Characteristics 104: Voids and Distortions

In Characteristics 104 you will be learning about the various kinds of voids and distortions that graders must be able to identify to accurately grade lumber.

Syllabus

104: Compression Wood

Compression wood is abnormal wood that forms on the underside of leaning and crooked coniferous trees.  Compression wood is characterized, aside from its distinguishing color, by being hard and brittle and by its relatively lifeless appearance.  [Standard Grading Rules for Northeastern Lumber para. 706.0]

This image shows one example of compression, commonly called a compression failure.

104: Decay

Decay (or Unsound Wood) is a disintegration of the wood substance due to action of wood-destroying fungi, and is also known as dote or rote.  [Standard Grading Rules for Northeastern Lumber para. 708.0]

104: Decay - Incipient

An early stage of decay in which disintegration of the wood fibers has not proceeded far enough to soften or otherwise change the hardness of the wood perceptibly.  It is usually accompanied by a slight discoloration or bleaching of the wood.

104: Decay - Advanced

The older stage of decay in which destruction is readily recognized by soft, pitted or crumbly areas of wood.

104: Holes

Holes are either extended partially or wholly through the piece.  An alternate designation for holes which extend only partially through the piece is “surface pits.”  [Standard Grading Rules for Northeastern Lumber para. 716.0].   Holes are identified as follows:

Knot Hole – a portion of a branch or limb that has become incorporated in a piece of lumber.

Pin Hole – not over 1/16” in diameter

Medium – is not over 1/4” in diameter

Large – is not over 1” in diameter

Very Large – is over 1” in diameter

104: Holes (Manufactured)

A hole that is not natural to the characteristics of the lumber or tree, typically created during machining and handling of the lumber or logs.

104: Pocket

A Pocket is a well-defined opening between the growth rings.  It usually contains pitch or bark.  Pockets are described as follows with equivalent areas being permissible. [Standard Grading Rules for Northeastern Lumber para. 734.0]:

Very Small – is 1/16” in width and 3” in length, or 1/8” in width and 2” in length

Small – is 1/16” in width and 6” in length or 1/8” in width and 4” in length, or 1/4” in width and 2” in length

Medium – is 1/16” in width and 12” in length, or 1/8” in width and 8” in length, or 3/8” in width and 4” in length

Large – is not over 4 square inches in area

Very Large – is over 4 square inches in area

104: Warp : Bow

A deviation flatwise from a straight line drawn from end to end of a piece.  It is measured at the point of greatest distance from the straight line. [Standard Grading Rules for Northeastern Lumber para. 752.0 (b)].

104: Warp: Crook

A deviation edgewise from a straight line drawn from end to end of a piece.  It is measured at the point of greatest distance from the straight line. [Standard Grading Rules for Northeastern Lumber para. 752.0 (c)].

104: Warp: Cup

A deviation in the face of a piece from a straight line drawn from edge to edge of a piece. [Standard Grading Rules for Northeastern Lumber para. 752.0 (c)].

104: Warp: Twist

A deviation flatwise, or a combination of flat wise and edgewise in the form of a curl or spiral, and the amount is the distance an edge of a piece at one end is raised above a flat surface against which both edges at the opposite end are resting snugly. [Standard Grading Rules for Northeastern Lumber para. 752.0 (d)].

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