You grow girl: how Aretha, Nina and Dolly can help save the ash tree

<span>Photograph: Alamy</span>
Photograph: Alamy

The seedlings growing in the John Innes Centre’s ash dieback laboratory have been adorned with unexpected names. According to their tags, the shoots are called Suzie and Chrissie and Aretha, as well as Kate, Dolly and Nina.

It is an odd nomenclature for a world-leading crop research centre – though plant health expert Professor James Brown has an explanation: “These seedlings are part of Diva: our Diversity In Ash research project, so we decided to name them after real divas – and in particular the divas of my day: Suzie Quatro, Aretha Franklin, Kate Bush, Chrissie Hynde, Dolly Parton and others like them.”

Such rock roots are intriguing – though Brown stresses this research on ash tree seedlings has a very serious purpose. He and his colleague, Dr Elizabeth Orton, hope they will help Britain offset the repercussions of ash dieback which now threatens to eradicate up to 95% of the trees it infects in this country.

The disease first appeared in the UK a decade ago when experts predicted it could kill off swathes of the country’s woods and forests. Now these warnings are being realised as more and more ash trees succumb to infections.

Ash dieback is caused by a fungal pathogen, Hymenoscyphus fraxineus, and originated in Asia before it spread to Europe, where it has already killed or severely damaged a quarter of the species in southern Sweden, and destroyed more than 80% of young ash trees in Norway. Now Britain has begun to suffer in a similar way as the disease continues to spread through woods. Huge decaying trunks of dead ash loom over paths and clearings, posing a threat to visitors and forestry workers.

“There is no doubt that ash dieback is having a real impact, and that raises a lot of management issues for those in charge of our woods and forests,” added Brown. “It is undoubtedly a very serious problem but it would be wrong to say that the ash is going to be wiped out in this country – that is definitely not the case.”

This point was backed by Orton: “Yes, a lot of trees are doing very badly and are dying, but don’t forget there are around a hundred million ash trees in this country, and several million will still survive by not succumbing to dieback: it’s a very low percentage, but it is still quite a number of trees – enough to make a difference.”

Brown and Orton estimate that between 2% and 10% of ash trees show resistance to dieback. “You can stand in a wood where there is dead ash around you and right in the middle you can also see young ash trees that are clearly quite healthy and unaffected by disease,” said Brown. “That shows that some trees are probably being protected by some kind of genetic resistance.”

On its own, such resistance would ensure that the ash tree – which can grow 35 metres high and form distinctive domed canopies – would eventually be restored to our woodlands, though this could take decades. However, the John Innes Centre team hope to speed up this process. “We have gone to woods and looked for ash that is surrounded by infected trees but which are themselves unaffected by dieback thanks to their resistance,” said Orton.

Seeds have been taken from these healthy ash trees, and 150 of these are now being grown in trays in the John Innes Centre. “Some of these look very promising – the Chrissie line looks especially healthy,” added Orton.

Next year, these seedlings will be planted, grown and cross-pollinated with each other. “From these, we would expect to produce some especially healthy, disease-resistant ash trees,” said Brown. “These would then provide seeds that could be used to restore the ash to Britain.

“We would be looking at getting these seeds to landowners or farmers or conservation groups or anyone else who is interested in bringing back this wonderful tree to our woodlands.”