If you have an ash tree on your property, there's a good chance it's already fighting a losing battle. Ash dieback is now Ireland's biggest tree health crisis, present in every county where ash grows, and it's quietly changing how our hedgerows and gardens will look for a generation. Here's how to recognise it, why it matters for your safety, and what to do next.
What Is Ash Dieback?
Ash dieback is a fungal disease caused by Hymenoscyphus fraxineus (formerly known as Chalara fraxinea). It attacks common ash trees, causing leaf loss, bark lesions, and dieback of shoots and branches, often leading to the tree's eventual death. It was first confirmed in Ireland in 2012 and has since spread to every county. Some estimates suggest that without intervention, the majority of Ireland's ash trees could eventually be lost to the disease.
How to Spot Ash Dieback in Your Own Tree
The symptoms usually develop gradually over several years, but there are clear signs to look for:
- Wilting or blackened leaves during the growing season
- Diamond-shaped or blackish lesions where branches meet the trunk
- Thinning of the crown, with dead twigs and branches visible from below
- Bushy, unusual regrowth low on the trunk (a stress response called epicormic growth)
- Overall decline year on year, rather than a single obvious cause
If you're seeing more than one of these on an ash tree, it's worth having it looked at properly rather than guessing from a photo online.
Why a Dying Ash Tree Is a Safety Risk, Not Just an Eyesore
This is the part homeowners often miss. As ash dieback progresses, the wood becomes brittle, and branches can fail and drop with little or no warning, even in calm weather. That's different from most storm-related tree risk, and it's exactly why a diseased ash near a house, driveway, or garden where people spend time deserves a proper tree risk assessment rather than a wait-and-see approach.
The Fight Back: Ireland's Search for Disease-Resistant Ash
It's not all bad news. Teagasc's AshforFuture project, backed by the Department of Agriculture, is working to identify ash trees that show natural tolerance to the disease, with the aim of breeding a more resilient generation of Irish ash. Members of the public have already reported over 400 healthy-looking ash trees nationwide to help with this research. If you have an ash tree that looks strong and symptom-free despite the disease being widespread in your area, it could genuinely be worth reporting to the project.
What to Do If You Think You Have Ash Dieback
- Don't panic, but don't ignore it. Early-stage dieback doesn't always mean immediate removal.
- Get a professional assessment. A qualified tree surgeon can tell you how advanced the disease is and whether the tree is currently safe.
- Plan removal before it becomes an emergency. Dead and dying ash is more brittle and unpredictable to fell than most trees, so this is a job for an experienced, insured tree removal team, not a DIY weekend.
- Think about replacing it. If a tree does need to come down, replanting with a different, resilient species helps keep your garden's canopy, and the wildlife that depends on it, going strong.
Why Cork & Kerry Homeowners Trust Heritage Tree Care Ltd with Ash Dieback
Our team is experienced at spotting the early signs of ash dieback and safely removing trees that have become genuinely hazardous, backed by full insurance and NPTC and ISA qualifications. We know that brittle, diseased ash behaves differently to a healthy tree, and we plan every job accordingly.
Frequently Asked Questions
What causes ash dieback?
A fungal disease called Hymenoscyphus fraxineus, which spreads through airborne spores and infects common ash trees, causing progressive dieback and often death.
Can an ash tree recover from ash dieback?
Some trees show natural tolerance and survive longer than others, but most infected trees decline over several years. Ongoing research is focused on identifying and breeding from these more tolerant trees.
Is it dangerous to have a dead or dying ash tree in my garden?
It can be. Diseased ash becomes brittle and can drop branches unexpectedly, so a tree near a house, path, or seating area should be professionally assessed.
Do I need permission to remove a diseased ash tree?
It depends on the tree's size and location. Some trees are exempt from felling licence requirements, but it's best to check before starting any work. A qualified tree surgeon can advise you.
How can I help fight ash dieback in Ireland?
Reporting healthy-looking ash trees to research projects like Teagasc's AshforFuture helps scientists breed a more disease-tolerant generation of Irish ash.
Worried about an ash tree on your property? Contact Heritage Tree Care Ltd for a professional assessment.