Ash dieback

Ash dieback, also known as Chalara dieback of ash is a serious disease that is killing ash trees right across northern Europe. Usually fatal, it causes leaf loss, lesions on the bark and dieback of the tree crown. The disease was first identified in the UK in 2012.

There are several key signs to look out for on ash trees but as all of these symptoms can also be caused by other problems, it is important to take expert advice such as that offered by Elmbridge Tree Services.

Symptoms include dark lesions which appear on the trunk at the base of dead side shoots. These are often long, thin and diamond-shaped. The tips of shoots shrivel and turn black and leaves blacken and die – this can look like frost damage. The veins and stalks of leaves turn brown and infected saplings will have dead tops and side shoots. Mature trees often display dieback of twigs and branches in the crown of the tree, but with bushy growth further down the branches where new shoots have been produced. Small white fruiting bodies can be found on blackened leaf stalks between July and October.

Ash dieback disease is spread by spores from the fruiting bodies of the fungus produced on fallen ash leaves. These airborne spores can be carried naturally on the wind over a wide distance.
Since October 2012, there has been a ban on the movement of ash trees as this was contributing to the spread of the disease.
Ash dieback was first discovered in the UK in February 2012 at a tree nursery and subsequent cases were linked to the importation of infected nursery stock. It is now found in both young and mature trees across the country.

There are 130,000 hectares of ash woodland in the UK, but the greatest risk is to the 12 milllion ash trees outside woodlands, such as in parks, gardens, hedgerows and on roadside verges.
Ash dieback spores can be carried on clothing, footwear and vehicles, so effective biosecurity is vital.

The full impact of ash dieback is not known yet as it is believed that while young trees succumb and die quickly, mature trees may resist infection for some time before weakening and eventually dying.

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