We're being urged not to prune or damage oak trees through October to prevent the spread of a fungal disease.
Oak wilt is spread by beetles and can kill a tree just weeks after being infected, by restricting the flow of water and nutrients.
Manager of Parks, Forestry, and Horticulture Patti Ross said the disease hasn't been found in Ontario but they're being cautious.
"They only attack the oak trees, so we just want to be preventative with that," said Ross. "We have about 15 per cent oak in the city of Sarnia, so we just want to prevent the disease from attacking the oaks. We started these measures last year. So far it hasn't been detected in Canada but it's just across the border so we want to play it safe."
Ross said oak wilt is present on Belle Isle and in the Detroit River.
She also encourages residents not to move firewood, and to use weed trimmers and mowers cautiously around trees.
