A simple and accessible tool for understanding the fundamental terms related to wood. From the meaning of sapwood and heartwood to the characteristics of texture, grain, and density. A useful resource for professionals, citizens, and students who want to familiarize themselves with the language of the sector.
General term used to refer to a single cell. Note: It is used in wood anatomy primarily to distinguish vessels from the individual cells of which they are composed.
In wood flooring, it is the smallest single piece.
Wood species Scientific name: Ulmus sp.p Origin: Central and Southern Europe, Southern Siberia, North Africa, Minor Asia, from West and North Asia to Japan.
Referring to panels, this refers to a surface treatment by which heat and pressure determine a variety of textured effects to panel surfaces that remain smooth and paintable.
Hole made by an insect to get out of wood.
Period of the year during which insects, whose larvae are xylophagous, emerge from wood.
A prompt phytosanitary action carried out in a new or unforeseen phytosanitary situation.
A phytosanitary measure determined urgently in a new or unforeseen phytosanitary situation. These emergency measure may or may not be an provisional measure.
Treatment process of impregnating wood with preservatives or chemicals in which air, trapped inside the wood under pressure, expands when the pressure is released resulting in the release of part of the preservative or other injected substances. The distinguishing feature of the process is that a depression is not achieved before the preservative is applied. The goal is to achieve a good distribution of the preservative on the wood cell walls and to only partially fill the cell lumens. Basically, it is a pressure/vacuum procedure that consists of the following steps: – initial pressure to compress the air inside the wood; – introduction of impregnant and application of pressure; – discharge of the impregnant and final vacuum to remove excess liquid from the surface of the wood. With this procedure, the impregnant does not fill the wood cells but forms a light layer on their walls. An example of an empty cell process is the Rueping process.
Dispersion of active ingredients in water stabilised with emulsifying agents
Knot surrounded by bark for more than 3/4 of its perimeter.
Structure intended to delimit and enclose a space of land, often made in the form of a wooden palisade.
Ending part of a wooden element in which the main anatomical constituents (fibers or tracheids) are cut transverse to the grain
A union, end to end, between two pieces of wood by means of gluing (finger joint or juxtaposed joints) or mechanical fasteners (for example: wavy fasteners).
Juxtaposition of sliced veneers arranged one after the other along the narrowest margin, i.e., arranged head to head.
Also called X-shaped stacking, or inverted V stacking. It consists in arranging boards upright and resting with the edge on a common support so that two rows of boards form an X or an inverted V. It is employed to accelerate air drying.
Crack appearing on the surface of the top end.
Vertical stacking of boards lying against a wall or support, with the faces more or less in contact. Frequent in retail places.
Drying level of the wood suitable for the use to which the material is intended.
Moisture suitable for the environmental conditions of the end use.
Conventional term in wood anatomy for: (a)-a cell wall at right angles to the longitudinal axis of a parenchymal cell. Meaning tangential walls of radius cells or the transverse walls of axial parenchymal cells; (b)- the oblique or transverse cell walls between two vessel elements.
Arrangement of timbers introduced into a dryer with the major axis in the direction of the length of the kiln.
In wood flooring, both the smaller surfaces of an element.
Chemical or physical reaction with a cooling effect.
Wood species Scientific name: Picea engelmannii Parry ex Engelm. Origin: North America
Wood species Scientific name: Picea engelmanni Engelm. Origin: Western regions of Canada and northwestern United States.
Structural panel able to provide special performance characteristics.
Generic term used for sawn timber, reconstituted products and wood structures to which reliable and consistent performance values can be applied. Most wood-based panels satisfy the above definition as well as OSB, PSL, LVL, glued laminated timber elements and “I” beams.
Treatment carried out on the faces of timber using appropriately shaped and arranged teeth. The purpose is to achieve one or more of the following effects: -Ease the seasoning of the wood. -Improving the preservative’s penetration. -Reduce stresses and cracking.
Heated and humidified air which flows into the wood pile as it circulates within the kiln.
In a pallet, side opening through which forklift forks are introduced.
Plate with a small group of circular perforations (as in Ephedra).
See “epicormic shoot”.
Branch or trace of a branch visible on the peripheral surface of the stem.
Shoot developing from a bud or dormant
The outermost layer of cells in the primary plant structure often with strongly thickened and cutinised outer cell walls.
Cell of the epithelium.
Layer of secretory parenchyma cells surrounding an intercellular canal or cavity.
Joint where parts are joined by elements that have been fixed with epoxy in oversized holes.
Joint whose parts are glued together with an epoxy-based adhesive.
Stage at the end of the drying process during which the moisture distribution between and within individual load components is equalized to the specific desired value.
Moisture achieved stably by wood depending on the thermo-hygrometric conditions of the surrounding environment (so wood neither absorbs nor gives up moisture). It can also take quite some time for wood to equilibrate with the surrounding environmental conditions. In relation to the different composition of wood-based panels, the equilibrium moisture content (and the resulting level of risk of biological attack that is associated with it) may differ from that of the solid wood used to produce the panels themselves.
Odorous substance derived from plant organisms or plant secretions.
Issued by the European Union, it is a document of general application and mandatory in all member states where it becomes part of national legislation. Unlike Directives, Regulations also include detailed rules for the application of the law.
Wood species Scientific name: Populus tremula L.
Wood species Scientific name: Buxus sempervirens L. Origin: Mediterranean basin
Wood species Scientific name: Ostrya carpinifolia Scop. (O. vulgaris Willd.). Origin: South Europe.
Wood species Scientific name: Aesculus hippocastanum L. Origin: Italy, North Greece, Bulgaria, Caucasus.
Wood species Scientific name: Tilia platyphyllos Scop. e Tilia cordata Mill. Origin: Central and Southern Europe, Caucasus, Urals, Southern Siberia.
Wood species Scientific name: Quercus petraea (Matt.) Liebl. In the wood trade, no distinction is made between European oak and oak (Quercus robur L.). Origin: Europe, Caucasus, Asia Minor.
Technical assessment of the suitability of a product for its intended use. It is based on correspondence to the essential requirements for the application in which the product is intended to be used.
European Standard (EN), European Technical Assessment (ETA) that is based on a European Assessment Document (EAD) or on a transparent and reproducible assessment that fulfils all requirements of the relevant EAD.
The technical standards issued by the technical standards body (CEN) of the European Union. More than 2000 working groups are currently engaged in harmonising the standards of the individual states and defining common standards for each category of products or services. For each of these, when a CEN working group is in operation, the standardisation activities of individual states are not permitted (so-called ‘standstill’ rule).
Term used quite incorrectly in the wood industry. See “steaming”.
See “heat and vent drying”
Forest consisting of trees of approximately the same age.
Earth-moving machine intended for digging. It consists of a base, with wheels or tracks, on which is mounted a turret (rotating around a vertical axis with respect to the base) that includes the manoeuvring place, the engine and the articulated arm with spoon bucket. The advancement of the machine, the rotation of the turret, the operation of the articulated arm and the spoon bucket are carried out with hydrostatic transmissions.
Pallet that, upon specific agreement, can be exchanged for a pallet of identical conformation.
Hot and humid air exiting the kiln through vents (pipes).
Chemical or physical reaction with a heating effect.
Steel tube of expanded diameter used as dowel-type fastener.
Gap that should be provided between the contact areas of the edges of semi-finished wooden products (e.g., between the boundary of a wooden floor formed by glued frise and the wall) to allow for possible swelling due to moisture absorption.
Heartwood not enclosed by sapwood
Pith visible on one face or edge.
Application of the adhesive by extrusion process.
A substance used in the formulation of an adhesive mixture intended for gluing plywood or a wood-based panel. It is added for the purpose of changing the viscosity and reducing the cost of the adhesive (resin). Typically, additives are further divided into “excipients” and “fillers” and result in a decrease in the durability of an adhesive.
A low-cost additive used in the formulation of an adhesive mixture intended for bonding plywood or a wood-based panel. It is added for the purpose of changing the viscosity and reducing the cost of the adhesive (resin).
See “waterproof bondig”.
Conditions corresponding to service class 3 of EN 1995-1-1:2004, characterized by conditions that lead to higher moisture contents than those in service class 2.
Substances present in the lumen of wood cells that are not part of their cell wall. They can be removed since they are soluble in hot or cold water, ether, benzene or other solvents that do not chemically react with wood components. A variety of substances (phenols, tannins, terpenes, pigments, oils, gums, resins) belong to the group of extractives. Some of them are very important for their influence on the natural color of wood and its natural durability.
Particlepanel obtained by introducing wood particles mixed with glue under two flat heatable elements. The latter are placed at the distance corresponding to the thickness of the panel so that the particles remain oriented in the direction perpendicular to the faces of the panel.
A manufacturing process that involves alternating pressing of particles as they are placed within two heated plates spaced the thickness of the finished panel. In this way the particles are oriented with their largest dimension perpendicular to the thickness of the panel and will then manifest a greater possibility of swelling as a result of any moisture changes along that direction. Appropriately spaced steel bars can be placed between the plates, resulting in panels characterized by a series of “channels” running perpendicular to their thickness (useful, for example, for inserting cables or other accessories of electrical, telephone installations).
Each of the two widest opposite longitudinal surfaces of the sawn timber or, if the sawn timber has a square cross-section, any of the longitudinal surfaces. Sometimes the term is used to indicate the best quality surface of a sawn timber, a semi-finished product or a wood-based panel. In the case of plywood, where no quality distinction is possible, both surfaces are considered to be faces. For example, in the case of a B/C plywood, the face is the side with the B-quality outer ply; in the case of a BB/BB plywood, both sides are faces.
A joint between two faces of wooden pieces.
Knot visible on one or both faces of a sawn timber.
Face and eye protector from small branches, chips or shavings that may be thrown during chainsaw use.
Fissure noticeable on one face and possibly at the end.
Industrial establishment conveniently equipped for a specific production.
In glue products, it includes separations both within the glue layer (fracture due to lack of cohesion) and between the glue layer and the glued piece (fracture due to lack of adhesion), as well as wood fractures in the proximity of the glue expressed in percent of the glue line under consideration.
Market held in special buildings and with a given frequency. It is normally intended for the presentation of goods and the meeting of producers and buyers.
Device, with blocks or rolls, of windlass that allows a mainline to be used without damage in directions other than perpendicular to the axis of the drum.
Additional growth ring, apparently complete, with well-marked boundaries, formed within a vegetative period. In contrast to density fluctuations, false rings are not morphologically distinguishable from true annual rings and can only be detected by cross dating.
Abnormal duramification sometimes visible on the cross-section of logs or other assortments that generally do not show color differentiation between the sapwood and heartwood portions. False heartwood is common in Beech (where it is also called “red heart”), Ash (“black heart” or “olivate”) and Poplar (“green heart” or “brown heart”). It appears as a darker-colored central zone (around the pith), the edges of which do not precisely follow the boundary between growth rings but show concentric zonations of different color shades that overlap irregularly. False heartwood does not have the advantages offered by regular duramification, which consist mainly of greater hardness and mechanical strength of the wood and greater natural durability than sapwood tissues, but it is often a defect that compromises the aesthetic appearance of a semi-finished product.
Sawn timber in which most of the angles between the beams and the face are between 30° and 70°. Note: The corresponding thresholds for species where the rays are not visible are 20° and 60° for most of the angles between the growth rings and the face.