Ash Dieback has been spotted at ten sites in the Lake District.
That's a major concern for one of the UK's most famous landscapes, because the fungal disease kills an estimated nine out of ten of the trees it infects.
What is being done to stop Ash Dieback?
The disease is incredibly difficult to stop, because it is airborne.
Forestry organisations are pushing for better screening of ash trees that are brought into the UK.
When the disease was first spotted here in East Anglia in 2012, it was caused by trees imported from the Netherlands.
The Government has put around £8 million into forestry research, and some of this is going towards studies that could help fight the disease.
Some strains of ash tree are thought to be resistant to the disease, so research is centred on these.
Organisations like the Royal Forestry Society are also working to educate forestry experts, and the wider public, about Ash Dieback, and how to spot it.
How can I help?
People who notice ash trees that may be infected, should report them on the Forestry Commission's TREE ALERT website.
Here are some of the tell tale signs of Ash Dieback:
The first sign that an ash tree is infected is the leaves withering, and turning brown. They will eventually fall out. This is because the chalara fungus enters through the leaves
The twigs close to the leaves also lose their colour, and curl back
Distinctive diamond-shaped lesions then form on the bark
Once a tree is infected there is currently little that can be done to save it, so it's important to raise the alert if you spot Ash Dieback, to prevent it from spreading throughout the Lake District.