[vc_row][vc_column][vc_column_text]For those of us living in the Derbyshire Dales the common Ash tree (Fraxinus excelsior) is a familiar sight with its open canopy and graceful appearance. It is sad that these iconic landscape trees now face a threat that may result in a large percentage of them being lost to a fungal disease called Hymenoscyphus fraxineus. This fungal disease originated in Southern Asia and is now widespread across Europe including almost every part of the UK.
What does this mean for our trees? Well, one thing is certain, in the forthcoming years we will lose a great many Ash trees either directly to the fungal disease or indirectly where weakened trees succumb to other diseases such as Armillaria sp. (Honey fungus).
Whilst Ash trees are always the last to ‘flush’ it has been noticeable this spring that a great many young trees and ‘self sets’ on the dale sides have not produced any leaves, resulting in some areas taking on the appearance of ‘winter in early summer’. When you look more closely at the young, stick-like trees they have no apical buds (the very ends of the branches where you’d expect the leaves to grow from) and are brittle and snap easily. This is one of the symptoms of ash dieback since the disease appears to cause the wood to become dry and weak.
Most of the larger Ash trees still have a reasonably full canopy.
Research has suggested that single trees out in open fields and particularly those with grazing animals around them are doing better than those in densely packed ash woodlands. This is because the fungus overwinters in the stalks of dropped leaves which are then eaten by the grazing animals so lowering the amount of fungus the tree has to cope with in the spring, we’ve been reading some research recently that advocates clearing the fallen leaves and either burying or burning them; if you can it may help to slow the disease. Domestic composting doesn’t reach a high enough temperature so if you can’t bury or burn the leaves then disposal at a Council household waste site or in your ‘green bin’ is your best bet.
This summer we’ve been pretty shocked to see just how many of our ash trees are affected and after our training course, last year and attending talks by the Forest Research Council once you know what you’re looking for it becomes clear that the disease is far more widespread in this area than we once thought.
How these trees are managed is going to be as difficult but much more dangerous than the management of Dutch Elm disease was because these trees aren’t just dying they are becoming weakened and unpredictable. We would love to be able to keep as many trees as possible but of course, this will depend on where they are and how badly affected they are, there is some small chance that some trees will recover or develop some sort of resistance but at the moment this kind of scenario is unknown.
We’ll continue to keep up with the latest research and management advice from our industry bodies and keep hoping that some of those icons of the tree world survive…
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