South Yorkshire Police has received allegations of assaults from both demonstrators and staff working for city council contractor Amey, which is involved in the removal and replacement of thousands of street trees in the city as part of a £2.2bn Streets Ahead highways improvement project for Sheffield City Council.
There have been repeated clashes on Meersbrook Park Road for more than one week. It comes after Amey brought in a "specially-trained stewarding team" to remove protesters going inside safety zones around trees that are due to be felled earlier this month.
Some 20 trees on the road were referred to an Independent Tree Panel set up by the council which said 11 could be saved through engineering works. But Sheffield Council overturned the decision in nine cases and only two were retained.
A spokeswoman for South Yorkshire Police said: "We have received a number of allegations of assault in relation to this matter. Police are now reviewing these reports. Enquiries are ongoing and anyone with information is asked to contact 101. We can’t take crime reports over social media."
Streets Ahead account director Darren Butt said work had now been stopped because of concerns about staff safety.
“We welcome safe and peaceful protest but unfortunately this is not what we experienced in Meersbrook Park Road on Monday. In the interests of everyone’s safety we withdrew from site, and we will resume as soon as we can ensure the safety of our staff, local people and the protestors themselves.
“Re-planting certain street trees which are ailing or damaging is one of the ways we deliver the council’s legal duty to maintain the city’s highways, which is why a High Court injunction is in place to keep our working areas safe.
“We urge people to respect peaceful communities and not to wilfully obstruct our works on the highway by staying outside the safety zones, so we can complete this programme for the benefit of everyone in Sheffield.”
Around 5,500 trees have been removed and replaced with saplings in the city since 2012 but campaigners argue that many of the removals are unnecessary.
Tree campaigners have alleged that Amey staff have been using force against demonstrators.
Paul Brooke, a member of the Save Gleadless Valley Trees Group, said: “The people that live in Meersbrook Park Road voted overwhelmingly to save the healthy street trees that make such a big difference to their wellbeing.
"Amey seem prepared to go to any length to enforce this misguided contract, even though experts across the country say there’s no practical or economic need to do so. But the harder they push the more determined we all become to oppose this destruction."
Sheffield Heeley MP Louise Haigh called earlier this week for the work on Meersbrook Park Road to be halted because of the 'completely unsustainable' situation.
She said: "The daily events on Meersbrook Park Road are deeply distressing for local residents and those walking through the area and the park alike. I am therefore calling on the Council to cease felling until the ITP decisions have been reviewed, all options reconsidered and there has been full disclosure of any and all final decisions to fell.”