Felled trees are turned into logs at the same location where they are cut down, and then saws are used to cut the logs into usable sections. The process of cutting the felled trees into logs is known as bucking. After bucking is completed, the logs are hauled to a central location called the landing. From there they are transported to a sawmill to turn the logs to lumber. Sometimes when a property owner wants to use his own trees for lumber, he buys or rents a portable sawmill to turn the logs to lumber at the same location where they are felled.
The logs are sorted by species and graded for quality before being cut into lumber. A log scaler identifies the species of tree, measures the logs, and identifies any defects, such as rot, that need to be removed. The purpose of scaling is to determine the type and price of the wood. Scaling may take place on the same premises as the sawmill or at another location before being transported to the sawmill. Logs are usually hauled to the sawmill by rail or truck, or floated there on a waterway.
After the logs are sorted, graded, and priced, the logs are commonly sent through a debarking machine to have the bark removed. The log is turned inside the debarking machinery while saws remove the bark. After debarking, the logs are typically loaded onto a carriage, a platform that moves the logs to the headsaw.
In an industrial sawmill, the headsaw is usually a circular saw, while most portable sawmills use a bandsaw. Each time the carriage moves the logs past the headsaw, the saw slices a section from the log at a predetermined width until the log has been turned into a pile of rough boards. During the next step in turning logs to lumber, the rough boards are sorted. Any defective boards are usually fed into a chipper, while the boards appropriate for lumber are run through an edger.
An edger trims rough edges to create straight sides in each board. After the edging process is complete, the ends of each board are trimmed to the desired length. The finished boards are graded again, and then are ready for the final step in the process of turning logs to lumber: drying. Boards are dried in the open air or in heated rooms. When the moisture level in the boards falls to around 15%, the boards are suitable to be used in different construction projects and can be sold as lumber.
