Can Ireland's ash trees stage a comeback against deadly dieback?

Irish Examiner

2 days ago

For more than a decade, Ireland's ash trees have been quietly dying. Victims of a deadly fungal disease known as ash dieback, they have withered in woodlands, fallen from hedgerows, and left gaps in a landscape where they once stood proud and plentiful. Since its arrival in 2012, ash dieback has spread relentlessly across the island, and with it has come growing concern for biodiversity, forestry, and even national identity.
Yet, amid the losses, a new hope is sprouting. Science shows our ash trees may be fighting back.
A devastating foe
Ash dieback, caused by the fungus Hymenoscyphus fraxineus, sneaked into Ireland through imported plants, spreading like wildfire. Its spores attack ash trees' leaves, choking their ability to carry water and nutrients.
Ash dieback
The result? Withered branches, cracked bark — and, for many young trees, a death sentence. It's estimated that up to 90% of Ireland's ash trees could be at risk, with entire woodlands and hedgerows fading away.
The fallout is more than just a loss of trees. Ash trees are the backbone of our ecosystems, supporting more than 40 species of insects, lichens, and fungi that keep our woodlands teeming with life. Their decline ripples through the food chain, threatening birds and other wildlife.
And then there's hurling. Our beloved sport that relies on ash for crafting hurleys. With local ash in short supply, we've had to turn to imported timber... a bittersweet shift for a game woven so deeply into our national identity.
Nature fights back
But the story doesn't end there. A groundbreaking study from Britain, hot off the press in the journal Science , brings a ray of hope. Researchers from Kew Gardens and Queen Mary University of London studied a woodland in Surrey and discovered that young ash trees are tougher than their parents. By comparing DNA, they found that these saplings have inherited thousands of tiny genetic tweaks that help them fend off the fungus.
It's evolution in action, happening right before our eyes.
Here in Ireland, this discovery hits home. Our ash trees share the same genetic roots as those in Britain, and Irish scientists are already spotting survivors in our woodlands. By collecting their seeds and using cutting-edge genetic tools, foresters are working to determine if they can grow a new generation of ash that can stand strong. But this process will take time. Resistance is not immunity, and many trees, particularly older ones, will continue to die. But it's a start.
Echoes from the past
This isn't the first time Ireland's trees have faced a crisis. While ash dieback is a modern disease, the idea of trees succumbing to disease is not new. Thousands of years ago, around 5,000–6,000 years back, our elm trees vanished in a mysterious 'elm decline'. Ancient pollen buried in bogs and lakes show a dramatic and rapid drop in elm (Ulmus) trees.
For years, scientists debated whether this decline was caused by early farming practices or a natural disease outbreak. Today, many palaeoecologists believe that a form of Dutch elm disease (or a closely related pathogen) may have triggered this ancient collapse.
Though not directly linked to ash, the elm decline provides a powerful precedent for how tree disease can reshape entire landscapes. More subtle changes in the pollen record, such as temporary declines in ash or oak, might also reflect short-lived disease events or stressors like drought or fire.
New techniques, such as sedimentary ancient DNA (sedaDNA) analysis, are beginning to offer even greater insight, detecting not only the presence of tree species but also the DNA of associated fungi and pathogens preserved in sediment layers.
These long-term records remind us that forest ecosystems are dynamic and resilient, capable of both suffering and recovering from shock. They also provide a long-term perspective on how tree species may have responded to past climate changes and biological threats.
A path forward
Today, scientists and foresters are working together to manage the immediate crisis and prepare for the long haul.
Elongated angular stem lesions, one of the symptoms to look out for with ash dieback /(Chalara fraxinea).
Across Ireland, seeds are being collected from surviving ash trees, saplings are being tested for resistance, and new planting strategies are being explored to determine if resilient stock could be reintroduced into the landscape.
At the same time, it's important to not view the ash crisis in isolation. A more diverse forest, one that includes native species like oak, birch, rowan and hazel, is more likely to withstand future challenges, whether from disease, invasive pests, or a changing climate.
Still, the idea that ash could one day reclaim its place in Irish hedgerows, woodlands, and hurley workshops is no longer just wishful thinking. It won't happen overnight. Rebuilding our ash woodlands will take decades, blending nature's resilience with human ingenuity. But imagine a future where ash trees once again shade our fields and fuel our hurling matches. So, while ash trees are down, they're not out of the game just yet.