A family whose members sustained injuries when a massive tree branch at the San Antonio Zoo fell on them in March is suing for more than $1 million in damages. The law offices of Thomas J. Henry filed the suit Tuesday in Bexar County District Court on behalf of Librado and Crystal Rodriguez and the latter’s two minor children. The petition alleges the zoo and its tree-care service, Alamo City Arbor Care Inc., acted negligently and knew the limb posed a safety risk to visitors.