New hope as latest generations of wild ash trees evolve resistance to deadly fungus

New generations of wild ash trees are rapidly evolving resistance to the fungus devastating their numbers, scientists have discovered.

- Damian Carrington

The discovery gives hope, the researchers said, and shows that allowing the natural regeneration of woodlands is vital to enabling this evolution to take place. However, it remains too early to say if the development of resistance in the ash trees can outpace the destruction being caused by the ash dieback fungus.

The genetic analysis is also a scientific breakthrough. It is the first convincing proof of a prediction made by Charles Darwin that natural selection can drive the evolution of important traits in organisms.

Ash dieback is caused by the invasive Hymenoscyphus fraxineus fungus, which was first identified in the UK in 2012 and is also killing trees across Europe. It has killed millions in the UK and is expected to wipe out up to 85% of the older, non-resistant ash trees, incurring costs of £15bn. Previous studies found apparent resistance in some ash saplings but the new study gives in-depth genetic information that could help breeding programmes to support the natural recovery of ash trees.