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.
Moisture in the centre of the cross-section of a wooden element.
See “core moisture content”.
See “laminboard”
Plywood panel containing a core which can be made of jointed laths or of thin wooden strips glued together vertically oriented.
Residual woody cylinder of the peeling, corresponding to the central portion of the log after it has been peeled down to the smallest possible diameter.
Extruded or pressed particleboard intended to form the middle layer of a multilayer panel. It will normally be covered with two sheets of plywood to provide rigidity, which is especially necessary for extruded panels whose fibers are placed mostly perpendicular to the plane of the panel.
Also called Trametes versicolor, it is a saprophytic fungus belonging to the family Polyporaceae
In botanical terms, it is the epidermal tissue produced by the phellogen. From a commercial point of view, the only species that produces it in interesting quantities is the Cork tree, for which the term is normally identified with its bark.
A product obtained from cork fragments (cork granulates) among which a distinction is made between pure agglomerates (made with binders other than cork or not) and expanded and un-expanded agglomerates (whether or not fabrication has resulted in alteration of the material).
Coating composed of individual cork elements or a combination of a cork top layer and additional underlays placed on the subfloor or primary structure.
Wood species Scientific name: Quercus suber L. Origin: Italy (Central-Southern maritime region), Sardinia, Corsica, Spain, Portugal, North Africa.
In dendrochronology, the term indicates the destruction of the cambium as a result of extensive debarking, due to mass movements, such as landslides, boulder rolling, disintegrating landslides, etc.
Dimensions of a cross-laminated timber corrected by calculation from the actual size to the size at the reference moisture content.
A value which, when added algebraically to the raw result obtained from a measurement, compensates for an assumed systematic error. The correction is equal to the assumed systematic error, but has an inverse sign.
Veneer with waves caused by an uneven structure of the wood.
Wood species Scientific name: Pinus laricio Poir. (Pinus nigra Arn.).
Wood species See “corsican pine”.
Primary fundamental tissue of a stem or root between the epidermis or phellerm and the vascular system.
The ply glued behind a valuable rotary cut veneer or sliced veneer (and intended to form the better face). It has the function of giving the latter a minimal amount of mechanical strength for handling and assembly operations.
Knot not visible on the outer surface (usually the term is used in the case of round timber).
Outer layer of sliced or peeled veneer, single or split, which is glued to each face of the core.
Visible crack on the peripheral surface which may extend as a end shake.
Steel frame with 1 or 2 prongs that is fixed to boots for climbing trees. Also denotes a steel frame with 4, 6, or 8 prongs that is attached to loggers’ boots to grip wood and be able to walk over logs without slipping, especially with wet or frozen wood (e.g., in stacking).
Thicker portion of the intercellular layer and primary cell walls between the primary pit fields.
See “crawler”.
Tractor on crawlers in which the steering is given by the difference in speed between the two crawlers.
Thin cracks in the surface caused by the telegraphy of peeler checks.
Deformation noticeable in a material subjected to stress (load) of long duration that occurs after its instantaneous elastic deformation. It may be reversible (deferred elastic deformation) or irreversible ( determined by the onset of visco-elastic phenomena).
Liquid obtained from the distillation of coal tar or wood distillation. It is composed mainly of aromatic hydrocarbons.
Stacking of boards or other sawn timber executed in such a way that it forms a hollow triangular prism: the boards touch only at the corners. Analogously, there can be a hollow quadrangular stacking (“pigsty stacking”).
Irregular corrugations on the surface of a piece of wood due to collapse or irregular shrinkage.
The portion of a timber element with a length of 150 mm, or equal to the depth of the element, that is considered to be relevant to the structural performance of a structure due to the strength reduction characteristics, location, state of preservation and also the stress conditions determined by the structural analysis. This zone is important because it can affect the load-bearing capacity of the timber element and the stability of the entire structure.
It is the highest biological reference value (in grams per square metre or kilograms per cubic metre) obtained from all biological tests carried out in accordance with EN 599-1 for a given use class. NOTE 1: This is the minimum quantity of wood preservative (as a product) required to ensure efficacy for that use class according to the tests performed. NOTE 2: The critical value varies depending on the use class, the method of application, the organisms against which the preservative is to provide protection and whether softwood or hardwood is to be applied.
Short, naturally curved board, usually obtained from the base of the tree. In Italy it is a widely recognized assortment for larch wood.
Vegetation on a wooded area, with particular reference to trees of major forest interest (forest stand).
The inner layer of a plywood whose grain is perpendicular to that of the outer layers.
Any ply of a plywood with the grain arranged in a direction perpendicular to that of the sheet forming the better face.
Separation of wood cells perpendicular to the grain. These breaks may be due to internal stresses resulting from different longitudinal shrinkage or external stresses.
Wood cutting in a direction perpendicular to the grain. It is performed, for example, in the cross cutting of trunks to obtain logs of desired dimensions or, in the docking of veneers, to regularize their lateral edges and thus make the length of the sheets compatible with that of the panels to which they will be glued. Since most wood-based panels are made with elements that have grain perpendicular to each other or variously oriented, any cutting operation of the aforementioned panels takes the form of a cross cutting.
See “cross cutting”.
Operation consisting of reducing a stem into shorter portions (trunks or logs). As such, it is also a type of cross-cutting. It is usually performed using a large diameter circular saw or a chain saw hinged to a fulcrum.
Plywood panel in which the grain of the faces is parallel, or nearly parallel, to the smaller dimension of the panel.
Wooden structures consisting of at least three layers glued on their faces that include structural wood lamellas and may include wood-based panels, with at least one layer oriented orthogonally to the two adjacent layers.
Structural wood made up of at least three layers, of which at least three are glued orthogonally. It always includes layers of wood and may also include layers of wood-based panels. Note 1: Cross-laminated timber conforming to EN 16351 and multilayer solid wood panels conforming to EN 13353 may have the same layup, but the wood used for laminations is classified according to EN 14081-1.
Atom or group connecting adjacent molecules within a complex molecular structure.
Also known simply as ‘section’, it is the section of a semi-finished product arranged in a right angle to the longitudinal axis.
Stacking accomplished in such a way that the lengths of the pieces making up the various layers are perpendicular to those of the adjacent layers. If no laths are interposed, this is known as “contiguous cross stacking”.
A cut perpendicular to the grain direction in order to create an end.
Intersection, observable in a radial microscopic section, between the walls of the axial tracheids and those of the radial parenchyma cells (and any radial tracheids, if present).
Small openings (pits) in the walls of the cells that make up the crossfield, of different shapes and sizes depending on the wood species. They constitute an important identification criterion.
Stacking of timber intended for kiln drying. It is performed in such a way that the length of the pieces is perpendicular to the length of the dryer.
Internally ventilated kiln in which fans are mounted on ventilation ducts arranged perpendicular to the length of the kiln.
An increase in the nominal (commercial) length of timber assortments (mainly round timber) to take into account both the decrease in length due to shrinkage, as well as the waste (e.g. due to debarking) and the deterioration of the ends that occur during bunching and extraction. The effective length of a woody assortment is equal to the sum of the nominal length and the superlength.
Point where a trunk or log will be sectioned.
See ” crotch figured wood”.
Aesthetic effect achieved by cutting a log at a fork passing through the axes of both sides.
Upper portion of a tree comprising branches, twigs and eventually part of the stem. Along with the roots and stem it forms one of the three portions that characterise the morphology of a standing tree.
They are cellular inclusions, formed mainly of calcium oxalate, which form mainly in the parenchyma cells of many broadleaf trees. The following main types are distinguished: – ACICULAR: thin, needle-shaped crystal; – DRUSE: globular concrescence of crystals, sometimes with an organic center. It is attached to the cell wall with a stalk or free in the cell; – RAPHIDE: needle-shaped crystal typically forming part of a strongly pressed bundle; – CRYSTALLINE SAND: granular mass of very fine crystals; – STYLOID: elongated crystal with pointed or square ends that is about four times longer than wide.
Cell containing one or more crystals. Note: Radial and axial parenchyma cells are often crystalliferous while fibres less frequently.
See “foot”.
A stem, trunk, or log that cannot be used because of the high presence of defects; volume deduction or loss of manufacturing determined by the presence of a defect; generally, any part removed from the production process because of dimensional or quality nonconformities.
Rudimentary chute consisting of a simple, small excavation made transversely to the road axis and usually on half of the roadway. Its purpose is to collect surface runoff water to remove it from the road surface.
An artifact to allow substantial amounts of water to pass under a road. It is used instead of small bridges.
Deformation in the width direction of a semi-finished product. In the case of tangential sawn timber, it is due to the anisotropy of the shrinkage (whereby tangential shrinkage is approximately double that of radial shrinkage) and is therefore an unavoidable defect.
Check that can be removed by planing (depth less than 2 mm).
Temperature required for an adhesive to achieve polymerisation. Time is the other key factor: both the time an adhesive must remain at a certain temperature in order to cure effectively and the time it takes to reach that temperature.
1) The time during which an adhesive sets and provides the desired bonding strength. 2) The time during which a bonded joint must be subjected to the action of pressure or heat for the adhesive to set. 3) The length of time during which a bonded joint is subjected to heat or pressure, although the setting phenomenon may be complete later after the joint has been released from pressure and heat conditioning.
Curing or other change in the physical properties of an adhesive due to a chemical reaction (vulcanization, condensation, or continuation of polymerization), usually induced by the action of heat and a catalyst, added alone or in combination, with or without pressure. More specifically, the term denotes the change in state of an adhesive or adhesive mixture that, in the case of certain thermosetting adhesives, cross-links and cures in an irreversible and nonhydrolyzable way.
Fibre presented in the form of irregular curves, due to anomalies in the structure of the wood.
Simple kiln where moisture condenses on fabric curtains. The surfaces of the curtains are ventilated to keep them cool and to remove the moisture that impregnates them.
Cross-laminated timber with pre-chamber greater than 1% of the respective span.
See “moulded plywood”.
Anyone who purchases goods or services from a given store or business.
Separation of a body into parts. It is used to indicate the severing of a plant, parts of it or its branches. However, the term is also broadly applied to that operation by which a forest stand is cut down and partially or totally harvested.
Machinery used for the cutting of semi-finished products .
English term not used in Italy, meaning either a machine equipped with knives (e.g. a chipping machine) or one of the knives with which the machine is equipped.
Cutting angle, symbol: alpha. In the case of a rotary blade or a circular saw tooth, it is the angle, in the plane perpendicular to the axis of rotation, formed on the one side by the blade cutting edge or the tooth attachment face, and on the other side by the radius of the rotary machine (or circular saw) circle, which passes through the cutting edge of the blade or the tooth tip. In the case of a band saw or reciprocating saw or orthogonal cutting iron, it is the angle (measured in the plane of the blade or in the plane perpendicular to the blade faces) formed: (a) – for saws, by the tooth attachment face and the surface generated by the cutting edge during the cutting motion; (b) – for the knife of a veneer peeling lathe, by the face of attack and the plane passing through the axis of rotation and the knife edge; (c)-for other irons and cutting edges, from the face of attack or the bevel of attack and the plane perpendicular to the generated surface. The angle formed by the direction of the grain and the face of attack of the saw tooth is also called “cutting angle”.
The area described by the rotation of the cutting edge of the tooth of a circular saw or other rotating tool for tangential machining.
Concept that considers: (a) the angle formed by the edge of the cutting iron and the direction of the wood grain; (b) the angle of the cutting speed vector in relation to the workpiece, and the wood grain. Note: Three main cutting directions are distinguished: the 90-0 cutting direction, which is parallel to the grain of the wood, and the cutting edge is perpendicular to it; the 0-90 cutting direction which is perpendicular to the grain and the cutting edge is parallel to it; and the 90-90 cutting direction which is perpendicular to the grain and the cutting edge is perpendicular to the grain too.
Grading method of sawn timber used in many Anglo-Saxon countries mainly for grading hardwood timber intended for further cutting for the long term before final use. It consists of establishing the category of a piece, mostly on the basis of examination of the worse face, by estimating the number and quality of rectangular type cuts that could be made from it. The minimum size of a type cut depends on the purpose of the piece and is conventionally fixed; their size is expressed in elementary cuts of 12 square inches of flat face surface; the quality is established on the basis of a first choice and a second choice. The first choice literally could be translated in “clear face cutting” on the better face, with tolerance of non-serious defects on the worst face; the second choice would be traslated in “sound face cutting”.
Operation by which a standard-size semi-finished product is reduced into pieces of shorter length and width required by a work order. Modern sizing systems involve the simultaneous stacking and processing of multiple semi-finished products (e.g., panels) and the use of computer-assisted systems to manage and optimize multiple cuts.
Wood species Denomination of the wood of several species of the genus Cupressus (Cupressus sempervirens L.; Cupressus lusitanica Mill.; Cupressus arizonica Greene), wild or cultivated in the Mediterranean basin.
Wood species Scientific name: Taxodium distichum Rich. Origin: Coastal or wetland regions of the south-eastern United States.
Deterioration of dried timber that is determined in the drying process. It cannot be related exclusively to the improper control of the drying process or the use of an unsuitable regime, but rather is caused by natural defects such as ring shake, slope grain, interlocked grain, reaction wood, etc…
Wood species Scientific name:Nesogordonia papaverifera. Origin: Africa
Day designated for delivery of a particular commodity to the buyer.
Knot tightly connected for less than 1/4 of its perimeter to the surrounding wood (or semi-finished product).