The Ash Tree Crisis in the U.K.
The decades of the 70s and 80s saw most of the elm trees in the Netherlands succumb to Dutch Elm Disease.
The problem then spread to the United Kingdom and many trees here also perished as a result.
As the Dutch were ahead in terms of managing the crisis, they researched methods of tree management and reported their findings to help other countries who were suffering.
The infestation of Dutch Elm Disease seriously affected canopy coverage and streets were left decimated.
Aside from the devastating effects on the look of the streets and parks, the crisis cost lots of money by way of tree felling, tree pruning, and other tree care.
The Ash Tree Crisis
In recent years and months, the U.K. finds itself in an even worse position than during the Dutch Elm Disease crisis because of Ash Dieback.
In fact, it could cost the U.K. almost £15 billion pounds to clean up the problem, according to The New Scientist magazine.
This is because the country has significantly more Ash trees – around 80 million.
The Ash Tree Crisis: Ash Trees in the U.K.
In the U.K., the ash tree ranks 3rd as most common after the oak and the birch trees. What’s more, its presence is widespread, and you can find ash trees in almost all regions of the United Kingdom.
Many places here take their name from this tree: Ashby-de-la-Zouch, Ashford, Ashtead, and Ashton-Under-Lyne to mention a few.
The ash tree is a member of the same family as the olive tree, the Oleaceae, despite them being visually different. Ash trees are large deciduous trees that have a smooth, light grey bark and black buds.
During the autumn and winter, ash trees have “keys”. These are bunches of seeds that are encased individually in papery wings.
During the spring, purple-green male and female flowers begin to sprout on branch tips before the first leaves grow.
The ash tree is one of the last to be in full leaf and does not reach this stage until sometime in May.
You may have heard of the weather forecast-predicting rhyme: “oak before ash, you’re in for a splash, ash before oak, you’re in for a soak.”
The Ash Tree Crisis: Uses for Ash Wood
As well as being elegant, decorative trees, the timber from ash trees is tough but has good elasticity.
This means it is good at withstanding stress and strain. It is often used in the construction of tool handles, walking sticks, oars, hockey sticks, snooker cues and parallel bars.
Ash Dieback History
The cause of Ash dieback is a fungus called Hymenoscyphus fraxineus.
It was first described in science in 2006 and was given the name Chalara fraxinea. However, in 2010, it was discovered that Chalara fraxinea was only the asexual stage of the fungus and so it was then renamed Hymenoscyphus fraxineus.
The first trees to be infected with this fungus were reported in 1992 in Poland. Since then, it has spread widely throughout Europe.
Originally, it is thought to have come from Asia. By 2010, the fungus had begun to affect large parts of woodland in the northern parts of the Netherlands, but it took a further six years for a major epidemic to break out.
In the U.K., ash dieback was first identified in February 2012. This was in nursery stock and imports of saplings of ash trees were banned in October of the same year. It was one year later when ash dieback was first discovered in established woodland.
Ash trees become infected because the spores of the fungus can travel up to 20 miles. Usually, a year after being infected, spores form on fallen ash leaves.
There is also a risk of infection further afield if ash saplings are moved around the country. This could also happen if infected felled ash trees are moved around too.
How to Spot Ash Dieback
When ash trees are in leaf, trees suffering from ash dieback will have wilting appearing on the new leaves. They will look as though they need a good watering.
When inspected more closely, you can see a brown-coloured central midrib on the leaves. This is more apparent on the underside of the leaf.
It is possible to see this brown colouring appearing towards the stalk ad the leaf shoot. Leaves that are infected will go dry and crispy, but they will not fall off. Instead, they stay on the twigs and will gradually turn black.
With the disease taking hold, the twigs will start to discolour too around where the leaves come out. Inside, the ash wood will no longer be white but instead will be stained brown.
For mature trees, the crown periphery will have lots of dieback on the twigs, before displaying dead side branches and tops. Eventually, the whole of the ash tree will die.
Ash Dieback Management
The problem with ash dieback is so severe that there was even a Cobra meeting about the disease. This type of meeting only happens when there is a national crisis or emergency.
Ash dieback poses different risks for different types of ash trees. For example, the weeping ash always succumbs for the Golden ash and Jaspidea ash, 90% of trees will die.
Common Ash has a survival rate of between 10 and 20%. Once trees have more than 50% defoliation from ash dieback, they should be felled. To manage ash dieback, the should be checked by a tree surveyor every year.
It is hoped that ‘enriched biochar’ – a natural soil treatment combining purified charcoal, seaweed, worm casts and fungi – will help ash trees to become resistant to ash dieback.
Tree experts in the UK carried out research on two thousand ash trees over the course of three years.
They found that although over 30% of the monitored trees became infected with ash dieback, none of the trees that had the enriched biochar on their roots got infected.
As well as this company’s efforts, The Woodland Trust has been carrying out studies to discover ash trees that are naturally resistant to ash dieback.
If fungus-resistant ash trees can be saved, we could find that we are able to begin replanting the U.K.’s ash trees in a decade or so.
How the General Public Can Help?
If you see ash trees that you think are infected, you can report it here: https://www.treecheck.net/
There is no need to do anything special if you have an infected ash tree on your property. If your tree is a mature ash tree, it will likely live a long time and does not need to be felled. If your tree does succumb to the disease, its wood is still a great habitat for animals.
If you do want to help, you can compost, bury or burn fallen ash leaves to help stop the disease from spreading.
Article was written by Louise W.