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.
Reducing, by friction, particles or other fibrous material into the form of bundles of fibers suitable for the production of fiberboard. Refining can involve atmospheric or pressurized pressure action and uses steam to condition (“cook”) the material in a way that facilitates cell separation.
Formation of a forest by direct seeding or planting. In the strict sense: on land already covered by forest at a more or less remote time.
Term used to indicate high resistance to moisture loss during wood drying.
Wood resisting the penetration of preservatives.
Treatment stage in which the wood can no longer absorb a significant amount of wood preservative.
Ban on entry of a consignment or other regulated article if it does not comply with phytosanitary regulations.
Developmental stage of an even-aged forest from seed germination (or from planting) to the age at which the crowns, as they come into contact with each other, result in canopy closure.
Sawn timber that, after reaching the end-use moisture content, is processed in such a way that the allowable deviations are narrower than those normally adopted.
Sawn timber presenting minor deviations in thickness and/or width from those established for rough sawn timber.
Round wood that has taken on a cylindrical shape as a result of manufacturing.
Especially in the case of international transport, it refers to any plant, plant-derived product, storage, packaging, transport, container, soil, and any other organism, object or material that may harbor or spread harmful organisms, which is considered to require phytosanitary measures.
Non-quarantine pest that, if present in plants intended for planting affects the intended use of those plants with an unacceptable economic impact. Therefore, it is regulated within the territory of the importing contracting party.
Quarantine pest or a regulated non-quarantine pest.
Document issued by an authority, containing mandatory requirements.
Indicates the water vapor content in the air, expressed as a percentage of the maximum amount of water in gaseous form (therefore water vapour) that can be present in a given volume. The maximum value, equal to 100 %, corresponds to saturation.
The ratio of the tip gap to the length of the finger.
Authorization for entry following the clearance of customs.
Any tree, wood, isolated bark, soil or cultivation soil subject to regulation under the Plant Health (Forestry) Order 2005.
Attitude of an object to perform the required function under the established conditions and for a specified period of time. The term “reliability” is also used to refer to the specific reliability characteristic that indicates the probability of success or the success rate.
Conversion of a sawn timber or wood-based panel into a higher-value product through further production process.
Preservative treatment of wood aimed at preventing the continuation of an attack by xylophagous organisms.
Appeal to perform a specific task within a short time.
Energy produced and/or derived from sources that renew themselves indefinitely (hydro, solar, wind), or generated from renewable fuels (sustainably produced biomass).
Resource that regenerates naturally and can be used without depletion, provided it is managed properly (e.g. forests, soil…).
In wood flooring, it is the restoration operation carried out by sanding and treatment, without intervening on the installation.
A patch or filler material inserted and/or glued to achieve a sound surface.
In wood flooring, it indicates the operation of replacing or reinstalling damaged elements (or parts of them).
Provision that defines the needs to be met.
See “requirement”
Glued laminated timber, sectioned into parts along the length.
Period of time between two successive instrument settings or reference sample calibrations with the exception of the first and second setting.
Drying stresses that remain in the wood once the drying process is completed.
By-products of primary manufacturing, once discarded but currently used as fuel or chipping material.
1) Natural vegetable substance contained in the leaves, bark and wood of many trees, especially conifers. 2) Commonly used term for synthetic adhesives. Of these, the most widely known in the wood industry are those based on urea and phenol-formaldehyde (UF and PF). Resins are substances with a high molecular weight or that can be converted into them.
Tubular intercellular space of varying length, delimited by secretion tissue and filled with resin. It is found in certain conifers and tropical deciduous trees.
Outflow of resins from pockets and resinous areas, especially around knots, during drying or final use.
Lenticular cavity which contains or has contained resin. It is visible on the surface of some softwood assortments and semi-finished products.
A fraction of the resin (dry substance) present in the anhydrous weight of the solid component of a mixture or solution. The term is used to indicate the actual amount of resin contained in a liquid adhesive.
Wood having an excessively high resin content.
Resin extraction and collection operation performed on a standing tree.
In the drying or gluing process, it is an operation whereby an electric current is passed through the wood so that its resistance produces heat.
Situation in which the wood (or one of its portion) is difficulty penetrated by, for example, a preservative.
See “durable”.
Wood not included in impregnability class 1 as defined in EN 350-2 (the Standard distinguishes between: class 2, moderately resistant; class 3, resistant; class 4, extremely resistant).
Product load requirement in the analytical zone NOTE: It is expressed in grams of product per square metre in the case of surface application processes and in kilograms of product per cubic metre in the case of penetrating treatment processes. This value is obtained from the critical value in different ways depending on the specific test.
An artifact intended to support landslide slopes upstream of roads or to support the embankment downstream.
Descriptive term for the network-like arrangement formed, in cross section, by the rays and regularly spaced bands or lines of axial parenchyma. Bands or lines and rays are about the same thickness and equidistant.
Plate with multiple perforations, similar in appearance to a net (as in certain Bignoniaceae).
Subterranean termites that need moisture therefore their nests are in the ground and they reach the wood through underground tunnels and surface tunnels. They cause very serious damage to wood in buildings.
Pallet that can be used for numerous rotations.
The phenomenon whereby, in the last stage of drying, the surface layers, previously subjected to tension, are subjected to compression, while the inner layers of wood, previously subjected to compression, remain subjected to tension.
Condition of dry wood whereby tension stresses in the outer layers and compression stresses in the inner layers result from excessive conditioning (over-conditioning).
Veneering with layers arranged head to head but reversed from their original position in the log.
Pallet having the top and bottom decks consisting of boards of equal number and size. Therefore both decks are capable of carrying the load.
Science concerned the behaviour over time of wood under static loads and the deferred deformations associated with these stresses.
Technical term for the outer bark.
Reinforcing steel having at least two rows of transverse ribs, evenly distributed along the entire length.
Minimal undulations due to different shrinkage of the early and late zones of the growth rings.
Element whose function is to support the top of false rafters.
A right to free collection of firewood on public or consortium property.
Element that, when seen from the face with the edge tongue facing the observer, presents the leading tongue on the right.
Marine plywood whose production is subject to control by RINA (Italian Naval Registry). In addition to fulfilling the requirements for marine plywood, it provides specific composition requirements for the panel, which can give it even higher mechanical strength and durability characteristics.
Removal of a narrow strip of bark around the entire circumference of a trunk or stem of a standing plant.
Separation along the wood grain that develops in a tangential longitudinal plane. Typically occurs at the boundary between two contiguous growth rings due to traumatic causes or internal growth or drying stresses.
Width of an annual ring measured along a ray.
See “ring-porous wood”.
Characteristic feature of wood of some broadleaf trees in which the vessel elements (or pores) in cross section appear comparatively large in cell lumen at the beginning of each growth ring and decrease in size more or less abruptly toward the outer portion of the ring. Hence, they form a distinct inner porous circle, known as earlywood, and an outer zone of reduced-lumen pores, known as latewood.
Timber cutting parallel to the grain direction.
Thin horizontal marks visible on the tangential longitudinal surface of some timbers, due to serrated arrangement of rays or axial elements or both.
Considering the different general use situations to which solid wood and wood-based products may be exposed, the following five risk classes are defined: Risk class 1: Situation in which the wood or wood-based product is sheltered, fully protected from the weather and not exposed to humidification (e.g., out of contact with the ground, indoors and always dry). In this environment, the moisture content of solid wood is such that the risk of attack by surface mold, bluing fungi or xylophagous fungi is insignificant (the moisture content of the wood should be a maximum of 20 percent throughout virtually its entire service life). However, attack by xylophagous insects, including termites, is possible, but the frequency and extent of the “insect” risk depends on the geographical region. Risk class 2: Situation in which the wood or wood-based product is sheltered and fully protected from the weather, but high ambient humidity may result in occasional but not persistent wetting (e.g., outside of ground contact, indoors but where there is a risk of wetting). In this environment, the moisture content of solid wood is sometimes greater than 20 percent in all or only part of the component, thus allowing attack by xylophagous fungi. For wood also used for decorative functions, alteration of appearance may occur as a result of the development of surface mold and chromogenic fungi. The risk of insect attack is the same as indicated for risk class 1. Risk class 3: Situation in which the wood or wood-based product is unprotected but not in contact with the ground. It is either continuously exposed to the weather or, while protected against the weather, is subject to frequent wetting. In this environment, solid wood can often have a moisture content greater than 20 percent and, therefore, will be frequently exposed to attack by xylophagous fungi. For wood also used for decorative functions, altered appearance may occur as a result of the development of surface mold and chromogenic fungi. The risk of insect attack is the same as indicated for risk class 1. Risk class 4: Situation in which the wood or wood-based product is in contact with soil or fresh water and is, therefore, permanently exposed to humidification. In this environment, solid wood permanently has a moisture content greater than 20 percent and is exposed to attack by xylophagous fungi. In some geographical regions, termites can be an additional problem. In addition, in the case of certain components, such as fence posts, the above-ground (or above-water) part is exposed to possible attack by xylophagous beetles. Risk class 5: Situation in which the wood or wood-based product results in permanent exposure to salt water (in seawater). In this environment, solid wood has a moisture content permanently greater than 20 percent. The main problem is the attack of marine invertebrate organisms, especially in warm waters. Organisms such as Limnoria sp.p. and Teredo sp.p. can cause considerable damage. The part that emerges from the water of certain components, such as pontoons, may be exposed to xylophagous insects including termites. Regarding wood-based panels, on the other hand, depending on the different characteristics of composition and production process under the same thermohygrometric conditions, their equilibrium moisture content may differ from that of solid wood. Some of the aforementioned artifacts also may be suitable for use only in certain risk classes, so for more details on this topic, please refer to consulting the relevant product specifications and the UNI EN 335-3 standard.
A set of adequate and proportionate measures and procedures to effectively minimise the identified risk.
Road width for vehicle transit.
Steel device for covering the detected ribs of track soles when the tractor has to run on the road.
Wood species Scientific name: Robinia pseudoacacia L.
Threaded or ribbed steel rod
Shear stresses in which the complementary components of the shear forces are perpendicular to the direction of the grain.
Transverse stability problem of tractors. It occurs when the weight force of the tractor, imagined to be concentrated at its center of gravity, is no longer upstream of the ground contact point of the track or wheels located downstream.
Stem originating from root buds.
Hypogeal portion of a tree that is of fundamental importance for the absorption of raw sap. Along with the stem and crown, it forms one of the three portions that characterize the morphology of a standing tree.
In yarders, it is a piece of rope, usually of steel, used to tie together parts of towers or supports.
Concentric folds on the cortex indicating the presence of a node or other singularity.
Structural fungal alteration of the chemical constituents of the cell walls that constitute woody tissues. Rot results in progressive loss of mass, mechanical strength and hardness. Generally it also causes changes in color and appearance. The various types of rots are: honeycomb rot, white rot (also known as “fibrous” or “corrosive”), brown rot (also known as “cubic” or “destructive”), lamellar rot, soft rot, red streak and dote. Wood moisture greater than 20% is required for the development of carigenic fungi.
Sheet of wood obtained by peeling.
Industrial processing by means of which it is possible to turn an assortment of suitable characteristics into sheets (called ‘veneers’). It consists of fixing a log, previously debarked, possibly steamed and suitably centred, to a chuck shaft that gives it a rotating movement around its axis while the log itself comes into contact with a cutting system formed by a knife and a pressure bar at least as long as the workpiece. Generally, cutting starts from the lateral surface of the log and is carried out along tangential planes with respect to its spindle centring axis. In an initial ’rounding’ phase, the log is made perfectly cylindrical and strips or ‘lists’ of veneer of limited width can be obtained. Subsequently, the combined movements of rotation of the log and the advancement of the cutting system, which moves at a predetermined distance towards the geometric centre of the log at each rotation, make it possible to obtain a continuous strip of veneer of the desired thickness (generally between 1 and 5 mm). The strip develops until the log reaches the size of a cylinder (roundel) with a minimum diameter close to that of the chucks. In the production of plywood, this tape is then “clipped,” i.e., sectioned parallel to the grain, to obtain sheets of dimensions conforming to those of the finished panels (which, however, include the necessary oversizes to allow for the development of drying shrinkage and facilitate the compounding operation). The sheets produced by veneer clippling are also stacked separately according to different sizes, grades and moisture content. Rotary cutting is usually performed on high moisture content logs (fresh-cut wood), the processing of which allows lower energy consumption and the production of sheets of better quality and surface regularity. However, it is not only reserved for plywood production but is also performed to make other semi-finished products that are mainly used in the packaging industry.