Red oak, black oak, is the easiest to find around here. Its easy to split and dries fast once split. For that reason, it makes up the bulk of my firewood. I will go out of my way to gather whiteoak, even tho it is stringy and dries slow, even once split. Whiteoak will put out the most heat and burn the longest of any species I have access to. My wood pile right now contains good bit of river birch and red maple, which dries very fast and burns very hot and ashes to dust. I also have a right smart of popular and even some yellow pine, and maybe a little whitepine. All burn hot once dry, but wont last long in a stove. Yellow locust is high on my list of favorites, and there is plenty of it around here, but I seldom get any, most folks that harvest the locust split it into fence rails. I seldom sort my wood by species. It all goes in the stacks as its processed so my stacks always have a mix of woods and go into my stove the same way. What ever I lay my hands on is what I burn. Nothing like a little yellow pine to rekindle a fire early in the morning, or when you want to warm things up fast and then let the fire die down on those warm days. I seldom see any kind of elm unless it comes from a lawn somewhere, and ash, while around, just isnt plentiful.