The lookout for killer tree disease “ash dieback” is stepping up in Hainault Forest as the leaves begin turning for spring.

Fungus Chalara fraxinea has wiped out millions of trees in central Europe and the disease was found to be spreading in the UK in November.

Its presence has now been confirmed in Theydon Bois wood, just a couple of miles away from Hainault Forest.

Tony Chadwick, who manages the site on behalf of the Woodland Trust, has investigating trees reported by members of the public.

He said: “As spring arrives and the leaves start to turn, it will become more obvious.”

The disease was brought over from Europe with imported plants and material.

Mr Chadwick said authorities buying native trees of UK origin were not told seeds were sent to Europe for cultivation before being sent back.

He added: “These little tiny trees are having a nice grand tour of Europe and on the way they pick up all sorts of pests and diseases.”

But ash trees seem to be fighting back in some places by developing resistance to the pest.

Resistant trees will be propagated and planted in efforts to defend against Chalara, which is lethal for trees but harmless for animals and people.

It is spread by spores from infected trees and starts with small spots, leading to lesions on stems and branches and the death of the top of the tree.

Ash is a dominant species in Hainault Forest but Mr Chadwick said other trees including hornbeam and oak will survive any outbreak.

He added: “There’s a fear that it will spread across the country and that will impact on Hainault Forest.

“However what we have seen in other places is natural regeneration where other trees start growing in their place.

“We may lose ash and we will miss it but there will always be trees in Hainault Forest.”

The Woodland Trust is working with the government and other agencies to pool knowledge to create a mobile phone app for members of the public to help identify diseased trees.

For information on Chalara fraxinea, visit www.forestry.gov.uk/chalara.