When growing trees for lumber, it is a good idea to understand the ways that rough lumber is cut. This will help you know the best time to harvest a stand of timber for the saw mill. Definitions of rough-cut lumber involve looking at the way the log is sawn and at the part of the tree from which the board originates. Rough wood can give an enticing look to certain projects or can be planed down for a smoother lumber.
Sapwood is the softer, outer portion of a tree trunk. Sapwood is sometimes, but not always, lighter in color than the center part of the tree, which creates heartwoods. Young trees have more sapwood than heartwood. However, as the tree grows, the percentage of heartwood usually becomes greater. Sapwood tends to have a higher moisture content than heartwood and thus can shrink more. Because of this moisture, it is also more susceptible to problems with fungi.
Heartwood is the harder, drier deadwood portion of a tree trunk. Heartwoods are usually, but not always, darker than the sapwood portion of the tree. Heartwoods often have higher concentrations of chemicals created during the decomposition of the living portion of the tree. These compounds can include turpentines, or other compounds that make the wood more resistant to insects and rot. Heartwoods are usually the part of the tree from which the traditional dark woods of the black walnut come or the red colors of black cherry.
Unselected rough-cut wood is wood that doesn't differentiate between heartwood and sapwood. Boards of this type have both kinds of wood. In many cases, the outer portion of a board is sapwood, while the remainder is heartwood. Some unselected boards still have the bark attached, making them ideal for certain woodworking or craft projects.
Quarter-sawn refers to the way that the rough wood is cut. In quarter-sawn lumber, the grain of the wood is vertical. With this technique, a log is sawn into quarters, with boards cut from each flat surface of the log quarter. Quarter-sawn lumber is often called rift sawn, end grain or vertical-grain lumber. Quarter sawing of prime logs can result in unusual grain patterns such as flame or figured maple.
Plain-sawn lumber is sometimes called flat-sawn or grain-sawn lumber. Flat-sawn lumber has a horizontal grain patter because the lug is cut into boards the width of the log in a series of unidirectional cuts. Although a more simple form of creating rough lumber, selecting the starting point for flat sawing can create grain patterns in boards that are wider than boards that are quarter-sawn.