Every piece of lumber begins as a log. When logs arrive, they are sorted by specie and grade (a measure of the log's quality). Logs are then fed into a sawmill. Depending on the specie of wood and type of sawmill, some logs are debarked before going into the sawmill. The length of the log determines the length of the boards that are cut from it.
Logs go through the main saw. Several boards can be cut from a single log. Some sawmills have computerized systems that allow the sawyer to "see" where the boards are in the log. The cut lumber goes down one conveyor and the waste wood goes down another belt.
The lumber is transported down a conveyor belt and trimmed to specifications. The ends may be edged or trimmed if they are not straight. The finished lumber is given a grade for quality purposes and stacked. The packs of lumber are then entered into inventory and sold to customers.
The pieces of wood that do not qualify as lumber are waste. Most of the waste can be chipped and sold as a byproduct. Sawing lumber also produces sawdust and bark, which can also be sold. These byproducts may be made into press board, used as mulch or burned as fuel.
- Library of Congress, Andrzej Pobiedziński, Lars Sundström, Diego Gagliardi, Ontanu Mihai