The log is undoubtedly the oldest form of wood fuel known to mankind. Even today, logs are the most traditionally used wood heating system for domestic heating.
Logs come from forest harvesting (coppice or branch recovery in commercial logging) and hedgerows. These are woods whose quality and dimensions are not sufficient for so-called noble uses, such as sawing, slicing or peeling.
Hardwood is often preferred to softwood because it is denser and does not contain any resin.
To obtain a good fuel, the wood must be nice and dry. For this reason, loggers usually cut trees when the sap no longer circulates, namely in winter. For the wood to dry properly, it is cut in logs of one meter, which are then split along their length. This allows the wood to dry more quickly (bark is an effective physical barrier against evaporation) and not to be the target of mushroom attacks, but it also eliminates much of the bark, which is not necessarily desirable.
In general, it takes between one and two years of natural drying to ensure that the wood is nice and dry (less than 25% moisture). Some more industrial processes allow the wood to be dried in ovens, therefore reducing the drying time to just a few days!
The logs are then re-cut to the desired size by the users, generally 33 or 50 cm. They will then be used to produce heat.