8 Signs Your Tree Is Dangerous (And What to Do)

Written By Wez - 04/08/2026

1. Fungal brackets and toadstools at the base

Fungal fruiting bodies on the trunk, root flare, or soil immediately around the base are the classic indicator of internal decay where it matters most: the structural root and butt zone. Different fungi mean different things (some rot fast, some slowly, some barely matter), which is exactly why this sign warrants professional identification rather than either panic or a shrug. Urgency: assess soon, especially on mature trees near targets.

2. A lean that's new, or growing

Plenty of trees lean and always have; established leans with the crown grown to balance are usually fine. The dangerous version is a change: a tree that’s recently shifted, a lean that’s visibly increasing, or, the serious one, soil cracking, mounding, or lifting on the side opposite the lean, which suggests the root plate itself is moving. Urgency: root-plate movement is an emergency. Keep people away and call the same day.

3. Large dead branches

Dead limbs, leafless in summer, bark sloughing off, often pale or “stag-headed” at the crown top, will eventually shed, and big ones don’t need a storm to do it. A few small dead twigs are normal life; substantial deadwood over a drive, lawn, footpath, or roof is a scheduled drop waiting for a date. Urgency: routine but real, deadwooding is quick, cheap surgery compared with the alternative.

4. Cracks, splits, and weak unions

Vertical cracks in the stem, splits where major limbs join, and tight V-shaped forks with bark trapped in the union (compression forks) are structural weak points. A union that’s begun to open, sometimes visible as a seam, sometimes as fresh exposed wood, can fail in the next strong wind. Urgency: visible movement or fresh splitting means act now; old stable seams need assessment.

5. Cavities and hollowing

Holes, rot pockets, and hollow sections aren’t automatically fatal: trees engineer around hollows surprisingly well, and a hollow tree can stand for decades. What matters is how much sound wood remains relative to the loads the tree carries, which is a judgement call for someone qualified, sometimes with decay-detection input on valuable trees. Urgency: assessment, not assumption, in either direction.

6. Crown dieback and sparse leafing

A crown thinning over successive years, dying back from the tips, leafing late and small, signals root or vascular trouble below: disease (around here, very often ash dieback), root damage, or decline. Declining trees lose structural reliability before they look dramatic. Urgency: get a diagnosis this season; the treatable causes are time-sensitive and the untreatable ones are planning matters.

7. Root damage and disturbed ground

Roots are the tree, structurally speaking, and they extend far beyond the canopy edge. Trenching for utilities, new drives and extensions, soil compaction from parked machinery, and significant level changes within root range can destabilise a tree that looks untouched, with failure following years later. If major works have happened near a big tree, that’s a reason for a check in itself. Urgency: assessment after any significant works within root range.

8. Hangers and storm damage

Broken branches lodged in the crown (“hangers” or, bluntly, widow-makers), torn limbs, and partial failures after storms are the most immediate hazard on this list: already broken, just not yet landed. Urgency: immediate. Keep everyone out from underneath and call.

What to actually do

Don’t DIY any of this. Compromised trees are the most dangerous trees to work on, and chainsaw-plus-ladder-plus-homeowner is how the worst accidents happen. Do get suspect trees assessed: for homeowners, Silver Tree Services looks at worrying trees across Gloucestershire as part of a free quote; for landowners, businesses, and anyone with trees over roads, footpaths, car parks, or neighbours, a documented tree survey is your duty-of-care evidence under the Occupiers’ Liability Acts, and the thing that protects you if a claim ever arrives. And remember the paperwork: even a dangerous tree in a conservation area or under a TPO has notification rules, with narrow genuine-emergency exemptions, which we handle as part of the job.

Worried about a tree? Photos are often enough for a first opinion: free quotes on 01242 472560, and genuinely dangerous trees get prioritised.

Related: Tree surgery · Tree surveys · Ash dieback signs

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