Ash dieback

A woodland in summer

We're concerned about ash dieback, a fungal disease that's affecting many woodlands, parks and gardens across the country. We're doing all we can to tackle the disease in Gloucestershire.

There are an estimated 80 million ash trees in the UK, helping to shape some of our best loved landscapes. They make up a third of our entire tree population.

Ash trees are a common feature in several of our woodlands, including those at Crickley Hill, Standish Wood and Woodchester Park. 

A healthy tree
A healthy tree
A healthy tree

It's thought that 95% of ash trees will be lost to the disease, having a devastating impact on the countryside and biodiversity of our woodlands. 

What is ash dieback?

Ash dieback, Chalara or Chalara dieback is a disease that affects ash trees and is caused by a fungus called Hymenoscyphus fraxineus. The disease originated in Asia and its spread attributed to the movement of plants as part of the global trade. The fungus spreads quickly as its spores are windborne. 


Ash dieback can affect ash trees of all ages, although younger trees succumb to the disease much quicker. As the name suggests, the disease causes ash trees to slowly die, drop limbs, collapse or fall.

Signs of the disease include;

  • Leaves developing dark patches in the summer. They then wilt, turn black and begin to fall to the ground
  • Dark brown lesions develop where branches meet the trunk
  • Shoots, especially those on the crown dieback during the summer

Once a tree is infected the disease is usually fatal. There is no cure, but some trees are less susceptible than others.

Our response

The rangers are doing as much as possible to tackle the disease, including monitoring infected trees, felling those that are affected and pose a risk to visitors and monitoring and identifying trees that seem to be resistant.

Tree felling as a result of ash dieback
Tree felling as a result of ash dieback
Tree felling as a result of ash dieback

Despite the tragic loss of trees, the rangers will be seizing the opportunity to increase the diversity in areas hardest hit by ash dieback. They'll be planting native trees and allowing other areas to regenerate naturally. 

The long-term aim is to help the woodlands we look after be better equipped to face climate change and diseases like ash dieback.