Next time you are driving or walking down a country road, you may notice that something is wrong. If you look around, you may see that the tall ash trees in the roadside hedges are no longer looking so pretty, their leaves sparse and scattered, even brown and wilted, while the bare branches point accusingly towards the sky. A disaster is looming that at first glance seems hardly less dire than the one that struck the countryside in the early 1970s, when the “Dutch” elm disease was brought in with the wood from Canada and destroyed 30 million trees. This time the victim is the European ash (Fraxinus excelsior).

Hymenoscyphus sylvatica is a fungus native to Asia, where ash species tolerate it because pathogens and trees have co-evolved. The fungus arrived in Europe 30 years ago. Due to deficiencies in biosecurity, it then crossed the English Channel, possibly as early as 2006, but certainly in 2012, in a consignment of young infected plants. The fungus produces spores that are released in the summer and carried by the wind, causing a disease called Chalara Ash dieback. This leads to crown loss, root collar necrosis and ultimately death – which is often accelerated by secondary pathogens such as honey fungus and tree fungus.

When the disease was first reported in 2012, it sparked widespread horror and fascination. But over time, the threat to ash trees became background noise that was easy to ignore. That is over. The disaster is obvious even to city dwellers, because ash trees grow in city parks and suburban streets as well as in hedgerows in the countryside. The sound of chainsaws and tree shears is loud in the countryside.

The ash is a broad-leaved hardwood with a smooth, grey trunk that fissures with age. It has unique velvety black leaf buds followed by long, green, compound leaves. These flower later in the spring compared to other native broadleaf trees, meaning that rich flora can develop in woodland areas at ground level. Male and female flowers usually grow on separate trees, and the wind disperses the pollen; distinctive hanging clusters of brown seed heads appear in late summer. After a frosty night, the leaves often fall off in a heap.

The ash (unlike the elm) is a tree native to Britain, with its range extending across England and Wales into Scotland, particularly on alkaline soils over limestone. Ash trees are vital inhabitants of forest ecosystems because the leaf litter is high in nutrients and decays quickly, which greatly benefits soil fungi and invertebrates. The flora of ash woodlands is very diverse, and five rare species, including the tall primrose, are particularly associated with it. Like all large trees, ash trees filter out pollutants, mitigate stormwater runoff and store carbon.

The wood, unless infected by disease (which turns the wood from white to brown), is used for flooring, tool handles, oars, Irish hurling sticks and Morgan car frames – due to its remarkable ability to absorb shock. Ash is also the best firewood, which is perhaps just as well as there will be plenty of it as landowners salvage something valuable from their infected forests. In Lady Celia Congreve’s 1930 poem about the different types of firewood, ash is mentioned first: “On ashes wet or dry a king shall warm his slippers.”

Ash leaves were once used as fodder for livestock during dry winters, so the trees were part of the old ‘wood pastures’. Ash tolerates coppicing or topping well, so there are some very old trees here. (Coppering involves cutting the trunks almost to the ground, creating ‘stocks’, whereas topping involves cutting the tree’s crown back completely.) My husband and I used to rejoice when we saw the ash stocks by the side of a country road near Loweswater in the Lake District. We estimated them to be a couple of centuries old, so wide and almost hollow were the trunks, but they still bore strong, straight young spears. Joy turned to dismay when – years before ash dieback – we came across men uprooting them. Heaven knows why.

Thirty years ago we planted hundreds of 18″ “whips” of a mix of native tree species on an acre of pasture behind our garden. Previously there had been a single hundred-year-old hollow ash tree there, inhabited by tawny owls and woodpeckers. Our little “grove” and the birds and insects it attracts have become as dear to us as anything else we own. It contains 47 ash trees, a dozen of which we cut down to stumps when they began to overgrow their neighbors. We used the wood for firewood.

It is the young shoots from the stems that are most quickly affected by ash dieback. Removing the infected stems will make no difference, as the fungal spores can be carried for miles by the wind, so the rest will simply be infected from somewhere else. Mature trees take longer to decay, but most will eventually die, even if it takes a decade or two. Every day I anxiously look down the crowns of 15-metre-tall ash trees, looking for signs of thinning at the ends.

If we care so much about these trees, how much more must we care about the 30 invertebrates, four lichens and 11 fungi that are “obligatory” to ash trees, meaning they only occur on ash trees. In total, 955 species benefit in some way from their association with ash trees.

In 2019, a University of Oxford study estimated that the cost of ash dieback in terms of lost benefits and the removal of dead and dying trees over the next 100 years would be £14.8 billion – more than half of that, £7.6 billion, would be incurred by 2030. What else can we expect when large tracts of land, many of them sites of particular aesthetic or scientific value, are affected? I might add that there are no grants available to private landowners for the felling of ash trees. Yet many of them grow in field hedgerows, beside roads or footpaths; these risk becoming unsafe if they die or die, and are another damning burden for struggling farmers. Some of our trees we can safely leave standing, but those close to our neighbours’ property lines may have to be felled – at considerable cost.

The Oxford report estimates that communities in Devon, a badly affected county, could face costs of over £30 million a year just to remove dangerous roadside trees. In the Peak District, ash trees make up 80 percent of the woodland, and in the steep glens, a special area of ​​conservation, the percentage is even higher. There is good news here. Thanks to a diverse partnership led by Natural England, the glens are being replanted with ecologically similar small-leaved lime and wych elm. But it is painstaking and skilled work that will have to continue for years to come.

The reason for the almost complete extinction of the elm population in the 1970s was that the vast majority were genetically identical. Wonderful wordsas the Romans would say, most of the elms in Britain descended from a single clone, the Antinian elm, which was imported from Italy via Spain to be used as a support for grape vines. Such an extinction will not happen Fraxinus excelsiorThank God, because it is more genetically heterogeneous.

Dr Jo Clark, head of research at the Future Trees Trust (a charity dedicated to improving the population of broadleaf trees), estimates that 1 per cent of ash trees, or around 1.5 million, have significant tolerance to the disease and can either live with the disease or regrow after infection. These trees have been the focus of the FTT’s research and propagation project, carried out in partnership with Forest Research, RBG Kew and Fera under the umbrella of the Living Ash Project and funded by Defra for the past decade, until this month. The work has led to the establishment of a ‘National Archive of Tolerant Ashes’, a collection of grafted plants – the basis for large-scale production of resistant trees in future years – assembled and maintained at a site in Hampshire and soon one in Scotland. It is hoped that Defra will want to fund a seed production programme to build on this success. Dr Clark believes there is hope for the ash in the future. It certainly looks like it, but the present still looks grim.