BERKELEY – A planned sports center at the University of California at Berkeley that ignited a tree-sitting protest moved a step closer to reality when a judge gave campus officials the go-ahead to build.

Ruling late Tuesday, Alameda County Superior Court Judge Barbara Miller said her previous injunction blocking construction will dissolve in seven days. However, Miller is giving opponents time to appeal her ruling, something they promised will happen.

The proposed sports center has spurred an 18-month-long tree-sitting protest in an oak grove that would make way for the new building.

Campus spokesman Dan Mogulof said officials are “very pleased” with the decision. But Doug Buckwald, spokesman for a group called Save the Oaks, said opponents hope to stop the project by going to the Court of Appeals.

“It would be a real tragedy to lose the beloved oak grove now, and then win in court later when it would be too late to save the trees,” he said in a statement. “You can't put stumps and sawdust back in the ground and make things all better again.”

Neighbors, city officials and the California Oak Foundation filed suit challenging the project on environmental and seismic safety grounds. The center is next to Cal's Memorial Stadium, which sits on top of the Hayward fault.

Miller blocked construction in January 2007, issuing an injunction. Following a trial, she issued a ruling that favored the university on most points but said she had remaining questions about a few aspects of the project.

Campus lawyers responded by eliminating the items Miller questioned and argued there was no longer a reason not to lift the injunction.

University officials have stepped up eviction tactics against the tree-sitters in recent weeks. As of Tuesday, three people remained in the trees.