Ash dieback is a phrase that has, unfortunately, become all too familiar in recent years. It’s hard to overstate just how big a problem it’s become for our native ash, Fraxinus excelsior. This is a tree that’s been part of our hedgerows, woodlands and fields for centuries, giving structure to the landscape and providing everything from wildlife corridors to the raw material for hurleys and tool handles. Now it’s under real threat.
The trouble starts with a fungus called Hymenoscyphus fraxineus. It spreads by spores that drift through the air in summer and settle on ash leaves. From there, it works its way into the shoots, eventually blocking the tree’s water supply. You’ll see the first signs as blackened patches on the leaves or wilting new growth. As it progresses, branches die back and often sprout new shoots lower down in a desperate effort to survive.
This disease has been moving through Europe since at least the 1990s. It was first officially identified here a little over a decade ago, but by then it had likely already arrived. Now it’s widespread across much of Ireland and the UK.
The scale of the impact is staggering, not just for the trees themselves but for all the birds, insects and mammals that rely on ash. There’s also the enormous cost of removing dangerous trees from roadsides and public spaces, which is running into the billions.
Still, it’s not all bleak. Rough estimates suggest that about one to five per cent of ash trees show some natural tolerance. These are the trees that might help us rebuild in the future if we can protect and encourage them.
Because the disease is so serious, there are strict controls on moving ash plants. Since 2012, it’s been illegal to trade or plant ash saplings, seeds or young trees in most situations. That’s been a hard blow for nurseries, but it’s necessary to slow the spread.
The advice these days is not to rush out and fell every infected ash. In fact, experts now recommend a more measured approach. Keep an eye on your trees. If they’re holding their canopy reasonably well and aren’t close to paths or property, it can be better to leave them standing. Some of these trees might prove to be the naturally tolerant individuals we’ll rely on in future.
There is no treatment or cure yet, though research is ongoing. Breeders are working on raising young ash from those rare tolerant trees, and some hopeful trials are taking place.
In the meantime, there are a few simple things that help slow the disease. Clearing up fallen ash leaves in autumn, keeping trees healthy by avoiding heavy pruning and reducing competition around them can also help.
It’s also worth taking a bit of time to look at what’s growing nearby. If an ash does have to come out eventually, think about what you’ll plant in its place. Increasing the diversity of species makes future woodlands and hedgerows more resilient. Native trees like birch, alder and oak all have their place, and in time, perhaps more tolerant ash will be available too.
When you look across old fields and lanes where ash trees stand like sentries of our landscape, it brings home just how much we stand to lose. These are trees that hold together so many of our local ecosystems. They’ve long been part of the backdrop to country life, providing shelter, shade, and the raw material for so many traditional uses.
Ash dieback disease starts with a fungus called Hymenoscyphus fraxineus. It spreads by spores that drift through the air in summer and settle on ash leaves. File picture
If you’re managing land or even just tending a garden with an ash, the best thing you can do is take a balanced approach. Watch for signs of dieback, clear fallen leaves when you can, and prune out dead wood if it’s safe and sensible.
If a tree becomes dangerous, then by all means get it assessed and, if needed, taken down by a qualified professional, but equally, don’t be too quick to remove every infected tree. Some may surprise us by pulling through.
It’s also worth remembering that even a dying ash still plays a role in the wider garden or landscape. Dead and decaying wood provides a valuable habitat for countless insects, fungi and birds.
Standing dead trees, if safely away from paths and buildings, can become living food sources and nesting sites. We often think that a tree has to be lush and green to be of any use, but in reality, the gradual breakdown of timber supports a whole web of life. So, where it’s safe to do so, leaving a dead or dying ash standing can be just as important.
It’s a challenge, but with thoughtful management, a willingness to adapt, and perhaps a bit of patience, we might still see ash as part of our hedgerows and woodlands for generations to come. Nature, after all, often finds a way, and it’s up to us to give it every chance.
