Ash Dieback

Chalara fungus has been effecting ash trees across Europe since it was first indentified in Poland in 1992. Infected trees have included forest trees, trees in urban areas such as parks and gardens, and also young trees in nurseries.

In February 2012 Chalara was found in a consignment of infected trees sent from a nursery in the Netherlands to a nursery in Buckinghamshire. Then in October 2012, Food and Environment Research Agency (FERA) scientists confirmed a small number of cases in East Anglia, in ash trees which did not appear to have any association with recently supplied nursery stock. Since then Chalara has been found in a number of locations and situations in England and Scotland, including Sussex.

It is now clear that eradication is no longer a realistic possibility. Ash dieback is here to stay and all we can do is try to minimise the impact and learn from our mistakes.

I think my tree is infected. What should I do?

It is vital that people who are concerned about the trees in their garden or woodland do not start to panic and simply cut them down, please get expert advice:
  • Leave healthy ash trees well alone. Ash trees are a vital habitat for birds and insects. Some ash trees may have a natural resistance and seeds from surviving trees could be used for replanting schemes
  • If you think a tree might be infected by Chalara, look at the videos below and visit the Forestry Commission's website to check their symptom guides.
  • Check that the tree is an ash rather than a rowan (also known as mountain ash). Rowan trees are easily mistaken for ash but are not susceptible to Chalara
  • If you think a tree is infected with Chalara, report it to the Forestry Commission using their Tree Alert system.
  • The Forestry Commission will look into the report and may send out an inspector to take samples and confirm the disease.Please do not do anything to a tree that has not been confirmed as infected.
  • If a tree is infected, the Forestry Commission’s inspector will tell you what to do next. This will probably follow the advice set out in the Action Plan published by the Government:
  • Newly-planted diseased trees and diseased trees in nurseries will be traced and destroyed. This is because once young trees are infected they succumb quickly.
  • Mature trees will not currently be removed, as they are valuable to wildlife, take longer to die and can help us learn more about genetic strains that might be resistant to the disease.
  • Further advice for woodland owners and managers is available here.

My trees are fine, but I would still like to help. What can I do?

  • Be vigilant Chalara dieback could appear in ash trees anywhere in Britain, especially where young trees imported from continental Europe have been planted. The Forestry Commission urges you to inspect any ash trees you come across and to make sure you are familiar with the symptoms of Chalara dieback. Why not download their Pest Alert Factsheet
  • Buy with care Be careful to only by plants from reputable suppliers and specify disease-free stock. A list of countries where C. fraxinea is known to be present is available in the Forestry Commission's Questions and Answers document.
  • Be diligent Practice good plant hygiene and biosecurity in your own gardens and woodlands to prevent accidental spread of plant diseases. The Forestry Commission has produced posters that can be put up in woodlands to let people know if Chalara infected trees have been found there.
  • Keep up to date Check the Forestry Commission website regularly for updates on developments. ‘Follow’ the Tree Pest News account on Twitter to receive rapid intelligence of new developments.

Why aren't the Government being more proactive?

Following advice from woodland ecologists and plant health specialists it has been agreed that ash dieback cannot be controlled in any permanent way. Scientific evidence suggests that the best way to fight this disease is to allow it to spread through the ash population and wait for trees with natural resistance to regenerate woodlands. Whilst the 'slash and burn' proactive response worked to some degree with Dutch Elm Disease in Brighton and Hove, it would not be appropriate in this case for two reasons.Chalara spores are spread by the wind so it would be extremely difficult to create an effective barrier and ash is much more genetically diverse then English elm, so is more likely to develop an natural resistance to the disease.


Chalara fraxinea - Life Cycle and Symptoms - Ash Dieback disease