Biomass comprises all the renewable fuel from animal or plant origen, including the use of forest residues and agricultural waste. Also considered as biomass are crops whose production is exclusively devoted to the generation of fuel and gases from the decomposition of organic matter.
Firewood has benn used up to day as main biomass source. It comes from the cleanting and coltrolated cut of trees. This wood cannot be used for wood industry.
This wood has received no treatment at all and it is like you find it on the Nature, in difference of pellets. This produces variations in the calorific power of this biomass fuel.