A FUNGUS with the potential to kill off thousands of trees in Cumbria has been found at four sites in the Lake District.

New data from the Forestry Commission shows that the deadly Chalara ash dieback disease has been confirmed in the far south of the National Park, at two sites between Ambleside and Kendal, and one between Ambleside and Keswick.

A spokesman for the Forestry Commission said the symptoms found in the newly-discovered cases were ‘very subtle’ and mostly affected very young trees.

“One site is on privately owned farmland, one is alongside a country lane, another is on roadside land, and one is in a privately owned planted woodland," they said.

“At three sites the symptoms are on young, naturally regenerated (self-seeded) ash trees, and at the other they are in a planted woodland.

"This degree of local occurrence is to be expected. We are continuing our surveys to monitor the disease, and offering management guidance to land and woodland owners."

The disease has also been confirmed on ash trees at 11 other widely distributed sites elsewhere in Cumbria in southern, eastern and northern parts of the county.

Forestry expert Professor Ted Wilson, director of the Penrith-based Silviculture Research International, said the arrival of ash dieback in the Lakes was ‘concerning, but unsurprising’.

“When it was discovered in Lancashire last year it was quite obvious that it would spread upwards,” he said.

In Cumbria and north Lancashire there are internationally important ash woodlands which have prospered on limestone pavements in Silverdale, Arnside and the Orton fells, as well as significant ash populations throughout the Lake District.

Professor Wilson said the disease could have “a significant impact in the landscape” if it reaches any of the Lake District’s mature trees, some of which date back hundreds of years and are connected with historic farming practices.

“There are also ecology issues in the Lake District with the unique habitats – these trees support lichens, mosses, insects and birds,” he said.

Ash dieback is caused by the fungus Chalara Fraxinea and is thought to be transmitted by the wind, insects and rain splash. It causes leaf loss and kills off the tree’s crown, often resulting in the death of the ash tree.

The first confirmed case in Cumbria was found in recently-planted young saplings at an Aspatria tree nursery in 2012, and last year it was identified at 14 sites on the western fringes of North Yorkshire.

Professor Wilson is urging people to help reduce the spread of the disease by reporting sightings on the Forestry Commission website.