Sheffield City Council has won a court battle to bring injunctions against protesters taking "unlawful direct action" to prevent trees being felled.
About 5,000 trees have been cut down after being assessed as diseased, dying or damaging, but campaigners say some healthy trees have also been lost.
Orders have been made against three people, including Green councillor Alison Teal, and "persons unknown".
The council say the ruling will prevent "catastrophic financial consequences".
Regular demonstrations have taken place where campaigners believe the trees being felled are healthy, and on occasion protesters have stood beneath trees to prevent contractors from removing them.
Under the terms of the injunction protesters will be barred from "continuing to take unlawful direct action" or from encouraging others to direct action, including entering "safety zones" erected around trees being felled.
Councillor Bryan Lodge said: "We will continue to support the right to peaceful protest, but this is different from trespassing, preventing vital highway works from continuing.
"We never wanted to be in this position and those stepping inside the safety zones were given numerous opportunities to prevent us seeking injunctions.
"We have a responsibility to the taxpayers of Sheffield to do everything we can to avoid catastrophic financial consequences if the Streets Ahead work is not completed by the end of the year.
The council had initially applied to bring injunctions against nine campaigners, but six of those agreed to sign an undertaking with the same prohibitions as the injunction.
'Campaign goes on'
The injunctions come in to effect from midnight on 22 August, pending any appeal, and run until 25 July 2018.
Speaking after the hearing, Sheffield Tree Action Group (STAG) said its campaign to "save healthy trees goes on" and that the defendants Ms Teal, David Dillner and Calvin Payne were "taking advice on their next steps".
Ms Teal said: "I am massively disappointed, particularly that the injunction includes "persons unknown", I find that really worrying.
"That means that in the future people are going to be much less inclined to stand up for their rights."
She said that while the campaign may potentially be approaching "the end of the road in legal terms" she expected it to become "increasingly creative".
Fourteen protestors were arrested between November and March for preventing tree felling but the Crown Prosecution Service dropped charges in March because of insufficient evidence.
Mr Lodge added that the council "will be looking to seek associated costs and damages".
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