ASTM D9-20

Standard Terminology Relating to Wood and Wood-Based Products

SCOPE
1.1 This terminology covers a repository of definitions essential for the business of Committee D07.  
1.2 The following criteria shall be followed by Subcommittee D07.91 in selecting terms and associated definitions for inclusion in this terminology.  
1.2.1 Terms and associated definitions shall be selected if they are in general use in the conduct of the standards over which D07 has jurisdiction.  
1.2.2 Terms and associated definitions in general industrial or technical use that are not unique to wood or wood-based products are not included.  
1.2.3 Terms and associated definitions that are unique to a single D07 standard and defined therein or generally understood or adequately defined in other readily available sources may not be included in this terminology.  
1.3 When a term is used in an ASTM document for which Committee D07 is responsible, it is included in this terminology only when judged an essential term by Subcommittee D07.91.  
1.4 A definition is a single sentence with additional information included in discussion notes.  
1.5 Terms and definitions shall be reviewed every 5 years; the year of last review is appended.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jul-2020
• ICS: 01.040.79 - Wood technology (Vocabularies)
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.91 - Terminology and Editorial

Relations

• Refers: ASTM D2555-17a(2024)e1 - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Feb-2024
• Refers: ASTM D2555-17a(2024) - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Feb-2024
• Refers: ASTM D143-23 - Standard Test Methods for Small Clear Specimens of Timber
• Effective Date: 15-Nov-2023
• Refers: ASTM D2016-74(1983) - Methods of Test for Moisture Content of Wood (Withdrawn 1987)
• Effective Date: 29-Sep-2023
• Refers: ASTM D1038-19 - Standard Terminology Relating to Veneer, Plywood, and Wood Structural Panels
• Effective Date: 01-Mar-2019
• Refers: ASTM D2555-17a - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Aug-2017
• Refers: ASTM D2555-17 - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 15-Apr-2017
• Refers: ASTM D2555-16 - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Aug-2016
• Refers: ASTM D2555-15 - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Sep-2015
• Refers: ASTM D2395-14e1 - Standard Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
• Effective Date: 01-May-2014
• Refers: ASTM D2395-14 - Standard Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
• Effective Date: 01-May-2014
• Refers: ASTM D907-12a - Standard Terminology of Adhesives
• Effective Date: 01-Jul-2012
• Refers: ASTM D907-12 - Standard Terminology of Adhesives
• Effective Date: 01-May-2012
• Refers: ASTM F547-06(2012) - Standard Terminology of Nails for Use with Wood and Wood-Base Materials
• Effective Date: 01-Apr-2012
• Refers: ASTM D907-11a - Standard Terminology of Adhesives
• Effective Date: 01-Dec-2011

Overview

ASTM D9-20, Standard Terminology Relating to Wood and Wood-Based Products, is an essential reference developed by ASTM International. Supervised by Committee D07 on Wood, this standard maintains a comprehensive, authoritative collection of definitions specific to wood and wood-based materials. It ensures clear, precise communication across the wood products industry by standardizing vocabulary and terminology commonly used in the field. By defining key terms, this terminology underpins consistent understanding among manufacturers, suppliers, regulators, and professionals involved with wood products, supporting compliance and best practices worldwide.

Key Topics

• Selection and Inclusion Criteria:
  Only terms uniquely significant to wood and wood-based products, regularly used under Committee D07's jurisdiction, are included. Terms of very general technical use or unique to a specific standard not in broad use are not listed here.

• Comprehensive Definitions:
  Each definition is concise, with a single-sentence description and, when needed, followed by discussion notes for context or clarification. The document undergoes periodic review at least every five years to ensure ongoing accuracy and relevance.

• Specific Wood-related Concepts:
  Definitions cover a broad range of wood and wood product terminology such as "annual ring," "bark pocket," "beam," "board foot," "casehardening," "decay," "density," "grain," "heartwood," "knot," "lumber," and more.

• Standardized Measurement Units:
  Common units (e.g., board foot, nominal size, moisture content) are defined to eliminate ambiguity in trade, construction, and manufacturing processes.

• Alignment with International Principles:
  ASTM D9-20 was developed in accordance with recognized international standardization principles, ensuring its application is globally compatible, especially regarding technical barriers to trade.

Applications

• Product Manufacturing & Quality Control:
  Wood product manufacturers utilize ASTM D9-20 terminology for accurate product specification, labeling, and compliance with technical standards. Clear definitions help maintain production consistency and facilitate the implementation of quality control systems.

• Construction & Building Codes:
  Builders, engineers, and architects reference these terms to ensure plans, blueprints, and communications are unambiguous and meet industry norms, particularly when specifying materials (e.g., lumber grades, timbers, panels).

• Trade & Procurement:
  Suppliers and buyers across global markets rely on standardized definitions to ensure proper understanding in sales, contracts, import/export documentation, and technical specifications.

• Regulatory & Certification Activities:
  Regulators, auditors, and certifying bodies use this standard terminology to anchor assessments, certifications, and inspections, thereby supporting safety, sustainability, and code compliance.

• Education & Training:
  Educational programs and industry training reference ASTM D9-20 for accurate and uniform instruction on wood properties, wood-based materials, and their uses.

Related Standards

The terminologies and concepts outlined in ASTM D9-20 are complemented by other important ASTM standards, including:

• ASTM D245 – Practice for Establishing Structural Grades and Allowable Properties for Visually Graded Lumber
• ASTM D907 – Terminology of Adhesives
• ASTM D1038 – Terminology Relating to Veneer, Plywood, and Wood Structural Panels
• ASTM D1165 – Nomenclature of Commercial Hardwoods and Softwoods
• ASTM D1554 – Terminology Relating to Wood-Base Fiber and Particle Panel Materials
• ASTM F547 – Terminology of Nails for Use with Wood and Wood-Base Materials
• PS-20 – American Softwood Lumber Standard

By referencing ASTM D9-20 alongside these related standards, professionals in the wood products industry can ensure comprehensive and harmonized understanding, specification, and implementation of wood materials in their projects and operations.

Keywords: ASTM D9-20, wood terminology, wood-based products, standard definitions, lumber standards, wood industry standards, ASTM wood committees, wood product specifications, building material standards, international wood trade.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D9 − 20
Standard Terminology Relating to
Wood and Wood-Based Products
This standard is issued under the fixed designation D9; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The definitions contained herein constitute a lexicon of terms of general interest. Definitions in
more specialized wood product or process use will be found in other standards.These include Practice
D245, Terminology D907, Terminology D1038, Nomenclature D1165, Terminology D1554, Termi-
nology F547, Practice D2555, and Terminology C274.
1. Scope mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This terminology covers a repository of definitions
essential for the business of Committee D07.
2. Referenced Documents
1.2 The following criteria shall be followed by Subcommit-
2.1 ASTM Standards:
tee D07.91 in selecting terms and associated definitions for
C274 Terminology of Structural Sandwich Constructions
inclusion in this terminology.
(Withdrawn 2016)
1.2.1 Terms and associated definitions shall be selected if
D143 Test Methods for Small Clear Specimens of Timber
they are in general use in the conduct of the standards over
D245 Practice for Establishing Structural Grades and Re-
which D07 has jurisdiction.
lated Allowable Properties for Visually Graded Lumber
1.2.2 Terms and associated definitions in general industrial
D907 Terminology of Adhesives
or technical use that are not unique to wood or wood-based
D1038 TerminologyRelatingtoVeneer,Plywood,andWood
products are not included.
Structural Panels
1.2.3 Terms and associated definitions that are unique to a
D1165 Nomenclature of Commercial Hardwoods and Soft-
single D07 standard and defined therein or generally under-
woods
stood or adequately defined in other readily available sources
D1554 Terminology Relating to Wood-Base Fiber and Par-
may not be included in this terminology.
ticle Panel Materials
D2016 Methods of Test for Moisture Content of Wood
1.3 When a term is used in an ASTM document for which
(Withdrawn 1987)
Committee D07 is responsible, it is included in this terminol-
D2395 TestMethodsforDensityandSpecificGravity(Rela-
ogy only when judged an essential term by Subcommittee
tive Density) of Wood and Wood-Based Materials
D07.91.
D2555 PracticeforEstablishingClearWoodStrengthValues
1.4 A definition is a single sentence with additional infor-
F547 Terminology of Nails for Use with Wood and Wood-
mation included in discussion notes.
Base Materials
1.5 Terms and definitions shall be reviewed every 5 years;
2.2 U.S. Products Standards:
the year of last review is appended.
PS-20 American Softwood Lumber Standard
1.6 This international standard was developed in accor-
3. Terminology
dance with internationally recognized principles on standard-
allowable properties, n—mechanical properties of a material
ization established in the Decision on Principles for the
as prepared for design use.
Development of International Standards, Guides and Recom-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This terminology is under the jurisdiction of ASTM Committee D07 on Wood Standards volume information, refer to the standard’s Document Summary page on
and is the direct responsibility of Subcommittee D07.91 on Terminology and the ASTM website.
Editorial. The last approved version of this historical standard is referenced on
Current edition approved Aug. 1, 2020. Published September 2020. Originally www.astm.org.
approved in 1907. Last previous edition approved in 2012 as D9 – 12. DOI: Available from the National Institute of Standards and Technology https://
10.1520/D0009-20. www.nist.gov/standardsgov/voluntary-product-standards-program.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D9−20
DISCUSSION—Allowable properties of structural wood products are
veneer; and
identified with stress-grade descriptions and reflect the orthotropic
(3)shortportionofalogpreparedforproductionofshingles,
structure of wood. Often considered synonymous with allowable unit
staves, etc.
stresses, working stresses, and design stresses.
bow, n—see warp.
American Softwood Lumber Standard, n—voluntary prod-
uct standard (PS-20) of the U.S. Department of Commerce
brashness, n—conditionthatcausessomepiecesofwoodtobe
which serves as a basis for the preparation and revision of
relatively low in shock resistance for the species and, when
industry-sponsored grading rules for lumber.
broken in bending, to fail abruptly without splintering at
comparatively small deflections.
American standard lumber, n—lumber conforming to the
basic provisions of PS-20 – American Softwood Lumber
buck, v—see crosscut.
Standard.
built-up timbers, n—assembly made by joining layers of
annual ring, n—growth ring(s) corresponding to an annual
lumber together with mechanical fastenings or adhesives, or
period of growth.
both, so the grain of all laminations is essentially parallel.
DISCUSSION—In temperate and boreal regions, usually, includes one
ring of earlywood and one ring of latewood. In tropical and subtropical burl, n—(1) hard, woody outgrowth on a tree, more or less
regions and areas with variable climate, more than one growth ring a
rounded in form, usually resulting from the entwined growth
year may be produced.
of a cluster of adventitious buds; and (2) in wood or veneer,
localized severe distortion of the grain generally rounded in
bark, n—layer of a tree outside the cambium comprising the
outline, usually resulting from overgrowth of dead branch
inner bark and the outer bark.
stubs, varying from ⁄2 in. to several inches in diameter;
bark pocket, n—opening between growth rings that contains
frequently includes one or more clusters of several small
or that has contained bark.
contiguous conical protuberances, each usually having a
DISCUSSION—Bark pockets appear as dark streaks on radial surfaces
core of pith but no appreciable amount of end grain (in
and as rounded areas on tangential surfaces.
tangential view) surrounding it.
inner bark, n—layer of living bark (bast or phloem) that
cambium, n—tissue layer that provides cells for plant growth.
separates the outer bark from the cambium and which in the
DISCUSSION—Lies between phloem and xylem.
living tree generally is moist and soft.
outer bark, n—layer of dead bark outside the inner bark,
cant, n—log that has been slabbed on one or more sides,
forming the exterior surface of the tree stem.
usually with the intention of resawing at right angles to the
DISCUSSION—The outer bark frequently is corky and dry.
widest sawn face.
basic stress (archaic), n—term once used for an allowable
casehardening, n—condition of stress and set in wood due to
property for clear, straight-grained lumber.
dryinginwhichouterfibersareundercompressivestressand
inner fibers under tensile stress, a condition that often exists
bast, n—see inner bark and phloem.
during subsequent processing.
batten, n—narrow strip of lumber for covering the adjoining DISCUSSION—In commerce, the term often connotes a degree of
severity regarded as detrimental in use.
edges of roofing or siding, often designated as batts.
cell, n—general term for the minute units of wood structure
batts, n—see batten.
having distinct cell walls and cell cavities including wood
beam, n—horizontal load-carrying structural member of a
fibers, vessel segments, and other elements of diverse
building or other structure; see composite wood beam and
structure and function.
structural wood beam.
cellulose, n—carbohydrate that is the principal constituent of
board foot, n—unit of measurement represented by a board
wood and forms the structural framework of the wood cells.
1 ft long, nominal 1 ft wide, and nominal 1 in. thick (abbre-
viation: ft. b.m., bd. ft., fmb, or fbm). characteristic, n—distinguishing feature or trait; in grading
lumber and other wood products, a feature in or on the wood
DISCUSSION—In finished or surfaced lumber, the board-foot measure
isbasedonthenominalsize.Inpractice,theworkingunitis1000board
which by its nature, extent, and frequency of occurrence
feet (abbreviation: M bd. ft., M B.M., M B.F, or MFBM).
determines the grade or level of quality.
board measure, n—unit of measurement of the volume in
characteristic size, n—standard dimensions of the piece at
board feet of logs or lumber (abbreviation: B.M.).
which the characteristic value is calculated.
boards, n—see lumber.
characteristic value, n—structural property estimate, typically
a population mean, median, or tolerance limit value esti-
bole, n—trunk of size sufficient to yield lumber, veneer, or
mated from the test data that is representative of the
poles.
population being sampled.
bolt, n—(1) short section of a tree trunk or limb;
DISCUSSION—Test data is typically adjusted to standardized condi-
(2) short log of a length suitable for peeling in a lathe for tions of temperature, moisture content, and characteristic size.
D9−20
occurs, and its lack of demarcation between earlywood and latewood in
check, n—separation along the wood fibers that usually ex-
the same annual rings. Compression wood shrinks excessively
tends across the growth rings as a result of stresses set up in
lengthwise, as compared with normal wood.
wood during seasoning.
conifers, n—see softwoods.
end check, n—seasoning check occurring on the end of a
board or other piece of wood.
crook, n—see warp.
heart check, n—check that extends across the growth layers
cross break, n—separation of the wood cells across the grain.
in one or more directions from the pith toward, but not to, the
DISCUSSION—Suchbreaksmaybeduetointernalstressresultingfrom
surface of a piece of wood; synonym for pith check.
unequal longitudinal shrinkage or external forces.
pith check, n—see heart check.
cross grain, n—see grain.
roller check, n—crack occurring in cupped lumber being
cross section, n—plane section perpendicular to the longitudi-
flattened between machine rollers.
nal axis.
star check, n—heartcheckinwhichtheseparationextendsin
more than one direction from the pith.
crosscut, v—to cut a board, timber, or log generally transverse
to the direction of the fibers; synonym for buck.
surface check, n—check occurring on the surface of a piece
of wood, usually on the tangential face not extending through
cup, n—see warp.
the piece.
decay, n—decomposition of wood substance caused by action
through check, n—check that extends through a piece of
of wood-destroying fungi, resulting in softening, loss of
wood, or from a surface to the opposite or to an adjoining
strengthandweight,andofteninchangeoftextureandcolor.
surface.
advanced (or typical) decay, n—older stage of decay in
chips, n—small fragments of wood chopped or broken by cuts
which the destruction is readily recognized because the wood
such as by a planer, chipper, mechanical hog, hammermill.
has become punky, soft and spongy, stringy, ring-shaked,
pitted, or crumbly.
clear, adj—free of defects or imperfections.
DISCUSSION—Decided discoloration or bleaching of the rotted wood
coarse grain, n—see grain. is often apparent.
incipient decay, n—early stage of decay that has not pro-
collapse, n—flattening of single cells or rows of cells during
ceededfarenoughtosoftenorotherwiseperceptiblyimpairthe
the drying or pressure treatment of wood, characterized by a
hardness of the wood.
caved-in or corrugated appearance.
DISCUSSION—It may be accompanied by a slight discoloration or
bleaching of the wood.
composite wood beam, n—laminar construction comprising a
combination of wood and other simple or complex materials
pocket rot, n—advanced decay that appears in the form of a
assembledandintimatelyfixedinrelationtoeachothersoas
hole, pocket, or area of soft rot usually surrounded by
to use the properties of each to attain specific structural
apparently sound wood.
advantage of the whole assembly.
defect, n—irregularity or imperfection in a tree, log, piece,
compression failure, n—deformation of the wood fibers re-
product,orlumberthatreducesthevolumeofsoundwoodor
sulting from excessive compression along the grain either in lowers its durability, strength, or utility value.
direct end compression or in bending.
degrade, n—reduction in quality of lumber, logs, or other
DISCUSSION—Itmaydevelopinstandingtreesduetobendingbywind
wood products due to processing.
or snow or to internal longitudinal stresses developed in growth, or it
may result from stresses imposed after the tree is cut. In surfaced
dense, adj—(1) term used in stress grading of certain softwood
lumber, compression failures appear as fine wrinkles across the face of
species to signify a high specific gravity; and (2) visual
the piece.
estimate of high specific gravity.
compression parallel to grain, n—compression, endwise
DISCUSSION—To be classified as dense, the softwood species shall
(parallel to the grain). average on one end or the other of each piece, not less than six annual
rings per inch and one-third or more latewood. Pieces not less than four
DISCUSSION—The imposition of a compressive stress that acts in a
rings per inch shall be accepted as dense if they average one-half or
direction parallel to the grain of the wood, as in a column.
more latewood.
compression perpendicular to grain, n—compression, side-
density, n—mass per volume of a specimen at specified
wise (perpendicular to the grain).
moisture content.
DISCUSSION—The imposition of a compressive stress that acts in a
DISCUSSION—The moisture content is specified for both mass and
direction approximately perpendicular to the grain of the wood.
volume. For further discussion, see Test Methods D2395.
compression wood, n—abnormal wood formed typically on
depth factor, n—factor included in deriving the allowable
the lower side of branches and inclined stems of softwood
bending stress for rectangular members which takes into
trees.
account the somewhat lower unit strength developed in
DISCUSSION—Compression wood is identified by its relatively wide
larger members as compared to smaller members; archaic
annual rings, usually eccentric, relatively large amount of latewood,
sometimes more than 50 % of the width of the annual rings in which it terminology more correctly termed size factor.
D9−20
depth of beam, n—dimension of the beam that is perpendicu- flat grain, n—see grain.
lar to the span and parallel to the direction in which the load
form factor, n—factor used in the calculation of the bending
is applied.
strengthofwoodmemberstocompensatefornonrectangular
diffuse-porous woods, n—hardwoods, in which the pores
shape.
exhibitlittleornovariationinsizeordistributionthroughout DISCUSSION—Defined as the ratio of the modulus of rupture of a
member of desired shape to that of a “standard” member.
the growth ring, only decreasing slightly in size, gradually
toward the outer border of the ring.
fracture toughness, n—conventional fracture mechanics
strength parameter indicating the resistance of a material to
dimensional stabilization, n—treatment of wood to reduce
crack extension.
swelling and shrinking caused by changes in its moisture
content.
glued-laminated timber (glulam), n—term used to denote a
dote, n—see decay. product made from suitable selected and prepared pieces of
wood bonded together with an adhesive, either in a straight
dressed size, n—see lumber.
or curved form, with the grain of all pieces essentially
parallel to the longitudinal axis of the member.
drying, n—see seasoning.
grade, n—designation of the quality of logs, lumber, or other
dry-bulb temperature, n—temperature of the air as indicated
wood products.
by an accurate thermometer, corrected for radiation if
significant.
grade quality index (GQI), n—numerical assessment of the
visual growth characteristics found in the sample specimens
durability, n—general term for permanence or resistance to
deterioration. that are considered to be strength related and are limited as
DISCUSSION—Frequently used to refer to the degree of resistance of a part of the grade description.
species of wood to attack by wood-destroying fungi under conditions
grain, n—direction, size, arrangement, appearance, or quality
that favor such attack. In this connection, the term “decay resistance”
is more specific. of the fibers in lumber or other wood products.
DISCUSSION—To have a specific meaning the term must be qualified.
duration of load, n—duration of stress or the time during
chipped grain, n—machine defect of surfaced lumber, where
which a load acts on a member.
thegrainofthewoodhasbeentornoutinsmallparticlesbythe
DISCUSSION—In wood, a design consideration for modifying allow-
action of the planer knives.
able stresses, based on the accumulated loadings anticipated in the life
of a structure.
close grain, n—(1) narrow, inconspicuous annual rings; (2)
in stress grading, annual ring count limited to rings per unit
E-rated lumber, n—lumber graded for use in manufacturing
glued-laminated timber by nondestructive measurement of a distance specifications on one end or the other of the piece.
DISCUSSION—The term is sometimes used to designate wood having
modulus of elasticity (E), and by visual inspection in
small and closely spaced pores, but in this sense the term “fine
accordance with the grading rules of the applicable grading
textured” is more often used.
or inspection agency.
coarse grain, n—wide conspicuous annual rings in which
earlywood, n—less dense, large-celled, part of the growth
there is considerable difference between earlywood and late-
layerformedfirstduringtheannualgrowthcycle;asynonym
wood.
for springwood.
DISCUSSION—The term is sometimes used to designate wood with
large pores, such as oak, ash, chestnut, and walnut, but in this sense the
equilibrium moisture content, n—moisture content at which
term “coarse textured” is more often used.
wood neither gains nor loses moisture to the surrounding air.
cross grain, n—anygraindeviationfromalineparalleltothe
extractives, n—compounds occurring in plant materials but
sides of the piece.
not forming part of the structural elements, that are removed
DISCUSSION—Cross grain may be either diagonal or spiral grain or a
with neutral solvents such as ether, alcohol, and water.
combination of the two.
curly grain, n—grain distortion with an irregular curled
face, n—wide surface of rectangular pieces of lumber that is
often the surface that determines the grade of lumber appearance.
DISCUSSION—“Birdseye” is an extreme case of curly grain.
destined for remanufacture.
diagonal grain, n—grain pattern in which the annual rings
fiber, n—see wood fiber.
are at an angle to the sides of a piece as a result of sawing at
fiber saturation point, n—moisture content at which the cell
an angle to the bark of the tree.
walls are saturated with water (bound water) and no water is
DISCUSSION—Diagonal grain is a form of cross grain.
held in the cell cavities by capillary forces.
edge grain, n—grain pattern exposed on a face of lumber
DISCUSSION—It ranges from 25 to 30 % moisture content in most
that has been sawed in a plane approximately perpendicular to
wood, based on weight when oven-dry.
the growth rings.
fire retardant, adj—having or providing comparatively low
DISCUSSION—Lumber is considered edge grained when the growth
flammability or flame spread properties. rings form an angle of 45° to 90° to the face.
D9−20
end grain, n—grain pattern exposed when ends of logs or growth ring, n—layer of wood produced in one growing
timbers, dimension, boards, and other wood products are cut season.
perpendicular to the fiber direction. DISCUSSION—In temperate and boreal regions, growth rings generally
correspond to annual rings. In tropical and subtropical regions, growth
fine grain, n—synonym for close grain.
rings are often indiscernible.
flat grain, n—grain pattern exposed on a face of lumber that
hardness, n—term relating to the capacity of wood to with-
has been sawed in a plane approximately parallel to the growth
stand denting and abrasion.
rings.
DISCUSSION—For purposes of comparison, hardness in wood is often
DISCUSSION—Lumber is considered flat grained when the growth
measured as the load in pounds (kilograms) required to embed a
rings form an angle of less than 45° to the face.
0.444-in. (11.3 mm) ball to one-half its diameter (Test Methods D143).
interlocked grain, n—wood in which the fibers are inclined
hardwood dimension, n—hardwood stock processed to the
in one direction in a number of growth rings, then gradually
specified thickness, width, and length, or in multiples
reverse and are inclined in an opposite direction in succeeding
thereof.
growth rings, then reverse again.
loosened grain, n—separation or loosening of the earlywood hardwoods, n—generally, trees of the botanical class
from the latewood due to defects in the wood or processing
Angiospermae, subclass Dicotyledonae that have broad
such as planing. leaves.
DISCUSSION—The term has no reference to the actual hardness of the
medium grain, n—used in stress grading to denote wood
wood in these trees.
averaging on one end or the other of each piece not less than
four annual rings per inch.
heartwood, n—inner layer of a woody stem wholly composed
of nonliving cells and usually differentiated from the outer
mixed grain, n—grain pattern in lumber unrestricted or
enveloping layer (sapwood) by its darker color.
unsegregated as to the grain angle on either face.
DISCUSSION—It is usually more decay resistant than sapwood.
open grain, n—(1)commonclassificationrelatedtofinishing
of woods with large pores, such as oak, ash, and chestnut; also holes, n—openings in or through lumber that may extend
known as “coarse textured;” and (2) used in stress grading to partially or entirely through a piece and may be from any
denote no limitations on rate of growth as measured by annual
cause.
rings per inch.
honeycomb, n—advanced stage of decay caused by Phellinus
plainsawn, adj—synonymous with flat grain.
pini (formerly named Fomes pini).
quartersawn, adj—synonymous with edge grain.
honeycombing, n—in lumber and other wood products, sepa-
raised grain, n—condition of the surface of dressed lumber
ration of the fibers in the interior of the piece, usually along
in which the hard latewood is raised above the softer early-
the wood rays.
wood but not torn loose from it.
DISCUSSION—The failures often are not visible on the surfaces,
although they can be the extensions of surface and end checks.
rift sawn, adj—synonymous with edge grain.
slash grain, n—synonym for flat grain. horizontal shear, n—shear that occurs in planes parallel to the
longitudinal axis of the member; sometimes referred to as
spiral grain, n—grainpatterninwhichthefiberstakeaspiral
longitudinal shear.
course about the stem of a tree instead of the normal vertical
course.
impact bending, n—application of an impact load in bending
DISCUSSION—The spiral grain may extend in a right-handed or
to obtain a measure of the ability of wood to absorb shock
left-handed direction around the tree stem. Spiral grain is a form of
loads.
cross grain.
in-grade sampling, n—collection of samples from lumber
straight-grained wood, n—wood in which the fibers run
grades as commercially produced.
parallel to the axis of a piece.
DISCUSSION—Samples collected in this manner are intended to
torn grain, n—machine defect of surfaced lumber, where the
represent the full range of strength and modulus of elasticity values
fibers of the wood have been torn out around knots and curly
normally found within a grade.
places by the action of the planer knives.
incise, v—to make slitlike lacerations generally parallel to the
vertical grain, n—synonym for edge grain.
grain in the lateral surface of timbers that are resistant to
wavy-grained wood, n—wood in which the fibers form a
treatment, so that deeper and more uniform penetration of
pattern of fairly uniform waves or undulations.
preservative may be obtained.
green, adj—(1) as applied to wood, freshly sawed that has
increment borer, n—augerlike instrument with a hollow bit,
received no or limited drying in ambient conditions (syn-
used to extract cores from trees for study of growth and age
onym for unseasoned); and (2) as applied to lumber, having
and for other research purposes.
a moisture content above a stipulated value.
joint, n—junction of two or more pieces of wood.
DISCUSSION—Lumber above 19 % moisture content, at the time of
manufacture, is considered green in accordance with the American DISCUSSION—Usually implies a structural junction in which stress is
Softwood Lumber Standard. transmitted from one piece to another.
D9−20
juvenile wood, n—wood formed adjacent to the pith, charac- sound knot, n—knot that is solid across its face, at least as
terized by progressive change in cell dimension, different hard as the surrounding wood, and shows no indication of
microstructure than mature wood, and greater shrinkage decay.
parallel to the grain.
spike knot, n—knot cut at from 0° to 45° to the long axis of
DISCUSSION—In softwoods, juvenile wood is characterized by lower
the limb.
specific gravity and strength. It may vary in quantity from tree to tree
and extend from the pith 5 to 20 growth rings.
tight knot, n—knot so fixed by growth or position that it will
firmly retain its place in the piece.
kiln, n—chamber used for drying and conditioning lumber,
veneer, and other wood products in which the temperature
unsound knot, n—knot which is not solid across the face as
and relative humidity of the circulated air can be varied and
a result of decay and is not as hard as the surrounding wood.
controlled.
laminated strand lumber (LSL), n—structural composite
kiln schedule, n—in kiln drying, time schedule of predeter-
lumber made of wood strand elements with wood fibers
mined or actual dry-bulb and wet-bulb temperatures used in
primarilyorientedalongthelongitudinalaxisofthemember,
drying a kiln charge of lumber or other wood products.
where the least dimension of the wood strand elements is
0.10 in. (2.54 mm) or less and their average length is a
knot , n—portion of a branch or limb which has been sur-
minimum of 150 times their least dimension.
rounded by subsequent growth of the wood of the tree.
DISCUSSION—As a knot appears on the cut surface it is merely a
laminated veneer bamboo (LVB), n—structural composite
section of the entire knot, its shape depending upon the direction of the
lumber made of bamboo strand elements, edge-bonded to
cut.
form veneer sheets which are then face-bonded to form
branch knots, n—two or more knots diverging from a
finished products, with bamboo fibers primarily oriented
common point at or near the pith.
along the longitudinal axis of the member where the least
decayed knot, n—knot that, due to advanced decay, is softer
dimension of the strand elements is 0.25 in. (6.4 mm) or less
than the surrounding wood.
and their average length is a minimum of 300 times their
edge knot, n—(1) knot located at the edge of the face in a
least dimension.
piece of lumber; and (2) in stress grading under Practice D245,
laminated veneer lumber (LVL), n—structural composite
knot whose perimeter falls within one-sixth of the knot width
lumber made of wood veneer sheet elements with wood
from the edge of the piece.
fibers primarily oriented along the longitudinal axis of the
DISCUSSION—The knot width is measured along a line transverse to
the piece. member, where the thickness of the veneer sheet elements is
0.25 in. (6.4 mm) or less.
encased knot, n—knot whose growth rings are not inter-
grown with those of the surrounding wood.
latewood, n—denser, smaller-celled, later-formed part of a
firm knot, n—knot that is solid across its face, but which
growth layer; synonym for summerwood.
contains incipient decay.
lath, n—thin, narrow strips of rough wood.
fixed knot, n—knot that will hold its place in dry lumber
under ordinary conditions, but can be moved under pressure,
log, n—section of the trunk of a tree usually referring to a
although not easily pushed out.
length suitable for conversion to commercial produ
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D9 − 12 D9 − 20
Standard Terminology Relating to
Wood and Wood-Based Products
This standard is issued under the fixed designation D9; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The definitions contained herein constitute a lexicon of terms of general interest. Definitions in
more specialized wood product or process use will be found in other standards. These include Practice
D245, Terminology D907, Terminology D1038, Nomenclature D1165, Terminology D1554, Termi-
nology F547, Practice D2555, and Terminology C274.
1. Scope
1.1 This terminology covers a repository of definitions essential for the business of Committee D07.
1.2 The following criteria shall be followed by Subcommittee D07.91 in selecting terms and associated definitions for inclusion
in this terminology.
1.2.1 Terms and associated definitions shall be selected if they are in general use in the conduct of the standards over which D07
has jurisdiction.
1.2.2 Terms and associated definitions in general industrial or technical use that are not unique to wood or wood-based products
are not included.
1.2.3 Terms and associated definitions that are unique to a single D07 standard and defined therein or generally understood or
adequately defined in other readily available sources may not be included in this terminology.
1.3 When a term is used in an ASTM document for which Committee D07 is responsible, it is included in this terminology only
when judged an essential term by Subcommittee D07.91.
1.4 A definition is a single sentence with additional information included in discussion notes.
1.5 Terms and definitions shall be reviewed every 5 years; the year of last review is appended.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This terminology is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.91 on Terminology and Editorial.
Current edition approved Oct. 15, 2012Aug. 1, 2020. Published November 2012September 2020. Originally approved in 1907. Last previous edition approved in 20092012
as D9D9 – 12.– 09AE01. DOI: 10.1520/D0009-12. 10.1520/D0009-20.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D9 − 20
2. Referenced Documents
2.1 ASTM Standards:
C274 Terminology of Structural Sandwich Constructions (Withdrawn 2016)
D143 Test Methods for Small Clear Specimens of Timber
D245 Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber
D907 Terminology of Adhesives
D1038 Terminology Relating to Veneer, Plywood, and Wood Structural Panels
D1165 Nomenclature of Commercial Hardwoods and Softwoods
D1554 Terminology Relating to Wood-Base Fiber and Particle Panel Materials
D2016 Methods of Test for Moisture Content of Wood (Withdrawn 1987)
D2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
D2555 Practice for Establishing Clear Wood Strength Values
F547 Terminology of Nails for Use with Wood and Wood-Base Materials
2.2 U.S. Products Standards:
PS-20 American Softwood Lumber Standard
3. Terminology
allowable properties—properties, n—mechanical properties of materials a material as prepared for design use.
DISCUSSION—
Allowable properties of structural wood products are identified with stress-grade descriptions and reflect the orthotropic structure of wood. Often
considered synonymous with allowable unit stresses, working stresses, and design stresses.
American Softwood Lumber Standard—Standard, n—a voluntary product standard (PS-20) of the U.S. Department of
Commerce which serves as a basis for the preparation and revision of industry-sponsored grading rules for lumber.
American standard lumber—lumber, n—lumber conforming to the basic provisions of the PS-20 – American Softwood
Lumber Standard.
annual ring—ring, n—the growth layer produced by the tree in a single growth year, including earlywood and latewood.growth
ring(s) corresponding to an annual period of growth.
DISCUSSION—
In temperate and boreal regions, usually, includes one ring of earlywood and one ring of latewood. In tropical and subtropical regions and areas with
variable climate, more than one growth ring a year may be produced.
bark, pocket—n—the layer of a tree outside the cambium comprising the inner bark and the outer bark.
bark productpocket,—n—an opening between annual growth rings that contains bark. or that has contained bark.
DISCUSSION—
Bark pockets appear as dark streaks on radial surfaces and as rounded areas on tangential surfaces.
inner bark,—n—the layer of living bark (phloem) (bast or phloem) that separates the outer bark from the cambium and which
in the living tree generally is moist and soft.
outer bark,—n—the layer of dead bark outside the inner bark, forming the exterior surface of the tree stem.
DISCUSSION—
The outer bark frequently is corky and dry.
basic stress (archaic)(archaic),—n—the term once used for an allowable property for clear, straight-grained lumber.
bast, n—see inner bark and phloem.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from the National Institute of Standards and Technology https://www.nist.gov/standardsgov/voluntary-product-standards-program.
D9 − 20
batten—batten, n—a narrow strip of lumber for covering the adjoining edges of roofing or siding, often designated as
“batts.”batts.
batts, n—see batten.
beam, n—horizontal load-carrying structural member of a building or other structure; see composite wood beam and structural
wood beam.
board foot—foot, n—a unit of measurement represented by a board 1 ft long, nominal 1 ft wide, and nominal 1 in. thick
(abbreviation: ft. b.m., bd. ft., fmb). fmb, or fbm).
DISCUSSION—
In finished or surfaced lumber, the board-foot measure is based on the nominal size. In practice, the working unit is 1000 board feet (abbreviation:
M bd. ft., M B.M., M B.F).M B.F, or MFBM).
board measure—measure, n—a unit of measurement of the volume in board feet of logs or lumber (abbreviation: B.M.).
boards,—n—see lumber.
bole—bole, n—the stem or trunk of a tree of size sufficient to yield lumber, veneer, or poles.
bolt—bolt, n—(1) a short section of a tree trunk or limb;
(2) a short log of a length suitable for peeling in a lathe for veneer; and
(3) a short portion of a log prepared for production of shingles, staves, etc.
bow—bow, n—thesee distortion warp.of a piece of lumber in which there is a deviation in a direction perpendicular to the flat
face from a straight line from end to end of the piece.
brashness—brashness, n—a condition that causes some pieces of wood to be relatively low in shock resistance for the species
and, when broken in bending, to fail abruptly without splintering at comparatively small deflections.
buck, v—see crosscut.
built-up timbers—timbers, n—an assembly made by joining layers of lumber together with mechanical fastenings or
adhesives, or both, so the grain of all laminations is essentially parallel.
burl—burl, n—(1) a hard, woody outgrowth on a tree, more or less rounded in form, usually resulting from the entwined growth
of a cluster of adventitious buds; and
(2) in wood or veneer, a localized severe distortion of the grain generally rounded in outline, usually resulting from overgrowth
of dead branch stubs, varying from ⁄2 in. to several inches in diameter; frequently includes one or more clusters of several small
contiguous conical protuberances, each usually having a core of pith but no appreciable amount of end grain (in tangential view)
surrounding it.
cambium—cambium, n—thetissue layer of cells that lies between the inner bark and the wood of a tree, that repeatedly
subdivides to form new wood and bark cells.that provides cells for plant growth.
DISCUSSION—
Lies between phloem and xylem.
cant—cant, n—a log that has been slabbed on one or more sides, usually with the intention of resawing at right angles to the
widest sawn face.
D9 − 20
casehardening—casehardening, n—a condition of stress and set in wood due to drying in which outer fibers are under
compressive stress and inner fibers under tensile stress, a condition that often exists during subsequent processing.
DISCUSSION—
In commerce, the term often connotes a degree of severity regarded as detrimental in use.
cell—cell, n—a general term for the minute units of wood structure having distinct cell walls and cell cavities including wood
fibers, vessel segments, and other elements of diverse structure and function.
cellulose—cellulose, n—the carbohydrate that is the principal constituent of wood and forms the structural framework of the
wood cells.
characteristic—characteristic, n—a distinguishing feature or trait; in grading lumber and other wood products, a feature in or
on the wood which by its nature, extent, and frequency of occurrence determines the grade or level of quality.
characteristic size—size, n—the standard dimensions of the piece at which the characteristic value is calculated.
characteristic value—value, n—the structural property estimate, typically a population mean, median, or tolerance limit value
estimated from the test data that is representative of the population being sampled.
DISCUSSION—
Test data is typically adjusted to standardized conditions of temperature, moisture content, and characteristic size.
check—check, n—a separation of the wood separation along the fiber directionwood fibers that usually extends across the rings
of annual growth, commonly resulting from growth rings as a result of stresses set up in wood during seasoning.
end check,—n—a seasoning check occurring on the end of a board or other piece of wood.
heart check,—n—a check that extends across the growth layers in one or more directions from the pith toward, but not to, the
surface of a piece of wood; a synonym isfor pith check.
pith check,—n—see heart check.
roller check,—n—a crack in the wood structure caused by a piece of occurring in cupped lumber being flattened between
machine rollers.
star check,—n—a heart check in which the separation extends in more than one direction from the pith.
surface check,—n—a check occurring on the surface of a piece of wood, usually on the tangential face not extending through
the piece.
through check,—n—a check that extends through a piece of wood, or from a surface to the opposite or to an adjoining surface.
chips—chips, n—small fragments of wood chopped or broken by cuts such as by a planer, chipper, mechanical hog,
hammermill.
clear—clear, adj—free of defects or imperfections.
coarse grain,—n—see grain.
collapse—collapse, n—the flattening of single cells or rows of cells during the drying or pressure treatment of wood,
characterized by a caved-in or corrugated appearance.
composite wood beam—beam, n—a laminar construction comprising a combination of wood and other simple or complex
materials assembled and intimately fixed in relation to each other so as to use the properties of each to attain specific structural
advantage of the whole assembly.
D9 − 20
compression failure—failure, n—deformation of the wood fibers resulting from excessive compression along the grain either
in direct end compression or in bending.
DISCUSSION—
It may develop in standing trees due to bending by wind or snow or to internal longitudinal stresses developed in growth, or it may result from stresses
imposed after the tree is cut. In surfaced lumber, compression failures appear as fine wrinkles across the face of the piece.
compression parallel to grain—grain, n—compression, endwise (parallel to the grain).
DISCUSSION—
The imposition of a compressive stress that acts in a direction parallel to the grain of the wood, as in a column.
compression perpendicular to grain—grain, n—compression, sidewise (perpendicular to the grain).
DISCUSSION—
The imposition of a compressive stress that acts in a direction approximately perpendicular to the grain of the wood.
compression wood—wood, n—abnormal wood formed typically on the lower side of branches and inclined trunksstems of
softwood trees.
DISCUSSION—
Compression wood is identified by its relatively wide annual rings, usually eccentric, relatively large amount of latewood, sometimes more than 50 %
of the width of the annual rings in which it occurs, and its lack of demarcation between earlywood and latewood in the same annual rings. Compression
wood shrinks excessively lengthwise, as compared with normal wood.
conifer—conifers, n—a tree belonging to the order see Coniferae,softwoods. usually evergreen, with cones and needle-shaped
or scalelike leaves, and producing wood known commercially as “softwood.”
crook—crook, n—asee distortion warp.of a piece of lumber in which there is a deviation in a direction perpendicular to the
edge from a straight line from end to end of the piece.
cross break—break, n—a separation of the wood cells across the grain.
DISCUSSION—
Such breaks may be due to internal stress resulting from unequal longitudinal shrinkage or external forces.
cross grain,—n—see grain.
cross section—section, n—a section of a stem, board, or other piece of wood taken at right angles to itsplane section
perpendicular to the longitudinal axis.
crosscut—crosscut, v—to cut a board, timber, or log generally transverse to the direction of the fibers; a synonym isfor
“buck.”buck.
cup—cup, n—asee distortion warp.of a board in which there is a deviation flatwise from a straight line across the width of the
board.
decay—decay, n—decomposition of wood substance caused by action of wood-destroying fungi, resulting in softening, loss of
strength and weight, and often in change of texture and color.
advanced (or typical) decay,—n—the older stage of decay in which the destruction is readily recognized because the wood has
become punky, soft and spongy, stringy, ring-shaked, pitted, or crumbly.
DISCUSSION—
Decided discoloration or bleaching of the rotted wood is often apparent.
incipient decay,—n—the early stage of decay that has not proceeded far enough to soften or otherwise perceptibly impair the
hardness of the wood.
DISCUSSION—
It may be accompanied by a slight discoloration or bleaching of the wood.
D9 − 20
pocket rot,—n—advanced decay that appears in the form of a hole, pocket, or area of soft rot usually surrounded by apparently
sound wood.
defect—defect, n—any irregularity or imperfection in a tree, log, piece, product, or lumber that reduces the volume of sound
wood or lowers its durability, strength, or utility value.
degrade, n—a reduction in quality of lumber, logs, or other wood products due to processing.
dense—dense, adj—(1) term used in stress grading of certain softwood species to signify a high specific gravity; and
(2) a visual estimate of high specific gravity.
DISCUSSION—
To be classified as dense, the softwood species shall average on one end or the other of each piece, not less than six annual rings per inch and one-third
or more latewood. Pieces not less than four rings per inch shall be accepted as dense if they average one-half or more latewood.
density, n—mass per volume of a specimen at specified moisture content.
DISCUSSION—
The moisture content is specified for both mass and volume. For further discussion, see Test Methods D2395.
depth factor—factor, n—the factor included in deriving the allowable bending stress for rectangular members which takes into
account the somewhat lower unit strength developed in larger members as compared to smaller members; archaic terminology
more correctly termed size factor.
depth of beam—beam, n—that dimension of the beam that is perpendicular to the span and parallel to the direction in which
the load is applied.
diffuse porousdiffuse-porous woods, wood—n—certain hardwoods hardwoods, in which the pores exhibit little or no variation
in size or distribution throughout the growth ring, only decreasing slightly in size, gradually toward the outer border of the ring.
dimensional stabilization—stabilization, n—treatment of wood to reduce swelling and shrinking caused by changes in its
moisture content.
dote,—n—see decay.
dressed size,—n—see lumber.
drying,—n—see seasoning.
dry-bulb temperature—temperature, n—temperature of the air as indicated by an accurate thermometer, corrected for
radiation if significant.
durability—durability, n—a general term for permanence or resistance to deterioration.
DISCUSSION—
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.
duration of load—load, n—the duration of stress or the time during which a load acts on a member.
DISCUSSION—
In wood, a design consideration for modifying allowable stresses, based on the accumulated loadings anticipated in the life of a structure.
E-rated lumber—lumber, n—lumber graded for use in manufacturing glued-laminated timber by nondestructive measurement
of a modulus of elasticity (E), and by visual inspection in accordance with the grading rules of the applicable grading or
inspection agency.
D9 − 20
earlywood—earlywood, n—the less dense, large-celled, part of the growth layer formed first during the annual growth cycle;
a synonym for springwood.
equilibrium moisture content—content, n—a moisture content at which wood neither gains nor loses moisture to the
surrounding air.
extractives—extractives, n—compounds occurring in plant materials but not forming part of the structural elements, that are
removed with neutral solvents such as ether, alcohol, and water.
face—face, n—the wide surface of rectangular pieces of lumber. Often lumber that is often the surface that determines the grade
of lumber destined for remanufacture.
1 1
fiber, wood—n—a comparativelysee long ( ⁄25 in. or less to ⁄3 in.), narrow, tapering wood cell wood fiber.closed at both ends.
fiber saturation point—point, n—the moisture content at which the cell walls are saturated with water (bound water) and no
water is held in the cell cavities by capillary forces.
DISCUSSION—
It usually is taken as 25 % ranges from 25 to 30 % moisture content, content in most wood, based on weight when ovendry.oven-dry.
fire retardant—retardant, adj—having or providing comparatively low flammability or flame spread properties.
flat grain,—n—see grain.
form factor—factor, n—a factor used in the calculation of the bending strength of wood members to compensate for
nonrectangular shape.
DISCUSSION—
Defined as the ratio of the modulus of rupture of a member of desired shape to that of a “standard” member.
fracture toughness—toughness, n—a conventional fracture mechanics strength parameter indicating the resistance of a
material to crack extension.
glued-laminated timber (glulam)—(glulam), n—a term used to denote glued-laminated timber that is a product made from
suitable selected and prepared pieces of wood bonded together with an adhesive witheradhesive, either in a straight or curved
form, with the grain of all pieces essentially parallel to the longitudinal axis of the member.
grade—grade, n—the designation of the quality of logs or of a manufactured piece of wood.logs, lumber, or other wood
products.
grade quality index (GQI)—(GQI), n—a numerical assessment of the visual growth characteristics found in the sample
specimens that are considered to be strength related and are limited as part of the grade description.
grain—grain, n—the direction, size, arrangement, appearance, or quality of the fibers in lumber or other wood products.
DISCUSSION—
To have a specific meaning the term must be qualified.
chipped grain,—n—a machine defect of surfaced lumber, where the grain of the wood has been torn out in small particles by
the action of the planer knives.
close grain,—n—(1) narrow, inconspicuous annual rings; the term is sometimes used to designate wood having small and closely
spaced pores, but in this sense the term “fine textured” is more often used; and
(2) in stress grading, wood averaging annual ring count limited to rings per unit distance specifications on one end or the other
D9 − 20
of each piece not less than six nor more than 30 annual rings per inch; pieces averaging at least five or more than 30 rings per inch
are accepted as close grain if containing one-third or more summerwood.the piece.
DISCUSSION—
The term is sometimes used to designate wood having small and closely spaced pores, but in this sense the term “fine textured” is more often used.
coarse grain,—n—wide conspicuous annual rings in which there is considerable difference between earlywood and latewood.
DISCUSSION—
The term is sometimes used to designate wood with large pores, such as oak, ash, chestnut, and walnut, but in this sense the term “coarse textured”
is more often used.
cross grain,—n—fiber any grain deviation from a line parallel to the sides of the piece.
DISCUSSION—
Cross grain may be either diagonal or spiral grain or a combination of the two.
curly grain,—n—grain distortion with an irregular curled appearance; “birdseye” is an extreme case of curly grain.appearance.
DISCUSSION—
“Birdseye” is an extreme case of curly grain.
diagonal grain,—n—grain pattern in which the annual rings are at an angle withto the axissides of a piece as a result of sawing
at an angle withto the bark of the tree or log; a form of tree.cross grain.
DISCUSSION—
Diagonal grain is a form of cross grain.
edge grain,—n—grain pattern in which the wide surfaces of the sawn piece extend approximately at right angles to the annual
exposed on a face of lumber that has been sawed in a plane approximately perpendicular to the growth rings.
DISCUSSION—
Lumber is considered edge grained when the growth rings form an angle of 45° to 90° with the wide surface of the piece.to the face.
end grain,—n—the grain pattern exposed when ends of logs or timbers, dimension, boards, and other wood products are cut
perpendicular to the fiber direction.
fine grain,—n—a synonym for close grain.
flat grain,—n—the grain pattern resulting when lumber exposed on a face of lumber that has been sawed in a plane
approximately perpendicularparallel to the radius of the log. growth rings.
DISCUSSION—
Lumber is considered flat grained when the annual growth rings makeform an angle of less than 45° with the surface of the piece.to the face.
interlocked grain,—n—wood in which the fibers are inclined in one direction in a number of rings of annual growth, growth
rings, then gradually reverse and are inclined in an opposite direction in succeeding growth rings, then reverse again.
loosened grain,—n—a separation or loosening of the earlywood from the latewood due to defects in the wood or processing such
as planing.
medium grain,—n—used in stress grading to denote wood averaging on one end or the other of each piece not less than four
annual rings per inch.
mixed grain,—n—lumber and other wood products grain pattern in lumber unrestricted or unsegregated as to the grain
angle.angle on either face.
open grain,—n—(1) common classification related to finishing of woods with large pores, such as oak, ash, and chestnut; also
known as “coarse textured;” and (2) used in stress grading to denote no limitations on rate of growth as measured by annual rings
per inch.
plainsawn,—adj—a synonym for synonymous with flat grain.
quartersawn,—adj—a synonym for synonymous with edge grain.
raised grain,—n—a condition of the surface of dressed lumber in which the hard latewood is raised above the softer earlywood
but not torn loose from it.
rift sawn,—adj—a synonym for synonymous with edge grain.
slash grain,—n—a synonym for flat grain.
spiral grain,—n—wood grain pattern in which the fibers take a spiral course about the trunkstem of a tree instead of the normal
vertical course.
DISCUSSION—
The spiral grain may extend in a right-handed or left-handed direction around the tree trunk.stem. Spiral grain is a form of cross grain.
straight-grained wood,—n—wood in which the fibers run parallel to the axis of a piece.
torn grain,—n—a machine defect of surfaced lumber, where the fibers of the wood have been torn out around knots and curly
places by the action of the planer knives.
vertical grain,—n—a synonym for edge grain.
wavy-grained wood,—n—wood in which the fibers form a pattern of fairly uniform waves or undulations.
D9 − 20
green—green, adj—(1(1)) freshly sawed wood, or wood as applied to wood, freshly sawed that has received no drying;
unseasoned; lumber that may have become wet to above the fiber saturation point may be referred to as being in the “green
condition;” andor limited drying in ambient conditions (synonym for
( 2unseasoned) wood); and (2) as applied to lumber, having a moisture content above a stipulated moisture content, as lumber
above 19 % moisture content in accordance with the American Softwood Lumber Standard.value.
DISCUSSION—
Lumber above 19 % moisture content, at the time of manufacture, is considered green in accordance with the American Softwood Lumber Standard.
growth ring, n—layer of wood produced in one growing season.
DISCUSSION—
In temperate and boreal regions, growth rings generally correspond to annual rings. In tropical and subtropical regions, growth rings are often
indiscernible.
hardness—hardness, n—a term relating to the capacity of wood to withstand denting and abrasion; for purposes of comparison,
hardness in wood is often measured as the load in pounds required to embed a 0.444-in. ball to one-half its diameter (Test
Methods abrasion.D143).
DISCUSSION—
For purposes of comparison, hardness in wood is often measured as the load in pounds (kilograms) required to embed a 0.444-in. (11.3 mm) ball to
one-half its diameter (Test Methods D143).
hardwood dimension—dimension, n—hardwood stock processed to the specified thickness, width, and length, or in multiples
thereof.
hardwoods—hardwoods, n—generally onegenerally, trees of the botanical groupsclass ofAngiospermae, treessubclass
Dicotyledonae that have broad leaves in contrast to the conifers or softwoods. leaves.
DISCUSSION—
The term has no reference to the actual hardness of the wood.wood in these trees.
heartwood—heartwood, n—the inner layer of a woody stem wholly composed of nonliving cells and usually differentiated
from the outer enveloping layer (sapwood) by its darker color.
DISCUSSION—
It is usually more decay resistant than sapwood.
holes—holes, n—openings in or through lumber that may extend partially or entirely through a piece and may be from any
cause.
honeycomb—honeycomb, n—advanced stage of decay caused by Phellinus pini (formerly named Fomes pini.pini).
honeycombing—honeycombing, n—in lumber and other wood products, separation of the fibers in the interior of the piece,
usually along the wood rays.
DISCUSSION—
The failures often are not visible on the surfaces, although they can be the extensions of surface and end checks.
horizontal shear—shear, n—shear that occurs in planes parallel to the longitudinal axis of the member; sometimes referred to
as longitudinal shear.
impact bending—bending, n—application of an impact load in bending to obtain a measure of the ability of wood to absorb
shock loads.
in-grade—in-grade sampling, n—collection of samples collected from lumber grades as commercially produced.
DISCUSSION—
Samples collected in this manner are intended to represent the full range of strength and modulus of elasticity values normally found within a grade.
D9 − 20
incise—incise, v—to make slitlike lacerations generally parallel to the grain in the lateral surface of timbers that are resistant
to treatment, so that deeper and more uniform penetration of preservative may be obtained.
increment borer—borer, n—an augerlike instrument with a hollow bit, used to extract cores from trees for study of growth and
age and for other research purposes.
joint—joint, n—the junction of two or more pieces of wood.
DISCUSSION—
Usually implies a structural junction in which stress is transmitted from one piece to another.
juvenile wood—wood, n—the wood formed adjacent to the pith, characterized by progressive change in cell dimension,
different microstructure than mature wood, and greater shrinkage parallel to the grain.
DISCUSSION—
In softwoods, juvenile wood is characterized by lower specific gravity and strength. It may vary in quantity from tree to tree and extend from the pith
5 to 20 growth rings.
kiln—kiln, n—a chamber used for drying and conditioning lumber, veneer, and other wood products in which the temperature
and relative humidity of the circulated air can be varied and controlled, often steam heated and vented.controlled.
kiln schedule—schedule, n—in kiln drying, the time schedule of predetermined or actual dry-bulb and wet-bulb temperatures
used in drying a kiln charge of lumber or other wood products.
knot —, n—that portion of a branch or limb which has been surrounded by subsequent growth of the wood of the tree.
DISCUSSION—
As a knot appears on the cut surface it is merely a section of the entire knot, its shape depending upon the direction of the cut.
branch knots,—n—two or more knots diverging from a common point at or near the pith.
decayed knot,—n—a knot that, due to advanced decay, is softer than the surrounding wood.
edge knot,—n—(1) a knot located at the edge of the face in a piece of lumber; and (2) in stress grading under Practice D245,
a knot whose perimeter falls within one-sixth of the knot width from the edge of the piece.
DISCUSSION—
The knot width is measured along a line transverse to the piece.
encased knot,—n—a knot whose rings of annual growth growth rings are not intergrown with those of the surrounding wood.
firm knot,—n—a knot that is solid across its face, but which contains incipient decay.
fixed knot,—n—a knot that will hold its place in dry lumber under ordinary conditions, but can be moved under pressure,
although not easily pushed out.
group knots,—n—two or more single knots grouped together.
intergrown knot,—n—a knot whose rings of annual growth growth rings are completely intergrown with those of the surrounding
wood.
knot cluster,—n—two or more knots grouped together as a unit, the fibers of the wood being deflected around the entire unit.
DISCUSSION—
Distinct from a group of single knots in which each is a unit.
loose knot,—n—a knot that is not held firmly in place by growth or position and that cannot be relied upon to remain in place.
pith knot,—n—a sound knot having a pith hole not over ⁄4 in. (6.4 mm) in diameter.
round knot,—n—a knot that is cut at approximately right angles to its long axis of the limb.
single knot,—n—a knot having adjoining wood fibers deflected around it alone and not around another knot.
sound knot,—n—a knot that is solid across its face, at least as hard as the surrounding wood, and shows no indication of decay.
spike knot,—n—a knot cut at from 0° to 45° to the long axis of the limb.
tight knot,—n—a knot so fixed by growth or position that it will firmly retain its place in the piece.
unsound knot,—n—a knot which is not so
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