Tens of thousands of trees could be lost to North Wales due to an outbreak of a “highly destructive” fungal disease.

Chalara ash dieback has been found in various North Wales areas, leaving environment watchdog Natural Resources Wales (NRW) with no alternative than to fell around 2,800 ash trees.

Councils and landowners will also have to cull affected native ash trees blighted with the fungal infection, latin name Hymenoscyphus fraxineus.

There is no way to control the spread, which happens when fungal spores are carried on the wind.

Chris D Jones, NRW’s senior specialist adviser in plant health said: “Ash trees are widespread in Wales, and are valuable for biodiversity and timber.

“As the third most common tree in Britain, ash trees make a substantial contribution to many landscapes.

“Ash dieback is a highly destructive disease of ash trees. Whilst the overall responsibility for plant health lies with Welsh Government, we deal with ash dieback on land managed by NRW, as part of our tree safety obligations.

“In Conwy County, as in other counties, we have surveyed high-risk areas of our estate, and are managing this, usually by felling.

“In North Wales, we estimate we need to manage – which usually means felling – over 2,800 trees.

“Elsewhere in Conwy County, as in all other local authority areas, landowners are responsible for managing ash dieback on their land.”

Chalara ash dieback is caused by an Asian fungus first recorded in the UK in 2012.

It blocks trees’ water systems and causes leaves to wilt, shoots to die back, lesions on branches and eventually the death of the tree.

It is commonly known as chalara ash dieback to distinguish it from ash dieback caused by other agents, and is commonly found in continental Europe and Ireland.

Conwy county council is looking to remove affected trees and is inspecting those on its land and next to highways.

It has also called on landowners to check their ash populations and consult professionals if they believe there is a problem.

Landowners have a duty of care to check ash tree populations, especially those near to paths or highways as they can shed limbs in their weakened state or fall completely – and records need to be kept of tree inspections.

The council says the problem will incur costs “likely to be far beyond our normal budgets”.

The latest infections have been called “the most significant tree disease to affect the UK since Dutch elm disease”, which decimated millions of UK elms from the late 1960s on.

The disease has the potential to infect the UK’s two billion ash trees leading to the death of approximately 90% of them. Infected trees become brittle as they decay and can fall without warning.

The UK’s native common and European ash trees are the worst affected by chalara ash dieback.

According to the latest map from the UK Government’s department for environment, food and rural affairs (Defra), most coastal area in North Wales are affected by the issue.

Woodlands within inland areas of Flintshire, Wrexham, Denbighshire, Conwy and Gwynedd are also tainted by the condition.

The disease is now widespread in Flintshire where the council estimates there are around 12,000 ash trees above five feet tall adjacent to the county’s main roads.

In Wrexham the county council tendered for experts to check trees in January and estimates around 5% of them are ash in urban settings, as well as many more in rural areas.

There are some things the public can do to help prevent the spread:

Make sure your shoes and boots are clean before you visit the countryside

Make sure any vehicles are cleaned regularly preventing any build-up of mud especially around wheels and wheel arches

Keep to hard tracks where practical