BERKELEY, Calif. (AP) -The University of California, Berkeley has begun cutting down trees at the center of a dispute over its plans to clear the area to make way for a new sports center.

Protesters sitting in a nearby redwood tree on Friday refused to move.

University spokesman Dan Mogulof says school officials want to make it difficult for the tree protesters to remain, although they do not want anyone to get hurt or to get into a confrontation.

“The last thing we want to do is to get to that forcible extraction,” he said.

The tree felling will continue over the next few days, Mogulof said.

He added that university officials have not decided what they will do if the protesters do not come down peacefully.

Protesters with sticks swatted at the workers in cherry pickers. Officials say a worker was hit on the head by a bottle from the tree-sitters’ perch but was able to keep trimming.

The cutting began after the California Court of Appeal on Thursday denied a request from two citizens groups for an injunction barring construction of the athletic training facility. The groups say they plan to take the case to the state Supreme Court.