According to the U.S. Environmental Protection Agency, wood that contains glue or that has been painted, coated or pressure treated should not be burned because it can release toxic chemicals. Ocean driftwood and molded or rotten wood also should not be used as fuel.
It is far more important to consider dryness over species when choosing firewood. Freshly cut wood may contain up to 45 percent water, while seasoned wood should contain less than 20 percent. Moist wood does not burn efficiently, resulting in smoke and creosote build-up. Creosote built up in a chimney or furnace exhaust can cause dangerous chimney fires.