anyone that grew up on a farm and has "MADE FENCE" KNOWS YOU USE LOCUST FOR THE POSTS, ATLEAST THATS WHAT WE USED. THEY GROW QUICK,STRAIGHT, AND GET HARD AS BONE, THE ROCK BREAKS ON PAPS FARM WHERE ALLOWED TO GROW UP FOR THE PHEASANTS ,QUAIL AND RABBITS, AND THATS WHAT GREW THERE, HONEY LOCUST AND YELLOW LOCUSTS. YOU HAD TO "PLANT" THEM IN THE GROUND WHILE THE WOOD WAS STILL GREEN , JUST TO DRIVE THE STAPLES IN. ONCE THE BARK CAME OFF, THE OUTSIDE WOULD TURN WHITE AND GET SO HARD, DRIVING THE STAPLES WAS OF NO USE, THEY WOULD JUST "MASH UP AND BEND UP". MY GUESS IS LOCUST.