Types of Wood Grain Patterns

You are probably familiar with the pattern of growth rings on the surface of the sawn wood. Depending on the method of lumbering, this pattern has different appearance and expressions called "flat grain" and "straight grain".

The "flat grain" is a curvy wood grain pattern, whereas "straight grain" is a straight wood grain that is close to straight lines. Why is the pattern so different? The reason is the difference in how the wood is cut.

The straight grain is cut vertically from the core of the log to the edge. It is easier to understand if you imagine the cross section of a baumkuchen cut into several equal parts. On the other hand, the curved grain of flat grain pattern is cut from one end of the log to the other. As a result, the growth rings become curvy patterns. As shown in the figure, while the flat grain pattern can be neatly obtained from one end of the log to the other, the straight grain pattern is cut out centering on the core, leaving parts that can't be utilized for lumber. Consequently, in terms of cost and rarity, it can be said that the straight grain is more valuable than the flat grain.