Been burning on my maple stump for 6 years. It was 3 maple trees grown together and stump is around 8ft x 10ft and has huge runners going from it. Took a mini excavator and dug around it and it didn't like it at all. Figured after 6 years it would be rotten but it wasn't. Big roots 18 inches and bigger was going away from it. I have several different styles of drill bits stuck in the stump that I can't get out. Tore up my brushless battery Dewalt drill and my corded Milwaukee drill trying to drill a hole in it. Now I've resorted to piling dirt on top and keep it wet in hoping it will rot away eventually.