Halton Council in Cheshire says it's working with national agencies to save its trees from the deadly condition known as "ash dieback".
It's feared 120,000 trees in the borough are at risk from the disease, spread by a fungus transmitted in the wind, which the council says will cost the country £15 billion.
Infected trees, which can become a safety risk, are being replaced with a mix of other native trees, through the aid of a woodland stewardship grant.
Ash trees account for about 12 per cent of broadleaved woodland or individual trees planted in the UK and planted extensively around Halton.The Town Park in Runcorn will be one of the first places to have Ash trees replaced, according to the council.
Halton Borough Council's Executive Board Member for the Physical Environment, Cllr Ron Hignett, said: "The Council will retain as many disease tolerant Ash trees as possible. "These will be identified through careful inspection and selection, by letting nature take its course will improve the resilience of our woods to future disease and climate change."
He added: "This is going to have a devastating impact on the landscape and the biodiversity of Halton’s woodlands, as well as a major loss of connectivity between ecological habitats. "The disease is chronic with a high mortality rate and particularly destructive of young ash trees, killing them within one growing season of symptoms becoming visible. "Older more mature trees often survive an initial attack, but tend to succumb eventually after several seasons of infection."