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What it isSignsIs it dangerous?What to doThe rulesWorking safelyReplantingCost
The short answer. You don't need to remove ash trees that aren't showing signs of infection, and if they don't pose a danger you may simply want to monitor them. But infected trees can become brittle and dangerous before they die, so get an ash that looks unwell assessed, especially near a house, road or path. Don't fell it yourself: tree preservation orders and conservation areas still apply.
| Question | Answer |
|---|
| What is it? | A fungal disease, spread by airborne spores, that attacks ash trees |
| Do I have to fell my ash tree? | Not necessarily. Councils advise against felling healthy ash, because some trees show tolerance |
| When is it dangerous? | When an affected tree is within falling distance of people, buildings, roads or paths |
| Do I need a felling licence? | Trees in gardens are generally exempt, but larger-scale felling elsewhere may need one. See below |
| Do TPOs and conservation areas still apply? | Yes. A disease doesn't remove that protection |
| Who should do the work? | Only trained and experienced tree surgeons should work on ash showing obvious dieback symptoms |
What Is Ash Dieback?
Ash dieback is caused by a fungus that came to the UK from Asia and has spread across the country since it was first recorded in south-east England in 2012. The spores are carried on the wind, so you can't stop it reaching your tree, and there is no practical cure. Most ash trees are likely to be affected over time, but not all at the same speed. Some decline quickly, others slowly, and a small number appear to show some tolerance. That's why the advice is to assess and monitor, not to panic-fell.
In Croydon, ash is recorded in the woods and downs around Selsdon, Coulsdon and Kenley, and it also grows in gardens and along boundaries across the borough.
Signs of Ash Dieback
Symptoms change through the year, and one sign on its own doesn't prove anything. Look for several together.
| When | What to look for |
|---|
| Spring and summer | Late or sparse leafing, leaves with black or brown patches that wilt and die, shoots that die back |
| Summer | A thin, see-through crown, with dead twigs and branches among the leaves |
| Autumn and winter | Dead twigs and branch tips, bare areas in the crown, and tufts of new shoots on the trunk and main branches |
| On the bark | Diamond-shaped dark lesions where branches meet the trunk, with brownish or grey bark under the lesions |
| At the base | Lesions, decay or fungus, often secondary problems that weaken the tree further |
Not every thin ash tree has dieback. Drought, root damage, other fungi and old age can look similar. A professional assessment is the only way to be sure.
Is My Ash Tree Dangerous?
An infected tree isn't automatically dangerous. What matters is how far the disease has gone and what's underneath if it fails. The wood of an affected ash can become brittle, so limbs and whole trees can fail with little warning, and the risk rises as the disease advances and as winter weather arrives.
| What's within falling distance | Priority |
|---|
| Houses, conservatories, garages, outbuildings | High |
| Roads, pavements, footpaths, drives, parking | High |
| Play areas, school grounds, gardens in regular use | High |
| Railway, tram or overhead lines | High, and a job for specialists |
| Boundaries and neighbours' property | Medium to high |
| Open ground where no one goes | Lower |
| Stage | What you might see | Typical action |
|---|
| Early | Light thinning, some dead twigs, no structural problems | Monitor, and re-inspect annually |
| Moderate | Significant crown loss, dead branches, visible lesions | Professional assessment, deadwood removal or reduction, closer monitoring |
| Advanced | Severe crown loss, large dead limbs, trunk lesions, decay at the base | Remove or make safe, especially near a target |
| Dead | No living crown | Remove (see the rules below) |
Check ash trees after storms, and keep clear if they look unsafe. See storm-damaged tree: who is responsible?
What to Do: Step by Step
- Don't climb it, lean ladders on it or work under it. Brittle wood can fail without warning.
- Photograph the tree from several angles, with the date. Repeat once a year to track change.
- Work out what's within falling distance.
- Get a professional assessment. We can assess it and give you a written report. See tree surveys.
- Decide: monitor, prune or remove. The right option depends on condition and risk, not just whether the tree is ash.
- Check the rules before any work (TPO, conservation area, felling licence, wildlife).
- Use a qualified, insured tree surgeon. Ash dieback trees are among the more dangerous to work on.
- Plan replacement planting.
Don't fell it just because it's ash. Healthy-looking ash trees, and those with only light symptoms, may last for years, and some may prove tolerant.
The Rules: What Applies to Ash Trees
Felling Licences
The Forestry Act 1967 says that felling growing trees, including diseased and dying ones, requires a felling licence unless an exception applies, and dangerous trees are among the exceptions. The Forestry Commission expects most ash felling in response to dieback, including felling multiple individual trees, to need an approved licence. But this mostly matters for woodland, fields and larger-scale felling. A licence may be required where the trees are not part of a garden. If you plan to fell more than a few trees, check whether a licence is needed.
| Situation | Felling licence? |
|---|
| Ash tree in a private garden | Generally not needed, but check the exceptions |
| Ash in a hedge, field edge or woodland you own | May be needed, depending on volume and location. Ask the Forestry Commission |
| A single ash tree that is immediately dangerous | An exception generally applies, but keep evidence |
| Several ash trees on land that isn't a garden | Likely needed. Apply, or ask the Forestry Commission first |
TPOs and Conservation Areas
Croydon Council says a dead tree needs no formal permission, a dying tree does, and for a dangerous tree only the urgent works necessary can be done without consent, with five days' notice asked for. A tree with ash dieback is usually dying, not dead, so it generally needs consent or six weeks' notice first, unless it's dead or presents an immediate risk. Keep photographs and a report. See our TPO guide, conservation area guide and Do I need permission to fell a tree?
Wildlife
Older ash trees with holes and dead wood are valuable for nesting birds, bats and insects. Where a tree isn't immediately dangerous, plan felling for the autumn and winter, and check for nests and bats first. See our nesting season guide.
Who Is Responsible?
| Whose tree | Who is responsible |
|---|
| Your own garden | You |
| A neighbour's ash | The neighbour. Tell them in writing, with photos, if it looks unsafe |
| A council street tree or park tree | Croydon Council. Report it with photos and the exact location |
| Railway embankment | Network Rail |
| A rented property or communal garden | The landlord, freeholder or managing agent. Report it in writing |
Landowners are responsible for trees on their own land, including those beside roads and paths. A written assessment helps show you've taken reasonable steps.
Working on Ash Safely
Ash with dieback can fail in ways healthy trees don't, so this isn't a DIY job.
| Step | What we do |
|---|
| Assess before climbing | Check whether the tree can safely be climbed at all |
| Use alternatives to climbing | A platform, crane or rigging from a stable tree, where the tree isn't safe to climb |
| Control the fall | Remove in sections, or fell with care, depending on condition and surroundings |
| Check wildlife | Nests and bats, especially in hollow or dead trees |
| Clear everything | Chip, log and remove, and tidy the site |
Leaves, Timber and Firewood
The fungus spreads from fallen leaves, so clearing and collecting fallen ash foliage helps. Timber and firewood are considered low risk for spreading the disease, so ash logs can generally be kept and burned.
Replanting After Ash Dieback
Don't plant ash. Choose a species suited to the site, such as field maple, hornbeam, rowan, wild cherry, silver birch, hazel or a small ornamental tree, depending on space, and plant away from buildings. A mix of species is more resilient. Where a protected tree is removed with consent, the council may require a replacement.
What Does Ash Dieback Work Cost?
Ash dieback trees can cost more to work on than healthy trees of the same size, because brittle wood means more care, sometimes a platform or crane, and extra safety measures. See our cost guide. Typical ranges: assessment from £260; remove a small or medium ash £300 – £800, including the extra for brittle wood; remove a large, brittle ash near buildings or a road £1,150 – £4,100+.
