It's thought of as a scourge, a tree plague: chalara, the fungus that is threatening to destroy all of Britain's ash trees. It has grabbed the attention of the media for the past fortnight; it has sent Defra and the Forestry Commission into emergency mode; it has induced near-despair in naturalists – but what does it actually look like? What will it actually do?
I had a close look this week and came away chastened. For it's not hard to like ash trees. Not hard to love them, in fact. Take the leaves. The particular attraction of ash leaves is that they are, in botanical terms, pinnate, which means that pairs of leaflets sprout out, opposite each other, all the way along a shoot; there are usually half a dozen pairs, topped off with a single leaflet at the end, so the effect is of a giant, glossy green feather.
It's this feathery foliage which makes ash trees seem so light and airy, along with their pale grey bark and their slender, elegant form, even when 50 feet tall. Nothing chunky about the ash. This is something very different from the masculine solidity of the oak. This is "the lady of the woods".
In the wood at Ashwellthorpe in Norfolk, a slim young ash tree, not much bigger than I am, still has its bright, feather-like leaf fronds, even in November; but the older tree right next to it, which is about twice its height, appears very different. When I look at its leaves the words that come to mind are "wilted spinach".
They are changed, but not from any autumn transformation into gold. They are withered, more than withered, even: they hang limp and shrivelled and desiccated and dark as if the life has been sucked right out of them. As indeed it has, by Chalara fraxinea, or ash dieback disease, the malignant new organism suddenly present in our woodlands.
Chalara now seems likely to extend right across the land; there is no cure for it, no vaccination and, as Professor Ian Boyd, the chief scientist at the Department for Environment, Food and Rural Affairs, conceded this week, no practical defence against the aerial spread of its spores.
A fungus which was benign, in its home on ash trees in Japan, somehow got to eastern Europe 20 years ago and changed in its new environment into a killer. It is now likely to kill all our ash trees, just as Dutch elm disease knocked out all our elms. It may take 10 years, but it will get them. All 80 million of them.
Lower Wood in Ashwellthorpe, deep in the countryside a dozen miles south of Norwich, is where, in September, the disease was first discovered in mature, established woodland. Previously, since an earlier discovery in February, it was thought to be affecting only plantations of young saplings which had been imported from the continent – and which would be relatively easy to deal with.
But Ashwellthorpe is anything but a young plantation; it is an ancient woodland (one of the few left in Norfolk); the site has been continuously wooded almost certainly since the end of the last ice age. It's a magnificent place: 90 acres of oak and ash and hornbeam and hazel which in spring is floored with the azure of bluebells and the white stars of wild garlic and, most spectacularly, with swathes of early purple orchids. In high summer, white admiral butterflies glide along its rides, nectaring on the bramble flowers. Even in the November drizzle it feels rich in life.
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.
Ashwellthorpe: roll it around your tongue. If you know anything about English place names you will know that thorpe is a Danish word for a settlement, so this village was named for its ash trees when East Anglia was under Danish rule, which ended in the 10th century. People have been talking about Fraxinus excelsior here for more than a thousand years.
And why not? Ash is one of the best and most useful of woods, strong and straight-grained but light and easily worked; it was once the handle of every tool, it made bows and then it made oars and hockey sticks and even baseball bats. It has provided everything from the rear framework of the Morris Traveller estate car (remember that?) to the body of the Fender Stratocaster, most glamorous of rock guitars.
And it is not only useful to humans. Many small creatures are heavily dependent on ash, from the dusky thorn moth to the wood mice which feed on its seeds; more than 60 rare insects depend on it entirely.
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.
Rethink needed on plant disease, minister says
Britain needs a radical rethink of its defences against emerging plant diseases such as the chalara fungus now threatening ash trees, according to the Environment Secretary, Owen Patterson.
Announcing a series of interim measures yesterday to tackle the chalara problem, Mr Patterson said urgent measures were needed to prevent other infections being introduced, which might include setting up an international early warning system via British embassies, and stopping the free trade of trees and plants throughout the EU.
In future, he said, imported plant infections would have to be treated as seriously as imported animal diseases.
That meant there would have to be a shift of priorities within the Department of Environment, Food and Rural Affairs to address the issue, which might involve some of its present activities being sidelined – although he would not say which.
"For all we know there is a horrible disease in birch trees out in Slovakia or Poland at the moment," Mr Patterson said. "We know chalara was in Poland in the later 1990s. We should be working much more in advance, looking at these diseases as they find their way across the continent."