The tree that's fit for a king! As scientists launch a desperate bid to save it from extinction, the fascinating natural history of the forest giant that helped defeat the French at Agincourt (and makes the world’s best salad bowls)
It is one of our most stately trees. A hardwood that grows significantly faster than oak or beech – and, unlike the elm or the sycamore, is a true native of these islands.
Even in winter, the perfect symmetry of an ash tree has its own striking beauty, the deeply furrowed bark a testimony to its age.
Much of Ireland was once covered by ash forest – one of my favourite holiday walks, up the Cladagh Glen in County Fermanagh, is through one of just two surviving patches – and the wood of the ash, with its own remarkable properties, has been prized for centuries.
You might think oak the king of timber – from the historic ships of the Royal Navy and the rafters of Notre Dame to our late Queen’s coffin – but, says writer and broadcaster Rob Penn, oak ‘is the timber of gentry. It’s very expensive. Ash is the timber of the working man. And you find it all over Britain.’
Ash prefers alkaline to neutral soils, especially over limestone. And ash fashioned everything from Achilles’s spear in the Iliad to the framing of London’s celebrated Routemaster buses. The arrows that fell like deadly hail upon the French at Agincourt were made of ash.
The unfelled and living ash tree is of extraordinary environmental importance
So were the sledges by which Roald Amundsen, in 1906, beat Captain Scott to the South Pole. Ash wood is strong, flexible, non-poisonous (unlike oak) and easily ‘turned’.
Most notably, it has an astonishing capacity to absorb shock. Ash is used for flooring, tool handles, hurleys (for the Irish), camans (for Highland shinty) oars, paddles and Morgan car frames. It even makes very nice bowls. It is also the most prized firewood, uniquely catching flame even fresh-felled and green, and topped the list in Lady Celia Congreve’s cosy 1930 hymn to the fuel for wood fires – ‘Ash wet or ash dry, A king shall warm his slippers by...’
But the unfelled and living tree is of extraordinary environmental importance. In the desperate winters of long ago, stock could get by on its decomposing leaf litter, which was why ash trees dominated medieval ‘wood pastures’.
This leaf litter, says Ursula Buchan, ‘has a high nutrient content and decays rapidly, which hugely benefits soil fungi and invertebrates. Ash woodland flora is richly diverse and five rare species, including the oxlip, are particularly associated with it. Like all large trees, ash filter out pollution, mitigate storm run-off and store carbon...’
No fewer than 955 species benefit, in some respect or other, from association with ash – and four lichens, eleven fungi and 33 invertebrates are only found on ash.
Intriguingly, too, the ash is the last of our great trees to come into leaf each spring – and, even then, casts a very light shade, which means a rich ground-flora can prosper beneath it.
Male and female flowers are usually borne on separate trees, and the pollen is dispersed by wind. Late in summer, notable clusters of brown seed ‘keys’ appear – and the season’s leaves often drop, in a oner, after the first night of hard frost.
Ash dieback, an airborne fungal disease, has put the trees under threat
But anyone with an ear for the news or an alert eye in the countryside knows that fraxinus excelsior, the European ash, is in dire trouble.
All over the land, in our woods and hedgerows, leaves are browning; bare branches point despairingly at the sky. A magnificent ash tree in Edinburgh’s Morningside had several years ago to be felled, as ‘ash dieback’ rampages through the land.
It’s an airborne, fungal disease – the pathogen is hymenoscyphus fraxineus – and comes from Asia. Ash trees in the inscrutable Orient are largely safe because they have evolved alongside the bug for millennia and the more vulnerable are, naturally, extinct.
But it is a different story in Europe, where the pestilence arrived in the 1990s. Then, down to careless biosecurity, it jumped the Channel, tentatively around 2006 then spectacularly in 2012, in a single consignment of young, imported and sick saplings.
Ash dieback comes with crown decline, root collar necrosis and, eventually, death, often hastened by such secondary pathogens as honey fungus and bracket fungus. And no, there is no cure.
This is not quite a catastrophe like Dutch elm disease. Most British elms descend from a single clone and are genetically identical. Ash trees enjoy greater genetic diversity and 1 per cent – about 1.5million of the British population – are naturally immune to ash dieback.
But it is still a disaster. Up to 90 per cent of ash trees in Ireland are expected to perish. The lanes of County Leitrim, where the pandemic began, already resemble an ash tree graveyard.
Around 80 per cent of our own population has been all but written off; as of February 2018, hymenoscyphus fraxineus had been identified in 49 per cent of all ten kilometre squares of the United Kingdom. And the cost of felling dying or dead trees – not least for the safety of any people or vehicles passing by their decaying mass – is eyewatering. An Oxford University study in 2019 concluded that ash dieback could cost us £14.8billion over the next century – and half of that by 2030.
Nor are there any grants available to farmers or private landowners for cutting down trees. But a fightback is already under way – and spearheaded by our own James Hutton Institute, right here in Scotland.
Dr Ruth Mitchell and her team, it was last week announced, have been awarded almost £80,000 to devise a ‘road map’ to save – or at least to secure – our ash forest.
Central to their approach will be gene editing and selective breeding. Whitehall has spent some £8million over the past 12 years in exhaustive study of ash dieback: now Dr Mitchell will turn that laborious laboratory research into planned, practical fieldcraft.
‘When we first found it,’ says Professor Nicola Spence, Britain’s chief plant health officer, ‘everyone was looking around for a quick solution and it became quickly obvious that ash dieback was across the UK already and there wasn’t a silver bullet.
‘We are now understanding the resistance mechanism in the ash population and the different ways in which we can develop resistant ash through a combination of traditional breeding and enhanced breeding as well as natural selection for resistance.’
But, just when we thought things could grow no worse, a second pathogen has arrived – the hideous ash sawfly, first noted in Northern Ireland in 2016 and whose wholesale and munching grubs can devour the leaves of an entire tree in mere weeks, like something out of Doctor Who.
On mainland Britain, we harbour natural predators that keep ash sawfly in check: there is no such balance of nature in the Six Counties.
Beyond quantifying salad bowls, hammer handles and shinty sticks, we need the joy and mystery of woodland; deep forest echoing our own subconscious.
‘One of the great things about woods is that you are out of sight of your parents by going 30 metres that way,’ says Rob Penn.
‘You might be still within earshot but the trees cut you off – there is a sense of otherness and change. There is a reason fairy stories are invariably set in woodlands... when children walk into a woodland, they feel like they are walking into a fairy story.’
Arguably our loveliest tree is central to that experience – and why we must save it.
