Braod-leaved trees (oak, beech, ash, chestnut, hornbeam, walnut, fruit trees,…) supply a firewood from a better quality,
which emits more heat by burning longer than the coniferous.

The criteria of dampness remains essential because it directly intervenes on the energizing content.
Between a dry wood ready to use (less than 20% damp in the gross weight) and a recently cut wood (45% damp in the gross weight),
the energy is twice less. Using a damp wood leads to an increase in the polluting emissions.

The firewood recently cut, pre-packed in 1 m, has to be stocked at least 2 years to get an optimal combustion.
Cut, split and stored in a dry ventilated place, the wood is able to dry quicker and this only takes 1 year.

Any combustion of dirty wood (which means wood that has been treated or varnished), rubble wood or old furnitures damage the
longevity of your fireplace and generate polluting and toxic emissions for your health.

To sum up, a good firewood is a «clean» and dry wood.

FONTE FLAMME advices the use of firewood certified NF which guarantees you the species, the length, 
the dampness level and the quantity delivered in stere.

You can consult www.nfboisdechauffage.org in order to know everything about the certification and the distributors certified NF.