A man has been arrested at the site of tree-felling in Sheffield.
South Yorkshire Police said a 38-year-old man was arrested on suspicion of assault at the site of tree-felling work on Abbeydale Park Rise in Dore.
He remains in police custody being questioned by officers.
Officers also reported 'numerous people' for summons under section 303 of the Highways Act 1980.
One woman was injured at the site and taken home by officers.
A South Yorkshire Police spokesman said: "In response to queries about the number of officers deployed at the site today, we do not confirm the amount of officers involved in an operation while it is ongoing.
"However we can confirm there will be a higher number of officers at the site to allow their rotation throughout the day, and to provide support should they be required. This is standard procedure for operations of this nature."
Campaigners claim police officers and private security staff hired by council contractor Amey totalled 50 in today's standoff.
The trees on Abbeydale Park Rise are decorated with Christmas lights every year in a community event which attracts thousands of visitors over the festive season and raises money for charity.
Campaigners claim Amey are refusing to look at the engineering solutions that are included in the contract because it is cheaper to cut the tree.
Amey and Sheffield Council have both repeatedly said the trees are either dead, dying, diseased, dangerous or damaging the highway.