Specification
rift cut appearance.
Hardwood: General term referring to
solid wood or wood veneer originating
from one of the broad leaved trees be-
longing to the class angiosperm. Does
not relate to the hardness or fragility of
the wood.
Heartwood: The central core of the
tree consisting of wood that was once
active sapwood but that has been
transformed to a neutral state due
to the accumulation of extraneous
materials and the depletion of oxygen,
causing it to take on a generally darker
color than that of the outer bands of
sapwood.
Knot: Cross section of a limb that
transfers to the surface of lumber or
veneer as a round or elliptical form hav-
ing the general appearance of growth
rings. The condition of the knot will
depend on whether it was alive, dead,
or decayed at the time of harvest.
Knot (open): Opening pronounced
when a portion of a knot has dropped
out or separated due to seasoning.
Grain: The pattern, size and direc-
tion of the bers in wood or veneer.
Growth ring: Any of the number of
layers of wood added to the stem of
a tree during a given growth period,
generally annually for temperate spe-
cies, but not necessarily for all tropical
or arboreal species.
Gum spots or streaks: Accumu-
lations of dark, amorphous, water
soluble material often found embed-
ded between adjacent growth rings
of certain species of hardwoods,
most notably American black cherry
(Prunus serotina). Source is un-
known but thought to be a response
by the tree to heal itself from injury.
Half round slicing: An adaptation of
rotary cutting, utilizing a stay log that
replaces the spindles so that the log
half or quarter may be mounted offset
from the center. The resulting cut is
oriented tangentially to the growth rings
to produce a plain sliced appearance,
or across the grain and rays, usually in
the oaks (Quercus spp.), to produce a
Hardwood Plywood Grading Guide 2015 columbiaforestproducts.com
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Face: The better side of a decora-
tive panel intended to be exposed in
service.
False quarters: Sheets of veneer
consisting of individual components
from near the center of the tree and
having straight grain produced by
conventional slicing of a half log
rather than by quarter slicing the log.
Few: A small number of characteris-
tics without regard to their arrange-
ment on a given face.
Figure: Any acute deviation of the
normal grain direction in a given tree.
Depending on intensity and popula-
tion in the log, gure may be identi-
ed by several esoteric names such
as cross bar, swirl, burl, tiger stripe,
ddle back, mottled, ropey, birds’
eye, among others. Note: gure is
common in wood to the extent that
wood without gure is the exception,
not the rule.
Fire rating (re rated): A standard
classication relative to the rate of
ame spread over time in a tunnel
test environment. Most wood prod-
ucts meet the classication of “C” in
accordance with the National Fire
Protection Association, Life Safety
Code, NFPA 101.
Fire retardant treated: In this con-
text, any wood panel or solid wood
component that has been chemically
treated in order to retard the rate of
ame spread. Such treated products
usually meet the requirements for
Class “A” in accordance with the
National Fire Protection Association,
Life Safety Code, NFPA 101. Gener-
ally available with a particle board or
medium density ber core that has
been treated as described above.
Face and backs are not treated, but
any veneer having a thickness less
than 1/28” does not affect the rating
of the panel. As of this printing,
re retardant treated veneer core is
unavailable and impractical.
Formaldehyde: A pungent, irritating
gaseous chemical commonly used
in many consumer products, that
when off-gassed causes many acute
conditions including itchy watery
eyes, sore throat, and runny nose.
It was once used in large volume to
produce decorative and engineered
wood components destined for resi-
dential or commercial applications,
but because it is now considered
a carcinogen in the scientic and
environmental community, its use
in such products has largely been
replaced by lower emitting products,
or formaldehyde free panels such as
Columbia Forest Products Pure-
bond®.
FSC®:
Forest Stewardship Coun-
cil™. An open member-led nonprot
organization that sets independent
standards by which forests are au-
dited, protecting them for future gen-
erations. FSC uses the power of the
marketplace to promote responsible
forest management, creating an eco-
label that helps consumers identify
products from such forests.
Grade: A designation set forth by
the Hardwood Plywood and Veneer
Association and its membership in the
ANSI/HPVA HP-1 American National
Standard for Hardwood and Decora-
tive Plywood, including 6 face grades,
AA-E, and 4 back grades, 1-4, with
each descending grade having more
frequent and larger characteristics than
the higher grades.
HARDWOOD TREES
NATIONAL STANDARD
HALF ROUND SLICNG
GRAIN
GROWTH RINGS
GLOSSARY OF HARDWOOD PLYWOOD TERMS