What is Ash Die back?

What is Ash die back? Ash die back is when a tree starts to lose all its peripherals. These will include its leaves and roots meaning that it is unable to sustain itself and as a result of this, unfortunately will die. Ash die back refers specifically to one type of fungi which causes die back in ash trees – Hymenoscyphus fraxineus. This fungi is lethal to ash trees. However it can effect some other trees in the same family, among these mock privet and the white fringe tree. Therefore it is incredibly important to be able to identify the disease before it can spread.


What is Ash Dieback?

 Dead wood turns a brownish grey colour


So what are the symptoms of Ash dieback? Black blotches will start to become visible on the trees leaves. But that’s not all  – on the stem of the tree, bits of bark will start to die in lens shaped patterns. These areas of dead tissue will continue to expand until the tree is consumed. Furthermore the wood underneath the bark will start to become a brown or grey colour instead of the typical cream  you would expect of an ash tree. From a distance an ash tree with the Hymenoscyphus fraxineus fungi will look slightly different to the unaffected trees too, with many of its leaves and branches gone. These will be replaced by new branches which are growing through the bark – a phenomena know as epicormic shoots.


Leaves die off

What can we do?

What should you do if you see a tree with any of these symptoms? Firstly you need to check on the Forestry Commissions website  to see if an outbreak has been detected in your area. If not, you should then contact the relevant authorities and alert them to what you have found. This disease can spread up to 30km from 1 infected plant! So its of paramount importance that any new outbreaks are quickly identified so that the trees can be quarantined.

In addition to this if we find out that the area we live in is experiencing an outbreak, steps can be taken by us to help stop its spread. One way of doing this – if you plan to compost ash leaves – is to place 10 cm of soil or 25 cm of other plant material over the top of them. This will be thick enough to stop the spores from the fungi from being able to spread!

If you think you have a tree that has been infected with Hymenoscyphus fraxineus and you’re worried that it could be Ash die back contact Shawyers. With many years of arboricultural experience behind them, one of the team will be able to advise you on what to do next.