Grain refers to the unique lines that permeate all natural woods. These lines are a result of the growth rings of the tree. The rings are formed annually as trees grow. Since environmental conditions can never be the same, these growth rings are formed at random intervals and represents the varying degree of thickness which is accumulated during each growing season. The way a tree was cut at the sawmill is the chief determining factor of the wood grain orientation.

 

A popular technique of sawing wood logs is by quarter-sawing which uniformly cuts the timber into parallel plains. Another method which isn't as common is rift sawing whereby a halved after which boards are then cut at radial angles. This method wastes wood hence it is rarely used, mainly used when a desired grain style is to be achieved. Though it is more wasteful than alternative methods, this method of sawing gives the most wood pieces with very straight grain lines as the wood is cut perpendicular to the growth ring of the tree. Flat sawing is a very efficient and commonly used method of cutting boards as it yields minimal waste, but the pattern of the grain is considered unappealing for construction projects.