>>2072632There are several schools of thought. Some people long ago would grind or file the two edges differently, one with a thin bevel for some serious bite when making felling cuts and one a bit thicker, although still sharp for removing the bark which could have stones or earth on it and for limbing the felled tree. Often professional forest workers would have separate axes for these tasks though and having an adition edge meant you you could work for longer without having to stop and file your edge back. Much like now, I would speculate it was personal preference unless there were real constraints on what people could bring with them or afford in the first place.
