The London Borough of Bexley said several incidents of residents being targeted by rogue tree surgeons have been reported to its trading standards department in recent weeks.
"The con artists offer tree cutting services at bargain prices," the council warned. "They then charge large amounts of money to remove the chippings - or charge exhorbitant prices but do very little of the work for which they’ve quoted."
Councillor Peter Craske, cabinet member for places, said: "As we move into spring, residents start thinking about doing work to their homes and gardens. We need to be vigilant.
"We advise residents not to respond to any leaflet drops, or to deal with traders on the doorstep for any goods or services."
He urged residents to use instead the council's What Tradesman? scheme.
A non-returnable application fee of £75 plus VAT serves as the first year's membership fee for tradesmen accepted into the scheme, following background checks by the borough's trading standards officers.