The varieties of wood you can buy or cut in the mid-Atlantic region are mostly oak mixed with maple, hickory, ash, locust and walnut. All make excellent firewood. You do not want tulip poplar, catalpa, willow or box elder. They smolder. I also consider mulberry worthless as firewood. The yellow-green wood is difficult to season and burn, and it's somewhat malodorous when it catches fire. Reputable dealers should not sell these. Conifers or softwoods, such as pines, firs, spruces and hemlocks, can be burned, but they burn fast, pop and throw more sparks than hardwoods.