THE PILOT ALLOWED THE AIRCRAFT TO INADVERTENTLY TOUCH DOWN, HE DELAYED MAKING A GO-AROUND, AND HE DID NOT MAINTAIN SUFFICIENT SPEED TO CONTINUE THE GO-AROUND. CONTRIBUTING FACTORS WERE: THE PILOT'S SELECTION OF UNSUITABLE TERRAIN, HIGH VEGETATION IN THE SELECTED LANDING AREA, A DOWNDRAFT, AND ROUGH TERRAIN IN THE DRY RIVER BED.