12 June 2025

Branching out for ash

Ash dieback is one of the most serious threats to Irish native trees. As over 90% of ash trees are expected to be lost, urgent action is needed to identify and protect the small number of trees showing natural tolerance. AshforFuture is a four-year, all-island research project that combines genetics, forest pathology, silviculture, and public engagement to support long-term ash recovery.

The AshForFuture team in the micro-clima hub at Oak Park (L-R): Stephen Byrne, Dheeraj Rathore, Ricardo Pimenta, Abhishek Singh. Photography: Finbarr O’Rourke

Here, we meet the team behind AshforFuture: Dheeraj Rathore, Tree Improvement Research Officer and the project’s coordinator; Stephen Byrne, Research Officer in Genomics; Ricardo Pimenta, Postdoctoral Researcher in Genomics; and Abhishek Singh, Teagasc Walsh Scholar in Pathology. Together with a skilled technical team across Teagasc forestry, they are working to understand ash dieback disease, identify resilient trees, and guide the future of ash in Ireland’s forests.

How did the AshforFuture team come together?

Dheeraj: Teagasc has worked on ash improvement since the early 2000s, originally focusing on tree form and wood quality – traits linked to productivity. However, when ash dieback was identified in Ireland in 2012, our focus shifted to protecting and restoring this important native tree species. AshforFuture launched in 2024 and builds on that foundation, bringing together a multidisciplinary team of researchers and partners from across the island of Ireland to develop long-term solutions to conserve ash.

A unique part of our approach is the citizen science campaign, which is helping us find healthy ash trees that are surviving even in areas where most nearby trees are severely affected by the disease. These survivor trees are central to our efforts to conserve ash for the future.

Ricardo: This is a truly all-island project. Through AshforFuture, Teagasc is working with the Agri-Food and Biosciences Institute in Northern Ireland. The project is jointly funded by the Department of Agriculture, Food and the Marine in the Republic of Ireland and the Department of Agriculture, Environment and Rural Affairs in Northern Ireland. We’re also working closely with University College Dublin, None So Hardy Nurseries, Coillte, local authorities, and a range of NGOs.

What are the core goals of the AshforFuture project?

Dheeraj: A major focus is developing a robust communication plan to engage with the public, forestry specialists, policymakers, and other stakeholders. The goal is to effectively disseminate crucial research and updates, while also involving the public in identifying trees that remain unaffected by ash dieback and might possess high levels of natural tolerance.

Stephen: A core priority is developing genetic tools to support durable ash dieback tolerance. This includes identifying and using molecular markers linked to disease resistance, allowing us to screen and propagate ash trees that can survive Hymenoscyphus fraxineus infection, the causal agent of ash dieback disease.

Abhishek: We are also studying the ash dieback pathogen itself, Hymenoscyphus fraxineus, to understand how it has established, spread, and evolved since its arrival in Ireland. By examining different strains of the pathogen, and how they interact with potentially tolerant ash trees, we aim to develop strategies to protect and future-proof ash trees against the disease.

Ricardo: A key priority is exploring how different forest management approaches can help ash trees thrive despite the dieback disease. By testing mixed species planting instead of monocultures, the project aims to enhance resilience and biodiversity. It’s all part of a wider effort to protect Ireland’s ash trees for the future.

How does your work contribute to those goals?

Dheeraj: Engaging the public is a crucial element of our strategy. Through the AshComm work-package, led by Brian Clifford, (Forest Sector Development-DAFM), we run a citizen science campaign aimed at identifying and reporting healthy ash trees nationwide. We also strive to bridge the gap between research and the general public and policymakers. This includes media engagement, workshops and events to ensure the dialogue extends beyond the research community.

One challenge is that tree research works on much longer timescales than most funding cycles allow. Building lasting impact will depend on continued support and strong collaboration across sectors.

Abhishek: We’re studying different strains of Hymenoscyphus fraxineus, collected from across Ireland under AshPath work-package, led by Richard O’Hanlon (Plant Science Division-DAFM). By comparing their aggressiveness and genetic variation, we gain a better understanding of how the disease spreads and evolves. This helps us predict and manage its impact more effectively.

Ricardo: Our silviculture work focuses on how forest management can support ash re-establishment. We’re setting up field trials comparing monocultures with mixed species planting to see which strategies reduce disease impact. Through our experimental work and field trials, we aim to generate reliable, evidence-based results that can be published in peer-reviewed journals and shared at conferences.

What are the main techniques and tools your team uses?

Ricardo: To assess tolerance to ash dieback, we are using high-throughput sequencing to analyse whole genome data from our ash tree collection. This helps us to identify genetic markers linked to tolerance and study how different trees respond to ash dieback. The data are processed using Teagasc’s high-performance computing infrastructure and will be used to link variation in the DNA among trees in the collection with differences in tolerance to ash dieback. Alongside this, we are establishing field trials under the AshSilva work package, led by Ian Short (Teagasc), to explore how forest management, including mixed species planting, can support resilience. We also contribute to AshComm by helping share updates through outreach activities and events.

Abhishek: In the pathology work, we collect Hymenoscyphus fraxineus samples from infected ash trees across Ireland and Europe. We use molecular sequencing to examine variation between isolates and carry out artificial stem inoculations in the lab under controlled environmental conditions to assess how aggressive each strain is. This combination of lab and field data helps us understand how the pathogen behaves under Irish conditions and how tolerant trees respond.

The AshForFuture team at the Ash gene bank at Oak Park: Linking tree phenotype with genomics is an important step in combatting ash dieback disease. Photography: Finbarr O’Rourke

Why is this project important for Ireland’s environment and forestry sector?

Dheeraj: AshforFuture is a practical step towards protecting one of Ireland’s most valuable native tree species. Ash trees are deeply rooted in our landscape – culturally, economically and ecologically. They provide habitat for nearly 1,000 species, play a role in traditional farming systems and are the key source of timber for making hurleys. However, ash dieback has affected most trees; without action, the species is at risk.

This initiative allows us to take coordinated measures while healthy ash trees remain, collaborating with the public to find solutions. While we don’t claim to solve everything in four years, we are laying the foundations for long-term recovery. This benefits biodiversity, supports rural livelihoods and informs future forestry policy.

Ricardo: Ash is a keystone species in Irish woodlands. Losing it would affect the entire ecosystem, from birds and pollinators to the fungi and insects that depend on it. By protecting tolerant trees and promoting resilience through forest management, we’re helping conserve both biodiversity and native woodland structure.

What progress has your team seen so far?

Dheeraj: Our work builds on years of ash breeding research at Teagasc. This year, we established a new field trial at Kinsealy with over 1,500 ash trees. Through our citizen science campaign and personal contacts, over 200 Irish ash genotypes showing signs of tolerance were reported. We’ve now grafted more than 3,000 trees from this material to generate the next population for field testing. Public engagement is also increasing, with more people aware of the disease and actively contributing to the search for survivor trees.

Ricardo: We’ve started analysing whole genome sequence data from a selection of tolerant ash trees identified in earlier research. This is helping us uncover potential genetic markers linked to disease tolerance, which will guide our future breeding efforts. The design phase of our field trials is also underway, with trials focused on comparing monocultures and mixed-species plantings to test durable resilience under field condition.

Abhishek: On the phytopathology side, we’ve collected over 40 Hymenoscyphus fraxineus isolates from infected ash trees across Ireland. We are preparing them for controlled inoculation experiments. These trials will help us assess their aggressiveness under standardised lab conditions. We’re also sequencing the isolates to understand genetic variation and how different strains interact with potentially tolerant ash trees.

In this short clip, Dheeraj talks about one of his research objectives to breed ash, a native tree species to Ireland, for dieback disease tolerance. Research shows that between 5 to 10% of trees will have good tolerance to ash dieback disease.

What role does your team play within Teagasc?

Dheeraj: AshforFuture strengthens Teagasc’s role in native tree improvement and conservation by combining applied research with practical tools for forestry. It connects long-running breeding work with new capacities in genomics, pathology and silviculture – creating a stronger base for future research programmes. The project also deepens collaboration across the island and builds public trust through citizen involvement. It’s not just about responding to a disease, it’s about helping shape how Teagasc supports resilient, biodiverse forestry into the future.

What changes or challenges do you see ahead?

Stephen: One major shift is the growing potential of genomic selection. As sequencing becomes more affordable and accessible, we can more efficiently identify trees with tolerance to ash dieback. But resistance is complex, and we’ll need to keep refining our tools and approaches as new pathogen strains emerge.

Dheeraj: The big challenge is translating our research into action on the ground. We’ve identified promising genotypes and set up new field trials, but long-term success depends on collaboration with forest managers, policymakers and communities. As the disease continues to spread, adapting our methods and staying aligned with on-the-ground needs will be critical for long-term conservation.

Ricardo: We’re beginning to integrate environmental data such as soil and micro-climate, along with seasonal changes into our genomic analyses. This will help us understand not just which trees are tolerant, but where and why they thrive. It’s a more holistic approach to ash conservation.

Abhishek: We’re watching for changes in the pathogen itself. Hymenoscyphus fraxineus could become more aggressive or adapt to new conditions. Tracking its genetic variation and understanding interactions with microbes inside the tree may offer new insights into resistance.

What does the future of your work look like?

Stephen: Advances in genomic selection are moving fast, and we’re well placed to apply those tools. As sequencing becomes more accessible, we can increase the accuracy and speed of identifying tolerant ash trees. We’ll need to stay flexible, though; ash dieback is a moving target, and our methods will have to evolve with it.

Dheeraj: The next few years will be about turning early progress into long-term solutions. We’ve identified promising trees and set up trials, but now comes the real test – monitoring their performance, refining our selection methods and supporting replanting on a wider scale. One challenge is that tree research works on much longer timescales than most funding cycles allow. Building lasting impact will depend on continued support and strong collaboration across sectors.

What are you proudest of as a member of the AshforFuture team?

Stephen: I am proud to be part of a team that strives to find solutions to difficult challenges, and I am optimistic that the AshforFuture project will help secure a future for ash in Ireland.

Ricardo: It’s been rewarding to connect science with public action; sampling over 200 healthy ash trees this year with help from people across 23 counties was a real highlight.

Abhishek: I’m proud to contribute to understanding this destructive pathogen. Studying its behaviour across Ireland and building lab assays has been a challenging and valuable learning experience.

Dheeraj: Leading this project, I’m proud of building a collaborative, all-island team that’s working across science, policy and society. Seeing public engagement grow around ash conservation has been one of the biggest rewards.

Meet the tech team

The AshforFuture project is supported by a skilled technical team with expertise across genetics, propagation, field trials and nursery management.

Tomás Byrne
Tree Improvement Technologist, Forestry Development Department, Ashtown:

“I apply phenotypic and genetic data to help select and cross ash trees with improved traits, including dieback tolerance. I also manage our forestry laboratory and nursery facilities to support research across the programme.”

Donna Gregan
Laboratory Assistant, Forestry Development Department, Ashtown:

“I assist with mass propagation of ash and other native species, harvesting seed from selected trees, and maintaining healthy nursery stock for ongoing research trials.”

Derek Gibson
Forestry Research Technician, Forestry Development Department, Oak Park:

“I work on the vegetative propagation of tolerant ash through grafting and air layering. I also help establish and maintain field trials, monitoring tree health and growth performance.”

Rory Newell
Forestry Research Technician and Horticulturist, Forestry Development Department, Athenry:

“I provide technical support across forestry projects, with a focus on propagation and plant care. I’m particularly interested in native tree conservation and support work on ash field trials.”

This video is part of a series produced by the Forestry Development Department of Teagasc. The purpose of this series is to provide objective advice to forest owners whose ash plantations have been affected by ash dieback and the important factors that need to be considered when removing the infected ash trees and replaced with alternative tree species.