04 February 2025

How you can help save Ireland’s native ash tree

Dheeraj Rathore, in a recent RTÉ Brainstorm article, highlighted the critical role of ash trees in Ireland’s biodiversity and culture. He examined the devastating impact of ash dieback disease and the ongoing efforts to preserve this iconic species.

Trees and forests are often called the “lungs of the planet” because of their vital role in producing oxygen and absorbing carbon dioxide. Trees play a pivotal role in mitigating climate change, preserving biodiversity, and enhancing human health by improving air quality and providing mental health benefits. This interconnection underscores the urgency of protecting our trees to ensure environmental resilience and societal well-being for future generations.

Ireland has one of the lowest levels of forest cover in Europe, with just 11.6% of its land area covered by trees, compared to a European average of 40%. Despite this, trees have long held a profound significance in Ireland’s landscape, culture, and ecosystems. Among them, the ash tree (Fraxinus excelsior) – in Irish fuinseóg – stands as a cornerstone of biodiversity and Irish culture. However, the ongoing threat of ash dieback disease, caused by invasive fungal pathogen – Hymenoscyphus fraxineus, raises urgent questions about our responsibility to protect native trees and, with them, the future of Ireland’s natural heritage.

The importance of native trees

Ireland’s native trees play crucial ecological roles, providing food and habitat to countless species. The ash tree alone supports nearly 1,000 species, including insects, mammals, bryophytes, and lichens. While many species can adapt to other trees, some are entirely dependent on ash. Losing ash trees would therefore disrupt entire ecosystems, affecting pollinators, birds, and other wildlife.

Beyond biodiversity, ash trees are culturally symbolic. As one of the ‘noble’ trees in ancient Irish law, ash has been celebrated in folklore, poetry, and sports. Its flexibility and strength famously make it the wood of choice for crafting hurleys. Place names and local traditions across Ireland further illustrate its embeddedness in Irish life.

A tree in crisis: the threat of ash dieback

Ash dieback is decimating ash populations across Europe, including Ireland. First detected here in 2012, the disease spreads through airborne spores and infects trees via leaf litter. It causes leaf wilting, crown dieback, and root rot, ultimately leading to death. Young ash trees are more susceptible, with mortality rates nearing 100% in some areas.

Signs of the disease are now evident in Irish hedgerows, where skeletal ash trees with barren tips are becoming increasingly common. The impact is significant to that of the Dutch elm disease (DED), which wiped out elms across Ireland and Europe.

Teagasc Forestry Adviser Frances McHugh describes the life cycle and symptoms of the fungal disease ash dieback

Millions of elms have been lost since the disease spread began in the 20th century, reshaping landscapes and ecosystems. Once a common sight in Ireland, mature elms are now rare, with only a small number of survivors scattered across the country.

Efforts are underway to restore elms through breeding programmes focused on disease-tolerant varieties, such as those led by Teagasc in Ireland. This loss parallels the current challenges facing ash trees due to ash dieback disease, highlighting the importance of safeguarding native trees for biodiversity and cultural heritage.

Lessons for the future

Ash dieback underscores the risks associated with low genetic and structural diversity in forests. Many Irish ash plantations are even-aged (where all trees are of the same age), which makes them more vulnerable to diseases like ash dieback. Building resilient forests requires embracing close-to-nature forestry principles that promote mixed-species woodlands, diverse tree ages, and genetic variety.

Mixed forests (forests with a variety of tree species) not only support greater biodiversity but also create ecosystems better equipped to withstand environmental pressures, including diseases and climate change. By prioritising these strategies, Irish forestry can transition from vulnerable monocultures to resilient, thriving ecosystems.

The AshForFuture project

Despite the challenges posed by ash dieback, there is hope through scientific research and conservation efforts. Since 2015, Teagasc has led an ash-breeding program to develop disease-tolerant genotypes. Early research has shown that up to 10% of ash trees have some tolerance to the disease, with 1-3% showing a high level of tolerance. This resistance, controlled by multiple heritable genes, provides the foundation for breeding programmes focused on producing tolerant ash genotypes.

As part of this work, a trial of 1,000 Irish ash genotypes was established in Lithuania, a region with high disease pressure, to identify highly tolerant trees. Additionally, Teagasc has created gene-banks, including one comprising of 208 ash genotypes from 15 European countries. Preliminary results from these trials in Ireland show promising levels of tolerance: approximately 28% of genotypes display good tolerance, and 5% exhibit a higher level of tolerance, with no signs of dieback.

The research also incorporates cutting-edge techniques such as genomic selection, identifying molecular markers for dieback disease screening, micropropagation techniques to rapidly multiply tolerant trees and establish seed orchards for future testing. Through partnerships with organisations such as Coillte, None-So-Hardy Nurseries, the Office of Public Works, and international researchers, provide additional support for this critical research. The Department of Agriculture, Food and the Marine continues to fund these advancements, ensuring long-term progress.

A vital component of this work is the recently launched AshforFuture project, which further enhances the conservation and restoration of ash in Ireland. This focuses on identifying and propagating disease-tolerant trees while safeguarding the genetic diversity of Ireland’s native ash. Key contributions include rigorous testing under high-pressure conditions to identify durable tolerance, studying the pathogen’s behaviour, and refining silvicultural practices. These efforts represent an essential step toward preserving this iconic tree and its critical role in Irish biodiversity and cultural heritage.

Furthermore, Teagasc’s “Report a Healthy Ash Tree” initiative invites the public to actively participate in conserving Ireland’s ash trees. By identifying and reporting healthy ash trees, citizens contribute to preserving genetic diversity and help researchers in finding naturally resistant individuals. This community-led approach is vital in speeding up the selection process and ensuring that future forests are both resilient and diverse. Reporting a healthy ash tree is simple, making this initiative accessible to everyone who cares about Ireland’s natural environment.

A call to protect our trees

The plight of the ash is symbolic of a larger issue: the need to protect all of Ireland’s trees. Whether through active conservation efforts, sustainable forestry practices, or citizen engagement, we must act to preserve the natural and cultural heritage tied to our forests. The loss of species like ash threatens both natural ecosystems and the cultural fabric that ties communities to the land. Sustainable forestry practices and conservation efforts are essential to building resilient woodlands capable of withstanding environmental challenges.

By supporting research projects like AshforFuture and participating in citizen science initiatives, we can work together to ensure that ash trees, and all trees, remain integral to Ireland’s landscapes for generations to come. Trees are not merely a link to our past but essential to a sustainable tomorrow.

AshForFuture is funded by the Department of Agriculture, Food and the Marine and the Department of Agriculture, Environment and Rural Affairs

Read the article on RTE Brainstorm here