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

To ask His Majesty's Government what assessment they have made of spread of ash dieback; and what preventative measures are being put in place to minimise the impact.

The fungus responsible for ash dieback disease can spread up to 75km via air borne spores. It is not possible to limit the spread of the disease at a national level, and it is now present in all counties, moving across the country at the expected rate from modelling by Cambridge University. There are an estimated 125 million ash trees in UK woodlands and up to 60 million ash trees outside of woodlands. From observations in Europe and the UK, we expect 1-5% of these trees to be naturally resistant to the disease.

The disease progresses quickly in young trees, trees growing in stressed conditions and ash dominated woodlands with higher levels of leaf litter and spore loads. Removal of leaf litter may be an effective way to limit the spread in certain conditions, for example around high value trees in urban environments.

The Government has published guidance for landowners on managing diseased ash, including a toolkit for Local Authorities, which has been downloaded nearly 20,000 times. Through the Local Authority Treescapes Fund, Defra funds treescape restoration with alternative species. Since 2021, over £15 million has been awarded through this fund. Countryside Stewardship tree health woodland grants also provide funds for private landowners to restock after felling due to ash dieback, and we are piloting grants that provide financial support for ecological surveys and road closures.

The Government has invested more than £8 million into ash dieback research, including the world’s largest screening trials for resistant trees. 1000 genotypes drawn from a wide geographic spread and genetic diversity are being tested for resistance to facilitate the possibility of a future breeding programme of resilient ash.