To be sung to the tune of Max Boyce’s Hymns and Arias:

The disease they call ash die back, its sweeping through the land
Chalara said the Government, it needs no helping hand
So many trees are dying, its a disease we can’t control
That green and pleasant countryside thats deep inside our soul

But is disease for Politicians, should they stay away?
Their cock-ups and their arguments, ends up making us all pay
And they were singing Hymns and Arias,
Land of Chalara
Ar hyd y nos

Deep in the forests of Poland, the tall trees suddenly vanish. A vast clearing opens up, a boggy landscape studded with the remains of dead ash trees. Half have been chopped to the stump, half are jagged like rotten teeth. The mystery fungus killed the leaves first, then moved into the stalk and down the trunk, cutting off the water supply and choking the tree. Then it rotted the roots.

By 2003, the fungus had moved into the older trees, some of which had been planted in the time of Stalin. Still the full horror of what was happening here was not revealed until one night in February 2007, when strong winds blew.

Prof Kowalski does not rule out the possibility that it was created by natural genetic mutation in the forests of Poland. However, a second theory is gaining more support in the scientific community.

“There are suggestions that Hymenoscyphus pseudoalbidus comes from Asia, where it lived on a different species of ash tree and caused no damage,” he says. “Then it came here, perhaps carried by the wind or by birds, or on clothes, and found the European ash more vulnerable.” Until the latest research is confirmed, he is not willing to say for sure. He does, though, think the row over imports in Britain is irrelevant now, or at least too late.

[He said] “Cooler temperatures in summer are better for some strains of the disease, so it is possible that the colder, wetter summer in Britain this year could have contributed to what is happening there. In most instances in Poland, we are finding that 15 to 20 per cent of trees do not die, and show no symptoms.”

“How many trees are at risk?” Eighty million. “Wow.” He looks shocked. “Has it been seen in the older trees?” It has. This experienced man of the forests puts his hand on his heart. “Then I am afraid it is over for you. It is too late. The game is over.”

Yggdrasil, the World-Tree

According to the 13th century Icelandic Edda

“The ash Yggdrasill endures anguish,

more than men know.

A hart gnaws it on high, it rots at the side,

While Niohoggr devours it below.”

Let us hope that the predictions of Norse mythology of the end of the world with the death of the world-tree do not come true.

Ash accounts for about 40 per cent of the trees in the wood, says Steve Collin, the Norfolk Wildlife Trust warden who first noticed the wasted, shrunken leaves on 13 September and, after a second check on 4 October, when he realised a great number of trees were affected, notified the Forestry Commission; by 17 October, chalara was confirmed.

Walking around the wood with him, looking at the wilted leaves and the lesions which are starting to appear on the bark of some of the infected trees, it is clear that nothing can be done; as Steve points out, any large-scale application of fungicide would destroy the wood’s ancient soil, as would the compacting by any heavy machinery brought in to take diseased trees out.

But perhaps we can be excused for mourning, not only the coming loss of its usefulness, but the loss of its beauty. Trees in general are emblems of sturdiness, of rugged robustness, but here is one which adds something else to our woodlands: a feeling of feminine grace. It is indeed not hard to love it, and not hard to lament the fact that the lady of the woods is now in dire distress, but there’s no knight in shining armour coming to relieve her.

The dieback disease “could be the end of the ash tree” and it was unlikely that its spread could be stopped, said Austin Brady from the Woodland Trust.

And he said government action was needed on other “pest and diseases threats” on the UK’s borders.

Tim Briercliffe, Director of Business Development at the Horticultural Trades Association, said there was no point in “chopping down” trees like the UK did during the Dutch Elm Disease crisis.

He pointed out most of Europe has no regulations on ash dieback because it is impossible to control.

Instead, he said the UK should gradually replace native ash trees with resistant varieties while working to prevent more diseases and taking plant health more seriously.

“If a mature tree gets ash dieback there no point in chopping it down. On the Continent they just live with it and live with the fact ash trees will die and just do not sell it or grow it.”

Dr Tony Whitbread, chief executive of Sussex Wildlife Trust, explained to the Today programme’s science correspondent Tom Feilden that “it is difficult to know the impact” of the disease but added “to say that it will make the Dutch Elm Disease look trivial is an understatement”.

Dr Glynn Percival, an expert on tree diseases at Reading University, explained to Today presenter Justin Webb that that ash dieback is “beyond containment and beyond eradication”.

“We’re now looking at management” of eradication, he added.

Ash dieback not only affects ash trees but also the birds, mammals, insects and plants whose lives are linked to the tree.

But it is not just specialists that will be affected. Ash is a wildlife all-rounder; it is an important habitat and food source for many species, particularly roosting birds and bats, as well as hole-nesting birds. Great spotted woodpeckers happily plunder ash keys and use the trees as a sap run. And, in ash-dominated habitats, birds such as redstarts use trees for nesting and breeding – they could be seriously affected if ash dieback reaches these habitats.

But it is our bugs and insects that will bear the brunt of any ash tree fallout.

More than 30 species of moth are dependent on Ash in some way including two UK Biodiversity Action Plan (BAP) species, one provisional Red Data Book list species and two nationally scarce species.

Some eight species of moth are solely dependent on the tree as a foodplant including the provisional Red Data book listed Pammene suspectana.

Director of Conservation, Dr Nigel Bourn, said: “Ash dieback poses yet another threat to Britain’s dwindling butterfly and moth populations.

“It could repeat the devastating losses of Elm-feeding species that we saw as a result of Dutch Elm Disease during the 1970s.”

The killer fungus threatening a third of Britain’s woodland could take a terrible toll on rare insects, birds and bats that rely upon ash trees for their survival, according to wildlife experts.

Martin Harper, the RSPB’s director of conservation, said: “Ash trees are the crowd pleasers of nature – they do a lot for all kinds of different animals and plants, from providing great roosting sites and warm holes to nest in, to perfect places to forage for food and ideal spots to flourish and grow. This disease has the potential to damage ecosystems in a big way.”