bucking

Bucking is the operation of cutting a felled and delimbed tree trunk into sections called logs, which can then be transported, stored, and milled. The cuts are made perpendicular to the grain, and the resulting pieces must meet length and diameter specifications for their intended market or mill. A bucking saw, typically a chainsaw in modern forestry, makes crosswise cuts at predetermined intervals along the length of the trunk.

Log length varies by end use and geography. Sawmill logs for dimensional lumber typically run 8, 10, 12, or 16 feet; pulpwood logs are often shorter, around 4 to 5 feet. Hardwood logs for veneer or specialty products may be bucked to 8 or 10 foot lengths to maximize recovery of clear wood. Bucking operators must account for defects, splits, and sweep (curvature) in the trunk when deciding where to cut, aiming to isolate damage and maximize the volume of usable sections.

Each cut wastes material as kerf, the thickness of sawdust removed by the blade; a chainsaw kerf is typically 0.25 to 0.375 inches. Over a long log, multiple cuts compound this loss. Bucking also exposes end grain, which dries faster than the rest of the log, leading to checking (radial splitting) if logs are not sealed or moved promptly. This is why freshly bucked logs are either processed quickly or stored in cool, shaded conditions.

The name reflects the motion: to buck originally meant to resist or push back, and bucking a log means cutting across it against the growth direction. It contrasts with ripping, which cuts parallel to grain. In modern timber operations, bucking is usually the first step after delimbing and must be coordinated with log grading, skidding, and transport logistics to avoid bottlenecks.