Warburg Nature Reserve is one of the jewels of the Chiltern Hills. In autumn, its birches and oaks transform into a canopy of red, yellow, brown, and golden leaves. The 100-hectare woodland is home to an astonishing range of fungi. Yet, this curtain of multi-coloured joy hides a grim secret. A walk through the reserve, which is owned by the Wildlife Trust, reveals gaps that have recently appeared in the canopy.

Rising above the paths are stark, white, leafless trunks, victims of a devastating plague that is set to deplete our forests and drain millions of pounds from the budgets of conservation charities: ash dieback.

This disease, caused by the fungus Hymenoscyphus fraxineus, first appeared in the United Kingdom ten years ago. At the time, experts warned that ash dieback would have dire consequences, although some hoped that resistance would spare some trees and leave parts of the forest area unaffected. Now, 10 years later, those prospects look bleak.

“I think we will be lucky if 5% of the ash trees in the country survive this plague,” said Debbie Lewis (Debbie Lewis), head of ecology at the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust, BBOWT), which manages Warburg Nature Reserve.