THE VEHICLE CAME OUT OF GEAR (PARK), IT PROCEEDED TO ROLL BACKWARDS DOWN THE HILL. THE DRIVERS SIDE DOOR WAS OPEN AND CAUGHT ON A TREE WHICH WAS NEAR THE VEHICLE. IT ALSO KNOCKED DOWN AND INJURED A 4 YEAR OLD AS IT WAS ROLLING DOWN THE HILL. THE VEHICLE WAS SLOWED DOWN BY THE TREE, WHICH BARELY GAVE THE DRIVER ENOUGH TIME TO CLIMB INTO THE VEHICLE AND BRING IT TO A COMPLETE STOP BEFORE IT WENT BACKWARDS INTO A REVINE. IT HAS NOT YET BEEN DETERMINED WHY THIS INCIDENT OCCURRED.