Question to the Department for Environment, Food and Rural Affairs:

To ask His Majesty's Government what steps, if any, they are taking to ensure that valuable, potentially tolerant, or disease-resistant trees, such as ash trees that have survived chalara ash dieback, are not unnecessarily felled.

From observations in Europe and the UK, we expect 1-5% of ash trees to show useful levels of genetic resistance to ash dieback, caused by the fungal pathogen Hymenoscyphus fraxineus. Resistance is heritable which offers hope for a future breeding programme.  We recommend that land managers consider this resistance in ash trees and retain ash trees where they stand out as being healthier than those around them, providing it’s safe to do so.

The Government has invested more than £8 million to advance our scientific understanding of this disease since it was first detected, including into the development of resistant ash trees. We have conducted the world’s largest screening trials for tolerant trees have planted two living archives, one in Southern England in 2019 and the second in Scotland in 2025, to protect and maintain these important genotypes and facilitate the possibility of a future breeding programme of resilient ash.

Decisions about the management of individual ash trees are the responsibility of the landowner, but the Government has worked with partners to publish tailored guidance for woodland owners, farmers and local authorities on managing diseased ash, including a Local Authority Ash Dieback Toolkit (second edition published in 2025). The guidance recommends the identification of ash trees showing the highest levels of disease tolerance, before any felling action takes place, as the retention of these trees will help maintain a genetically diverse ash tree population in the future.