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7 Signs a Tree May Be Dangerous and Needs Professional Attention

Trees are an important part of our gardens and local environment, but damaged, diseased or structurally weakened trees can sometimes pose a risk to people, buildings and surrounding property.

Knowing how to recognise the warning signs of a potentially dangerous tree can help you take action before a problem becomes more serious.

Some signs, such as broken branches or a newly leaning trunk, may be easy to spot. Others, including internal decay or root damage, can be much harder to identify without professional assessment.

At Oxleas Tree Care, we provide professional tree surgery, tree surveys and emergency tree removal services across South East London and Kent. In this guide, we explain seven signs that a tree may need professional attention and what you should do if you’re concerned about its condition.

1. The Tree Is Leaning or Has Suddenly Changed Position

Not every leaning tree is dangerous. Some trees naturally grow at an angle and remain stable for many years.

However, a tree that has recently started leaning or has noticeably changed position may indicate a problem with its roots, structural stability or the surrounding ground. Warning signs can include:

A sudden or increasing lean.
Soil lifting or cracking around the base.
Exposed or damaged roots.
Movement of the root plate following strong winds.
Cracks developing in the ground near the trunk.

A newly leaning tree can present a serious risk, particularly if it is close to a house, road, footpath or neighbouring property.

What should you do?

Avoid standing or working beneath the tree and arrange a professional assessment as soon as possible. If the tree appears unstable or at risk of falling, keep people away from the affected area.

2. Large Branches Are Dead, Broken or Hanging

Dead or damaged branches are among the more visible signs that a tree may require attention.

Branches can die for several reasons, including disease, damage, environmental stress or natural ageing. While the presence of deadwood doesn’t automatically mean the entire tree is unsafe, large dead or hanging branches can pose a risk if they fall.
Look out for:

Large branches without leaves during the growing season.
Broken branches caught within the crown.
Hanging or partially detached limbs.
Cracked branches following storms.

Dead branches extending over buildings, paths or parking areas.

What should you do?

A professional tree surgeon can assess whether the affected branches need to be removed.
In many cases, selective pruning or deadwood removal may address the problem without requiring the whole tree to be felled.

3. There Are Cracks or Splits in the Trunk

Visible cracks in a tree’s trunk or major branches should not be ignored.

Some cracks are superficial and may not indicate a significant structural problem. However, deep splits, particularly where major branches join the trunk, can sometimes indicate weakness.
Warning signs include:

Deep cracks extending along the trunk.
Splits where two large stems meet.
Recently exposed internal wood.
Cracks that appear to be widening.
Separation between major branches or stems.

Trees with multiple stems can sometimes develop weak unions, particularly where bark becomes trapped between the stems as they grow.

What should you do?

Have the tree professionally assessed before deciding whether pruning, crown management or removal is necessary.
A tree with a structural defect does not always need to be removed, but the extent of the problem needs to be understood.

4. You Can See Fungal Growth or Signs of Decay

Fungi play an important role in the natural environment, but certain types of fungal growth can indicate decay within a tree.

Mushrooms or bracket fungi growing around the trunk, roots or base may sometimes be associated with internal wood decay.

Other possible warning signs include:

Fungal brackets growing from the trunk.
Mushrooms appearing around the base.
Soft or visibly decayed wood.
Cavities or hollow sections.
Areas of bark separating from the trunk.

Not all fungi indicate that a tree is dangerous, and some trees can remain structurally sound despite having cavities or areas of decay.

The important consideration is where the decay is located, how extensive it is and whether it affects the tree’s structural stability.

What should you do?

Avoid attempting to remove or treat the fungi yourself as a solution to the underlying problem.

A professional tree assessment can help establish whether the tree requires further investigation, monitoring or remedial work.

5. The Tree Has Damaged or Exposed Roots

A tree’s root system plays a vital role in keeping it stable and supplying water and nutrients.

Damage to major structural roots can affect the tree’s stability, particularly when combined with other problems such as decay, soil movement or strong winds.

Possible warning signs include:

Roots damaged during building or landscaping work.
Excavation close to the trunk.
Soil lifting around the base.
Exposed or visibly damaged major roots.
Changes in the tree’s position following ground disturbance.

Construction work, trenching and changes to ground levels can sometimes affect trees even when the trunk and branches appear healthy.

What should you do?

If significant roots have been damaged, particularly on a large tree near buildings or frequently used areas, arrange a professional assessment.

Avoid cutting additional roots without advice, as this could make the situation worse.

6. The Tree Is Losing Leaves or Showing Signs of Decline

A tree that is declining in health may display visible changes in its foliage, branches or overall appearance.

However, leaf loss alone does not mean a tree is dangerous. Deciduous trees naturally lose their leaves in autumn, and some species respond to drought or other environmental conditions by shedding foliage.

Signs that may justify further investigation include:

Significant leaf loss during the normal growing season.
Large sections of the crown failing to produce leaves.
Unusual discolouration or wilting.
Progressive dieback in major branches.
A noticeable decline over successive growing seasons.

These symptoms can have several causes, including drought stress, disease, root problems or environmental changes.

What should you do?

A tree surgeon can assess the visible symptoms and advise whether pruning, monitoring, further investigation or another form of tree management is appropriate.
A declining tree does not automatically need to be removed.

7. The Tree Has Been Damaged by Strong Winds or Storms

Storms can cause significant damage to trees, particularly where branches or stems already have structural weaknesses.

Some damage is immediately obvious, such as a fallen branch or split trunk. Other problems may be less visible from the ground.

After strong winds, look out for:

Broken or hanging branches.
Newly developed cracks.
A change in the tree’s angle.
Uplifted soil or exposed roots.
Damage to major branch unions.
Large branches resting against buildings or other trees.

Even if the tree remains standing, it may have sustained damage that requires professional attention.

What should you do?

Keep away from visibly damaged trees and avoid attempting to remove large hanging branches yourself.

Where there is an immediate risk to people or property, urgent professional assistance may be required.

Does a Dangerous Tree Always Need to Be Cut Down?

No. A potentially dangerous tree does not automatically need to be felled.

The appropriate action depends on the nature and extent of the problem, the condition of the tree and its surroundings.

In some situations, selective pruning, deadwood removal or other tree-management work may be sufficient to reduce the risk.

In other circumstances, particularly where the tree is severely compromised and cannot reasonably be made safe, complete tree removal may be necessary.

A professional assessment can help determine whether the tree can be retained or whether felling is the more appropriate option.

What Should You Do If You Think a Tree Is Dangerous?

If you notice any of the warning signs described above, the first step is to consider whether there is an immediate risk.

If a tree appears unstable, has a large hanging branch or could fall onto an occupied area, keep people and pets away from the affected location.

Do not attempt to climb the tree, cut large branches or carry out dangerous work yourself.

Contact a professional tree surgeon who can assess the situation and recommend the appropriate action.

Where the tree is close to overhead electricity lines, stay well clear and contact the electricity network operator.

If there is an immediate danger to life, contact the emergency services.

Do You Need Permission to Remove a Dangerous Tree?

Potentially.

Trees protected by a Tree Preservation Order (TPO) or located within a conservation area may be subject to restrictions on pruning and removal.

There are legal exemptions for certain circumstances, including work urgently necessary to remove an immediate risk of serious harm, but these exemptions are specific and should not be assumed to apply simply because a tree looks unhealthy.

Where an exemption is being relied upon, appropriate evidence and any applicable notification requirements are important.

If there is no immediate danger, check the tree’s protected status and obtain the necessary consent or provide the required notice before carrying out work.

For more information, read our guide: Do I Need Permission to Cut Down a Tree? A Guide to TPOs and Conservation Areas.

How Can Regular Tree Maintenance Help?

Regular tree maintenance and appropriate professional inspections can help identify developing problems before they become more serious.

A tree surgeon may identify dead or damaged branches, structural defects, signs of disease or changes in the tree’s condition that warrant further attention.
Not every tree needs frequent pruning or intervention. The aim is to maintain trees appropriately while avoiding unnecessary work.

For mature trees, particularly those close to buildings, roads or areas regularly used by people, periodic professional assessment can be particularly valuable.

Professional Tree Surveys and Emergency Tree Removal Across South East London and Kent

If you’re concerned that a tree may be unsafe, Oxleas Tree Care can help assess the situation and recommend the appropriate next steps.

Our experienced team provides professional tree surveys, tree pruning, tree felling, tree removal and emergency tree surgery across South East London and Kent, including Bromley, Lewisham, Greenwich, Dartford, Sevenoaks and surrounding areas.

Whether you’re dealing with storm damage, a leaning tree, dangerous branches or concerns about a tree’s condition, we can help determine the most appropriate course of action.

Concerned about a potentially dangerous tree? Contact Oxleas Tree Care for professional advice and a quotation.

Frequently Asked Questions

How do I know if a tree is dangerous?

Warning signs can include a sudden lean, deep cracks, large dead or hanging branches, root movement, significant decay or storm damage. However, not every visible defect means a tree is unsafe. A professional assessment can help determine the level of risk.

Can a healthy-looking tree still be dangerous?

Yes. Some structural defects and areas of internal decay may not be obvious from the outside. A tree can have healthy foliage while still having a structural weakness that requires assessment.

Does a leaning tree need to be removed?

Not necessarily. Some trees naturally grow at an angle and remain stable. A sudden or increasing lean, particularly with ground movement or root damage, is more concerning and should be assessed promptly.

Can a tree with fungal growth be saved?

Sometimes. The significance of fungal growth depends on the species of fungus, the location and extent of decay, and the condition of the tree. Professional assessment is needed before deciding whether the tree can be retained.

Who should I contact about a dangerous tree?

If the tree is on private property, contact a professional tree surgeon or suitably qualified tree consultant. For trees on public land, contact the relevant council or landowner. If there is an immediate danger to life, contact the emergency services.

Do I need permission to remove a dangerous tree?

You may need consent or to give notice if the tree is protected by a TPO or located within a conservation area. Specific exemptions can apply to urgent safety work, but these have legal conditions.

Can pruning make a dangerous tree safe?

In some circumstances, appropriate pruning can reduce the risk posed by damaged or poorly positioned branches. However, pruning will not resolve every structural problem, and tree removal may sometimes be necessary.