Glossary of wood terms

AD, Air Dried Air dried, typically 12-20% moisture content
BF, Board Foot Board foot. Standard unit of lumber measurement equal to one foot square by one inch thick (144 cubic inches). Calculated by multiplying length by width by thickness in inches and dividing by 144. Example: 2 x 3 x 36"=216 divided by 144=1.5 bf. Usually any thickness under 1" is sold by the square foot.
Bird's-eye Figure Figure on the plain-sawn surface of wood showing many small, rounded, lustrous areas resembling bird's-eyes. Most common in Eastern Hard Maple.
Boxed Heart When the pith falls entirely within the four faces of a board or timber.
Burl An abnormal, warty growth which usually develops at the base of certain trees. A cut through a burl reveals tight bunches of small knots or eyes. Also called burr.
Cant A squared up log or a large slab cut from a log, destined for further processing by other saws.
Chatoyance A changeable color or luster. Wood appears to shimmer when moved.
Curly Figure Wavy grain forming undulations or distortions in the wood fibers. Can be found on both tangential and radial surfaces, although the figure is bolder and brighter on the radial surface (example: fiddleback maple).
EMC, Equilibrium Moisture Content The point at which wood is stable and in equilibrium with the humidity of its surroundings-it is no longer gaining nor losing moisture.
FC, Flitch cut or sawn Boards from logs sawn through and through. Will have waney edges, i.e. with bark and sapwood. Also called log run lumber.
Feather Crotch Figure resembling a cluster of feathers. Found in the segment where a fork in the tree occurs.
Figure The pattern produced on a board surface by prominent rays or deviation from regular grain. Types of figure include: birds-eye, burl, crotch, curly, quilted, and ribbon stripe.
Flat-sawn Lumber sawn so that the annular growth rings are parallel to the face of the board. Also called plain-sawn.
Grain The direction, size, arrangement, appearance, or quality of the fibers in wood.
Green Green or freshly sawn lumber.
H&M Hit and miss.
Hardwoods A botanical group of trees with broad leaves. Does not refer to hardness of the wood.
Heartwood The dead inner core of a tree. In most species darker and denser than the sapwood.
Interlocked Grain Grain in which the direction of the longitudinal fibers alternates to the right and left at intervals, resulting in a ribbon-stripe figure on the quartersawn surface.
KD Kiln dried. Typically 6-12% moisture content.
LR Log run. The full yield of a log.
LTL Less than truckload.
MBF Thousand board feet.
PAD Partially air dried. 20-25% moisture content. Needs further drying before use.
Quarter Measure A reference to the thickness of lumber using a one-quarter inch scale. Thus, 4/4 is a nominal 1 inch, 5/4 is 1 1/4 inches, 6/4 is 1 1/2 inches, etc.
Quilted Figure Blister-like figure most commonly found in Oregon Big-leaf Maple.
RGH Rough. Lumber not yet planed or surfaced.
RWL Random widths and lengths.
S2S Lumber surfaced on two faces.
S4S Lumber surfaced on four sides.
Sapwood The outer, younger portion of the tree, usually distinguishable from the heartwood by its lighter color.
Shorts This depends on the species, usually 4" and wider by 36" and longer, but sometimes 2" and wider by 12" and longer. Also called a billet.
Slab Boards The outer portion of a log removed by the saw, having one flat and one curved surface.
Softwoods A botanical group of trees that in most cases have needlelike leaves. Does not refer to the hardness of the wood.
Thickness As lumber, expressed in quarters of an inch. 4/4=1", 5/4=1 1/4", 8/4=2", etc. When surfaced two sides 4/4 must yield at least 13/16", 5/4 yield is 1 1/16", 8/4 yield is 1 3/4", etc.
VG or Qrtd Vertical grained or quarter-sawn, i.e. the annular or growth rings are close to perpendicular to the board face. Also called edge-grained.