Thousands of conker trees on streets in Nottinghamshire may have to be cut down if they are found to be infected by a deadly disease.
Experts are monitoring the horse chestnuts for bleeding canker, a disease which has already appeared in trees in parts of the county.
The fungus eats around the bark and can kill the trees, leaving them in a dangerous condition.
Signs of infection include brown leaves and fewer conkers.
It costs about £1,000 to remove and replace each tree.
Dr Trevor Mabbett, a plant pathologist, said he did not think the disease would completely wipe out the species.
"I don't think you're going to see them (the trees) all go completely and quickly like with the Dutch Elm Disease - but it is a serious problem," he said.