South Yorkshire Police has promised to have more officers on the scene of tree felling works after council bosses announced that work would resume - even though it may lead to a lack of resources to cover day-to-day policing.
The controversial works were halted last month following clashes between campaigners and Sheffield council contractor Amey staff on Meersbrook Park Road.
Assistant Chief Constable Dave Hartley said two people had been arrested following the incident on January 22, in which a security worker had his wrist broken and pledged to have additional resources available to respond to any further clashes across the city as part of the £2.2 billion road improvement programme.
He said: "We are fiercely independent in all of this. We are here to balance the rights of Sheffield Council and their contractor to undertake lawful maintenance work and those who object to that and wish to protest.
"We have been doing that all along and up until the Meersbrook Park Road incident but what we saw there was a real change in the behaviour of the protesters in that we saw disorder break out and direct action led to a number of injuries to security workers.
"There a number of offences we are investigating and that does include a broken wrist. Some arrests have been made and more could be made as the investigation continues."
Asst Chief Con Hartley said the force had now changed its plans for policing the protests as there was now a 'reasonable expectation' of disorder when work resumes.
He said: "We are going to work very closely with Sheffield Council and Amey so we are aware of where their work is and initially it will be local police officers just there to monitor that the protest is peaceful and Amey and security staff are operating within the legal framework.
"If it's needed then there will be a rapid change in the response and we'll have further resources available and have the ability to move to a different policing style.
"We have an obligation wherever there is a protest to provide the resources but we all know the situation, I don't have warehouses full of support offices - South Yorkshire Police is much smaller than it used to be.
"Whenever we are policing a protest it has an impact on normal service delivery. We might have to pay staff overtime or bring people from core services and that affects other services."