These two are abundant in my area and no problem getting lots to cut for firewood. I realize that oak, hickory, beech.........ect is preferred however I have easy access to these right now (for next season) and I have to be patient to get a downed oak. Seems like most people around here are more than glad for you to come and cut river birch and sycamore just to get them out of their way. It is an abundant resource that is hard to pass up. What are your opinions (based on actual burning experience only please) as fuel for the wood stove.