Glossary
ACRE2:
A unit of land comprising 43,560 square feet.
A-GRADE:
Plywood face grade with excellent appearance.
ADHESIVE:
A substance that bonds two other materials together. Commonly referred to as glue.
AGE, ROTATION2:
Age at which a stand is considered to be ready for harvesting under the plan of management.
AIR-DRIED LUMBER3:
Boards that have dried naturally by stacking them in the open air, as shown above and right. Air flows between the boards, allowing the moisture in the wood to evaporate. Air drying can take as long as one year per inch of board thickness. In all but the driest regions, moisture content rarely falls below 12 to 20 percent without additional drying indoors.
ANNUAL RING2:
A tree's layer of wood growth for one year. Annual rings can be seen on the cross sections of tree stems or branches.
ARCHITECTURAL GRADE VENEER:
Top-quality wood veneer made from select logs, usually in lengths greater than 8-1/2 feet.
B.F. 2:
This is an abbreviation for "board feet."
B.M. 2:
This is an abbreviation for "board measure," which usually refers to the board feet of lumber.
BACKS:
The reverse side to the face of a plywood panel. Typically backs are of a lower grade of veneer than the face on plywood panels that call for a face and a back.
BARK:
The outer protective layer of a tree. Severely damaged bark is a defect that can lower the value of a log. At the sawmill, a log is first debarked, then slabs are cut off, leaving a square cant to be cut into lumber.
BARK POCKET:
A small area of bark surrounded by a newer growth of normal wood.
BARBER POLE:
This effect may occur when book matching veneers. Alternating tight and loose sides of the veneer causes contrasting light reflections on the finished surface.
BIRD’S EYE:
A figure found almost exclusively in hard maple, characterized by variously scattered pin knots having an appearance similar to a bird’s eye.
BLOW DOWN:
A tree or trees felled by wind. Also known as wind fall.
BOARD FOOT2:
A unit of measurement represented by a board, which is typically unfinished and unsurfaced, 1 foot long, 1 foot wide and 1 inch thick. In practice, the working unit is 1,000 board feet, which normally is abbreviated MBF.
BOARD FOOT, LOG SCALE2:
A unit of measure of the content of a log determined using a log rule; also the common unit of measure of timber volume.
BOARD FOOT, GREEN CHAIN TALLY2:
A unit of measurement represented by unfinished lumber as it comes from the saw.
BOLE2:
The trunk of a tree; typically where the usable wood is located.
BOLTS2:
Short logs or sections of a large log, usually less than 8 feet long.
BOOK MATCHED:
The pattern created when sequentially sawn lumber from the same log can be opened like a book, resulting in grain that is mirror-imaged.
BOULE:
A log live-sawn and kept together in the order in which it was sawn.
BOXED HEART:
The term used when the pith falls entirely within the four faces of a piece of wood anywhere in its length.
BUCK2:
To saw felled trees into smaller units, such as logs or bolts.
BURL:
A swirl or twist in the grain of wood. It usually occurs near a knot, but does not contain the knot itself.
BUTT2:
The base of a tree; the large end of a log.
BUTT-MATCHED:
The pattern created when two re-sawn pieces of wood are arranged end to end, resulting in grain that is mirror-imaged along the shorter dimension
BUTTRESS:
The ridge of wood that develops n an angle between a lateral root and the butt of a tree, which may extend up the stem to a considerable height.
C.F.I. 2:
An abbreviation for Continuous Forest Inventory, a system of periodically monitoring the forest for growth, volume, composition, and mortality of the forest stands.
CAMBRIUM:
A thin layer of tissue between the bark and wood, which repeatedly sub-divides to form new wood and bark cells.
CANT:
A log that has been debarked and sawn square.
CARRIAGE2:
The frame for holding a log while it is being sawed. The carriage also advances logs toward the saw line after a cut has been made. It travels on tracks.
CASE HARDENING:
A drying defect where the surface of the wood dries faster than the core, causing permanent stresses that release when the board is cut.
CATHEDRAL:
A grain appearance characterized by a series of stacked and inverted “V” or cathedral-type of pattern common in flat cut or plain sliced lumber.
CENTER:
Another term for a core.
Checks1:
Longitudinal separation of the fibers in wood that do not go through the whole cross section. Checks result from tension stresses during the drying process.
CHERRY PICKER2:
A piece of machinery, generally attached to a truck, loading dock, etc., which is used to load and unload logs.
CLEARCUTTING2:
A process of removing all merchantable trees from an area in a logging operation.
COMB:
Rift-cut veneer with exceptionally straight grain, with growth increments closely spaced.
COMMON:
An NHLA grade of lumber that has too many defects to be graded either FAS or Select.
Compressive Strength Parallel to Grain1:
Maximum stress sustained by a compression parallel-to-grain specimen having a ratio of length to least dimension of less than 11.
Compressive Stress Perpendicular to Grain1:
Reported as stress at proportional limit. There is no clearly defined ultimate stress for this property.
CONIFER2:
Usually an evergreen tree that bears cones and needle-shaped leaves. Coniferous trees are known as softwood trees, and softwood lumber is produced from them.
CONVERSION COSTS2:
Costs of converting standing timber to a saleable product. Conversion costs include: costs of felling trees, removing limbs, bucking, skidding, loading logs, and transporting logs.
CORD2:
A unit of measurement of stacked wood (typically pulpwood). The standard cord consists of a pile of wood whose pieces are 4 feet long stacked 4 feet high by 8 feet long, containing 128 cubic feet of space. A long cord is a cord containing wood pieces longer than 4 feet; pieces 5 feet long result in 160 cubic feet of space. A common unit of measure of timber.
CORE2:
1. The inner layer(s) of plywood; it is commonly of low quality material. 2. That portion of a veneer bolt remaining in the lathe after rotary cutting in veneer production.
CROOK:
A defect which is an end-to-end curve (warp) along the edge line of the board.
CROSSBANDING:
An inner ply of veneer placed at right angles to the core, face, and back of a plywood panel.
CROSSBAR:
An imperfection or irregularity in the grain of wood that rums at right angles to the lengthwise grain.
CROSS CUT:
Wood cut against the grain, perpendicular to its length.
CROTCH LUMBER (CROTCHWOOD):
Wood obtained from the intersection of two major limbs of a tree, often yielding a desirable grain pattern. The wood grain swirls dramatically where the wood fibers have crowded and twisted together.
CROWN2:
The upper part of a tree, including branches, foliage, etc.
CRUISE2:
To survey forest lands for the purpose of locating and estimating volumes and grades of standing timber.
CUP:
A defect which is an edge-to-edge curve (warp) along the face of the board.
CURLY:
A desirable rippled grain pattern in certain woods; often referred to as tiger, and sometimes called fiddleback.
CYCLE, CUTTING2:
The planned intermission between harvesting operations within the same stand.
D.B.H. 2:
This is an abbreviation for Diameter (of a tree) at Breast Height; diameter of a tree at 4 1/2 feet above the ground.
DECAY:
The decomposition of wood substance by fungi (other terms: rot, dote)
DECIDUOUS2:
A deciduous tree is one that loses its leaves in the fall.
DECK, LOG2:
Area or platform on which logs are placed. 2. A pile of logs. 3. Portion of a sawmill on which logs are held before they are sawed.
DEFECTS:
Loose knots, splits, voids, wormholes, bark pockets, and other flaws that interrupt the smooth flow of a wood surface.
DELAMINATION:
The separation of the inner plys of a panel. This is typically caused by the failure of the adhesive bond.
Density1:
Weight per unit volume. Density of wood is influenced by rate of growth, percentage of late wood and in individual pieces, the proportion of the heartwood.
DIAMOND MATCH:
Usually done with straight grain figured veneers. Triangular cut pieces of veneer are joined with the figure running at a right angle to the adjacent piece, to make rectangular faces with a diamond pattern.
DIMENSIONAL LUMBER:
Lumber cut to any pre-determined size.
Dimensional Stability1:
A term that describes whether a section of wood will resist changes in volume with variation in moisture content (other term: movement in performance).
DRY WEIGHT:
The oven-dry weight, or simply dry weight, is the weight of the wood after drying at a temperature slightly above the boiling point of water (215-220 degrees Farenheit).
DURABILITY:
The resistance of wood to attack by decay fungi, insects and marine bores.
EDGE GRAIN3:
Wood characterized by the growth rings being 45 or more degrees, preferably perpendicular, to the surface of a board.
EDGED:
Processed lumber with no remaining bark or wane.
END CHECKING:
A defect resulting when the edges of a board dry faster than the remainder of the wood. This is typically caused by unrestrained evaporation from the ends of the board, and can usually be prevented by end coating.
END COATING:
A process of sealing the ends of a board to prevent end checking.
FACE:
The best side of a plywood panel on which the outer veneers are of different grades.
FACE GRAIN3:
The pattern made by growth rings in wood on the greatest surface of the board.
FELLED TIMBER2:
Timber which has been cut.
FAS3:
An abbreviation used in hardwood-lumber grading for Firsts-and-Seconds: the best boards cut from a log. An FAS board measures at least 6" wide by 8' long, and yields a minimum of 83 percent clear cuttings (areas free of knots and defects).
FIDDLEBACK:
A desirable rippled grain pattern in certain woods; often referred to as tiger, and sometimes called curly.
Figure1:
The pattern produced in a wood surface by annual growth rings, rays, knots, deviations from regular grain, such as interlocked and wavy, and irregular coloration.
FLAT CUT:
Wood and veneer that has been cut or sliced parallel to the pith of the log. Characterized by cathedrals in the figure. May also be called plain sliced when referring to veneer figure.
FLITCH:
A log or part of a log, trimmed and prepared for conversion into veneers, or part of a log suitable for further conversion.
FLITCH MATCHED
Sequentially sawn boards, cut from the same log.
GIRDLE2:
To encircle the stem of a living tree with cuts with the intention of killing the tree. The cuts are made to sever the bark and cambium. The tree dies by preventing the passage of nutrients. Toxic materials may be injected into the tree through the cut also.
GRADE:
The quality ranking of a log or sawn lumber. Grades are assigned according to strict NHLA rule
GRAIN:
The direction, size, arrangement, appearance, or quality of the fibers in sawn wood. Straight grain is used to describe lumber where the fibers and other longitudinal elements run parallel to the axis of the piece.
Specific types of grain:
- Coarse grained: Wide, conspicuous annual rings in which there is considerable difference between earlywood and latewood.
- Fine grained: Narrow, inconspicuous annual rings.
- Cross grained: Having fibers that deviate from a line parallel to the sides of the piece.
- Curly grained: Having fibers that are distorted so that they have a curled appearance, as in fiddleback wood. The areas displaying the curly grain may be several inches in diameter.
- End grained: The grain is seen on a cut made at a right angle to the direction of the fibers.
- Fiddleback grained: Having a figure that is produced by a fine, wavy grain – often in species of maple. This style got its name from the common practice of using this figured wood for the backs of violins.
- Flat grained: Lumber sawn parallel to the pith and approximately tangent to the growth rings, or set at an angle below 45 degrees with the surface of the board.
- Interlocked grain: Wood having grain in which the fibers put on for several years may slope in a right-handed direction, and then for a number of years slope reverses to a left-handed direction, then back to right-handed, etc. This type of wood is extremely difficult to split radially.
- Open grained: The common classification for woods such as oak, chestnut, ash, and walnut that have a distinctive difference in pore sizes between earlywood and latewood.
- Spiral grained: Fibers that take a spiral course about the trunk of a tree, instead of the normal vertical course. This is a form of cross grained.
- Straight grained: Wood in which the fibers collectively take the form of waves or undulations.
GREEN TALLY:
The actual board feet before kiln drying.
GREEN WOOD3:
Stock, usually in rough-cut lumber or log form, that has been cut but not dried, and retains a high moisture content. Woodturners often use green stock because of its workability.
GROWTH RING:
A pattern of alternating light and dark wood created by seasonal changes during a single year of a tree's life cycle.
Gum Pocket1:
An excessive local accumulation of resin or gum in the wood. Also called “Gum Spots”.
HALF-ROUND SLICING:
Off center slicing cut slightly across the annular growth rings. This creates half-round, plain-sliced, or rotary characteristics.
Hardness1:
Generally defined as resistance to indentation using a modified Janka hardness test, measured by the load required to embed a 11.28 mm (0.444 in.) ball to one-half its diameter. Values presented are the average of radial and tangential penetrations.
Hardwood1:
Hardwoods are deciduous trees that have broad leaves (Angiosperms), produce a fruit or nut and generally go dormant in the winter. North America’s forests grow hundreds of varieties that thrive in temperate climates, including oak, ash, cherry, maple and poplar species. Each species can be crafted into durable, long-lasting furniture, cabinetry, flooring and millwork, and each offers unique markings with variation in grain pattern, texture and color. The term has no reference to the actual hardness of the wood.
HEAD SAW2:
The main log cutting saw in a sawmill.
Heartwood1:
The inner layers of wood in growing trees that have ceased to contain living cells. Heartwood is generally darker than sapwood, but the two are not always clearly differentiated.
HERRINGBONE:
This visual effect is achieved by bookmatching veneer at opposing angles.
HONEYCOMB:
A drying defect resulting in deep, internal checks. Honeycombing is typically caused when the lumber undergoes extreme case-hardening (where the surface of the wood dries faster than the inner core) during the early stages of drying.
Impact Bending1:
In the impact bending test, a hammer of given weight is dropped upon a beam from successively increased heights until rupture occurs or the beam deflects 152 mm (6 in.) or more. The height of the maximum drop, or the drop that causes failure, is a comparative value that represents the ability of wood to absorb shocks that cause stress beyond the proportional limit.
INCREMENT BORER2:
An instrument with a hollow bit, similar to an auger. It is used to extract cores from trees to determine growth, age, etc.
Janka Rating System (Janka Scale) 1:
When in doubt about the type of wood to select for your cabinetry, flooring, furniture or millwork project, refer to the Janka Rating System, which measures the relative hardness of woods. The hardest commercially available hardwood is hickory, and it is five times harder than aspen, one of the “soft” hardwoods. And while this example lists just some of the most popular hardwood species, there are hundreds of varieties, representing the North American hardwood population. Because hardness is an important factor, and hardness varies for each species, the Janka Scale of Hardness is an excellent tool to help identify appropriate choices.
| Species Pressure To Mar | (Kiln-dried) (in pounds) |
|---|---|
| Hickory, Pecan | 1,820 |
| Hard Maple | 1,450 |
| White Oak | 1,360 |
| Beech | 1,300 |
| Red Oak | 1,290 |
| Yellow Birch | 1,260 |
| Green Ash | 1,200 |
| Black Walnut | 1,010 |
| Soft Maple | 950 |
| Cherry | 950 |
| Hackberry | 880 |
| Gum | 850 |
| Elm | 830 |
| Sycamore | 770 |
| Alder | 590 |
| Yellow Poplar | 540 |
| Cottonwood | 430 |
| Basswood | 410 |
| Aspen | 350 |
JUVENILE WOOD:
The wood formed during the first 10 years of a tree’s life. This wood is typically undesirable due to low strength and high shrinkage along the grain of the wood.
KILN:
A chamber having controlled air flow, temperature, and relative humidity for drying lumber. The temperature is increased as drying progresses, and the relative humidity is decreased. Freshly cut green lumber ay be sold green, or first dried in a kiln to accelerate removal of the moisture in the wood. Drying wood in a kiln is an art to ensure that the wood is dried evenly to retain it aesthetic properties. Different species dry at different rates.
KILN-DRIED LUMBER3:
Stickered boards dried at an accelerated rate by exposure to warm, dry air inside a chamber called a kiln. By controlling airflow, humidity, and temperature, this process reduces moisture content in just days or weeks to desired levels--6 to 10 percent for hardwoods and high-grade softwoods, 12 to 20 percent for construction lumber.
KNOT:
The circular portion of a board or veneer that was once the base of a branch or twig growing from the trunk of the tree.
KNOT (OPEN):
Opening produced when a portion of a knot has dropped out or separated during the seasoning process.
KNOT (SOUND):
Knots that are solidly fixed by growth and retain their place in lumber or veneer.
KNOTHOLE:
Opening produced when knots drop from the wood in which they were once embedded.
LOG RULE2:
A table which shows the estimated amount of lumber which can be sawed from logs. One must know the log’s length and diameter to use a log rule. The tables are divided into four groups as follows:
- Diagram rules
- Formula rules
- Actual Output rules
- Hybrid rules
LUMBER:
A term for converted wood or sawn timber. Lumber mills and sawmills are terms used to describe the processing units that carry out this conversion.
MBF
Thousand board feet.
MARKING2:
The process of identifying trees which are to be cut and sold.
MEDIUM DENSITY FIBERBOARD (MDF):
A panel or core material manufactured using pressure-cooked wood fiber, resin, and wax.
MINERAL STREAK:
A discoloration of hardwood and hardwood veneer.
Modulus of Elasticity1:
An imaginary stress necessary to stretch a piece of material to twice its length or compress it to half its length. Values for the individual species are given in megapascals (MPa - equivalent to N/m2), and are based on testing small clear pieces of dry wood.
Modulus of Rupture1:
Reflects the maximum load-carrying capacity of a member in bending, and is proportional to maximum moment borne by the specimen. Modulus of rupture is an accepted criterion of strength, although it is not a true stress because the formula by which it is computed is valid only to the elastic limit.
Moisture Content (M.C. ) 1:
The weight of water contained in wood expressed as a percentage of the weight of the oven dry wood.
MOTTLE:
Wood figure characterized by irregular, wavy fibers extending short distances across the exposed face.
NATURAL EDGE:
The practice of leaving bark or wane along the edge of finished boards or slabs. This is often a popular or sought-after design style.
NET TALLY:
The actual board feet after kiln drying.
NHLA:
The National Hardwood Lumber Association. This is the governing body that regulates the grading of hardwood lumber.
NOMINAL DIMENSIONS:
The dimensions of a board based upon the rough-sawn dimensions of the wood, prior to planning. Example: A 2x4 is (nominally) 2”x4”. After planning, the finished board is actually 1-1/2” x 3-1/2”.
OLD GROWTH2:
Also known as first growth timber or virgin timber. It refers to a forest in which little, if any, cutting has been done.
OVERCUT2:
The excess of the quantity of timber cut from a tract over the estimated quantity on the tract.
OVERRUN2:
The excess of the lumber sawn from logs over the quantity estimated that could be sawn.
OVERSTORY2:
Refers to trees in a stand forming the upper crown cover.
PAR:
Planed (surfaced) All Round (same as S4S)
PARTICLEBOARD:
A panel or core material manufactured from pressed sawmill shavings, resin, and wax.
PATCHES
Filler material inserted into defects of veneers or panels, then sanded during repair process.
PEELER2:
The log used in the manufacture of rotary-cut veneer.
PITCH:
Thick sap or resin deposits in wood.
PITH:
The small, soft core occurring at the center of the tree trunk and branches.
Pith Flecks1:
Pith-like irregular discolored streaks of tissue in wood, due to insect attack on the growing tree.
Plain-Sawn1:
Plain-sawn hardwood boards are produced by cutting tangentially to a tree's growth rings, creating the familiar "flame-shaped" or "cathedral" pattern. This method also produces the most lumber from each log, making plain-sawn lumber a cost effective design choice.
Plain-sawn lumber will expand and contract more than boards sawn by other methods. However, it performs just as well when properly kiln-dried, when the job site is properly prepared and when the hardwood products are acclimated to the home before installation.
PLAIN SLICED:
Veneer sliced tangential to the tree’s annual rings.
PLANED:
Surfaced to create a smooth and level face without defects.
PLY:
A single sheet of veneer that forms one layer of a multi-layered piece of plywood.
PLYWOOD (HARDWOOD)
A panel composed of layers of inner plys, or other core material joined with an adhesive to a face veneer of hardwood and a back veneer, usually also composed of hardwood.
POMMELE:
The intermingling of broken cross markings with ribbon stripe figure, such as sapele.
PULPWOOD2:
Wood that is cut primarily to make wood pulp, which may be manufactured into the following: paper, fiber, paperboard, etc.
Quarter-sawn1:
Quarter-sawing means cutting a log radially (90-degree angle) to the growth rings to produce a "vertical" and uniform pattern grain. This method yields fewer and narrower boards per log than plain sawing, boosting their cost significantly. Quarter-sawn boards are popular for decorative applications such as cabinet faces or wainscoting. They will expand and contract less than boards sawn by other methods.
QUILTED:
This figure is found in veneers that have been sliced using the rotary or half-round methods. It is produced from logs with irregular, bumpy growth characteristics.
RWL:
Random widths and lengths.
RANDOM MATCHING:
Veneer leaves are placed next to each other in random order and orientation. This is often used to simulate a board to board appearance.
RAY:
A ribbon-shaped string of wood cells, extending from the inner bark to the pith, perpendicular to the pith axis of the log. This typically displays as flecks in finished quarter-sawn sawn boards.
REFORESTATION2:
The replenishing of an area with forest trees. It can be a natural or artificial process.
RELEASE CUTTING2:
The process of cutting large trees which over-shadow smaller, usually younger trees, thus allowing the younger trees to grow better.
REPRODUCTION2:
The process of renewing a forest. It can be artificial, renewed by direct seeding or planting by man, or it can be natural, renewed by self-sown seeds, sprouts, etc.
Rift-sawn1:
Rift-sawing at a 30-degree or greater angle to the growth rings produces narrow boards with accentuated vertical or "straight" grain patterns. Rift-sawn boards are often favored for fine furniture and other applications where matching grain is important. This type of lumber is available in limited quantities and species.
RIPPING:
Cutting wood parallel to (with) the grain.
ROT, HEART2:
Decay found in the heartwood of trees.
ROTARY CUT:
This cutting method slices a continuous sheet of veneer off a log rotating on the pith axis such as paper being pulled off a roll. Most often used in the production of plywood.
ROUGH SAWN3:
Hardwood boards cut to thickness, and sometimes width, during the initial milling process. This leaves telltale rough, splintery surfaces on all sides. Does not include planning or reripping.
RUNNING MATCH:
Veneer faces made from consecutive leaves. Any portion of a component left over from the preceding face is used as the first piece in the next face or panel.
S2S3:
A lumber-industry abbreviation for "surfaced on two sides". These boards are planed on both faces to final thickness after milling and drying.
Typical S2S Thicknesses (hardwoods):
Nominal -- Actual
4/4 (1") -- 13/16"
5/4 (1-1/4") -- 1-1/16
6/4 (1-1/2") -- 1-5/16"
8/4 (2") -- 1-3/4"
S3S3:
An abbreviation for "surfaced on three sides". Here, boards get planed on both faces, and then straight-line ripped on one edge, shown right. Most hardwood sells as S3S or S2S.
S4S3:
An abbreviation for "surfaced on four sides". These boards get planed on both faces, and then ripped on both edges to make them parallel. Most often, this process produces "dimensional" lumber in standard sizes, such as 1x6, 2x4, and so forth. You'll find softwood construction lumber sold this way, as well as hardwoods in home centers.
SAPLING2:
A young tree 2 to 4 inches D.B.H.
SAPWOOD2:
The light-colored outer ring of wood in a tree. It consists of living cells, and it is necessary to conduct water and minerals to the tree crown.
SAWTIMBER2:
Trees from which sawlogs may be cut. Sawtimber stands generally are stands where sawtimber-sized trees are the most important component.
SAWYER2:
The person who controls the sawing of sawlogs into lumber.
SCALER2:
The person who determines the volume of logs.
SCALING2:
The process of determining the volume of logs. Measuring the dimensions of the logs is part of the process.
SECOND-GROWTH2:
The new timber which develops after removing old-growth. Old-growth may be removed by cutting, fire, or other cause.
SECTION2:
A unit Of land measurement generally equaling one mile square or 640 acres.
SEEDLING2:
A young tree grown from seed that is smaller than a sapling.
SEED TREE2:
A tree that produces seed; usually trees left during logging to provide seed for reforestation.
SELECT:
The NHLA grade for clear lumber that is too narrow or too short to be graded FAS.
SELECTIVE LOGGING OR CUTTING2:
The selective removal of a single tree or small groups of trees during a timber harvesting operation. These trees may be removed because they are mature, large, or diseased.
SEQUENCE MATCHED PANEL SETS:
Panel sets that are manufactured to a specific size and are sequentially numbered. Succeeding panels of the set are nearly identical but with a gradual change in grain pattern.
SHAKE:
A defect resulting in lengthwise separation of the wood, most often along the growth rings.
Shear Strength Parallel to Grain1:
Ability to resist internal slipping of one part upon another along the grain. Values presented are average strength in radial and tangential shear planes.
Shrinkage1:
The contraction of wood fibers caused by drying below the fiber saturation point (usually around 25-27% M.C.). Values are expressed as a percentage of the dimension of the wood when green. Widths can be ¼” below minimum required. Thickness can be 1 /16” below minimum required.
SKID2:
To pull logs from the stump. The logs are pulled to a skidway, landing or mill.
SKIDDER2:
A four-wheeled or other self-propelled machine which is used to skid felled trees or logs. Also, one who skids logs.
SLASH2:
The woody debris remaining on the ground after logging: slash includes branches, bark, chunks, cull logs, uprooted stumps, and uprooted trees.
SLIP MATCHED
A veneer pattern created by aligning successive pieces side by side vertically but offsetting them horizontally.
SLR1E:
Straight line ripped 1 edge.
SLR2E:
Straight line ripped 2 edge.
SM:
Surface measure.
Softwoods1:
Softwoods or conifers, from the Latin word meaning “cone-bearing,” have needles rather than leaves. Widely available U.S. softwood trees include cedar, fir, hemlock, pine, redwood and spruce. In a home, softwoods primarily are used as structural lumber such as 2x4s and 2x6s, with limited decorative applications.
SPALTING:
A dark stain in some wood, commonly maple, caused by decay, and resulting in a very attractive figure.
SPECIFIC GRAVITY:
The relative weight of a substance compared with that of an equal volume of water. Specific gravity values given are based on wood volume at 12% moisture content (MC) and oven dry weight.
SPECK:
A defect in lumber caused by fungus in the tree and appearing is small light-colored pits or spots.
Split1:
Separation of the fibers in a piece of wood from face to face (other term: end-split).
Stain1:
Materials used to impart color to wood.
STRAIGHT-LINE RIPPING3:
A process for trueing one edge of a board that has no straight edge to work from.
STICKERS:
Pieces of wood, typically 1” square, inserted at regular intervals in a stack of wood during the kilning process, permitting optimum and even airflow as the wood dries – thus preventing most drying defects. Stickers should be aligned and extend the full height of the stack, from the top all the way to the ground to provide adequate support for the wood, thus preventing warp defects.
STICKER STAIN:
A stain that sometimes occurs under the stickers during the kilning process.
STRIPE:
A striping pattern that occurs when logs with alternately-sloping interlocked wood grains are quarter-sawn.
STUMP-WOOD2:
The resinous stump and root of longleaf or slash pine. It is often used to extract turpentine and rosin.
SURFACED:
Lumber that has been planed smooth.
SURFACE CHECKS:
A drying defect where the surface of lumber dries quicker than the core.
Tensile Strength Perpendicular to Grain1:
Resistance of wood to forces acting across the grain that tend to split a member. Values presented are the average of radial and tangential observations.
Texture1:
Determined by relative size and distribution of the wood elements. Described as coarse (large elements), fine (small elements) or even (uniform size of elements).
Tropical Hardwoods1:
Tropical hardwoods, including mahogany, rosewood, teak and wenge - are not native to North America. They grow in the tropical forests of the world and must be imported for domestic use. While some tropical hardwoods can be used for interior applications, including flooring, the color, grain pattern, hardness and luster of many imported woods differ from those of American hardwoods. For more information on non-native species, refer to the Don’t be fooled article.
TWIST:
A warp defect in lumber where one or more corners of the board are not in straight alignment with the other corners
UNDERRUN2:
The amount by which lumber sawn from logs is less than the estimated quantity expected to be sawn; descriptive term indicating this condition.
UNDERSTORY2:
Trees in a stand which grow under the trees forming the main crown canopy.
VENEER:
Peeled or sliced thin sheets of wood used as inner plys or as decorative faces
WANE:
The presence of bark or a lack of wood along the edge or corner of a board.
Warp1:
Distortion in lumber causing departure from its original plane, usually developed during drying. Warp defects include cup, bow, crook and twist.
Weight1:
The weight of dry wood depends upon the cellular space, the proportion of wood substance to air space.
Work to Maximum Load in Bending1:
Ability to absorb shock with some permanent deformation and more or less injury to a specimen. Work to maximum load is a measure of the combined strength and toughness of wood under bending stresses.
YIELD, SUSTAINED2:
The quantity of timber a forest can produce continuously under a given plan of management; a continuous production of timber with a balance between growth and harvest.
1 Source: www.hardwoodinfo.com ©2012 Hardwood Manufacturers Association
2 Source: www.timbertax.org
3 Source: www.woodmagazine.com ©2015 Meredith Corporation