Should I cut the fungus off the tree?

No. The mycelium is inside the wood and removing the bracket changes nothing except the evidence. Leave it in place so it can be identified, because the species is what tells you how serious the decay is.

Does fungus always mean the tree has to come down?

Not at all. Some species affect only dead wood, and many mature trees carry decay for decades with monitoring or a crown reduction. It is the location of the decay and what the tree could hit that decide the answer.

Is honey fungus a threat to the rest of the garden?

It spreads through the soil and can kill a wide range of woody plants, and it survives in old stumps and roots. Removing infected stumps and roots is the main practical control, since there is no chemical cure available to gardeners.

Can a tree with basal decay look healthy?

Yes, and that is exactly what makes it dangerous. Root and butt decay attacks the anchorage, not the leaves, so a tree can hold a full green crown right up to the point it falls over.

High risk

Updated 30 August 2026

Fungus Growing On The Trunk

Brackets, shelves or clusters of fungus have appeared on the trunk or at the base of the tree.

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What's happening?

Fruiting bodies on a trunk are the visible part of something that has been going on inside the wood for years. The fungus lives in the tree; the bracket is only its reproductive stage, so by the time you can see it there is usually established decay behind it. Where it appears is the important detail. Brackets at the base or on the buttress roots point to root and butt decay, which is the pattern behind trees that fall over with a full crown still on them. Brackets higher up the stem or at an old pruning wound suggest decay columns in the trunk or a major limb. Not every fungus on a tree is a structural problem — some live only on dead bark or already-dead wood — but identifying which is a job for someone who knows the species.

What usually causes it?

Root and butt decay fungi colonising through damaged or dying roots, typically after construction or compaction
Decay entering through an old pruning wound, a torn branch or a topping cut that never sealed
Bark damage from a mower, strimmer, vehicle or animals giving the fungus a way in
Honey fungus spreading through the soil from an infected stump or neighbouring plant
Long-term waterlogging or drought stress weakening the tree's own defences
Soil compaction and severed roots from paving, trenching or a driveway laid over the root area
Age, where a mature tree is simply carrying decay it has lived with for decades

Is it dangerous?

Potentially, and the danger depends on where the decay is rather than how impressive the fungus looks. Basal and root decay is the most serious, because it attacks the anchorage without weakening the crown, so the tree can look completely healthy and still go over. Decay in the stem or at a major union raises the chance of the trunk or a limb snapping. Take it seriously and keep people from beneath the tree if the brackets are at the base, if the trunk sounds hollow, if there is a cavity, weeping or bulging bark, or if the tree has also started to lean.

Can I fix it myself?

Record it and identify it, but do not treat it. Photograph the fruiting bodies close up, from the side and from underneath — the underside is often what identifies the species — and note exactly where on the tree they are and how many. Note the date, since some brackets are annual and some persist for years. Look for other signs: dieback in the crown, a cavity, cracked or bulging bark, or fine sawdust. Do not cut the brackets off; that removes the evidence and does nothing to the fungus inside the wood. There is no domestic treatment that reverses established decay, so the useful action is a proper assessment.

When should you call a tree surgeon?

Call a tree surgeon for an inspection when brackets appear at the base or on the buttress roots, when the trunk sounds hollow, or when the fungus is combined with crown dieback or a new lean. Those are the combinations that precede failure. Get it done sooner rather than at the end of the season if the tree could reach the house, a boundary or a road, and ask for the species to be identified — the answer changes whether the tree needs monitoring, reduction or removal.

What will the tree surgeon actually do?

Identify the fungus and determine whether it is a root, butt, stem or purely saprophytic species
Sound the trunk and buttresses and check for cavities, cracks, bulging and included decay
Assess how much sound wood remains relative to the load the tree carries, and what it could hit
Advise a monitoring interval where the tree is stable, with a defined re-inspection rather than an open end
Reduce the crown to lower the load on a decayed stem or root plate where retention is realistic
Dismantle and remove the tree where the decay has gone too far, and grind the stump out to limit spread

Frequently asked questions

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Sources & References

Tree Leaning With Lifted RootsHigh risk Ash Tree Dying BackHigh risk Stump Left After FellingLow risk

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