The potential impact of ash dieback in Cheshire


In October the Government announced that 'ash dieback' – a deadly disease of ash trees – had made its way into the UK, putting 80 million ash trees at risk and evoking stark memories of Dutch Elm disease 30 years ago.

Under a slate-grey autumn sky, a reserves officer carefully checks an ash stem for the tell-tale dark diamond shape of infection. They have a detailed sheet of pictures and smart phone videos in their hand, showing a range of characteristics that could spell disaster for the smallest of saplings to the 80ft high ash pillars that seem to hold up the woodland roof.

Today, it’s good news. This nature reserve and around 20 others that make up half of Cheshire Wildlife Trust’s 46 site network have the all clear. There are no blackened leaves or stems, the canopy appears healthy and the fateful black diamond feared by all checking their trees is nowhere to be seen.

So surely, with most confirmed cases of ash dieback around 200 miles away in East Anglia there’s nothing to fear? The Trust’s Head of Estates and Land Management Jacki Hulse disagrees, and says that complacency is simply not an option.

‘Sadly I can still remember how Dutch Elm Disease (DED) changed the face of the British countryside and that of Cheshire, in my early years in conservation’, says Jacki.

‘With this new disease, and others such as Phytophera affecting our coniferous woodlands, we could yet see another wholesale change in the make-up of our woodlands, this time for a new generation.’

What seems most ironic, as the team make their way along the leaf-strewn boardwalk of Cotterill Clough near Wilmslow, is that many of the ash woodlands of today are a product of the Dutch Elm Disease devastation.

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Cotterill Clough is particularly special for Cheshire. First recognised in 1912 by the forefather of the Wildlife Trusts, Charles Rothschild, it became one of Cheshire Wildlife Trust’s first nature reserves and remains so to this day.

As if the impact of DED and the new threat of ash dieback wasn’t enough, the site has already had to fend off potential damage from Manchester Airport not once, but twice in the 1960s and 1990s. A chequered history indeed for a protected ancient woodland whose floor is carpeted in spring with ramsons or ‘wild garlic’ and whose trees play host to woodpeckers and warblers among other guests. And now it seems the battle lines may be drawn again.

Any woodland is inherently precious as a wildlife refuge and a place to relax and enjoy being close to nature and, this is particularly relevant in Cheshire where our resource of these sunlit theatres is just 6.4 per cent – compare that to around 10 per cent for the rest of the UK and it’s easy to see why we can ill afford to see our trees lost to whatever enemy may arrive at the entrance gate.

So what of this latest threat? Ash dieback in the form affecting the UK was first recognised in Poland in 1992, and has made swift progress across Europe, wiping out almost 90 per cent of common ash tree species in Denmark before it’s believed it may have blown across the Channel.

The fungal infection at the heart of the disease – Chalara fraxinea – was first officially recorded in imported commercial nursery tree stock in the UK in March last year. It was then discovered in nature reserves in the wider countryside of eastern England just a few months later in October.

Within days, official surveys had been hurriedly set into action and at the time of writing, the confirmed number of cases in both plantations and the wider environment was more than 200. Whatever the risks of infection from imported ash trees – since banned by the Government – the peppering of red dots on the weekly-updated Forestry Commission map suggests that Chalara has almost certainly found its own way from mainland Europe.

With leading scientists and the Government’s own Secretary of State, Owen Paterson, confirming that eradication is ‘probably impossible’, the task for conservationists and foresters now is how to slow the progress of ash dieback, which is widely considered to be between 12 and 20 miles a year. With plantation cases already confirmed on the outskirts of Manchester, South Wales and a reported but unconfirmed case in Cheshire itself, there is real potential for the disease to be here within years, or perhaps months.

Although strongly criticised for what many believe were unacceptable delays in acting on the first case in Spring last year (on top of austerity cuts to the UK forest agency the Forestry Commission), conservation groups have welcomed the Government’s setting up of an ash dieback task force and a promise that healthy mature ash specimens will not be felled simply in attempt to stop the spread.

There is also a possibility that given the chance, our woodlands and mother nature herself may have a solution to the disease in the form of genetic immunity, a prospect that Jacki Hulse welcomes. ‘One job for the taskforce will be to urgently look into possible ash dieback immunity in some trees, another reason why it’s crucial the Government doesn’t take a knee-jerk reaction and destroy mature ash specimens simply in an attempt to create a firewall that may be ineffective anyway.’

Even though the risk of transferring ash dieback by people from woodland-to-woodland is considered to be low, Cheshire Wildlife Trust is still urging visitors to be sensible and take precautions like cleaning boots, pushchairs or bikes after a woodland visit.

‘Of course, there’s every likelihood that Chalara spores are passing above our heads in the wind, or even unwittingly being transferred by wildlife itself. But clearly we can do our best not to give the disease a helping hand, by ensuring that infected stems and leaves are not hitching a ride in our boot treads. This is especially critical when you may have visited parts of the UK where the disease has already taken hold.’

Clearly there is much at stake. Brown hairstreak butterflies, woodpeckers, flycatchers and 100 species of beetle alone call ash trees home, and with our woodlands already shaken-up once in the history of modern conservation, this latest enemy may be the toughest yet.

For Jacki Hulse, it’s simply a scenario that she can’t bear to see. ‘Woodlands like Cotterill Clough are what gets you out of bed, when despite loud jumbo jets and a bustling road just yards away you could be just about anywhere.

‘We simply don’t know how these woodlands will react if ash dieback arrived, we could find non-native species like sycamore take over, and almost certainly witness a structural change that would see us lose the unique characteristics that make these places what they are today.

‘After nursing the wounds of previous battles, I just hope at least for Cotterill Clough in years to come, ash dieback doesn’t prove to be the final nail in the coffin.’

What to look for

Ash dieback symptoms include:

1: A dark diamond-shaped lesion or indentation where stems enter the main part of the tree, especially on younger specimens.

2: Very dark or black shrivelled leaves, rather like frost damage.

3: Loss and damage to leaves at the crown of the tree (less obvious in winter).

4: Shrivelling and blackening of stem tips.

Don’t forget: Clumps of drooping seed pods around the size of a clenched fist, or ‘ash keys’ can be seen throughout the winter and are a normal feature of healthy ashes and not a sign of ash dieback.

If you are still unsure, contact the Ash Dieback helpline on 08459 335577 or email Cheshire Wildlife Trust is not able to visit or check individual sites or trees. You can also keep up to date via the Cheshire Wildlife Trust website,