A fungus called ash dieback (Hymenoscyphus fraxineus) originates in Asia. It doesn’t inflict much harm to its native hosts, the Chinese ash (Fraxinus chinensis) and the Manchurian ash (Fraxinus mandshurica), in its natural range. However, because our native ash species did not evolve with the fungus and as a result has any natural defence against it, its arrival to Europe around 30 years ago has wreaked havoc on the European ash (Fraxinus excelsior).
What are the signs of Ash Dieback?
All ages of ash trees are susceptible to ash dieback. Although younger trees succumb to the disease more quickly, all infected trees will often exhibit the following symptoms:
In the summer, dark spots appear on leaves.
- In the summer, dark spots appear on leaves.
- They eventually wilt and turn black. Early leaf shedding is possible.
- Summertime brings out the dieback of the shoots and leaves.
- Where the branches join the trunk, lesions appear. These are frequently dark brown and diamond-shaped.
- Under the lesions, the inner bark appears brownish-gray.
- New growth from buds deeper down the trunk that were previously dormant. Epicormic growth is a typical response to stress in trees, and it is known as such.
The fungus overwinters in ground-level leaf litter, notably on the stems of ash leaves. Between July and October, it produces tiny white fruiting bodies that disperse spores into the environment.
These spores have a range of tens of miles. They land on leaves, attach, and then pierce through and through the leaf. The tree eventually dies as a result of the fungus’s internal growth and eventual blockage of the tree’s water transport mechanisms.
Although the tree can fight back, repeated infections will ultimately cause it to die.
What areas has Ash Dieback mostly affected?
Although it wasn’t officially described until 2006, the ash dieback fungus has been well-known in Europe for around 30 years.
The south-east of England has been particularly affected by ash dieback in the UK. In 2012, here is where it was first noted in the UK. Before the symptoms appeared, the fungus may have been present in the area for some time, possibly years.
The disease is present throughout the UK. However, the epidemic is still in its early stages, so it will take some time before we fully understand its effects. This is made worse by the disease’s gradual development, so we must monitor the occasionally undetectable changes caused by ash dieback.
What are Severn Tree Management doing about ash dieback?
We are retaliating despite the fact that we are still learning about the effects of ash dieback. All of our trees and woods are carefully monitored for their condition.
By letting affected ash trees die naturally and attempting to save as many possibly tolerant ash trees as we can, we increase our forests’ resistance to disease and climate change in the long run. To achieve this, we broaden the genetic diversity of the trees in the current forests. Additionally, we use a variety of local tree species while creating new forests.
You can join the fight against Ash Dieback here at the Woodland Trust
