As Chalara ash dieback spreads across the British Isles, we aim to identify and secure ash trees that show good tolerance to Hymenoscyphus pseudoalbidus – the fungus that causes ash dieback (formerly known as Chalara fraxinea) – and use these individuals to form the nucleus of a future breeding programme.

We will be assessing the many thousands of trees that exist already in a breeding programme for ash, and we will use citizen science to screen the wider population. We will produce trees that show good tolerance to the fungus, and plant them on the public forest estate as an archive, freely available to the forest industry.

We will also develop techniques to enable us to rapidly produce large numbers of tolerant trees for reforestation.

We asked the public to get involved by tagging a tree and carrying out an annual survey using the Ashtag app. The survey ran from 2013-17 and is now closed.

This project will run for five years and is funded by Defra.