Vandals are putting up the cost of Sheffield's Streets Ahead programme by damaging newly-planted trees.
Sheffield Council this week revealed close to 100 trees had been snapped or broken in the four years since the start of the multi-million pound contract with Amey.
The trees - which were planted to replace more mature trees cut down as part of the programme - all have to be replaced at extra cost.
But taxpayers are not having to shell out any more, with the new trees paid for by Amey.
Sheffield Council pledges 'new start' on trees after year of protests
The council's cabinet member for the environment Bryan Lodge said: “Streets Ahead is overseeing a major tree replacement programme for the city of Sheffield that will ensure a plentiful, healthy and sustainable stock of trees for generations to come.
"Unfortunately, over the last four years around 100 newly planted trees have been damaged in Sheffield, requiring additional replacements under the Streets Ahead contract.
"We’d urge anyone who witnesses any sort of vandalism on the new trees to contact the police immediately.
“Additional funds, not borne by the council, are subsequently sourced for the planting of new trees to replace those which have been vandalised.”
The council said there was no set cost for replacing a tree and it depended largely on location and surroundings.
Under Streets Ahead, about 10,000 of the city’s 36,000 roadside trees will be replaced.
The council has faced fierce criticism for both its felling strategy and its handling of the programme.
Coun Lodge last week reiterated the council’s view that the 25-year contract with Amey was the best chance to replace trees so they 'don’t just last for the next ten years, but for the next hundred years’.
The authority has promised to be more open with residents over its intentions as the programme continues into 2017 amid a background of protests and arrests.
Today’s top stories:
REVEALED: Who won our poll to find Sheffield's best song?
Sheffield United: New striker set to arrive at Bramall Lane today
Sheffield Wednesday: ‘We need another winning run...we have no choice’ - Tom Lees