There are several good firewood species that are great for smoking bacon with.
But the overall best wood for smoking bacon with is Oak which is what most bacon is smoked with and I find the taste is great when smoking bacon with Oak wood.
Other good wood to smoke bacon with are, Cherry, Alder, Apple, Mesquite, Pecan, Maple and Hickory.
Those are all the best types of wood to smoke bacon with to give the smoked bacon a great flavor.