We have been anticipating the arrival of ash die back at Dartington for some years. It’s now unequivocally here – and its growing impact means we will need to remove diseased trees at key locations around the estate.
What is ash die back?
Ash die back, sometimes referred to as ‘chalara’, is a fungal tree disease, Hymenoscyphus fraxineus, which particularly affects the UK’s native ash tree Fraxinus excelsior.
The disease comes from Asia, is now widespread in Europe and was first identified in the UK in 2012, but had been present in some locations since at least 2004. It likely arrived in the UK on both infected planting material, as part of the international plant trade, and as airborne spores.
Ash trees are infected by the fungus’ airborne spores, which are most common in the summer on infected fallen leaves and in leaf litter.
Once the spores infect a tree, the fungus spreads through the wood and blocks the water transport system in the tree causing (typically) diamond-shaped lesions and leaf loss. This creates a yearly cycle of infection until ultimately the tree’s crown (the top of the tree) dies back.
Research is indicating that some ash trees have genetic traits which exhibit resistance to ash die back, but it’s a small number and environmental factors can play an equally important role. Overall it’s estimated that between 70% and 85% of our native ash trees will die.
Why does ash die back matter?
Ash trees are an incredibly important native tree. They are highly prevalent – our third most common native tree – and play a key ecological role in our woodlands, hosting 953 other species such as birds, insects and lichens, of which 45 are believed to have only ever been found on ash.
The loss of almost all of our ash trees means a loss of trees in the millions, potentially billions, and it is going to have a significant impact on the UK’s landscape, ecology and biodiversity.
This is even more serious at a time when we’re supposed to be planting 1.5 million new trees to help mitigate our carbon output whilst we decarbonise the UK’s social and economic structures. Ash die back could potentially kill more than 1.5 million trees, making it even more challenging to increase our tree numbers.
What does ash die back mean for Dartington?
We undertake a tree safety survey regularly on the estate to look for signs of disease, pests or stress so that we can manage our trees appropriately – particularly where trees could pose a risk to the health of other trees and/or people.
Our most recent survey has highlighted that we now have trees showing strong signs of dieback in areas of the estate we classify as high risk, because they’re adjacent to a road or public footpath. This means that from around September we will be removing a significant number of ash trees.
Where we have to fell trees we will act as safely and quickly as possible but please be forewarned that there will likely be a number of inconvenient road and path closures during this time. This includes the A385, the main road between Dartington and Totnes, but we will update you closer to the time with specific details.
Along main roads we will be felling all of the ash trees so that we only need to close the roads once to deal with the situation and can minimise the disturbance.
In other high risk areas we will be felling trees which show strong signs of dieback but leave healthy ones and continue to monitor them regularly.
In medium to low risk areas of the estate we will fell and remove ash trees which exhibit over 60% of crown dieback and are heavily affected.
Where trees are not heavily affected or do not appear to be affected at all we will leave them standing. We need to retain as many ash trees as we can to support the other species, insects etc., which depend on ash trees. We also hope that by leaving trees standing some will show resistance to ash die back and their progeny will enable the longer term survival of our native ash.
In the areas where we have felled trees we will recruit natural regeneration of ash and other species, as well as plant young trees of desirable species to fill the gaps.
What can I do?
Please work with us to ensure we can manage this situation as safely as possible for everyone involved. As the fungus consumes the trees the wood becomes incredibly brittle, making the trees particularly difficult to remove. Please help us by adhering to any health and safety signs, particularly relating to road or path closures. We do not want any harm to come to either a member of the public or a member of the forestry team during this time.
If you’re visiting outdoor areas, particularly where you know disease is present, take a few precautions: try and park on hard-standing surfaces; clean mud and other organic material off your boots/bikes/buggies/dog before you leave because fungi, bacteria and insects can live in this material; don’t bring or move plant material around with you, particularly if you’re travelling abroad.
Consider where you buy trees and wood products from, where you can try and buy trees and plants, or use wood which has been grown in the UK so as to reduce the risk of new pests and diseases being imported.
Do what you can to tackle climate change, be that reducing your emissions or lobbying your MP, for example. Changes in our climate directly link to the spread of new tree pests and diseases, and climate change increases the likelihood that trees won’t survive pests and diseases because symptoms of climate change, such as drought, weaken the trees.
If you’ve visited the estate and paid for parking or had a cup of coffee in The Green Table Café then thank you – because you’ve already contributed to the management of the estate. The estate team is constantly monitoring and trying to improve the existing habitat at Dartington, providing homes for wildlife and enabling species to move between sites. We are also looking at how we can make the landscape of the estate resilient in the different climate scenarios we will be dealing with in future. This may involve planting more trees or creating ponds, to give an example. If you would like to make a specific donation towards this work you can do so via our website.
In Devon, if you have concerns about ash trees that grow alongside highways, byways, bridleways or footpaths you can report trees to Devon County Council highways via their website.
If there are ash trees on your property which you think are exhibiting signs of ash die back and you need advice or assistance in removing them, you can find a suitably qualified and insured arborist through The Arboricultural Association.