The bark on walnut is a bit spongy, and can hold water for a long time if you do not cover it. So you want to make sure it is good and dry or you will get a musty smell when you burn it. Like burning wet paper. It is not a particularly good firewood to burn. It burns up fast when dry, no real particular smell as long as it is dry. It is best to take the bark off the logs to dry it properly. Firewood cutters like to cut it for firewood, it is soft to cut so it is easy on their saws, and it is normally very straight grained so it is very easy to split. Unless the price was extra cheap I would not accept it for firewood. Kind of like getting Poplar. It just burns up like paper, with not near the heat(or longevity) of Oak or Locust. Tom.