A report being discussed by cabinet next week says that the majority of the 500,000 or so ash trees in the county could be lost to ash dieback over the next five to 15 years.
It says it is ‘prudent to assume that the disease may result in losses of between 75 and 90 per cent of the entire ash population’.
Surveys undertaken in 2017 identified ash dieback in a number of younger plantations, landscape plots and self-set saplings, mainly in the north west of the county.
There is currently little evidence of the disease affecting mature trees.
Councillor Blake Pain, county council cabinet member for the environment, said: “The experts are still working to understand the full picture in the UK, so it’s really important that we take a measured and proportionate response.
“We’ll need a robust approach to dealing with ash dieback, including a good understanding of the logistical and financial implications of managing our own stock.
“We’ll also need to talk with landowners who may be affected, to ensure they understand their responsibilities.”
The fungus causes symptoms ranging from leaves and branches dying to complete death of ash trees.
Once infected, a high proportion of trees will die. A few may survive the infection because of genetic factors which give them tolerance of, or resistance to, the disease but the percentage of the UK’s ash trees that are likely to be resistant to the fungus is unknown.
The disease was first identified in Leicestershire in 2012 at the Park and Ride car park in Birstall. It is thought to have been brought to the site on infected nursery stock.
The Tory-run authority is responsible for around 6,000 trees on its highways, and around 2,000 trees on schools and other sites. Around 120,000 trees, which are near to highways, are privately owned.
An action plan, expected to be approved by the cabinet, will see the council devise an inspection regime to provide a better understanding of the risk of falling trees and branches, look at cheaper was to replant trees and work to minimise the impact on the landscape, ecology and the environment.