In woodworking, hewing is the process of converting a log from its rounded natural form into lumber (timber) with more or less flat surfaces using primarily an axe. It is an ancient method, and before the advent of the industrial-era type of sawmills, it was a standard way of squaring up wooden beams for timber framing. Today it is still used occasionally for that purpose by anyone who has logs, needs beams, and cannot or would prefer not to pay for finished lumber. Thus homesteaders on frugal budgets, for example, may hew their own lumber rather than buy it.
Hew is a general term meaning to strike or blow with a tool such as an axe or sword; to chop or gash, and is used in warfare, stone and wood cutting, and coal and salt mining in this sense. Hewing wood is to shape the wood with a sharp instrument such as an axe, specifically flattening one or more sides of a log.
As an ancient method of timber conversion, different methods of each step in hewing have developed in history.
After a tree is selected and felled, hewing can take place where the log landed or be skidded or twitched (skidded with a horse or oxen) out of the woods to a work site. The log is placed across two other smaller logs near the ground or up on trestles about waist height; stabilized either by notching the support logs, or using a 'timber dog' (also called a log dog, a long bar of iron with a tooth on either end that jams into the logs and prevents movement). The hewer measures and locates the timber within the log on both ends and marks lines along the length of a log, usually with a chalk line.
The next step is to chop notches every foot or two, almost as deep as the marked line using a chopping or scoring axe, called scoring. At least three methods are used in scoring. 1) Standing on the log and swinging an axe to chop the score; 2) In Germany a method of two carpenters standing on the ground with the log on trestles and swinging downward to slice the scores. (see video in link below); 3) A chainsaw is used to notch the log, the sections created by the notching are then split off using a felling axe.