An iconic tree at the junction of Penchwintan and Caernarfon Road in Bangor is being felled today due to rooting problems and Ash Dieback disease. The tree is also in a precarious condition as the root system will no longer support the tree.

 

Ash dieback disease damages a tree’s branches and causes them to become unsafe. These diseased trees have an increased risk of collapsing which can be dangerous, especially if they fall on a road.

The disease, also known as Chalara is caused by a fungus called Hymenoscyphus fraxineus (The fungus was previously called Chalara fraxinea, hence the name of the disease.) which affects the vascular system of ash trees, inhibiting the tree’s ability to draw nutrients up into its upper branches. Young ash trees are killed very rapidly by the disease. Older trees often resist the disease for longer periods but succumb with prolonged exposure.

Ash trees are the third most common tree in Britain after oak and birch – there are 80 million ash trees in the UK.

History of the disease

Ash trees suffering with Chalara dieback infection have been found widely across Europe since trees now believed to have been infected with this newly identified pathogen were reported dying in large numbers in Poland in 1992. These have included forest trees, trees in urban areas such as parks and gardens, and also young trees in nurseries.

The disease was first reported in Britain in February 2012 when it was found in a consignment of infected trees sent from a nursery in the Netherlands to a nursery in Buckinghamshire.

At the end of October 2012 the Government introduced a mandatory ban on imports of ash trees, saplings or seeds and restrictions on movement of trees around the country.

The disease has now been confirmed in most regions of the UK and Ireland.

What does it look like?

  • Wilting of leaves in summer
  • Black/browning leaf, often spreading down the stem
  • Black leaf may not drop as quickly as the usual autumn leaf drop
  • Lesions, spots and cankers appear on the bark
  • Shrivelled, contorted leaf

How is it spread?

Evidence suggests that Chalara spreads through woodlands via wind dispersal. Movement of diseased ash trees is likely to be the cause of spread over longer distances. Movement of infected logs, leaf litter and pieces of wood may also spread the disease.

Photos: Med Hughes