Why Are Mushrooms Growing Around My Tree?

Mushrooms Growing Around Your Tree? Here’s What They Could Mean

Autumn brings cooler temperatures, wetter ground and plenty of changes in the garden — including the sudden appearance of mushrooms and fungi.

If you've noticed mushrooms growing around the base of a tree, or bracket-like fungi appearing on its trunk, it's understandable to wonder whether something is wrong.

The first thing to know is that fungi around a tree doesn't automatically mean the tree is dangerous or needs to be removed.

But some fungi can be associated with decay within the roots, trunk or branches, so it's worth understanding what you're looking at.

Why do fungi appear around trees?

What we see above ground is usually only the fruiting body of a much larger fungal organism.

Fungi play an important role in the natural environment, helping to break down dead organic material. So mushrooms growing in soil near a tree may simply be feeding on old roots, buried wood or other decaying material.

Other fungi have relationships with the living roots of trees that can actually be beneficial.

However, some types of fungi cause decay in living trees, which is where their presence may need further investigation.

Does fungus mean my tree is dying?

Not necessarily.

The significance of fungal growth depends on the species of fungus, where it's growing, the tree species and the overall condition of the tree.

A healthy-looking tree can sometimes have decay developing internally, while a tree with visible fungi may remain standing safely for many years.

That's why identifying fungi is only part of the picture.

A tree surgeon will also consider the structure and condition of the tree, its surroundings and what could be affected if a branch or the tree itself were to fail.

What if fungi are growing from the trunk?

Fungal brackets growing directly from the trunk or major branches are worth paying attention to.

Some wood-decay fungi break down components within the tree's wood. Depending on the fungus and the extent of decay, this can affect the structural strength of the tree.

Look at where the fungi are appearing too.

Growth around the base may indicate something different from brackets appearing several metres up the trunk or on an individual branch.

Don't pull the fungi off before having them identified if you're concerned — take clear photographs first, including close-ups and a wider picture showing where they're growing on the tree.

What about mushrooms around the base?

Mushrooms growing from the soil around a tree don't automatically mean its roots are decaying.

They could be associated with buried organic material rather than the living tree itself.

However, some decay fungi affect a tree's root system and lower stem, so repeated or substantial fungal growth close to the base of a mature tree can be worth investigating — particularly if there are other changes to the tree.

What other signs should I look for?

Fungi shouldn't necessarily be considered in isolation.

If you've noticed fungal growth, also look for changes such as dead branches, cavities, cracks, areas of missing or damaged bark, changes in the canopy or movement around the base of the tree.

You don't need to try to diagnose the tree yourself.

Simply noticing and recording changes can be useful information when the tree is assessed.

What is Ganoderma?

One group of fungi we encounter during tree work is Ganoderma.

Ganoderma species produce distinctive brackets and can cause decay within the roots and lower stem of affected trees.

However, seeing a Ganoderma bracket still doesn't tell you everything you need to know about the condition or stability of the tree.

The species of tree, location and extent of decay, condition of the roots and trunk, and the surrounding environment all need to be considered.

We've covered this in more detail in our guide to Ganoderma and trees, which I'd internally link here.

Should I remove a tree with fungus?

Not automatically.

Finding fungi isn't, on its own, a reason to fell a tree.

The appropriate response might be monitoring, further investigation, pruning or other management. In some circumstances, where significant decay is affecting the structural integrity of a tree and the potential consequences of failure are high, removal may be recommended.

The important thing is making the decision based on the individual tree and an appropriate assessment, rather than simply because a mushroom has appeared.

Why autumn is a good time to take a look

Fungal fruiting bodies can be particularly noticeable during the wetter conditions of autumn.

So while you're clearing leaves or getting the garden ready for winter, take a look around the base, trunk and main branches of your trees.

If you spot something new, photograph it and keep an eye on whether it changes or reappears.

And if you're concerned — particularly with a large tree close to a house, road, footpath or other frequently used area — it's worth getting professional advice.

Spotted fungi on one of your trees?

Tall Tree Services provides professional tree surgery throughout Gloucester, Cheltenham, Stroud, Cirencester, the Cotswolds, Tewkesbury, Malvern, Ledbury and Ross-on-Wye.

Our NPTC-qualified arborists can take a closer look at your tree, identify potential concerns and advise on appropriate next steps.

Get in touch with Tall Tree Services for a free quote.