Ashes To Ashes

Across the UK, a deadly fungal disease is killing myriad ash trees. Helen Babbs looks at how this apocalyptic march will affect smallholders and what action they need to take

A long hedgerows, in woodland and among noble, stand-alone trees in fields, ash trees are dying. Their demise begins as scorched, blackened leaves on branch tips and then the stem dies back. Bare sections of dead branches develop in the tree canopy. Sooner or later, the whole tree is in its final death throes. This is Chalara ash dieback, the rampant disease caused by the fungal pathogen Hymenoscyphus fraxineus. This fungus grows in the tree’s water transport cells, blocking them so that the stems gradually die for lack of water and nutrients.

A RAMPANT KILLER

While the species of ash tree in Asia, where the disease originates, have resistance to dieback, the native British ash (Fraxinus excelsior) has none. Since the arrival of ash dieback in the UK in the early 2000s via wind-borne spores from Europe, the disease has spread rampantly across the country. A Forestry Commission survey in 2018 found that 68% of 10km grid squares in England had confirmed cases of ash dieback, rising to 80% in Wales.

“It’s extensive,” Nicola Spence, Defra’s chief plant health officer, confirmed. “There’s a higher density in the east, which is in a direct line for the spores from Europe and where the climatic conditions favour the disease. Where the trees are already under stress, with high temperatures, drought or suchlike, they succumb much faster. But ash dieback is now in most parts of the country, and all counties.”

One county where ash dieback is especially noticed by smallholders is Devon, where 100% of the 10km grid squares in the Forestry Commission survey have ash dieback.

“I first noticed ash dieback in 2018, and the trees are taking a year or two to die,” said Chris Murray from Pennywell Farm near Buckfastleigh. “It started with one and is now many. They’re 24 years old or less.”