Ash tree disease found in Pembrokeshire and Ceredigion

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A serious disease which kills ash trees has been found for the first time in Pembrokeshire and Ceredigion.

Chalara dieback of ash, caused by the fungus Chalara fraxinea, was identified at three newly-planted sites in private woodlands during a “trace forward” inspection of young trees sourced from known infected nurseries.

All the young trees on the three sites have been destroyed as a precautionary measure to try to contain the disease.

The three latest confirmed infections bring the total sites in Wales to 17, all of which were newly planted with trees traced back to nurseries known to have infected stock.

Forestry Commission Wales staff are checking all known recent ash plantings to establish the full extent of the outbreak, which has yet to be discovered beyond new planting sites in Wales.

John Browne, FC Wales Head of Forest Regulation and Tree Health, said, “While these newly confirmed infections have extended the known distribution of this disease in Wales, there is still no evidence that Chalara is present in the wider environment here.”

The disease was first recorded in Britain in early 2012 in Leicestershire and is known to have spread to the wider environment in the south-east of England from spores which are believed to have been blown across the English Channel and North Sea.

The UK Government has drawn up an interim disease control plan and has imposed a ban on imports and movements of ash plants and seeds into and within Great Britain to try to slow the spread and minimise the impact of Chalara.

FC Wales staff are liaising with the owners of infected trees and have written to landowners to offer guidance and to urge them to take simple precautions to protect ash trees close to infected new plantings.

They are also asking woodland users to familiarise themselves with the symptoms of Chalara, which can be found on the Forestry Commission website at along with other information about the disease.

Chalara poses no risk to human or animal health. Public access to woodlands is not restricted, but people are asked to behave responsibly and to be aware that the main source of spread is from the transport of infected ash plant parts, in particular the shoots and leaves from mature ash trees and the whole tree in the case of infected young ash transplants.

John said, “Taking simple precautions like removing mud from footwear and tyres can help to slow the spread of diseases, and in the case of Chalara it’s very important to make sure that you don’t inadvertently move ash leaves, living or dead, around the countryside.

“Please be aware of this threat to a native tree which forms an important part of the Welsh landscape, and if you think you’ve seen any trees with symptoms of dieback please let us know using Tree Alert, a freely downloadable app for smartphones, or call the helpline on 08459 335577.”

FC Wales is planning to hold a series of seminars in May, when ash trees will be in leaf, for those interested in learning more about Chalara.

Further information, including a pictorial symptoms guide and videos showing pictures of the symptoms of Chalara dieback of ash, is available on the Forestry Commission’s website at


1. The new 2012 census through the National Forest Inventory identifies 17,600 hectares of ash in Wales which represents 6.8% of the broadleaved woodlands in the country. The species is important for its timber, firewood, wildlife, biodiversity and landscape benefits.

2. Common ash (Fraxinus excelsior) is a deciduous species native to much of Europe, including the British Isles. After oak and birch, it is the third most common native broadleaf tree in Great Britain. It is important for its timber, firewood, wildlife, biodiversity and landscape benefits.

3. Chalara dieback of ash is a serious disease of ash trees caused by a fungus called Chalara fraxinea. The disease was recorded for the first time in Britain in 2012 at a car park in Leicestershire and subsequently at several sites in the south-east of England and Scotland.

4. Further information, including a “pest alert” factsheet showing pictures of the symptoms of Chalara dieback of ash and a map showing all locations with confirmed cases of Chalara, is available on the Forestry Commission’s website at

5. Media enquiries to Forestry Commission Wales press officer Clive Davies on 0300 068 0061, mobile 07788 190922, email