Sustainable Warminster member Clare Hancock writes about Ash Dieback.
Ash Dieback is a serious fungal disease of ash trees, caused by a fungus called Hymenoscyphus Fraxineus or Chalara.
It originated in Asia about 30 years ago. It was first recorded in the UK in 2012. There is no cure or treatment for the disease, and over time, infected trees will weaken, causing branches to fall and trees to eventually collapse and die.
It is predicted we are going to lose around 80% of our ash trees in the UK. At a cost of billions, the effects will be staggering. It will change the landscape forever and threaten many species which rely on Ash. There will be a great loss of its environmental services such as air purification. Ash and all trees capture C02 from the atmosphere – so trees are crucial for counteracting climate change.
Jim McConkie, Head Forester at Longleat said: “It is certainly beginning to take hold now, especially to the west towards Cheddar. It is advancing around Dilton Marsh, with totally dead trees in nearby areas. It will become very noticeable come next summer. What a shame to be losing a native tree in such large numbers so quickly. A positive is that the planting of new and different species of trees will give a chance of greater bio-diversity. Ash has been in our evolution since time began. Think of how many tool handles and cart wheels have been made from it!”
Infection can lead to the death of young trees in just two to three years and of mature trees within three to five years. Some mature ash trees show a degree of resistance to the infection, but there is a significant risk to young saplings. Some trees will fight back, but year-on-year infections will eventually kill it.
With this disease spreading throughout the UK, the landscape as we know it in every parish and town, will change significantly over the next few years sadly, with councils and landowners removing diseased trees for safety reasons. This will have a devastating impact on the landscape and woodlands.
The general approach is not the same with Dutch Elm disease when all the Dutch elms were felled, diseased or not, to prevent the spread. Some ash trees showing resistance and others are resilient, and while it’s important to remove trees which are dying and show disease, it’s important to get an expert opinion if it is suspected in a tree. We don’t want this to be used as an excuse to get rid of trees!
There are some examples of saplings with early signs of disease on Bradley Road, Warminster.
What does Ash Die Back look like?
Leaves develop dark patches in the summer; then wilt and discolour to black, leaves might shed early; die-back of the shoots and leaves is visible in the summer; lesions develop where branches meet the trunk often diamond shape and dark brown, inner bark looks brownish-grey under the lesions; new growth starts from previously dormant buds further down the trunk: this is called epicormic growth and is a common response to stress in trees.
Ash Dieback presents significant health and safety risks to the public, especially along roads, public rights of way and woodland areas used by the public, from suddenly falling branches. This increases liability for the legal tree owner.
Any Ash Trees infected with Ash Dieback should be removed by a qualified, fully-insured and professional arboriculturalist who is fully trained to work with dead or dying trees, with machinery appropriate for safe working practices and best industry guidance. A full risk assessment should be carried out prior to any works being undertaken.
Every landowner has a duty of care to ensure their trees within their curtilage are in a safe and reasonable condition. Steps must be taken to ensure public safety is top priority. It is the legal responsibility of the landowner to meet all costs of tree removal if trees are on private land.
Infected trees growing on council or Highways-maintained land will be dealt with by the relevant authorities as quickly as possible. Wiltshire Highways are surveying county-wide to identify trees that pose the most significant risk, and a management plan is being created to remove these risks.
Any ash trees a safe distance away from public rights of way, roads, parking areas and open spaces that would not affect the public if they fell over, can be left to decay in situ, made safe or removed at a later date.
How you can help? Clean your shoes before and after visiting a wood; avoid taking cuttings or plant material from the countryside; wash your car or bike wheels to remove mud or plant matter.
Plant many more trees of different varieties!
There is hope on the horizon for natural disease tolerance. Findings suggest we might have some trees tolerant to ash dieback, so the population could eventually recover over time, likely over 50 years.