3.3 : 木材

Long, rectangular pieces of wood used in construction are called lumber.

Logs harvested from trees are debarked and repeatedly fed through an automated saw.

Each time the log is sliced, the slabs are transported by conveyor belt to smaller saws. Here, the slabs are cut into square-edged lumber of the required widths.

At this stage, the cut pieces have rough surfaces, and their dimensions may slightly differ from one end to the other.

Lumber is obtained either by plainsawing or quartersawing. Plainsawn lumber portrays the growth rings of trees flat on the board's wider face and is typically used as structural lumber.

In quartersawn lumber, the growth rings align at roughly 45 degrees or more in softwoods and at 60 degrees or more in hardwoods to the board's wider face. Quartersawn softwood is used for flooring, trim, and siding.

Riftsawing is also used for hardwoods, with the growth rings in riftsawn hardwood aligning at a 30 to 60-degree angle to the board's wide face and used where appearance and durability are essential.