Bark around which normal wood has grown.

A patch of distorted grain resulting from birds pecking; sometimes containing ingrown bark.

The distortion in a board that deviates from flatness within the length of the board (board shaped like the bow of a bow & arrow).

A lengthwise separation in the wood surface caused by rapid or faulty seasoning.

The flattening of single cells or row of cells in hardwood during the drying or pressure treatment of wood, characterized externally by a caved-in or corrugated appearance. Also, termed Honeycomb.

Separation of the wood cells, often appearing as barely distinct fine irregular lines across the grain.  Such breaks are often due to internal stains resulting form unequal longitudinal shrinkage or to external forces. (Shake).

The distortion in a board that deviates flat-wise from a straight line across the width of the board.

Disintegration of wood substance due to the action of wood-destroying fungi...which affects wood color & fiber structure.

Stains in wood substances, Common veneer stains are sap stains, blue stains, stain produced by chemical action caused by the iron in the cutting knife coming in contact with the tannic acid of the wood, and those resulting from exposure of natural wood extractives to oxygen and light, to chemical action of vat treatments or the adhesive components, and/or to the surface finish.

A form of incipient decay characterized by a dull and lifeless appearance of the wood, accompanied by a loss of strength and softening of the wood substance.

Separation of the wood fibers at the end of a board.

A cellular separation that occurs in the interior of a board, usually along the wood rays. Also termed Collapse

Sound knots 1/4 inch or less in diameter containing dark centers.

A knot which is solid across its face, as hard as the surrounding wood and shows no indication of decay.

Pockets of disintegrated wood caused by localized decay, or wood areas with abrupt color change related to localized injury such as bird peck. Pecky is sometimes considered as a decorative effect, such as bird peck in Pecan and Hickory or Pecky in Cypress.

Defects resulting from resin accumulated between the growth rings in softwoods.

The small soft center core of a tree around which growth takes place. The Pith in hardwoods is usually a cavity (open) while the Pith in softwoods is usually sound.

A lengthwise separation of the wood occurring before the timber is cut into lumber, usually resulting from violent storms or in felling the log.

A distortion of a board in which there is a deviation edge-wise from a straight line placed from end to end of the board. Once referred to as "crooked".

Separations of wood fiber running parallel to the grain.

Discoloration in lumber caused by decay, fungi, etc. Normally avoidable through proper handling in the cutting and drying stages. Certain "white" hardwoods and pine are extremely susceptible to log or sap staining especially in warm weather; Stain is also, a finishing substance for coloring wood.

The separation of the wood fibers, producing small, shallow, length-wise separation of wood along the board's surface..

Spiral warping of a board. The board is no longer flat.

The presence of bark, or the lack of wood in processed lumber

A generic term that includes all variations from a true plane surface, i.e., bow, side bend, cup and twist.

Visible hole or track caused by various beetle larvae while the tree was living. Kiln drying sterilizes the boards from insects, fungi and other living organisms. Worm holes are considered desirable in character grade plank flooring and a defect in select or clear grade products.

Marks caused by various types of wood attacking larvae. Often appear as sound discolorations running with or across the grain in straight to wavy streaks. Sometimes referred to as "pith flecks" in certain species of maple, birch and other hardwoods because of a resemblance to the color of pith.