Wood Quality: Wet wood can cause the fire to smoke as the moisture produces more smoke than the flue can extract. The flue system needs to be hot to extract the smoke correctly.
Softwood (pine, redwood, douglas fir) is suitable for kindling and starting a fire. Once a good bed of coal is established, hardwood (manuka, gum or plantation wood) can be added as this will burn for longer.
Hardwood comes from a deciduous tree that loses its leaves annually, and softwood from conifers, which remain evergreen. Hardwoods tend to be slower growing and are therefore usually denser.
Do not use processed or chemically treated wood. Also, never use driftwood as the salt content is high and can cause corrosion in your woodburner and flue and may also emit toxic gases when burnt and will leave toxic residues in the ash and flue.