Residues from sawing wood include bark, sawdust and trimmings. For this type of waste, the volume of bark doubles during wet separation from the trunks. Most of the bark is burnt (in particular exotic wood which is often infested with insect eggs and larvae). However, branches and bark can be used to produce energy from biomass. These types of waste can be used as biofuels for district heating. The branches and bark recycling system burns the sawdust and scraps to produce thermal energy, used for dryers, for example.