Back
Generally a lower grade veneer than that of the opposing side of the same panel when a higher grade face is specified.
Barber pole
A phenomenon in a book matched face wherein adjacent components appear alternately dark and light due to the presence of lathe checks on the loose side of the veneer refracting light and absorbing slightly more finishing material.
Bark Pocket
An area of bark surrounded by wood of normal growth and color.
Burl
A swirl or twist in the grain of wood, usually occurring near a knot, but which itself does not contain a knot.
Check
Any fracture of a veneer surface along the grain generally resulting from stresses due to un-even shrinkage during seasoning or acclimatization, often exacerbated when extreme conditions of exterior cold and interior heat and relative humidity occur simultaneously.
Core
Any substrate upon which a decorative wood veneer face and or back may be applied by some means of adhesion. A core may be fabricated from hardwood or softwood veneers of various thicknesses, or as engineered wood produced utilizing wood fibers (Medium Density Fiberboard – MDF) or wood chips and smaller particles (Particle Board Core – PBC)
Cross band
A component ply in a veneer core hardwood plywood panel with a grain orientation at an approximate right angle to that of the face, back, and any other inner plies within the core of the panel. Also used to infer the inner ply in a veneer core panel occurring directly adjacent to the face and back of a given panel.
Defect
Any manufacturing mark or damage that interferes with the aesthetic appearance or usability of a given panel. Types of defects include delamination, machine or handling damage, dents or impressions (press fault) in a face or back, face or back visible due to excessive sanding (sand-through), core show through, and the like. A natural characteristic such as a knot, split, bark pocket, mineral streak, other color marks or streaks, worm holes, or worm tracks are not considered defects, but rather are limited in occurrence by one of the applicable grades. Allowable but unrepaired or poorly repaired natural characteristics may be considered as defects.
Delamination
A separation of two or more plies in a hardwood plywood panel due to adhesion failure that can result from a number of causes.
Equilibrium moisture content
The moisture content eventually attained in wood exposed to a given environment. Also, the moisture content a given wood component would need to attain to be in balance with its environment.
Face
The better side of a decorative 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.
Figure
Any acute deviation of the normal grain direction in a given tree. Depending on intensity and population in the log, figure may be identified by several esoteric names such as cross bar, swirl, burl, tiger stripe, fiddle back, mottled, ropey, birds’ eye, among others. Note: figure is common in wood to the extent that wood without figure is the exception, not the rule.
Grain
The pattern, size and direction of the fibers in wood or veneer.
Gum spots or streaks
Accumulations of dark, amorphous, water soluble material often found embedded between adjacent growth rings of certain species of hardwoods, most notably American black cherry (Prunus serotina). Source is unknown 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 rift cut appearance.
Hardwood
General term referring to solid wood or wood veneer originating from one of the broad leaved trees belonging 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 having 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.
Knot (Pin)
A knot 1/4″ or less in diameter, with no missing knot material. The center of a pin knot may be dark up to 1/8″ (conspicuous), or natural in color with no dark center (blending or inconspicuous).
Knot (Sound)
Knots that are solidly fixed by growth and that retain their place in lumber or veneer.
Knothole
Opening produced when knots drop from the wood in which they were once embedded.
Lap
A manufacturing defect that occurs when a portion of a sheet of veneer splits and subsequently overlaps itself due to uneven moisture movement. A lap may occur in a face and back where it may resemble a split if the errant portion is still intact in the lap or a press dent if the errant portion is missing. It may also occur in a core component wherein it will create a localized thickness difference in the panel that will result in the face or back veneer being sanded off or in the core itself showing through the face or back.
Medium Density Fiberboard (MDF)
Engineered wood panel product consisting of wood reduced to basic lignocellulosic fiber bundles integrated with adhesive and compressed under heat for use as a substrate for decorative hardwood plywood face veneers, paper and plastic laminates, and high pressure laminate (HPL), among others.
Mineral Streak
A generally blue-gray to black elongated discoloration on the surface of solid lumber or decorative veneer.
Moisture content
The percentage by weight of water in wood relative to the weight of the wood with all the moisture removed.
Particleboard (PBC)
Engineered wood panel product consisting of small wood particles and fiber bundles integrated with adhesive and compressed under heat for use as a substrate for decorative hardwood plywood face veneers, paper and plastic laminates, and high pressure laminate (HPL), among others.
Patch
Any repair to a decorative wood veneer, consisting of synthetic filler or wood veneer inserts.
Plain Sliced
Wood veneer cut roughly parallel to the pith of the tree on a tangent to the growth rings, generally having a relatively consistent appearance from piece to piece, and usually producing at least some semblance of a cathedral grain pattern at some point during the slicing process.
Ply
A single sheet of veneer forming one layer in a multi-layered piece of plywood.
Plywood, Hardwood
A panel composed of layers of one or more inner plies of wood veneer, MDF, PBC, or other core material joined with an adhesive to a face and back veneer of hardwood or decorative softwood veneer.
Quarter Slicing
Decorative face veneer cut on a radial angle to the growth rings of the tree by slicing a quarter log, or a half log as it is reduced to a point near the pith of the tree. Typically, quarter sliced oak (Quercus spp.) veneer will have relatively straight grain with pronounced flake across the growth rings due to the fact that the cut is roughly parallel to the oak rays which are wider than in most other species.
Ray
Flattened band of parenchyma cells projecting from the center of the tree to the cambium. Present in all species, but pronounced in some species, particularly red and white oak and alder.
Rift Cut
Decorative face veneer cut on a radial angle to the growth rings of the tree by slicing a quarter log, or a half log as it is reduced to a point near the pith of the tree. Typically, rift cut oak (Quercus spp.) veneer will have relatively straight grain with minimal flake across the growth rings due to the fact that the cut is roughly across rather than parallel to the rays.
Rotary Cut
Veneer peeled from a whole log set in a lathe and turned against a special knife.
Sapwood
The light colored, active portion of a tree located between the generally darker heartwood and the bark.
Shake (Ring shake, Wind shake)
A separation of wood structure parallel to one or more growth rings generally associated with traumatic shear stress that may result from wind storms, ice storms, or felling.
Shop Grade (Developed shop)
A common, non-standard industry term broadly defined in the glossary of the HPVA HP-1 standard, but not included as a part of the standard. Generally interpreted and accepted as a panel that is deemed by the final inspector at the producing mill to be less than 100% usable due to a manufacturing defect such as a dent, scratch, or damage, but having at least 85% of the surface area of the panel that is unblemished and assumed to be usable. Shop developed from a normal production run of panels.
Species
An internationally established and recognized Latin binomial nomenclature used to identify every living plant or animal. As with all such classifications, trees are identified by both genus and species, e. g.: Acer rubrum. Acer is the genus and rubrum is the species, in this case it refers to red or soft maple. Species with the “s” on the end is used for both singular and plural applications. It is always “species.”
Slip matched
Veneer sheets that consist of individual components spliced side by side without turning any of them over to form staggered but repetitive grain appearance with all components oriented so that the tight side of each veneer is on the same side of the sheet. Often specified as “Slip Match – Tight Side Out (SMTSO).”
Split, splice line
A separation occurring between adjacent components in a hardwood plywood panel face, generally resulting from stresses that cause the actual joint to fail, but not the wood fiber within the adjacent components.
Veneer
Peeled or sliced thin sheets of wood used as decorative faces or inner plies in a hardwood plywood panel
