Waste wood is disposed of as virgin wood (trunks and branches) and wood from recycling. Waste wood is collected and disposed of for various activities such as the production of biomass for energy recovery. Biomass is the biodegradable portion of products, waste and residues of biological origin from agriculture, forestry and related industries, as well as the biodegradable portion of industrial and municipal waste. Waste wood belongs to this large category. Waste wood is crushed and then shredded. It is 100% recyclable and is a good material for reuse. Non-recycled wood is a pollutant because it is bulky and produces methane: in an anaerobic environment (without oxygen) like a landfill, wood undergoes a process of methanisation. Methane is a greenhouse gas twenty times heavier than carbon dioxide.