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.
Degradation of wood caused either by physical agents (sunlight, wind, moisture) or by chemical agents (such as acids or bases).
Mechanical denuding action caused by rubbing, such as sanding wood with sandpaper.
Synthetic thermoplastic resin with high resistance to acids, but not to chlorinated solvents. It does not activate dust and does not deform. Due to these properties, ABS is a suitable material for the production of furniture and furniture components.
Results of a measurement net of the true value (conventionally) of the measurand.
Ratio of the mass of water vapor contained in a volume of air to the volume of air itself (usually expressed in g/mc or kg/mc).
Amount of impregnant that persists in the wood at the end of a treatment. It is generally expressed in kg of impregnant per cubic meter of treated wood.
Process by which liquids or gases are drawn into the voids or interstices of a solid, such as in a sponge.
Wood species Scientific name: Hallea ciliata (Aubrèv. & Pellegr.) Leroy ATIBT nomenclature: Abura. Origin: West and East Africa.
Treatment performed to obtain a measure of the suitability of a material to withstand long-term operation by exposure to severe test conditions that simulate the effect of the environmental conditions in which it will be placed.
Material quality control, including analytical checks, which are carried out at the moment of delivery of a load or eventually after delivery, provided that the material is still traceable to a individual supplier.
Adaptation of a plant to a locality (station) whose climatic conditions are more or less different from those of its area of origin.
Conferring credit, value, trust on an act, usually by an external organisation. For example, in Italy there is SINCERT, for the accreditation of certification bodies, SINAL, for the accreditation of testing laboratories, etc.
Formal recognition of a body’s suitability to certify products and/or quality systems. In the absence of a reference law, it is now carried out by SINCERT, which assesses the body’s compliance with UNI CEI EN 45011 (products) or 45012 (quality systems) standards.
Testing laboratory that has been granted accreditation.
Degree of agreement between measurement results and the (conventionally) true value of the measurand. It is a qualitative concept; the use of the term “precision” in place of “accuracy” should be avoided.
Technical requirement that a representative majority of experts recognize as reflecting the state of the art.
Fibreboard specifically manufactured to achieve good sound absorption characteristics.
Ingredient of paints and impregnating agents that use water as a solvent. It is a synthetic resin with excellent weathering resistance characteristics. It can be colourless, transparent or pigmented.
Presence of live organisms in the wood that are active in the attack.
Chemical compound included in a wood preservative to give it specific activity against biological deterioration agents.
Infestation in which insects are alive and continue their attack, e.g., of the crown of a tree by bud caterpillars, of a wood by termites, of soil or other substrates by nematodes or invasive plants.
Actual size at the time of measurement.
Condition that does not cause drying defects in timber.
Material held together with another thanks to the action of an adhesive.
Situation in which, in determining the bonding quality of a wood-based material (typically the plywood), the failure occurs predominantly in the wood and in such a way that a certain percentage of fibers remain on the delaminated surface of the specimen.
Breaking of a gluing in which the separation plane appears to be undone at the adhesive-adhering interface.
A state in which two surfaces are held together by interface forces that may consist of mechanical interpenetration, molecular attraction, chemical bonding, or their combination.
A substance that holds together two elements of the same or different material by forming an interface surface and thus promoting adhesion. It is a generic term that includes cement, mucilage, resins and others; it is used as a synonym for ‘glue’. See also ‘glue mix’.
Situation in which, in determining the bonding quality of a wood-based material (usually the plywood), the failure of the specimen occurs mainly through delamination in the thickness of the glue line.
See “drying potential”.
Process whereby the surface of a solid retains, through molecular attraction forces, an extremely thin layer of gas, liquid, or a dissolved substance, as in an activated carbon filter.
Insect that has reached the final stage of development.
The xylem located outside the juvenile wood core where the cells have reached their maximum size and structural development.
Wood species Scientific name: Terminalia superba Engl. & Diels. ATIBT nomenclature: Limba. Origin: West Africa.
Wood species Scientific name: Canarium schweinfurthii Origin: Africa.
Wood species Scientific name: Dalbergia melanoxylon Guill. et Perr. (the name ‘African Ebony’ is also referred to the wood of Diospyros sp.p.). Origin: Tropical Africa.
Wood species Scientific name: Khaya spp. Origin: Tropical Africa
Wood species Scientific name: Pterocarpus sp.p. (P. soyauxii). ATIBT nomenclature: Padouk d’Afrique. Origin: West Africa
Wood species Scientific name: Lovoa sp.pl. ATIBT nomenclature: Dibètou. Origin: West and East Africa.
Wood species Scientific name: Pericopsis elata (Harms) Van Meeuwen. ATIBT nomenclature: Afrormosia. Origin: West Africa
Wood species Scientific name: Afzelia spp. Origin: Tropical Africa
Wood species Scientific name: Gossweilerodendron joveri Normand ex Aubrèv. ATIBT nomenclature: Tola. Origin: West Africa.
Intermediary entrusted by a company to carry out business and sales activities.
Group of small, narrow wood rays that appear to the naked eye as one large ray.
Compartment in which an air jet is used to separate woody particles according to their different weight and grain size.
Timber dried by exposure to natural weather conditions, outdoors or in unheated sheds.
Lumber dried by exposure to natural weather conditions, outdoors or in unheated sheds.
A system that, in the production of recomposed panels, allows the deposition of the mat by the suspension of particles or fibers controlled by an air jet.
Leakage of conditioned air from the kiln through uncontrolled escape routes.
Method by which the loss of water contained into the wood (moisture) occurs through exposure in a ventilated environment, generally after stacking and surface protecting the wood material (typically, the sawn timber). The duration of the process depends on the climate and atmospheric conditions of the seasoning site, on the thickness of the material and on the final level of moisture to be reached (which in any case, for solid wood of coniferous, hardly reaches values lower than about 12%).
Lignin generally obtained for pulp production. It is derived from the liquid resulting from treating wood with alkali.
Wood species Scientific name: Alnus glutinosa (L.) Gaertn. Origin: Europe, Siberia, North Africa, West Asia, Japan.
Wood species Scientific name: Pinus halepensis Mill.
Paratracheal parenchyma with wing-shaped lateral extensions when seen in cross section.
Virtual line tangent to the vertices delimiting the height of the teeth of a blade. Prolonged use can change both the shape and height of the teeth. The original alignment is lost and teeth that have become shorter can no longer cut. A blade in this condition needs to be leveled.
The product obtained from the action of a concentrated solution of caustic soda added to cellulose. The composition of alkalicelluloses varies depending on the concentration of the soda solution used.
Any defect whose nature or small size would not exclude a piece of timber from a specific qualification category.
A value referred to the main mechanical properties generally used for structural design. The admissible stresses, mostly identified with the description of the quality class and reference standards, reflect the orthotropic structure of wood and anticipate certain final uses.
Allowed reduction relative to an actual measurement. Typically this occurs during testing due to the presence of some defect in the material under test.
Cellulose fraction insoluble in a 17.5% caustic soda solution. It consists of cellulose chains of the highest degree of polymerisation. It produces glucose by hydrolysis.
Pluriseriate pitting arrangement in diagonal rows. Note: When the pitting is thickened, the contours of the areolae tend to be hexagonal, in surface view.
Insects infesting unseasoned wood. Insects dig oviposition tunnels where the larvae do not feed on wood but rather on special fungi that develop on the walls of said tunnels causing pinholes.
Wood species Scientific name: Swietenia sp.p. (botanical genus belonging to the Meliaceae family) (S. mahagoni e S. macrophilla). ATIBT nomenclature: Mahogany. Origin: Central and South America, Caribbean.
Wood species Scientific name: Liquidambar styraciflua Origin: Southeastern United States
Wood species Scientific name: Quercus sp. pl. (Q. rubra L.; Q. falcata Michx.; Q. shumardii Buck.). Origin: North America (central and south-eastern US).
Wood species Scientific name: Juglans nigra L. Origin: North America.
Wood species Scientific name: Quercus sp. pl. (Q. alba L.; Q. prinus L.; Q lyrata Walt.; Q. michauxii Nutt.). Origin: North America (central and south-eastern US).
Wood species Scientific name: Liriodendron tulipifera L. Origin: East-central area of the United States.
Area of treated wood subjected to analysis for the evaluation of the retention requirement. NOTE: The analytical area to be analysed is selected from the side surfaces of the treated wood. The depth of sampling depends on the wood species analysed and the level of treatment.
An implement designed to firmly fasten ropes, tools, machines to the ground in various ways. It can be artificial (e.g., concrete plinth) or natural (usually live standing plants, stumps, rocks).
In yarders, it is a rope, normally of steel, used to support or hold the winch, the towers, the supports and any trees used in their construction.
The botanical name for the group of vascular plants with flowers that produce seeds contained in an ovary. It includes dicotyledons and monocotyledons but not conifers.
Fibre forming an oblique angle with the growth axis of a stem or with the edges of a semi-finished product.
Stem damage caused by animals (usually mammals).
Wood species Scientific name: Pouteria spp. Origin: Africa
Material in which property values differ when measured along different reference axes. Wood, like all fibrous materials, is strongly anisotropic. This particularly affects the extent of shrinkage and swelling as a result of moisture changes.
It is normally expressed by the ratio of linear radial shrinkage to tangential shrinkage. Typically, tangential shrinkage is twice that in the radial direction, while longitudinal shrinkage is very small (about 1/10th of radial shrinkage) so in many cases it can be neglected.
Annual growth in volume of a tree or forest stand.
Growth ring corresponding to the growth period of the plant in a year. It is the aggregate of xylem or phloem cells produced during the span of a growing season. The transition boundary between latewood and earlywood in successive rings is clearly distinguished (microscopically or macroscopically) and normally extends along the entire circumference of the stem. Note: the term “annual ring” should refer only to cross-sections; it is applicable by extension to the wood grain observed in any cross-section, even if it does not take the form of an annular ring.
Family of insects, many of which infest seasoned wood. Depending on the species, they can attack wood of Hardwoods and/or Conifers. They cause severe damage to artifacts.
Commonly known as “common furniture beetle”, it is an insect that attacks the sapwood of some wood species. In some cases, damage may extend to the heartwood. It can occasionally cause structural damage. It is particularly common in areas with a maritime climate and wherever high humidity conditions prevail.
See “Defect”.
Wood species Scientific name: Antiaris africana Engl. e Antiaris welwitschii Engl. Origin: Tropical Africa, particularly in the Western zone.
See “preservative”.
A Trade organisation representing most North American producers of structural plywood.The Association has three main functions: – coordination of research to improve plywood and other wood-based panels and systems; – management of quality audits and certifications to ensure the production of high quality wood-based panels; – promotion of wood-based panels and building systems.
A tissue located at the top of branches and roots, consisting of small, thin-walled cells which can initiate division and differentiation processes.
Axial parenchyma typically independent of vessels. Note: It includes terminal, diffuse and banded apotracheal parenchyma.
In a multilaminar wood, it is the combination of patterns and/or colors visible on the individual faces of the foils, block, veneer and boards. Some examples are: striped, flamed, figured (briar, pommelé…).