Abstract: A bidirectionally locking safety brake apparatus is rotatably connected to a climber's safety harness and slidingly installed approximately centrally on an overlength tree-encircling climbing lanyard line to effectively divide the line into two independently operable tree-encircling climbing line sections extending in opposite directions from the safety brake apparatus in order to permit climbing using one tree-encircling line section until a branch or other obstruction to continued climbing is encountered whereupon the other lanyard line section may be extended around the tree above the obstruction, connected to the safety harness and adjusted for use for continued climbing beyond the obstruction prior to disconnection of the one obstructed lanyard line section, thereby assuring that the climber is continuously and securely tethered to the tree by the tree-encircling climbing lanyard even when passing obstructions.