Country diary: Something’s eating away at this sycamore tree

The sycamore cut down on Hadrian’s Wall was back in the news. A man had appeared in court in connection with its felling, and this after regular stories on the subject, new shoots growing from its stump, artworks made in commemoration and a seedling, propagated from the tree’s remains, presented to King Charles. Standing on the verge of the busy road under Houndkirk Moor, I reflected that some sycamores are more equal than others.

No one, I assumed, had noticed the distressed youngster in front of me, about 10 years old, no more than a sapling. I was only paying it attention because a friend had mentioned seeing many more sycamores this summer with clumps of withered leaves in their crowns. And once I started looking, I saw them too. One culprit that sprang to mind was sooty bark disease, a fungus that arrived from North America in the mid-1940s. I have a rough idea of the symptoms, so when I spotted this example with a branch of prematurely bronzed leaves, I crossed the road to make a diagnosis.

Related: Country diary: A space where a great sycamore should be | Susie White

The clue with sooty bark disease is in the name, as a powdery, charcoal-coloured fungus coats the bark’s surface. The affected area of this sycamore was the exact opposite: a ring had disappeared from around a bough, revealing wood beneath that was dully off-white. Looking more closely, I saw tooth marks. The tree hadn’t succumbed to disease, but the voracious appetite of grey squirrels, which are partial to sycamore phloem, especially in early summer. Case solved, for this specimen anyway.

Grey squirrels are often judged unpopular interlopers. A couple of decades ago, there were plenty of conservationists who thought the same about sycamores. Their fecundity and accommodating nature were viewed with suspicion. Despite their presence here since (at least) the later middle ages, sycamores have struggled to catch our cultural imagination as they have elsewhere in Europe. Until Hadrian’s Wall, the most famous sycamore was the one that sheltered the Tolpuddle Martyrs.

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