Glossary
Advanced Decay
An older stage of decay in which disintegration is recognized because the wood has become punky, soft, spongy, stringy, shaky, pitted, or crumbly. Decided discoloration or bleaching of the rotted wood is often apparent.
Air Dried
Seasoned (dried) by exposure to the atmosphere, in the open or under cover, without artificial heat. (See kiln, kiln-dried, and seasoning).
ALS (American Lumber Standards)
This Standard provides for the grading of structural lumber by both visual and mechanical means. Any design values assigned to lumber are required to be in accordance with the criteria determined appropriate by the National Institute of Standards and Technology. A separate consensus body, the National Grading Rule Committee (NGRC) is established to develop and maintain nomenclature and descriptions of grades for dimension lumber that conform to this Standard. This Standard is used for domestic production consumed in and exported from the United States, and for lumber imported into the United States. The American Lumber Standards embody provisions for softwood lumber dealing with recognized classifications, nomenclature, basic grades, sizes, description, measurements, tally, shipping provisions, grade marking, and inspection.
ALSC (American Lumber Standard Committee)
The ALSC membership is appointed by the Secretary of Commerce to constitute a proper balance among producers, distributors, and consumers of softwood lumber. Pursuant to a U.S. District Court order, the ALSC and its Board of Review (Board) operate as independent bodies with defined functions with regard to establishing, maintaining, implementing and enforcing this Standard. Through a consensus process, the ALSC maintains the Standard and establishes policies and adopts other standards by which the Board certifies grading rules, approves design values, accredits agencies to grade and inspect under those rules and monitors the agencies' performance.
Bandsaw
A saw consisting of an endless toothed steel band passing over two wheels with teeth cut into one or both edges and is used to cut wood or other materials.
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. (See wane and bark pocket).
Bark Pocket
Patch of bark partially or wholly enclosed in the wood. Classified by size the same as pitch pockets. (See Pocket).
Beveled Skips
Beveled skips are areas on the surface of a piece that fail to dress due to sawing at an angle not parallel to the plane of the face. These skips are limited on the basis of an equivalent loss of wood from wane.
Blue Stain
Blue stain is a common cause for the discoloration of lumber. Certain dark-colored microscopic fungi cause a bluish or grayish discoloration in the sapwood of the tree. However, not all blue stains are blue. Common stain shades can be blue to bluish black or gray to brown. Sometimes, the stain coloration in lumber may appear as red, yellow, orange, or purple. Blue stain has no effect on the performance and strength of lumber.
Board Foot
A board foot is a unit of measurement of lumber represented by a board 1 foot long, 12 inches wide and 1 inch thick or its cubic equivalent. In practice the board foot calculation for lumber 1 inch or more thick is based on its nominal thickness and width.
Bow
Bow is 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. See warp.
Burl
Burl is a distortion of grain, usually caused by abnormal growth due to injury of the tree. The effect of burls is assessed in relation to knots.
Cant
A log that has been squared on two or more sides but still needs processing to make it into lumber.
Cant Hook
A device used for rolling cants or logs. Many people mistake cant hook for a peavey. The difference is that a cant hook doesn't have a point on the end like a peavey.
Carbide
A compound of carbon and other materials that is super hard. There are various grades of carbide depending on the application. In saw teeth they are brazed to the saw blade and ground to the proper configuration. These teeth are very hard and stay sharp longer than other types of teeth but, have a tendency to be brittle. See Stellite.
Ceiling
A piece of patterned, tongue and grooved lumber, used to cover the ceiling of a room, porch or other partially enclosed areas.
Centerline Knot
A centerline knot is a knot which has both sides located exactly in the center of the face of a piece of lumber that is called a centerline knot. If both sides of the knot are slightly off-center but would average to the center, it is still a centerline knot. It is important to be able to recognize centerline knots because they are the largest knots allowed for each grade and centerline knot sizes also limit combination knot sizes.
Check
A separation of the wood normally occurring across or through the annual rings and usually as a result of seasoning.
- Roller Check - a crack in the wood structure caused by a piece of cupped lumber being flattened in passing between the machine rollers.
- Surface Check - a separation that occurs on a face of a piece.
- Small Check - not over 0.8 mm (1/32 inch) wide or 102 mm (4 inch) long.
- Medium Check - not over 0.8 mm (1/32 inch) wide or 254 mm (10 inch) long.
- Large Check - over 0.8 mm (1/32 inch) wide or longer than 254 mm (10 inch) or both.
- Through Check - a separation that extends from one surface of a piece to the opposite or adjoining surface.
Chip Marks
Shallow depressions or indentations on or in the surface of dressed lumber caused by shavings or chips getting embedded in the surface during dressing.
- Very light chip marks - not over 0.4 mm (1/64 inch) deep.
- Light chip marks - not over 0.8 mm (1/32 inch) deep.
- Medium chip marks - not over 1.6 mm (1/16 inch) deep.
- Heavy chip marks - not over 3.2 mm (1/8 inch) deep.
Chipped Grain
A barely perceptible irregularity in the surface of a piece caused when particles of wood are chipped or broken below the line of cut. It is too small to be classed as torn grain and is not considered unless in excess of 25% of the surface involved.
Circle Saw
A machine that uses a flat thin disk with teeth cut into the outer edge to saw wood, plastic, metal, or other materials.
Combination Knot
Combination knots occur when two or more knots occupy the same cross-section of a piece of lumber. If you draw a line at 90 degrees (right angle) across the wide face of a piece of lumber and two or more knots intersect the line within the piece, you have a combination knot. Combination knots usually have a greater effect on the strength of a piece of lumber and are graded differently from single knots.
Compression Wood
Compression wood is abnormal wood that forms on the underside of learning and crooked coniferous trees. It is characterized, aside from its distinguishing color, by being hard and brittle and by its relatively lifeless appearance.
Construction (2" to 4" wide only) (dimension)
Recommended for general framing purposes. Good appearance, but graded primarily for strength and serviceability.
Crook
Crook is 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. See warp.
Cross Breaks
A cross break is a crack or separation of wood fibers across the width originating from the edge of the piece.
Cross Section
When reference is made to knots in the same cross section, the cross section is the area across the width of a piece equal to the diameter of the largest knot present.
Cross Section Knots
When two or more knots appear in the same cross section, the sum of their sizes or displacement shall not exceed the maximum size specified for the centerline knot. If loose knot, fixed knots or holes are involved the sum of the of their sizes or displacement is limited to the maximum edge knot size. When directly opposite spike knots in boxed heart pieces are involved, the sum of their sizes or displacement shall not exceed the allowable centerline knot.
Cup
Cup is a deviation in the face of a piece of lumber from a straight line drawn from edge to edge. It is measured at the point of greatest distance from the straight line. See warp.
Decay
Decay (unsound wood) is a disintegration of the wood substance due to action of wood destroying fungi, and is also known as dote or rot. See heart center decay, white specks, honeycomb, incipient decay, water soak, and peck.
- Advanced Decay - an older stage of decay in which disintegration is recognized because the wood has become punky, soft, spongy, stringy, shaky, pitted, or crumbly. Decided discoloration or bleaching of the rotted wood is often apparent.
- Heart Center Decay - a localized decay developing along the pith in some species and is detected by visual inspection. Heart center decay develops in the living tree and does not progress further after the tree is cut.
- Honeycomb - similar to white specks but the pockets are larger. Where permitted in the grading rules, it is so limited that it has no more effect on the intended use of the piece than other characteristics permitted in the same grade. Pieces containing honeycomb are no more subject to decay than pieces which do not contain it.
- Incipient Decay - 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.
- Peck - channeled or pitted areas or pockets found in cedar and cypress. Wood tissue between pecky areas remains unaffected in appearance and strength. All further growth of the fungus causing peckiness ceases after the trees are felled.
- Pecky - characterized by peck
- Pocket Rot - decay which appears in the form of a hole, pocket, or area of soft rot, usually surrounded by apparently sound wood.
- Water Soak or Stained-Water - soaked area in heartwood, usually interpreted as the incipient stage of certain wood rots.
- White Specks - small white or brown pits or spots in wood caused by the fungus Fomes pini. It develops in the living tree and does not develop further in wood in service. Where permitted in grading rules, it is so limited that it has no more effect on the intended use of the pieces than other characteristics permitted in the same grade. Pieces containing white speck are no more subject to decay than pieces which do not contain it.
Degrades
Pieces which on re-inspection prove of lower quality than the grade in which they were shipped.
Diagonal Grain
Diagonal grain is a deviation in the slope of grain caused by sawing at an angle with the bark of the tree.
Dimension Lumber
Dimension lumber is lumber with a nominal thickness of from 2 up to but not including 5 inches and a nominal width of 2 inches or more.
Displaceable Knots
Displaceable knots are knots away from the edge which are not centerline knots or knots which occupy less than half the edge. The maximum allowable size for displaceable knots increases as the knot is located closer to the centerline of the piece. Displaceable knots rarely affect the grade of a piece of lumber.
Double Arbor Mismatch
A depth offset across the face of the piece caused by misalignment of gang saws.
Double-End Trimmed (DET)
Lumber trimmed square on both ends. Tolerances are found in certified grading rules.
Dressed Size
The dimensions of lumber after being surfaced with a planing machine. The dressed size is usually 1/2" to 3/4" less than the nominal or rough lumber size.
Dry
Lumber of less than nominal 5-inch thickness which has been seasoned or dried to a maximum moisture content of 19 percent. Lumber of nominal 5-inch or greater in thickness (timbers) is often manufactured and sold without drying. When the maximum moisture content is specified for lumber of nominal 5-inch or greater thickness, it shall be in accordance with the provisions of the applicable lumber grading rules certified by the Board, which for some species defines dry lumber as having a maximum moisture content higher than 19 percent See drying defects and seasoning.
Drying Defects
Most southern pine is dried to about 19% moisture content before it is dressed. Warp, splits, and checks are all defects that can occur during the drying process and are called drying defects. See manufacturing defects.
Eased Edge
Eased edges means slightly rounded surfacing on pieces of lumber to remove sharp corners. The standard radius for 1", 2", 3", and 4" nominal thickness lumber shall not exceed 1/16", 1/8", 3/16", and 1/4" respectively. Note: Lumber 4" or less in thickness is frequently shipped with eased edges unless otherwise specified.
Edge
(1.) The narrow face of a rectangular-shaped piece. (2.) The corner of a piece at the intersection of two longitudinal faces. (3.) In stress grades that part of the wide face nearest the corner of the piece. See eased edge and edger.
Edge grain (EG) [vertical grain (VG)] [rift grain]
A piece or pieces sawn at approximately right angles to the annual growth rings so that the rings form an angle of 45 degrees or more with the surface of the piece.
Edge Knot
A wide face knot overlapping part of the edge shall be considered an edge knot if it occupies more than 1/2 the thickness. If both faces of a simple knot touch the edge of a piece of lumber or if more than half of the edge is occupied by a three-face knot, then the knot is an "Edge" knot. All spike knots on the narrow face are edge knots. Recognizing edge knots is important since grade rules for knots show the maximum size for either edge knots or centerline knots. Edge knots will grade most of the narrow lumber.
Edger
A machine used to cut straight edges on flitches and also used to rip boards into smaller pieces.
Equilibrium Moisture Content, (EMC)
The moisture content at which wood neither gains nor loses moisture when surrounded by air at a given relative humidity and temperature.
Finish
A high-quality piece of lumber graded for appearance, often used for interior trim or cabinet work.
Firm
"Firm" in relation to white speck and honeycomb provisions infers that it will not crumble readily under thumb pressure and cannot be easily picked out.
Firm Red Hart
A stage of incipient decay characterized by a reddish color in the heartwood which does not render the wood unfit for the majority of yard purposes.
Flat Grain (FG) (Slash grain SG)
A piece or pieces sawn approximately parallel to the annual rings so that all or some of the rings form an angle of less than 45 degrees with the surface of the piece.
Flitch
A piece of wood cut off a log that has two flat sides but still needs to be sawn on one or two edges.
f.o.h.c. (free of heart centers)
Without pith (side cut). An occasional piece, when showing pith for not more than 1/4 the length on the surface, shall be accepted.
Grade Mark
The official agency mark stamped on the lumber usually appearing near the end of the product. Most grade stamps, except those for rough lumber or heavy timbers, contain five basic elements: (1) Registered Trademark, (2) Mill Identification, (3) Grade Designation, (4) Species Identification, and (5) Condition of Seasoning at Time of Surfacing.
Grade Yield
The board foot volume of lumber, separated into each grade category expressed as a percentage of the total volume of board foot manufactured over a specified period of time. (See Grade).
Grain
The fibers in wood and their direction, size, arrangement, appearance or quality. (See slope of grain, summerwood, springwood, vertical grain, flat grain, mixed grain, spiral grain, torn grain, loosened grain, raised grain, and diagonal grain).
Green
Lumber of less than nominal 5-inch thickness, which has a moisture content in excess of 19 percent. For lumber of nominal 5-inch or greater thickness (timbers), green shall be defined in accordance with the provisions of the applicable lumber grading rules certified by the Board. (See KD19).
Green Lumber
Freshly sawed or undried wood. Wood that has become completely wet after immersion in water would not be considered green, but may be said to in the "green condition."
Gum Spot
An accumulation of gum-like substance occurring as a small patch. Often occurs in conjunction with a bird-peck or other injury to the growing wood.
Gum Streak
A well-defined accumulation of gum in more or less regular streak. Classified as pitch streaks.
Head Rig
The main breakdown saw in a sawmill. This saw cuts logs into cants that can be processed further by edgers and resaws.
Heart
Inner core of the tree trunk comprising the annual rings containing nonliving elements. See heartwood.
Heart Center Decay
A localized decay developing along the pith in some species and is detected by visual inspection. Heart center decay develops in the living tree and does not progress further after the tree is cut.
Heart Center Streaks
A localized decay peculiar to Southern Yellow Pine and the limitation applies to that species.
Heartwood
The inner core of the tree trunk comprising the annual rings containing non-living elements. In some species, heartwood has a prominent color different from sapwood. Heartwood and sapwood of equivalent character are compared as follows:
- With regard to strength, heartwood and sapwood are equal. No requirement of heartwood is made when strength alone is the governing factor.
- With regard to durability, heartwood is more durable than sapwood. When wood is to be exposed to decay-producing conditions without preservative treatment, it is permissible to specify the minimum percentage of heartwood to be present in all pieces of lumber in a shipment.
- With regard to preservatives, sapwood takes preservative treatment more readily than heartwood.
Hit and Miss
A term used to describe the occurrence of a series of skips not over 1.6 mm (1/16 inch) deep with surfaced areas between. Where this degree of skip is permitted, it shall be further clarified to include that the hit shall average one hit per four lineal feet of length. (See "Hit or Miss").
Hit or Miss
Lumber that is completely or partly surfaced or entirely rough with a maximum scantness of 1.6 mm (1/16 inch). When a grade rule allows "hit or miss" skip, 100% of the surface can have skip. Hit or Miss provisions shall not be used to permit surfacing below specified minimum sizes. A hit is a plainly visible surfaced area approximately 1/2 the width or more and 2" or more in length. No piece shall have less than two hits. When skips appear on opposing faces, the combined scantness shall not exceed the depth permitted. (See "Hit and Miss").
Holes
Openings that either extend partially or wholly through a piece. An alternate designation for holes which extend only partially through a piece is surface pits. Holes are classified by size as follows:
- Pin hole - not over 1.6 mm (1/16 inch) in diameter.
- Medium hole - (small hole) not over 6 mm (1/4 inch) in diameter.
- Large hole - not over 25 mm (1 inch) in diameter.
- Very large hole - over 25 mm (1 inch) in diameter.
Hollow Pith
Hollow Pith, usually caused by ants, is when the small central core of the cross section of a tree is hollowed out. This gives the appearance of decay but is allowed in No. 1 grade lumber. The major problem with Hollow Pith is a tendency for decay to form around the Pith.
Item
A quantity of lumber of a given size and grade, or if length is specified, of given size, length, and grade.
KILN
A chamber having a controlled air-flow, temperature, and relative humidity, for drying lumber, veneer, and other wood products. (See KD15, KD19, kiln-dried, seasoning, and air dried).
Kiln-Dried
Seasoned in a chamber by means of artificial heat. (See KD15, KD19, kiln, seasoning, and air dried).
Knife Marks
The imprints or markings of the machine knives on the surface of dressed lumber.
- Very slight knife marks-marks that are visible only from a favorable angle and are perfectly smooth to the touch.
- Slight knife marks-marks that are readily visible but evidence no unevenness to the touch.
Knot
A portion of a branch or limb that has become incorporated in a piece of lumber. In lumber, knots are classified as to form, size, quality, and occurrence.
- Knot Form
- Oval knot - produced when the limb is cut at slightly more than a right angle to the long axis.
- Round knot - produced when the limb is cut at approximately right angles to its long axis.
- Spike knot - produced when the limb is cut either lengthwise or diagonally.
- Knot Size
- Pin knot-not over 13 mm (1/2 inch) in diameter.
- Small knot-not over 19 mm (3/4 inch) in diameter.
- Medium knot-not over 38 mm (1-1/2 inch) in diameter.
- Large knot-over 38 mm (1-1/2 inch) in diameter.
- Knot Quality
- Black knot - results from a dead branch which the wood growth of the tree has surrounded.
- Decayed knot - softer than the surrounding wood, and containing advanced decay.
- Encased knot - not intergrown with the annual rings of the surrounding wood.
- Firm knot - solid across its face but contains incipient decay.
- Fixed knot - retains its place in dry lumber under ordinary conditions but is movable under pressure though not easily pushed out.
- Hollow knot - a sound knot containing a hole greater than 6 mm (1/4 inch) in diameter. The through opening of a hollow knot is limited to the size of other holes permitted.
- Intergrown knot - a knot whose annual rings are partially or completely intergrown on one or more faces with the annual rings of the surrounding wood.
- Loose knot - not firmly fixed; a knot not held tightly in place by growth, shape, or position.
- Pith knot - sound in all respects except it contains a pith hole not over 6 mm (1/4 inch) in diameter.
- Red knot - knot that results from a live branch grown in the tree and is intergrown with the surrounding wood.
- Sound knot - contains no decay.
- Star-checked knot - has radial checks.
- Tight knot - so fixed by growth, shape, or position that it retains its place in the piece.
- Unsound knot - contains decay.
- Water-tight knot - has annual rings completely intergrown with those of the surrounding wood on one surface of the piece, and it is sound on that surface.
- Knot Occurrence
- Branch knots - two or more divergent knots sawed lengthwise and tapering toward the pith at a common point.
- Corner knot - located at the intersection of adjacent faces.
- Knot cluster - two or more knots grouped together as a unit with the fibers of the wood deflected around the entire unit. A group of single knots is not a knot cluster.
- Single knot - occurs by itself. The fibers of the wood being deflected around it.
Lead
The amount of angle a circular saw blade or chipping head has in relation to the sawing plane. The front cutting edge is set closer to the log than the back edge. The amount of lead is usually between 0 and 1/16 of an inch on saws or chipping heads of 40 to 60 inches in diameter. The amount varies depending on species, sawing conditions, feed speeds, and other variables.
Limited
A term used to describe the maximum size or extent of a defect. For example: A No. 1 grade edge knot in a 2x6 is limited to 1 1/2".
Loblolly Pine (Pinus taeda)
Loblolly pine is found throughout the Southeast. Like Longleaf pine, its needles are in clusters of 3 with needles about 7" long, while the cones are approximately 3 1/2" long. Loblolly pine grows best on fairly moist, bottomland soil. It is very aggressive and quickly reseeds old fields and other abandoned lands. It can reach a size of 150 feet in height with a diameter of more than five feet. See Southern Yellow Pine.
Longleaf Pine (Pinus palustris)
Longleaf pine, is a pine native to the southeastern United States, found along the coastal plain from eastern Texas to southeast Virginia, extending into northern and central Florida. Longleaf pine has needles occurring in bundles of threes about 12" long with cones about 7" long. This pine is peculiar in that it develops very little during the first 1 to 5 years of its life. During this time the top is a dense bunch of green needles and is often mistaken for grass. This tree is found on a variety of sites but grows best on well-drained sandy soils. Longleaf pine can grow to 150' and a diameter of nearly 4'.(See Southern Yellow Pine).
Loose Knot
A knot which is not firmly fixed; a knot not held tightly in place by growth, shape or position.
Loosened Grain
A grain separation or loosening between springwood and summerwood without displacement.
- Very light loosened grain - not over 0.4 mm (1/64 inch) separation.
- Light loosened grain - not over 0.8 mm (1/32 inch) separation.
- Medium loosened grain - not over 1.6 mm (1/16 inch) separation.
- Heavy loosened grain - not over 3.2 mm (1/8 inch) separation.
- Very heavy loosened grain - over 3.2 mm (1/8 inch) separation.
Lumber
Lumber is defined as a manufactured product that has been derived from a log and processed into pieces through sawing or planing and used for structural and appearance purposes.
Machine Bite
A depressed cut of the machine knives at the end of a piece.
- Very light machine bite - not over 0.4 mm (1/64 inch) deep.
- Light machine bite - not over 0.8 mm (1/32 inch) deep.
- Medium machine bite - not over 1.6 mm (1/16 inch) deep.
- Heavy machine bite - not over 3.2 mm (1/8 inch) deep.
- Very heavy machine bite-over 3.2 mm (1/8 inch) deep.
Machine Burn
A darkening of the wood due to overheating by machine knives or rolls when pieces are stopped in the machine.
Machine gouge
A groove cut by the machine below the desired line.
- Very light machine gouge - not over 0.4 mm (1/64 inch) deep.
- Light machine gouge - not over 0.8 mm (1/32 inch) deep.
- Medium machine gouge - not over 1.6 mm (1/16 inch) deep.
- Heavy machine gouge - not over 3.2 mm (1/8 inch) deep.
- Very heavy machine gouge - over 3.2 mm (1/8 inch) deep.
Machine Offset
An abrupt dressing variation in the edge surface which usually occurs near the end of the piece without reducing the width or without changing the plane of the wide surface.
- Very light machine offset - a variation not over 0.4 mm (1/64 inch).
- Light machine offset - a variation not over 0.8 mm (1/32 inch).
- Medium machine offset - a variation not over 1.6 mm (1/16 inch).
- Heavy machine offset - a variation not over 3.2 mm (1/8 inch).
- Very heavy machine offset - a variation over 3.2 mm (1/8 inch).
Machine Stress Related
Machine Stress rated lumber (MSR) is lumber that has been evaluated by mechanical stress rating equipment. Each piece of MSR lumber is non-destructively tested to determine its Modulus of Elasticity (E), which is a measure of its stiffness. Research has shown that a direct relationship exists between the bending stiffness of a piece of lumber and its bending strength.
Manufacturing Defects
Defects that result from sawing and dressing lumber. (See mismanufacture and drying defects).
Manufactured Holes
Manufactured holes are defects caused by the manufacturing process that are not specifically listed in the grading rule (e.g. dog holes, log turner marks, debarker damage, etc.). The length of manufactured holes shall be the entire length of the defect encountered and limited to the frequency and length restrictions as listed. Manufactured holes that have no more effect on the grade of the piece than wane shall be assessed and limited as wane, but not a combination of the wane and manufactured hole limitations. The listed limitations for manufactured holes shall not be used to exceed the maximum wane limitations of the grade.
Mismanufacture
Includes all defects or blemishes, produced in manufacturing. (See chipped grain, hit-and-miss, hit-or-miss, loosened grain, machine burn, machine gouge, mismatched, raised grain, skip, torn grain, and variation in sawing).
Mismatch
An uneven fit in worked lumber when adjoining pieces do not meet tightly at all points of contact or when the surfaces of adjoining pieces are not in the same plane.
- Slight mismatch - a barely evident trace of mismatch.
- Very light mismatch - not over 0.4 mm (1/64 inch).
- Light mismatch - not over 0.8 mm (1/32 inch).
- Medium mismatch - not over 1.6 mm (1/16 inch).
- Heavy mismatch - not over 3.2 mm (1/8 inch).
Modulus of Elasticity
Modulus of Elasticity (E) is a ratio of the amount a material will deflect in proportion to an applied load.
Moisture Content (MC)
The weight of the water in a piece of lumber expressed in a percentage of the weight of the piece after being over dried.(See air dried, kiln-dried, and kiln).
No. 1 Grade (dimension)
Lumber recommended for general utility and construction where high strength, stiffness, and good appearance are desired.
No. 1 Prime (dimension)
Grade based on No. 1 Dimension Lumber characteristics except that holes, skip, and wane are closely limited to provide a high-quality product. (See Prime and No. 2 Prime).
No. 2 Grade (dimension)
Lumber recommended for most general construction uses where moderately high design values are required. Allows well-spaced knots of any quality.
No. 2 Prime (dimension)
Grade based on No. 2 Dimension Lumber characteristics except that holes, skip, and wane are closely limited to provide a high-quality product. (See Prime and No. 1 Prime).
No. 3 Grade (dimension)
Lumber appropriate for use in general construction where appearance generally is not a factor.
Nominal
As applied to timber or lumber, the size by which it is known and sold in the market. (See dressed size).
On The Chain
Commonly known as the grading chain, the chain is a conveyor system that moves the lumber past the grader just after the lumber leaves the planer machines. Lumber graders must grade lumber while it is "On the Chain."
Partition
A tongue and grooved piece of lumber with the same pattern run on both sides. For use where both sides may be exposed.
Peck
Channeled or pitted areas or pockets found in cedar and cypress. Wood tissue between pecky areas remains unaffected in appearance and strength. All further growth of the fungus causing peckiness ceases after the trees are felled.
Pitch
(1.) An accumulation of resinous material.
- Light pitch - the light but evident presence of pitch.
- Medium pitch - a somewhat more evident presence of pitch than in the light pitch.
- Heavy pitch - a very evident accumulation of pitch showing by its color and consistency.
- Massed pitch - a clearly defined accumulation of solid pitch in a body by itself.
- (2.) The number of teeth per inch on a saw blade or band.
Pitch Streak
A well-defined accumulation of pitch in the wood cells in a streak. Pitch streaks, with equivalent areas being permissible, are described as follows:
- Very small pitch streak - 10mm (3/8 inch) in width and 381 mm (15 inch) in length.
- Small pitch streak - 1/12 the width and 1/6 the length of the piece.
- Medium pitch streak - 1/6 the width and 1/3 the length of the piece.
- Large pitch streak - not over 1/4 the width by 1/2 the length of the surface.
- Very large pitch streak - over 1/4 the width by 1/2 the length of the surface.
Pith
The small soft core in the structural center of a log, often darker in color. The pith represents primary growth formed when woody stems or branches elongate.
- Very small pith - not over 3.2 mm (1/8 inch) wide and occupies on the face surface not over 161 square mm (1/4 square inch) [3.2 mm by 51 mm (1/8 inch wide by 2 inch long), or 1.6 mm by 102 mm (1/16 inch by 4 inch)]
- Small pith - not over 484 square mm (3/4 square inch) on the face surface [6 mm by 76 mm (1/4 inch by 3 inch), 5 mm by 102 mm (3/16 inch by 4 inch), 3.2 mm by 152 mm (1/8 inch by 6 inch), or 1.6 mm by 305 mm (1/16 inch by 12 inch)]
- Free of pith - the prohibition of pith on or within the body of the piece.
- Boxed pith - pith that is within the four faces of an end of a piece.
Pith Knot
A knot which is sound in all respects except it contains a pith hole not over 1/4" in diameter.
Planer Tear
A separation of wood fibers usually between springwood and summerwood caused by the tearing action of the planer knife where the grain runs out of the wood along the edge of the piece. See manufacturing defects.
A well-defined opening, between the rings of annual growth, which develops during the growth of the tree. It usually contains pitch or bark. Pockets are described as follows with equivalent areas being permissible:
- Very small pocket - 1.6 mm (1/16 inch) in width and 76 mm (3 inch) in length, or 3.2 mm (1/8 inch) in width and 51 mm (2 inch) in length.
- Small pocket - 1.6 mm (1/16 inch) in width and 152 mm (6 inch) in length, or 3.2 mm (1/8 inch) in width and 102 mm (4 inch) in length, or 6 mm (1/4 inch) in width and 51 mm (2 inch) in length.
- Medium pocket - 1.6 mm (1/16 inch) in width and 305 mm (12 inch) in length, or 3.2 mm (1/8 inch) in width and 203 mm (8 inch) in length, or 10 mm (3/8 inch) in width and 102 mm (4 inch) in length.
- Large pocket - not over 2581 square mm (4 square inches) in area.
- Very large pocket - over 2581 square mm (4 square inches) in area.
- Closed pocket - an opening on one surface only.
- Open (through) pocket - an opening on opposite surfaces. A through opening is considered the same as a through hole of equal size.
Plugs and Fillers
Wood plugs and fillers are inserted into pieces of lumber to improve their appearance and usefulness. Lumber containing plugs an filers shall only be shipped when the order, acknowledgment, and invoice carry reference to the inserts. Quality of the inserts and workmanship must be keeping with the quality of the grade. In dimension lumber and other lumber grader for strength, inserts are limited to the same size and location as knots.
Precision-End Trimmed (PET)
Lumber is trimmed square on both ends to uniform lengths with a manufacturing tolerance of 1/16" over or under in length in 20% of the pieces.
Prime
Prime lumber is a grade description for a special product variation of 2" Dimension Lumber intended for use where appearance and strength are a consideration. (See No. 1 Prime and No. 2 Prime).
Quarter Sawn
A method of sawing lumber to produce vertical grain lumber with no boxed heart. Boards are sawn on approximately radial lines from the center of the log.
Rabbeted Bevel Siding
Bevel siding with a rabbeted joint milled on the reverse of the thick edge to facilitate alignment of pieces.
Rabbeted Edge
A channel or recess cut out of the edge along the length of the piece caused by misaligned chipper heads or double arbor saws.
Raised Grain
A roughened condition of the surface of dressed lumber in which the hard summerwood is raised above the softer springwood, but not torn loose from it.
- Very light raised grain - not over 0.4 mm (1/64 inch).
- Light raised grain - not over 0.8 mm (1/32 inch).
- Medium raised grain - not over 1.6 mm (1/16 inch).
- Heavy raised grain - not over 3.2 mm (1/8 inch).
Resaw
A saw used to continue the breakdown of logs into lumber. These saws can be circle saws or bandsaws and come in a variety of orientations. They can process cants, slabs, or boards into smaller thinner pieces.
Right Angle
A right angle is equal to 90 degrees. A line segment (AB) drawn so that it forms right angles with a line (CD). In geometry and trigonometry, a right angle is an angle that bisects the angle formed by two halves of a straight line.
Roller Check
A crack in the wood structure along the length of the piece caused by a piece of cupped lumber being flattened between machine rollers.
- Light roller check - is a perceptible opening not over 2' long.
- Medium roller check - is a perceptible opening over 2' long but not exceeding 4' in length.
- Heavy roller check - is over 4' in length. (See Checks).
Roller Splits
A crack in the wood structure along the length of the piece caused by a piece of cupped lumber being flattened between machine rollers.
Rough Lumber
Lumber which has not been dressed (surfaced) but which has been sawed, edged, and trimmed.
Sapwood
The soft outer layers of recently formed wood between the heartwood and the bark, containing the functioning vascular tissue.
- Bright sapwood no defect (BSND)-an indication that bright sapwood is permitted in each piece in any amount.
Saw Cut
A saw cut is a cut perpendicular to the length of the piece and is usually caused by malfunctioning trimmer saw or saws. Cuts can occur in two ways: (1) the cut passes completely through the thickness and extends across a portion of the width and; (2) the cut does not pass completely through the thickness and may extend completely or partially across the width.
Scribner
A particular log scale rule. The Scribner scale has several different styles called a, b, and c. These were developed for logs smaller than 12 inch diameter because the original rule didn't take those sizes into account. There is another style of the rule called decimal. This means that log volumes are rounded to the nearest ten board feet. The most common Scribner rule is Scribner Decimal C.
Seasoning
Evaporation or extraction of moisture from green or partially dried wood. (See air dried, kiln-dried, and kiln).
Select Structural
Dimension lumber of this quality is limited in characteristics that effect strength and stiffness values. This grade is recommended for use in applications where both high strength and stiffness values and good appearance may be required.
Set
The difference between the thickness of the tooth in a saw and the thickness of the blade of the saw. Proper set is extremely important in saw maintenance. There are two types of set, Spring set and Swage set. Spring set means the teeth have been bent one way or another. Swage set means the teeth have been widened in both directions.
Shortleaf Pine
Shortleaf pine occurs throughout the Southeast. Like the slash pine, its needles are in clusters of twos, and the needles, which average about four inches in length, are the shortest of the four Southern pines. The cones are likewise the smallest, being about two inches long. Shortleaf pine is found on a variety of sites but it is most common on dry upland soils. It can attain a height of 130 feet with a diameter of four feet. (See Southern Yellow Pine).
Simple Knot
A knot that shows on the wide face of a lumber piece. Simple knots may show on the entire edge of a piece. A Simple knot may or may not pass completely through the piece depending on where the pith was/is located.
Shake
A lengthwise separation of the wood which occurs between or through the rings of annual growth.
- Fine shake - a barely perceptible opening.
- Light shake - not over 0.8 mm (1/32 inch) wide.
- Medium shake - not over 3.2 mm (1/8 inch) wide.
- Open shake - over 3.2 mm (1/8 inch) wide.
- Ring shake - occurs between the annual rings to partially or wholly encircle the pith.
- Surface shake - occurs on only one surface of a piece.
- Through shake - extends from one surface of a piece to the opposite or to an adjoining surface.
- Pith shake (heart check or heart shake)-extends through the annual rings from or through the pith towards the surface of a piece, and is distinguished from a seasoning check by the fact that its greatest width is nearest the pith, whereas the greatest width of a season check in a pith-centered piece is farthest from the pith.
Skip
An area on a piece that failed to surface clean. Skip is caused when the width or thickness of a piece is too small to allow the planer to remove the entire rough surface. (See "hit and miss", "hit or miss", and manufacturing defect). Skips are described as follows:
- Very light skip - not over 0.4 mm (1/64 inch) deep.
- Light skip - not over 0.8 mm (1/32 inch) deep.
- Medium skip - not over 1.6 mm (1/16 inch) deep.
- Heavy skip - not over 3.2 mm (1/8 inch) deep.
Slab
The piece of wood cut off a log that is round on one side and flat on the other. These are produced from the first cuts on logs and the edging of flitches. They can be used for firewood, siding, or can be processed into lumber if large enough. See edger.
Slash Pine
Slash pine is found primarily along the Gulf Coast. It is noted for its early fast growth. The needles occur in bundles of twos, and are about nine inches long. The cones average about four inches in length. Slash pine normally occupies low, moist sites, but - like loblolly pine - is aggressive and quickly takes over abandoned and cut-over land. The larger trees are sometimes 120 feet tall and three feet in diameter. See Southern Yellow Pine.
Select Structural (dimension)
High quality, limited in characteristics that affect strength or stiffness. Recommended for uses where high strength, stiffness and good appearance are desired.
Slope of Grain
The deviation of the line of fibers from a straight line parallel to the sides of the piece.
Softwoods
Generally, one of the botanical groups of trees that in most cases have needle-like or scale-like leaves; the confiers, also the wood produced by such trees. The term has no reference to the actual hardness of the wood.
Southern Yellow Pine
The Southern Pines, as a general group of individual tree species, include the four principal tree species of longleaf (Pinus palustris), slash (Pinus elliottii), shortleaf (Pinus echinata), and loblolly (Pinus taeda). The species grouping “Southern Pine”, also known as “Southern Yellow Pine” is abbreviated as “SYP” and refers to domestic southern pine grown and harvested from the states of Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia. Based on its rate-of-growth wood quality, southern pine may be classified as dense. (See Shortleaf pine, Slash pine, Loblolly pine, Longleaf pine, and Softwoods).
Spike Knot
A knot whose face is on the edge of a piece of lumber and "spikes" toward the middle of the piece. The most important thing to remember about Spike knots is that the knot occupies space from the edge of the lumber piece and tapers towards the pith of the piece. Spike knots are also easy to recognize and measure. See wide-face spike knot.
Spiral Grain
Spiral grain is a deviation in the slope of grain caused when the fibers in a tree take a spiral course around the trunk of the tree instead of the normal vertical course.
Splits
A separation of the wood through the piece to the opposite surface or to an adjoining surface due to the tearing apart of the wood cells.
- Very short split - equal in length to 1/2 the width of the piece.
- Short split - equal in length to the width of the piece and in no case exceeds 1/6 the length.
- Medium split - equal in length to twice the width of the piece and in no case exceeds 1/6 the length.
- Long split - longer than a medium split.
Splitter
A splitter is a device behind a circle saw that keeps the two pieces from binding together on the saw. These can be fixed or can be rotating.
Springwood
Springwood is the portion of the annual ring that is formed during the first part of the growing season. It is lighter in color, less dense and weaker mechanically than summerwood.
Square Corners
Square corners are corners without eased edges but having an allowance for wane in certain grades.
Square-End Trimmed
Lumber trimmed square and having a manufacturing tolerance of 1/64" for each nominal 2" of thickness or width.
Stained Wood
A discoloration in wood. Stained heartwood or firm red heart-heartwood that shows a marked variation from the natural color. In grades where it is permitted, stained heartwood has no more effect on the intended use of a piece than other characteristics permitted in the grade. Note: Stained heartwood ranges from pink to brown, and is not to be confused with natural red heart. Natural color is usually uniformly distributed through certain annual rings, whereas stains are usually in irregular patches.
Stained Sapwood
Sapwood with discoloration. In grades when it is permitted, stained sapwood has no more effect on the intended use of a piece than other characteristics permitted in the grade but it does affect appearance in varying degrees:
- Light stained sapwood - a discoloration so slight that it does not affect natural finishes.
- Medium stained sapwood - a pronounced difference in coloring. Note: Sometimes the usefulness for natural finishes but not for paint finishes is affected.
- Heavy stained sapwood - a so pronounced difference in color that the grain of the wood is obscured, but lumber containing it is acceptable for paint finishes.
- Stained wood resulting from exposure to the elements - discolored wood that is permitted in all grades of framing and sheathing lumber.
Standard (2" to 4" wide only) (dimension)
Recommended for same purposes as Construction grade. Characteristics are limited to provide good strength and excellent serviceability.
Standard A
Standard "A" Manufacture admits: very light torn grain; occasional very light chip marks; very slight knife marks.
Standard B
Standard "B" Manufacture admits: very light torn grain; very light raised grain, very light loosened grain; very light chip marks; average of one very light chip mark per lineal foot but no more than two in any lineal foot; very light knife marks; slight mismatch.
Standard C
Standard "C" Manufacture admits: medium torn grain; light raised grain, light loosened grain; very light machine bite; very light machine gouge; very light machine offset; light chip marks if well-scattered; occasional medium chip marks; slight knife marks; slight mismatch.
Standard D
Standard "D" Manufacture admits: heavy torn grain; medium raised grain, very heavy loosened grain; light manufacture bite; light machine gouge; light machine offset; medium chip marks; slight knife marks; very light mismatch.
Standard E
Standard "E" Manufacture admits: very heavy torn grain; raised grain, very heavy loosened grain; medium machine bite; machine gouge; medium machine offset; chip marks; knife marks; medium wavy dressing; medium mismatch.
Standard F
Standard "F" Manufacture admits: very heavy torn grain; raised grain, very heavy loosened grain; heavy machine bite; machine gouge; heavy machine offset; chip marks; knife marks; medium wavy dressing; medium mismatch.
Standard G
Standard "G" Manufacture admits: loosened grain; raised grain; torn grain; machine bite; machine burn; machine gouge; machine offset; chip marks; medium wavy dressing; mismatch.
Stellite
An alloy that is welded on to saw blade tips that is tough, hard, and durable. A bead is welded on and ground into the shape of a tooth. It is generally cheaper than carbide, less brittle than carbide, but somewhat softer than carbide.
Stepping
Lumber designed to be used for stair treads. Customarily surfaced three sides and bull-nosed on one edge.
Stress Grades
Lumber having assigned allowable design values in accordance with accepted basic principles of strength grading. (See 6.3.2.1 and 6.3.2.2 of the National Institute of Standards & Technology Voluntary Product Standard PS 20-20 Standard).
STUD
Dimension lumber from 2" to 4" thick and 2" wide or wider, in other words 2x2's through 4x18's, may be graded and classified as "STUD".
Summerwood
The portion of the annual ring that is formed after the springwood formation has ceased. It is darker in color, more dense and stronger mechanically than springwood.
Swage
A tool used to spread the end of a saw tooth to a width greater than the thickness of the saw blade. This is used to provide proper set in a saw.
Taper
The difference between the diameter of the large end of a log and the diameter of the small end of the log.
Three-Face Knot
When a knot occupies both wife faces of a lumber piece and a portion of the edge it is called a three-face knot. A three-face knot occurs when the pith is not located in the lumber piece. The larger the knot face on the edge is, the larger the knot is inside the piece. Three face knots are measured differently from a simple knot or spike knot.
Through Check
A check that extends from one surface of a piece to the opposite or adjoining surface. See checks.
Tight Knot
A knot which is so fixed by growth, shape, or position that it retains its place in the piece.
Timber Break
A compression failure across the grain that usually results from a shock to the tree or log that can occur in the forest or during processing.
Torn Grain
An irregularity in the surface of a piece where wood has been torn or broken out by surfacing.
- Very light torn grain - not over 0.4 mm (1/64 inch) deep.
- Light torn grain - not over 0.8 mm (1/32 inch) deep.
- Medium torn grain - not over 1.6 mm (1/16 inch) deep.
- Heavy torn grain - not over 3.2 mm (1/8 inch) deep.
- Very heavy torn grain - over 3.2 mm (1/8 inch) deep.
Total Measurement
Total Measurement (TM) is a practical method of quickly and accurately judging the grade of any knot on the chain. TM is the SUM of all of the parts of the knot which must be measured eliminating the need to determine the average knot size. Applying TM to grade any shape knot: Compare the observed Total Measurement (TM) of the knot to the twice the knot size allowed in the rules while using the width of the piece as a guide when estimating the knots total (TM).
Trim
To cross-cut a piece to a given length.
- Double-end trimmed (DET) - lumber trimmed square on both ends. Tolerances are found in certified grading rules.
- Precision-end trimmed (PET) - lumber trimmed square on both ends to uniform lengths with a manufacturing tolerance of 1.6 mm (1/16 inch) over or under in length in 20% of the pieces.
- Square-end trimmed - lumber trimmed square and having a manufacturing tolerance of 0.4 mm (1/64 inch) for each nominal 2 inch of thickness or width.
Twist
A deviation flatwise, or a combination of flatwise 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. (See Warp).
Under-Dried Lumber
Lumber which has not been dried to the specified MC allowed in the grade rules. Under-dried lumber is commonly called heavy lumber because of the extra weight the excess moisture provides.
Variation in Sawing
A deviation from the line of cut.
- Slight variation - not over 1.6 mm (1/16 inch) scant in nominal 1-inch lumber, 3.2 mm (1/8 inch) in nominal 2-inch, 5 mm (3/16 inch) in nominal 3-inch to 7 inch, and 6 mm (1/4 inch) in nominal 8-inch and greater thickness or width.
Vertical Grain
Vertical grain(VG) (Edge grain EG) (Rift grain) lumber is a piece or pieces of lumber sawn at approximately right angles to the annual rings so that the rings form an angle of 45 degrees or more with the surface of the piece.
Wane
Bark or lack of wood from any cause, except eased edges, on the edge or corner of a piece of lumber. Wane away from ends extending partially or completely through the narrow face is permitted for one foot if no more serious than skips in dressing allowed or across a narrow face if no more damaging than the knot hole allowed (not to exceed in length twice the diameter of the maximum knot hole allowed in the grade) and is limited to one occurrence in each piece. These variations shall not be allowed IN MORE THAN 5% OF THE PIECES. (This provision applies only to the National Grading rule for Dimension Lumber). Basic wane is maximum full length wane as stated in the NGR. The same concept of equivalent wane in thickness and width applies to all grades within their respective stated limitations.
Wane Dip
A wane dip extends across a surface to occupy full surface for a part of the length of the piece.
- Very short wane dip - occupies the full surface for not over 4" of length.
- Short wane dip - occupies full surface for not over 16" of length.
Warp
Any deviation from a true or plane surface, including bow, crook, cup, twist, or any combination thereof. Warp restrictions are based on the average form of warp as it occurs normally, and any variation from this average form, such as short kinks, shall be appraised according to its equivalent effect. Pieces containing two or more forms of warp shall be appraised according to the combined effect in determining the amount permissible. In grading rules, warp is classified as very light, light, medium, and heavy, and applied to each width and length as set forth in the various grades in accordance with the following provisions:
- 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.
- 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.
- Cup - a deviation in the face of a piece from a straight line drawn from edge to edge of a piece. It is measured at the point of greatest distance from the straight line.
- Twist - a deviation flatwise, or a combination of flatwise 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.
Water Soak
Water Soak or Stain is a water-soaked area in heartwood, usually interpreted as the incipient stage of certain wood rots.
Wavy Dressing
An involvement of more uneven dressing than knife marks.
- Very light wavy dressing - not over 0.4 mm (1/64 inch) deep.
- Light wavy dressing - not over 0.8 mm (1/32 inch) deep.
- Medium wavy dressing - not over 1.6 mm (1/16 inch) deep.
- Heavy wavy dressing - not over 3.2 mm (1/8 inch) deep.
- Very heavy wavy dressing - over 3.2 mm (1/8 inch) deep.
Well Spaced
The sum of the sizes of all knots in any 6" of length of a piece must not exceed twice the size of the largest knot permitted. More than one knot of maximum permissible size must not be in same 6" of length and the combination of knots must not be serious.