It depends on what kind of smoker you're using. If you are using the cardboard box smoker method, use wood chunks, they burn longer and slower. If you are using an electric smoker, chances are it does not have a large basin, so you’ll want to use wood chips. If you're using a pellet smoker, you'll need wood pellets. As always, look at the instruction manual of your smoker to determine the right type of wood you'll need.