified arborist can help you determine the species, evaluate the risk, and take the right steps—whether that’s pruning, treatment, or removal. For comprehensive solutions grounded in science and sustainability, SavATree’s team of ISA Certified Arborists is here to help. Sources: Penn State Extension. Understanding the Spread of Decay in Trees. https://extension.psu.edu/understanding-the-spread-of-decay-in-trees University of California Agriculture and Natural Resources. Wood Decay Fungi in Landscape Trees. https://ipm.ucanr.edu/home-and-landscape/wood-decay-fungi-in-landscape-trees/pest-notes/ USDA Forest Service. Armillaria Root Rot. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5353367.pdf Contact us today to schedule a consultation with an expert arborist.