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.
Sawn timber with any mixture of vertical and flat grain.
Wood species Scientific name: Baillonella toxisperma Pierre (= Mimusops djave Engl.). Origin: African equatorial zone, western sector.
Texture characterised by the presence of medium-sized cells and/or not very large and regular growth rings.
Wood subjected to the action of a chemical, biological, or physical agent, leading to a permanent improvement in the properties.
Rectangular solid wood element with smooth edges.
In physics and mechanics, it is the constant that indicates the relationship between the intensity of the physical effect and the intensity of the forces that produced that effect.
Symbol: E. A value that expresses the deflection, stiffness or elasticity of a semi-finished product or wood-based panel. Also known as E or “Young’s Modulus,” it is defined by the ratio of a stress (force/surface area ratio) to relative strain measured within the limit of proportionality and reduced to unit area. It is generally determined on test samples by static bending stress. It is expressed in N/mm2.
Symbol: G. It is the shear stress required to produce a deformation equal to the unit; G is equal to the ratio of shear stress to unit shear deformation.
Tension or compressive unit stress measured for both upper and lower fibres of a beam subjected to a breaking load during a bending test. In other words, it is the unit stress calculated at the top and bottom of the beam at the level of fracture.
In the characterization of a material by static tests, it indicates the value of the tension corresponding to the breaking load of a test specimen reduced to its unit area. It is expressed in N/mm2. In ordinary language, the term is used to indicate the load or tension that an element is capable of withstanding without breaking.
Symbol: Z. Factor derived from the shape and cross-section of a beam or other element.
Mass of water contained in wood, usually expressed as a percentage of its anhydrous mass. Since the term ‘moisture’ is to be interpreted as ‘water content’, it is quite incorrect (although common) to refer to “moisture content”. A correct statement is “wood with a moisture content of 12 %” and not “wood with a moisture content of 12 %”.
Average moisture content in wood that exceeds tolerances on nominal value.
How wood moisture is distributed within the piece.
See “moisture pocket”.
Portion of wood that retains too much moisture after drying.
Fungi that appears as variously colored stains on the surface of moist wood and occur only when moisture on the wood surface is greater than 20 percent (e.g., as a result of high relative humidity or water vapor condensation). These fungi do not significantly affect the mechanical properties of wood, only the aesthetic properties. The alteration of appearance may be undesirable or unacceptable. These fungi are not specific to wood and can appear on any material having high moisture content.
Private organisation with a legal presence that has been recognised by the Secretary of State to provide Operators with operational due diligence systems.
Forest consisting of a single wood species.
Substance capable of fixing, in the form of an insoluble combination, dyestuffs used for dyeing.
Machine designed to make holes or slots of various shapes (usually oblong holes) in wood. It is typically used to obtain the “groove” of a tongue-and-groove joint.
Solid wood element characterized by small size, rectangular shape and smooth edges.
Preassembled laying unit in which square components of equal size are placed side by side and arranged in a checkerboard geometry.
Non-flat plywood panel, obtained by pressing on a form. It is also called curved or curved plywood panel.
Chip removal machinery with rotary tool equipped with multiple blades used to obtain shaped profiles. It is possible to obtain different contours of the semi-finished product depending on the profile of the blades.
Shaped element of a piece of architecture or a piece of furniture, consisting of straight or curved profile segments.
A block used for erecting yarder installations and for supporting, during operation, the skyline, anchor cables and guyline. It is not subjected to high rope speeds.
Swelling and shrinkage of seasoned timber or other wood-based products due to changes in equilibrium moisture content.
Phase of felling and setting up operations during which the operator approaches the first tree or log to be worked or moves from the last one worked to the next.
Specialized cell of the radius or axial parenchyma that contains mucilage. It typically has a rounded shape.
Machine (portable) and tool (carried and operated by tractors) for mulching.
Cutting or shredding of bushy vegetation.
A term used to refer to a particle board formed by distinct layers of particles of different particle size. Typically it consists of a central layer of coarse particles covered by two outer layers composed of fine particles capable of determining a greater regularity of the panel’s surfaces.
Element formed by a layer of solid wood and one or more additional layers of wood, or wood-based materials, glued together.
Plywood composed of more than three layers.
A portion of multilaminar wood block with a thickness greater than 5 mm. It is obtained by sawing the multilaminar wood block.
Material consisting of plies of wood (both softwood and hardwood) stacked together after being coated with adhesive and pressed to form a block or board. From this, by subsequent processing, sawn or sliced timber may be obtained for mainly decorative purposes. Multilaminar wood elements are distinguished as follows: – Sliced: thickness between 0.2 and 5 mm; – Sawn: thickness greater than 5 mm, namely: – Board: thickness up to and including 100 mm; – Block: thickness greater than 100 mm.
Wood element with a thickness greater than 100 mm. It consists of adhesive coated sheets, oriented according to the intended appearance and pressed. The block is worked until it assumes a parallelepiped shape.
Wooden element having a thickness of not more than 100 mm. It consists of adhesive-coated sheets, oriented according to the desired appearance and pressed. The board is machined to a parallelepiped shape.
Multilaminar wood sheet whose nominal thickness is between 0.2 mm and 5 mm. It is obtained by slicing the multilaminar wood block.
Solid wood panel consisting of two outer layers with parallel grain direction and at least one inner layer with grain direction at 90° to the outer layers.
Perforated end wall of a vessel element consisting of a perforation plate with two or more openings.
Curvature characterized by two or more deviations placed in one or more planes.
See “multiple sweep”.
Propagation by the agamic or vegetative way. Propagation by the sexual (gamic) process is called ‘reproduction’.
Ray of two or more cells wide (seen in tangential section).
Laminated wood flooring with the upper layer consisting of solid wood with a thickness of at least 2.5 mm and one or more additional layers as a core consisting of wood or lignified material with a mass of at least 75 per cent.
Wood species Scientific name: Guibourtia arnoldiana (De Wild. & Th.D?r.) J.Lèonard. ATIBT nomenclature: Mutènyè. Origin: West Africa.
Vegetative part of fungi formed by a set of hyphae.
Engineered panels in which wooden elements are joined together by nails.
Pointed element used for connections.
Laying system in which the fixing of the elements to the supporting structure is done by nails or screws.
Face parallel to the grain surface of the cross-laminated timber, veneer-based panel or solid wood, perpendicular to the veneer or ply planes.
Timber that, in cross section, has growth rings of limited width.
The term, hardly used in Italian, denotes the width of an unedged sawn timber measured at the narrowest point of the narrowest face.
A sample recognised by official national decision as the basis for fixing the value of all other samples of a given size in a nation.
Geographical and altitudinal area within which a species or subspecific entity occurs naturally.
In general terms, it indicates the ability of an untreated wood or wood product to resist degradation induced by environmental (physical-chemical) and biological (caused by bacteria, fungi, insects, and marine organisms) stresses. It more properly denotes the wood’s own resistance to attack by lignivorous organisms, which should be evaluated separately for each organism or group of organisms, both overall and for the sapwood and heartwood portions, and in relation to the conditions of use (i.e., according to the different risk and service classes). In relation to such resistance of wood to lignivorous fungi, five classes are provided: 1 very durable; 2 durable; 3 moderately durable; 4 slightly durable; 5 not durable. In relation to xylophagous beetles (cerambycids, anobids, lyctids), on the other hand, wood is classified into: R resistant; NR not resistant (NRH indicates that the heartwood is not resistant). With regard to termites it is classified into: R resistant; MR moderately resistant; NR not resistant. In relation to marine organisms, wood is classified into: D durable; MD moderately durable; ND not durable.
A simple kiln in which air circulation is due to natural convection currents.
Negligible risk is to be considered applicable to the supply of timber if a full evaluation of the specific and general product information shows no cause for concern.
Quantity of preservative that remains in the wood after treatment (i.e. without considering drying operations).
Average quantity of dry preservative salts per unit volume of wood in the charge at the end of the treatment process.
Wood species Scientific name: Agathis australis (D. Don) Origin: Malaysia, Indonesia, Pacific Islands, New Zealand.
Wood species Scientific name: Heritiera sp.p. (H. utilis) ATIBT nomenclature: Niangon. Origin: West Africa.
End wall of a parenchymal cell. It has a warty (pearly) appearance in cross section.
Retention of the test product determined to provide the performance specified in ENV 807 corresponding to the target retention of the reference preservative.
Length specified for round wood, excluding crosscut allowance.
See “target moisture content”
A term applied to lumber and lumber products to indicate the dimension for which a product is known and marketed (desired dimension at the specified moisture content) and to which deviations (which ideally should be zero) are reported. In fact, it often differs from the actual dimension because of the effect of shrinkage and decrease in thickness due to sanding.
Commercial designation subject to allowable tolerances. Same criteria applies also to the length and width of a semi-finished product.
Laminated wood consisting of layers of veneers glued together under controlled conditions of heat and pressure using a hermosoluble synthetic resin adhesive.
Pallet having only one deck capable of carrying the load.
Failure in meeting specified requirements. The definition refers to the divergence or absence of one or more quality characteristics, or elements of the quality system, from specified requirements. The essential difference between “nonconformity” and “defect” is that the specified requirements may differ from those necessary for the intended use.
Measurement of the strength or other physical-mechanical characteristics of a material (e.g. of a semi-finished product, product or wooden structural element) that does not involve breaking.
Wood species Scientific name: Thuja occidentalis Origin: Northeastern North America
Wood species Scientific name: Pinus strobus L. Origin: North America; cultivated in Europe.
Wood species Scientific name: Picea abies (L.)
A bar generally in the shape of a bevel with a chamfered apex (nosebar), or also in the shape of a rotating cylinder (rollerbar), installed parallel to the cutting profile of the peeler and slicer blade. It has the function of compressing the workpiece immediately before cutting to avoid irregularities in sheets thickness.
In a two way pallet, it is the groove made in the joists to allow the forks of a forklift to be introduced.
Special circular saw blade in which sets of scoring teeth are alternated with planing teeth. It is used to obtain very smooth cutting surfaces.
Wood species. Common name of the botanical genus Quercus, which includes many species, including European Oak, Oak, Pubescent Oak, Turkey Oak, American Oak, etc.
Wood species Scientific name: Quercus robur L. See “European oak”.
Wood species Scientific name: Triplochiton scleroxylon K.Schum. ATIBT nomenclature: Obeche. Origin: West Africa.
A cut in a direction intermediate to the three main cutting directions, i.e. cutting the wood fibres at angles other than 0° and 90°.