You are not legally required to take any particular action if you own infected ash trees, unless your country forestry or plant health authority serves you with a Statutory Plant Health Notice (SPHN) requiring action. This is unlikely.

With the exceptions of felling for public safety or timber production, we advise a general presumption against felling living ash trees, whether infected or not. This is because there is good evidence that a small proportion will be able to tolerate H. fraxineus infection. There is also the possibility that a proportion of ash trees can become diseased, but then recover to good health. These, too, would be valuable for our research, although it is still too early to know whether there are such trees in the British ash population.

However, by keeping as many ash trees standing as possible, we can identify individuals which appear to survive exposure to the fungus and which can be used for breeding tolerant ash trees for the future. See ‘Our research’ below for further information.

That said, public safety must be the priority, so keep an eye on the trees’ safety as the disease progresses, and prune or fell them if they or their branches threaten to cause injury or damage. In particular, watch for basal lesions (lesions, or cankers, forming near the bottom of the trunk), which can weaken the trunk and make the tree more prone to falling.

There is no known cure, although some fungicides might be effective in suppressing the disease, enabling individual ash trees of particular value to be saved. These might include trees of high amenity, heritage or cultural value. However, such treatments often have to be re-applied periodically, perhaps every year, and can therefore be expensive.