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 may be
accompanied by a slight discoloration of the wood.
DELAMINATION. The separation of layers in a laminate through failure
within the adhesive or at the bond between the adhesive and the laminae.
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 a specified
DURABILITY. A general term for permanence or resistance to deteriora-
tion. Frequently used to refer to the degree of resistance of a species of wood
to attack by wood-destroying fungi under conditions that favor such attack. In
this connection the term "decay resistance" is more specific.
FUNGUS. A highly specialized group of primitive plants. Some fungi decom-
pose wood (see decay) while others discolor wood without affecting its strength
GRADE. The designation of the quality of a manufactured piece of wood
or of logs.
GRAIN. The direction, size, arrangement. appearance, or quality of the
fibers in wood or lumber. To have a specific meaning the terms must be qualified.
Diagonal-grained wood. Wood in which the annual rings are 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.
Edge-grained lumber. Lumber that has been sawed so that the wide sur-
face extends approximately at right angles to the annual growth rings. Lumber
is considered edge grained when the rings form an angle of 45 degrees to 90
degrees with the wide surface of the piece.
End-grained wood. The grain as seen on a cut made at a right angle to
the direction of the fibers (e.g., on a cross section of a tree).
Flat-grained wood. Lumber that has been sawed parallel to the pith and
approximately tangent to the growth rings. Lumber is considered flat grained
when the annual growth rings make an angle of less than 45 degrees with the
surface of the piece.
Straight-grained wood. Wood in which the fibers run parallel to the axis
of a piece.