That little Maple is about 14" across and I don't know the reason that they don't take all the way down. I've been watching them for several years knawing on it, not much at a time. Last winter (2013/2014) they had an acess hole through the ice next to the tree . The river is right there at the stump, still mostly ice right now. I found a dam that had prolly 5 ac. flooded on me a few years ago. I made a big hole in it and the next day they had it patched up. I now am in full agreement and understand the term "busy as a beaver". The trapper fixed that problemm for me, then the excavator drained the pond.