Crash of the Ash: The Ash Dieback Story

by Oisín Ó Néill and Eoghan Connaughton

Historical and Cultural Importance of the Ash Tree

Through the centuries, many invaders have reached the shores of Ireland, each leaving their mark. Some brought gifts that enriched the land; others, misfortune and destruction. Among the most recent of these arrivals is an invader that threatens one of Ireland’s most important symbols of strength and heritage, the native ash tree. This invader, a fungus named Hymenoscyphus fraxineus — better known as Ash Dieback —has swept through our already fragile native woodlands, leaving devastation in its wake.

Long before this modern scourge, other invaders landed on these shores. Among them were the Vikings, men of the North, who came first as plunderers but, over time, intermarried and wove themselves into the fabric of Irish society. Though foreign and alien at first, they shared with the Gaels a profound respect for one of Ireland’s most sacred trees: the Fuinseog, the Common ash. In Norse mythology Yggdrasil, the sacred World Tree was an ash tree, the Vikings believed this sacred tree connected all realms of existence. Its massive branches extended into the heavens, while its deep roots stretched into the underworld.

The natives of the island, the Gaels, also believed the ash was a sacred tree. Under the ancient Brehon Laws, trees were revered and classified into four distinct orders, each reflecting their importance, practical use, and symbolism. At the top stood the “Nobles of the Wood,” including the oak, the ash, and the yew, celebrated for their sacred presence in the Irish landscape.¹ Individual sacred trees, known as bile, were revered as living sentinels of power and sanctity. These hallowed giants stood on the grounds of royal inaugurations, sheltered the homes of kings, and watched over places of healing and holiness. Among the most renowned was Bile Uisig, rooted on the Hill of Uisneach, the ancient sacred heart of Ireland and the site of the Bealtaine fire festival. Another, Bile Tortan of County Meath, inspired lamentation in ancient verse: “The plain of Tortu is a plain without a ruler since it lost its noble tree.” Equally storied is Bile Daithí, the ash bough of Daithí, nephew of Niall Noigiallach, the legendary ancestor of the O’Néill dynasty. ²

The 7th-century text, Auraicept na n-Éces, contains the earliest record of the Ogham Alphabet, where the Ash tree is referred to as Nin (Nion). It is described as both a “sign of peace” symbolized by the spear and as the source of the “weaver’s beam,” essential for spinning a loom.³ While the Gaels revered the ash as sacred, this text reveals that it was actively harvested for practical uses—a tradition that continues to this day. Its remarkable flexural strength made it highly valued for crafting spears and for making hurleys. Much of Ireland’s ancient ash woodlands were felled, notably by the Gaels themselves, as they harnessed the tree’s unique qualities to meet the needs of their society. The use of ash in Ireland has endured through the ages, with its most iconic application found in the crafting of hurleys. Renowned for its exceptional shock resistance, ash wood remains the wood of choice in hurley making. The phrase, “the clash of the ash,” is a testament to the wood’s strength and resilience.

The Vital Role of Ash in Ireland’s Ecosystems

While Ireland was once synonymous with expansive oak forests, ash trees thrived alongside oaks and hazels in ancient woodlands, particularly in areas with less acidic soils. This combination contributed significantly to the ecological complexity of Ireland’s Atlantic Rainforests. Far from being an understory species, ash trees reached majestic heights of up to 27 meters, with a canopy spanning 21 meters and a trunk girth of 3 meters. With lifespans exceeding 250 years, they rivaled the oak in grandeur and ecological significance. Ash trees often dominated calcareous slopes, rising above oak-dominated lowlands. These mixed ash woodlands were distinct from the acidic oak forests below, supporting a diverse array of species like rowan and hazel. At higher elevations, these habitats transitioned into wetland ecosystems populated by downy birch and Scots pine.

Ash thrives in calcareous soils (derived from limestone bedrock) because of its need for calcium carbonate, which is crucial for healthy leaf development—similar to how humans require calcium for strong teeth. To access this vital mineral, ash roots, in partnership with fungal mycorrhizal networks, release acids and exert pressure to extract calcium from rock. This calcium is transported to the tree’s twigs to support leaf growth, which captures sunlight for energy. When ash leaves fall in autumn, they release calcium back into the soil, increasing its pH and counteracting acidification in the topsoil. The leaves also contain high levels of magnesium, making the ash a natural cultivator of fertile soil. As a result, ash woodlands are often teeming with mollusks, such as snails, which use the calcium to build their shells, adding another dynamic layer to the forest’s food web.

Ash trees also formed communities with willow and alder in wetlands, springs, and other saturated environments. Beneath their canopy thrived a rich understory, including species like remote sedge, meadowsweet, creeping bent, and lady fern. Today, however, much of Ireland’s ash woodland has vanished. While ash trees can still be found in wet woodlands, they are now primarily associated with hedgerows. Planted as field markers during the Acts of Enclosure to aid in taxation, these hedgerows now constitute over 10% of Ireland’s tree cover, with ash being the most common species. These hedgerows serve as vital ecological corridors. The ash tree’s flowers support pollinators, while its keys (fruits) provide sustenance for birds, bats, and small mammals like field mice. Standing tall at up to 27 meters, ash trees form the pillars of these hedgerows, offering perches and hunting stands for birds like the barn owl and buzzards, which use these trees as vantage points for navigating and hunting across farmland.

Ash Dieback: Understanding the Disease and Its Impact on Ireland’s Ash Trees

Ash Dieback, caused by the fungal pathogen Hymenoscyphus fraxineus, has devastated ash trees across Ireland. Airborne spores infect ash leaves, infiltrating the stems and spreading beneath the bark to colonize the cambium. This process blocks the movement of sap and nutrients, halting photosynthesis. Weakened trees become vulnerable to storm damage and secondary infections, such as Armillaria (Honey Fungus). Symptoms of the disease typically appear within 2 to 7 years, beginning with defoliation at branch tips and progressing until the crown is completely bare. In 2021, the Department of Agriculture, Food and the Marine (DAFM) concluded that the pathogen was “likely…introduced into Ireland from another EU Member State.” However, this assessment overlooked the role the DAFM’s Forestry Programme played in its introduction. Between 1990 and 2013, this program financed the importation of an estimated 31 million ash trees. The first recorded case of Ash Dieback in Ireland occurred in 2012 on a Forestry Programme-funded plantation of imported Dutch ash.⁴ That same year, infections were identified in plantations and hedgerows across the island, suggesting that human activity, including large-scale planting regimes, facilitated the spread of the pathogen.⁵

Attempts to enhance biosecurity began as early as 2006, when the DAFM recommended using Irish-provenance trees for infrastructure projects. However, these recommendations were not implemented due to insufficient nursery capacity. While the Forestry Programme made significant investments to promote native tree planting, it failed to build the necessary infrastructure to meet demand. This reliance on imported trees ultimately decimated Ireland’s native ash population, which had thrived for over 8,000 years.

Despite publishing a report titled “Lessons Learned from the Impact of Ash Dieback Disease,” the DAFM did not address the urgent need to expand Ireland’s indigenous nursery capacity. Instead, the Department’s response has focused on:

1. Providing €7.5 million in financial support to plantation owners to remove infected ash and replace them with other species, with additional funding anticipated.
2. Publishing the Plant Health and Biosecurity Strategy 2020-2025, including a prohibition on ash tree imports.
3. Establishing Pest Risk Analysis expertise and EU Border Control Posts in 2018.

Ireland and the UK are the only European nations to enact emergency legislation to combat Ash Dieback. The EU, where the disease was first recorded in 1990, has no border controls between member states, making containment of airborne pathogens nearly impossible. Ireland’s emergency legislation was ultimately deemed in violation of the EU Plant Health Directive (Council Directive 2000/29/EC), forcing the DAFM to admit that partner nations could not guarantee compliance with plant health measures.⁶ In 2019, new EU plant health regulations (2016/2031) introduced designated border points to assess imported plants and detect pathogens.⁷ While these measures are a step forward, they do not eliminate the need for tree imports, as Ireland still lacks sufficient nursery capacity to meet afforestation targets.

The DAFM has taken commendable steps to support research on dieback-resistant ash. Trials in the UK have identified resistant genotypes, leading to the establishment of conservation plantations in Kilkenny (2020) and Phoenix Park (2021). However, as Ash Dieback primarily affects mature trees, it will take decades to determine the efficacy of these efforts.The Ash Dieback crisis highlights the urgent need to build robust indigenous nursery capacity. Without this, Ireland remains reliant on imports, exposing its forests to further biosecurity risks. Sustainable forestry management, including the use of native tree stock, is essential to safeguarding Ireland’s ecological and cultural heritage. The lessons of Ash Dieback must drive long-term change in how Ireland approaches forestry, ensuring a more resilient future for the nation’s woodlands.

Understanding the Ash Dieback Replanting Scheme

The ash dieback crisis has had far-reaching consequences for forestry in Ireland, particularly for farmers who invested in ash plantations. Many farmers saw ash plantations as a way to reduce reliance on imported wood for crafting hurleys and other traditional uses. Backed by government grants, these forests were envisioned as sustainable, long-term investments. However, the arrival of ash dieback has ruined these plans, leaving farmers to contend with severe financial losses.

The Ash Dieback Replanting Scheme, introduced by the Department of Agriculture, Food, and the Marine, is a response to the devastating effects of Ash Dieback. The scheme provides financial support to forest owners to restore damaged woodlands, replant alternative species, and safeguard the ecological and commercial value of Ireland’s forests. The scheme supports the removal and destruction of infected trees and leaf litter, replanting with alternative tree species suited to the site and maintenance of replanted forests, including ground preparation, vegetation control, and shaping.⁸ The scheme offers financial aid for site clearance with up to €2,000 per hectare in funding available for removing and destroying infected trees. The scheme promotes diverse and sustainable forestry by funding a range of replanting options, including grants of €6,744/ha for (FT1) Native Forests, €6,744/ha (FT6) for broadleaf forests consisting of mainly oak/beech, €8,555/ha (FT8) for Agroforestry and €3,858/ha for mixed high forests (FT12) consisting of Sitka Spruce and 20% broadleaf.⁹

While the scheme provides much-needed support, concerns remain. Forest owners claim site clearance grants of €2,000/ha fall short, with actual costs ranging from €5,500 to €7,000/ha​. Forest owners receive no compensation for the commercial losses caused by ash dieback. This is a worrying situation for farmers who may be discouraged from further participation in forestry, eroding confidence in a system that has left affected farmers burdened with financial loss and uncertainty. Farmers and forestry groups have criticized the scheme for not involving stakeholders in its design​. Additionally, some argue that the government’s response to ash dieback, including early efforts to control the disease, was insufficient, allowing the problem to escalate

The Irish Farmers Association (IFA) has called for changes to the ash dieback support scheme. They are seeking grants to cover 100% of costs for clearing and replanting infected plantations with suitable species, fair compensation for the lost value of timber assets and strengthened measures to prevent the spread of tree diseases and ensure proper compensation for future outbreaks.¹⁰ While the Ash Dieback Replanting Scheme provides some relief through financial support for site clearance, replanting, and forest maintenance, it has drawn criticism for falling short of meeting the true costs of managing this crisis. The scale and complexity of the ash dieback crisis mean that certain groups—particularly those with older plantations or higher costs—feel under-supported. However, the scheme represents a step forward in addressing the issue, offering at least some assistance in a time of unprecedented challenges. By supporting replanting with diverse and sustainable species and funding efforts to restore damaged woodlands, the scheme contributes to safeguarding Ireland’s ecological and commercial forestry future. While it may not solve every issue or provide comprehensive compensation, it is a recognition of the problem and an attempt to provide a pathway toward recovery.

In addition to the reliance on imported ash trees over native Irish provenance, another significant issue in Ireland is the widespread use of even-aged ash plantations, where all trees are of the same age. This uniformity leaves woodlands particularly susceptible to disease outbreaks. To safeguard the future of Ireland’s forests, experts advocate adopting close-to-nature forestry principles. These principles emphasize the importance of mixed-species woodlands, a variety of tree ages, and greater genetic diversity, creating more resilient and sustainable ecosystems. Mixed forest ecosystems support richer biodiversity, offer more aesthetic value and are more resilient to environmental pressures such as disease outbreaks and climate change. Transitioning from monocultures to diverse woodlands would not only protect Irish forests but also help mitigate the broader challenges of a changing environment.

The Future for the Ash tree

While some sectors have begun to move away from ash, such as the transition to bamboo for hurley-making, a necessary but poignant departure from a tradition spanning over a thousand years, hope persists for the beleaguered ash in the form of scientific innovation and conservation efforts. Since 2015, Teagasc has spearheaded a pioneering ash-breeding program to develop disease-tolerant genotypes. Early findings show that up to 10% of ash trees show some tolerance to the disease, with 1–3% exhibiting high levels of resistance.¹¹ As part of this effort, a trial involving 1,000 Irish ash genotypes was carried out in Lithuania. With its severe impact from the disease, Lithuania offers an ideal testing ground for identifying highly tolerant trees. Teagasc has also established gene banks, including one composed of 208 ash genotypes from 15 European countries. Early results from trials in Ireland are promising, with 28% of genotypes showing good tolerance and 5% displaying exceptional tolerance, exhibiting no signs of dieback.¹²

The recently launched AshForFuture project is playing a critical role in conserving and restoring ash populations across Ireland. This initiative employs four interconnected strategies to tackle the challenges posed by ash dieback. A dedicated platform has been established to engage forestry practitioners, hurley manufacturers, policymakers, scientists, and the public. The AshGen team is focusing on identifying and propagating ash trees with demonstrated tolerance to dieback disease, ensuring the preservation of resilient genetic traits. The AshPath team is investigating the interactions between the fungal pathogen Hymenoscyphus fraxineus and its host, Fraxinus excelsior. By understanding these dynamics, AshPath seeks to develop strategies to future-proof ash populations against the disease. The Ash Silva team is advancing sustainable forestry practices, including mixed-species planting, to enhance the resilience of ash trees and promote biodiversity. To learn more about the AshForFuture project and its efforts to safeguard the future of ash in Ireland, visit: Teagasc – AshForFuture Project.

Teagasc’s “Report a Healthy Ash Tree” initiative invites the public to identify and report healthy ash trees, fostering community awareness and engagement and contributing to the preservation of genetic diversity and aiding researchers in selecting naturally resistant individuals. Guidelines on identifying healthy ash trees and instructions on how to report them are available at: Teagasc – Report a Healthy Ash Tree.

These initiatives offer hope to the Irish Ash tree. Across Europe there is cautious optimism. Earlier forecasts in the UK estimated that up to 95% of the country’s ash trees could perish, but the most recent Europe-wide data indicates an average loss of 50% over the next 30 years, with certain regions facing significantly higher impacts.¹³ It is worth noting that a pan-European study has identified factors such as excessive water regimes and extreme precipitation events as strongly linked to reduced survival rates. Southern Scandinavia and northeastern Europe are expected to be the worst hit regions, with overall survival probabilities now estimated to be critically low at 51%, varying significantly by region (20%–86%).¹⁴ These findings emphasize the urgency for coordinated, cross-border action to safeguard the future of ash species across Europe.

The Gaelic Woodland Project: Our Perspective and Role

The Gaelic Woodland Project recognizes the necessity of large-scale planting initiatives but emphasizes that a holistic approach to forestry management is crucial. This approach must be mindful of Ireland’s unique ecological and cultural relationship with woodlands. As an island, Ireland has been geographically isolated from continental flora migration for millennia, giving its ecosystems a distinct character. While historical deforestation has severely impacted this natural heritage, it is vital to respect and responsibly restore it.

Ireland’s native tree population consists of only 24 species, each deeply rooted in Gaelic culture. However, past actions, driven by haste and poor planning, have already caused significant damage, most notably the devastation of ash trees. The introduction of invasive pathogens, enabled by participation in the European Single Market, compromises the island’s natural biosecurity. Although new EU regulations aim to mitigate pathogen spread, they cannot guarantee the prevention of future ecological crises.

Several pathogens pose serious threats to Ireland’s woodlands:

• Phytophthora ramorum (Sudden Oak Death) could devastate native oak species.¹⁵
• Phytophthora cinnamomi is a highly aggressive pathogen that targets over 5,000 plants, including oak.¹⁶
• Dothistroma septosporum could lead to the loss of native Scots pine and conifer plantations, which make up over 70% of Irish forests.¹⁷
• Xylella fastidiosa has caused severe damage to olive groves in Italy and could threaten wild Irish cherry trees.
• Erwinia amylovora (Fireblight) has already been detected in hawthorn trees across the island.

Fireblight is believed to have been introduced through European nurseries as part of agricultural schemes incentivizing the planting of hedgerows. This mirrors the Ash Dieback crisis, where a lack of indigenous nursery capacity forced reliance on imported stock, leading to the spread of devastating pathogens. Such shortsightedness undermines ecological restoration efforts and forestry targets. To prevent further damage, Ireland must prioritize the development of indigenous tree nurseries that use seed collected from its ancient woodlands. This approach not only preserves Ireland’s unique genetic heritage but also creates employment opportunities and strengthens ecological resilience. The Republic can and should invest in and subsidize Irish nurseries to compete with imports effectively. An example of the impact of robust supply chains can be seen in the propagation of Cherry Laurel, an invasive shrub grown on over 200 hectares in Munster for the European bouquet market. Despite its invasive nature, it dominates the hedgerow market in Ireland due to an oversupply, making it the cheapest option. This highlights the potential for a similar market structure focused on Irish provenance trees. With a national target of 18% tree cover and a well-funded forestry program, it would be shortsighted not to seize the social and economic opportunities presented by indigenous nurseries. A careful, methodical approach to ecological restoration, rooted in the use of native seed stock, is the only sustainable path forward.

The Gaelic Woodland Project is dedicated to planting only indigenous tree stock, ensuring we support local businesses and entrepreneurs while avoiding contributions to a destructive tree market. We support the redress scheme for its focus on mixed native woodlands, encouraging the planting of mixed broadleaf species is a vital step forward, marking a shift from the historical reliance on monoculture plantations toward more biodiverse and resilient landscapes. We commend the Department of Agriculture, Food and the Marine (DAFM) for its efforts and strongly advocate for further investment in indigenous seed stock to safeguard against future challenges. The lessons from the devastating impact of Ash Dieback are clear: monoculture plantations are vulnerable, and the path to resilience lies in prioritizing Irish provenance trees and fostering mixed native woodlands. Ash Dieback should serve as a cautionary lesson for owners of Sitka Spruce plantations across the island. While we acknowledge the concerns raised by farmers, Ireland’s legislative response to Ash Dieback is one of only two in Europe, reflecting a commendable commitment to addressing this issue. Furthermore, initiatives to study the disease and identify resistant trees are significant strides toward long-term solutions. Together, these efforts highlight the importance of building a sustainable, resilient, and biodiverse future for Ireland’s forests. It is crucial for those involved in forestry to reflect on this experience and draw valuable lessons from it, it is time for a transition to a more sustainable model, prioritizing mixed native broadleaf plantations.

1https://www.forestryfocus.ie/social-environmental-aspects/cultural-heritage/trees-and-folklore/brehon-laws/
2 https://www.ancienttexts.org/library/celtic/ctexts/d02.html
3 Calder, W. (1917). Word Ogams of Morann Mac Main, The Scholars Primer.
4https://www.teagasc.ie/media/website/crops/forestry/research/Ash-Dieback-on-the-island-of-Ireland.pdf
5 DAFM. (2021). DAFM response to the Report of the Joint Oireachtas Committee on Agriculture and the Marine, on ‘Issues Impacting the Forestry Sector in Ireland’, Origins of Ash Dieback Disease in Ireland, Lessons Learned and Research Update. Department of Agriculture, Food and the Marine.
6 https://eur-lex.europa.eu/eli/dir/2000/29/oj/eng
7 https://eur-lex.europa.eu/eli/reg/2016/2031/oj/eng
8 https://www.gov.ie/en/service/f5e399-ash-dieback-replanting-scheme/
9 https://www.teagasc.ie/crops/forestry/grants/reconstitution-ash-dieback-scheme-20232027/
10 https://www.ifa.ie/wp-content/uploads/2023/08/Ash-Dieback-2023.pdf
11https://www.teagasc.ie/media/website/publications/2019/Finding-and-understanding-resistance-to-ash-dieback.pdf
12https://www.rte.ie/brainstorm/2025/0114/1490726-ash-trees-ireland-ash-dieback-conservation-protection/
13 https://www.theguardian.com/environment/2024/dec/20/ash-dieback-britain-threatened-trees-disease
14 https://www.nature.com/articles/s41598-022-08825-6
15 Teagasc. (n.d.). Phytophthora ramorum: An overview. Teagasc. Retrieved January 22, 2025, from http://www.teagasc.ie/crops/forestry/advice/forest-protection/phytophthora-ramorum/#:~:text=Phytophthora%20ramorum%20is%20one%20of%20the%20most%20damaging,nurseries%20in%20Europe%20and%20in%20forests%20in%20California.
16 Hardham, A. (2018). Pathogen profile update: Phytophthora cinnamomi. Molecular Plant Pathology, 19(2), 260–285.
17 Forest Research (UK). (n.d.). Dothistroma needle blight (Dothistroma septosporum). [online] Available at: www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/dothistroma-needle-blight-dothistroma-septosporum/#:~:text=DNB%20is%20mostly%20a%20disease%20of%20pine%20trees.%20In [Accessed 22 Jan. 2025].