THE WOOD GLOSSARY




Wood terms beginning with:

A B C D E F G H IJK L M N O PQ R S T UV W XYZ


Dark grain - Grain which is darker than the rest and should not be confused with pitch streaks.

DBH (Diameter Breast Height) - The diameter of a tree at breast height (4.5 feet above ground), together with the estimated height of the usable logs in a tree is used to determine the volume of lumber likely to be yielded in a log depending on the log scale used

Decay - Decay is disintegration of wood due to the action of wood-destroying fungi: the words "dote" and "rot" mean the same as decay.

Advanced decay - The older stage of decay in which the destruction is readily recognized because the wood has become punky, soft, and spongy, stringy, ringshaked, pitted, or crumbly. Decided discoloration or bleaching of the rotted wood is often apparent.

Incipient decay - The early stage of decay that has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood. It is usually accompanied by a slight discoloration or bleaching of the wood (see Spalting).

Decayed knot - A knot which, due to advanced decay, is not so hard as the surrounding wood.

Deciduous - Generally trees that have broad leaves that are shed in the fall. Usually it is a hard wood.

Defect - An irregularity found in a board that lowers its strength and value. Common defects are knots, staining, checks, etc.

Density - As usually applied to wood of normal cellular form, density is the mass of wood substance enclosed within the boundary surfaces of a wood-plus-voids complex having unit volume. It is variously expressed as pounds per cubic foot, kilograms per cubic meter, or grams per cubic centimeter at specified moisture content.

Diagonal grain - Annual rings at an angle with the axis of a piece as a result of sawing at an angle with the bark of the tree or log. A form of cross-grain.

Diffuse-porous wood - Certain hardwoods in which the pores tend to be uniform in size and distribution throughout each annual ring or to decrease in size slightly and gradually toward the outer border of the ring.

Dimension - Hardwood or softwood lumber, a term generally applied to lumber when the nominal size is 2 inches thick and 2 or more inches wide. The National Grading Rule for Softwood Dimension Lumber defines "dimension" as lumber from 2 through 4 inches thick and 2 inches and wider.

Dimension parts - A term largely superseded by the term "hardwood dimension lumber." It is hardwood stock processed to a point where the maximum waste is left at the mill, and the maximum utility is delivered to the user. It is stock of specified thickness, width, and length or multiples thereof. According to specification it may be solid or glued up, rough or surfaced, semi-fabricated or completely fabricated.

Dimensional Stability - a measure of movement in service when the wood is subjected to moderate changes in humidity. Descriptions include:
Very Unstable - Can be a large change.
Unstable - Fairly large change.
Stable - Small change.
Very Stable - Very little change.

Discoloration - Changes in the color of wood which affect only its appearance.

Domestic - Lumber that grows in the United States.

Dog - 1) A device used to hold a log in place on the sawmill while it is being sawn. 2) that critter that gets underfoot when you are trying to work in your shop!

Dote - "Dote," "doze," and "rot" are synonymous with "decay" and are any form of decay which may be evident as either a discoloration or a softening of the wood.

Double end trimmed - Both ends cut reasonably square by a saw.

Dressed - Surfaced with a planer.

Dressed and matched - Lumber that has been worked with a tongue off center on one edge of each piece and a groove on the opposite edge to provide a close joint by fitting two pieces together.

Dressed size - The dimensions of lumber after being surfaced with a planing machine. The dressed size is usually 1/2 to 3/4 inch less than the nominal or rough size. A 2x4-inch stud, for example, actually measures about 1 1/2 by 3 1/2 inches.

Dry - Seasoned, usually to a moisture content of less than 19%.

Dry kiln - An enclosed chamber in which temperature and humidity conditions are subject to control for the purpose of drying lumber.

Dry rot - A term loosely applied to many types of decay but especially to that which, when in an advanced stage, permits the wood to be easily crushed to a dry powder. The term is actually a misnomer for decay, since all fungi require considerable moisture for growth.

Durability - A general term for permanence or lastingness: frequently used to refer to the degree of resistance of a species or of an individual piece of wood to attack by wood-destroying fungi under conditions that favor such attack: in this connection the term "resistance to decay" is more specific.



The Wood Glossary






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