The best means to combat ash dieback if through harnessing the natural genetic diversity within ash. By bringing together trees showing high levels of tolerance we can start a new breeding programme for ash to ensure it remains a viable option for forestry and the wider environment.

Evidence from Europe, where the disease has been present longer, indicates that about 1% of all ash trees show a high degree of tolerance to ash dieback.  These trees show minimal crown dieback (less than 10%), and it is these trees that we are keen to learn about.  We are particularly interested in healthy trees that are located within woodlands, surrounded by other ash trees that are showing a high degree of dieback.

The easiest time to do this in during the summer months, when it is possible to make as assessment on crown health.  Trees showing up to 25% crown dieback are also of interest. The following images are reproduced from the Forestry Commissions publication: ‘Diseases and disorders of forest trees: a guide to identifying causes of ill health in woods and plantations.

We want to hear from you if you have a tolerant ash tree within a woodland setting.
The recording form (right) details the information we need to know.
You can fill it in online or print it off to record details in the field.
Please report any findings to