Wood Glossary

Area in which a set of observations or a sampling was performed.

In plywood, the term indicates either a single or several veneers of wood placed (and glued or unglued) together along the longitudinal or transverse (i.e. ‘sideways’ or ‘butt’) edges. In the American standards for traditional plywood, other terms are used: – “Cores (or Crossbands)” to indicate the inner ply whose grain runs perpendicular to that of the outer sheets, the function of which is to minimise shrinkage and swelling phenomena particularly in plywood with 5 or more sheets; – “Centers” to indicate the inner plies whose grain runs parallel to that of the sheets forming the face and back of the panel; – “Sub-face” to indicate the inner plies directly underneath the face of the panel; – “Sub-back”, similarly to above, to indicate the internal ply adjacent to the back of the panel. In some compositions, plies may be overlapped with parallel grain. Finally, the term “inner plies” refers to all the plies that make up a plywood with the exception of the face and back.

Plywood with one or more layers and (or) faces made of metal sheets.

See “plywood”.

Wood-based panel consisting of a set of layers (usually of odd number) made integral by gluing and overlapping with the direction of the grain of the adjacent layers generally at right angles. The outer layers and all inner layers of odd numbers generally have their grain oriented parallel to the largest dimension of the panel. Layering with alternating grain makes the resistance against major stresses uniform, reduces splitting and minimises dimensional variations and deformations of the panel. Plywood is generally classified according to the durability of exposure to specific environmental conditions (determined primarily by the gluing used) and according to the quality (appearance) of the faces and composition of the panel.

Plywood in which both the face and the back have been made smooth by a mechanical sander.

Plywood in which the face or back has been made smooth by a mechanical sander.

Rot caused by basidiomycetes. It is localized to small, lenticular-shaped areas in which a white residue is visible.

The place where the plants, plant products or other objects are first introduced into the customs territory of the EU or of a State.

Round wooden element of considerable length, used individually in an upright position.

A compound formed by the reaction of simple molecules characterized by functional groups that, under proper conditions, allow them to combine and form substances of higher molecular weight. When two or more different monomers are involved, the product is called a “copolymer”. The reaction is called “polymerization.”

Wood species Scientific name: Pinus ponderosa Dougl. Origin: Western regions of the United Stets, British Colombia.

Wood species Scientific name: Populus sp.p. Of particular importance in the trade is wood from Euramerican poplar clones (Populus x euramericana (Dode) Guinier), which are extensively cultivated in specialised tree plantations.

The set of all data being studied. Since their number is generally huge, the study of a population is carried out by extracting a sample from it (i.e., taking a sampling).

See “population”.

Another designation by which the vascular elements of the woody tissue of broadleaf trees are known. It also denotes the visible openings on the surface of the wood produced by both the aforementioned anatomical elements and, by extension, the tracheids in conifers.

Series or line of adjacent solitary pores.

Group of two or more pores crowded and flattened along contact lines so as to appear as subdivisions of a single vessel. Note: The most common type is the radial multiple pore, in which the pores are in radial rows with flattened tangential walls. Another type is the nest multiple pore, in which the grouping is irregular.

Term that describes the voids present in a piece of wood or its penetrability by liquids. It varies depending on the surface area of the wood being analyzed (i.e., whether it is a cross-section or a longitudinal section). It can also be defined as the ratio, expressed as a percentage, between the volume of voids and the apparent volume of a piece of wood.

Wood species Scientific name: Chamaecyparis lawsoniana (A. Murr.) Parl. Origin: Western areas of the United States, from California to Oregon.

Preassembled wooden panels that can be easily assembled and disassembled.

Temporary floor consisting of pre-assembled wooden panels that can be easily assembled and disassembled.

Recovered wood derived from a consumer or commercial product used, for its original purpose, by end users such as individuals, households, stores, companies (including industrial companies) or institutions.

Application of a laminated surface to an irregularly shaped substrate (usually curved or variously profiled), as in the case of machine edging a panel.

Period of time during which an adhesive, after being mixed with a hardener, solvent, and any other ingredients, remains usable and maintains its properties almost unaltered.

See “pot life”.

Group of beetles from the families Bostrychidae and Lyctidae, most of which are small in size. They are mainly parasites of hardwoods and only attack sapwood containing starch. NOTE: The damage caused consists of round holes up to about 1.5 mm in diameter. The galleries are unstained and loosely packed with a fine frond.

A device designed to derive power from the tractor engine, by means of a suitable transmission, in order to power operating machinery and equipment towed or carried by the tractor. It is often, but improperly, called “force take-off”.

See “power take-off”.

Pre-assembled flooring board formed by glued elements.

Recovered wood derived from secondary processing or industry whenever the material was not intentionally produced, is not suitable for end use, and cannot be reused there in the same production process in which it was produced.

Operation consisting of compression (usually by belts) performed during the forming of particleboards with the function of partially consolidating the mat before hot pressing.

Device used for precompression of particle mat.

Polymerization of adhesive after application to adhering but before pressing. It results in a lack of bonding failure. The bonding failure known by the term “dry-out” has similar connotations and effects, however, it is not due to precure but to solvent loss. The term “early hardening” includes both cases.

Timber to which moisture has been reduced by seasoning or artificial drying to a point where it will not deteriorate during storage or transportation prior to drying for final use.

Ready-to-use assortment to which a surface finish has already been applied during the production process.

A ready-to-use panel in which finishes are factory-applied: paints, overlays or coatings.

Panelized building whose wall, floor or roof sections are factory-framed and sheathed.

Conditioning treatment where wood is immersed in a hot wood preservative or steam before being subjected to pressure.

Sawn timber that, after reaching end-use moisture, is cut and/or processed on one or more surfaces to fit within the specified deviations.

Machinery used for prepressing.

Cold press that applies sufficient pressure to a stack of veneers to keep the integrity of the panel as it is conveyed to the hot press loading system.

Panel with primer or undercoat applied at the factory that requires only final finishing after the installation.

A product that prevents the degradation of wood by chemical-physical and biological agents. The main types of preservatives are: – creosote; – preservatives in organic solvent; – preservatives in aqueous solution; – fumigants.

Treatment using special preservatives in order to prevent xylophagous organisms from settling inside the wood. ([6])

Element or set of elements consisting of several layers, usually wood materials, with the surface layer of suitable wood species. It is sanded during production and with calibrated joints to ensure coplanarity between the various elements.

Machine used for pressing wood. Depending on the models and modes of pressing there are: – clamping presses (used mostly in carpentry and for the production of semi-finished products for the window and door industry); – platen presses (formed by only two large plates and in that case called “single-deck” or by series of overlapping plates and in that case called “multi-deck”); – calender or continuous presses (consisting of a lower and upper belt of steel heated by a system of internal plates, they are used to produce a continuous tape of particle or fiber boards); – membrane presses (used to apply surface coatings to shaped materials-doors and furniture components-because their soft membrane can conform to irregularly shaped surfaces. In fact, the top plate is contained within a membrane energized by heated compressed air); – steam injection presses (recently used in the pressing of recomposed panels; in them steam is injected inside the mat through orifices in the plates to facilitate the bonding of thick panels). Platen presses can also be equipped with flat or shaped plates.

Drying method in which individual wet sheets are dried between the plates of a press.

Amount of time during which an assembly actually remains under pressure.

Amount of time corresponding to the entire duration of the pressing cycle (including the time required to load and close the plates).

Mechanical action by which it is possible to keep in close contact with each other semi-finished wood or other material-based products, an assembly (“mat”) of particles or fibers. If these elements are properly treated with adhesive, this action allows proper polymerization of the adhesive mixture and mutual bonding. For the purpose of wood gluing, hot, cold or high-frequency pressing can be carried out. Besides, it can involve discontinuous or continuous conveying of the material being processed. Pressing is also carried out to apply a decorative coating to a supporting semi-finished product.

Any process in which impregnant is introduced into the wood by applying pressure. Examples of this process are the Bethell process, the Burnett process, and the Rueping process.

In rotary cutting, it is the distance, measured in the direction of motion, between the front edge of the pressure bar and the cutting edge of the knife.

In rotary cutting, it is the distance, measured in the direction perpendicular to the motion, between the front edge of the pressure bar and the cutting edge of the knife.

Any process in which impregnant is applied to wood without pressure. Examples of this process include: hot and cold in an open tank, diffusion, brush, immersion, and spray process.

Protection treatment of wood not attacked by fungi, insects and marine borers.

See “preservative treatment”.

Also ‘attack terminated’, this is the case when the organisms that caused the decay are no longer active.

Catalog showing prices of various products for sale.

Wood species Scientific name: Juniperus oxycedrus L.

Generic term used for the production of primary wood products (i.e. using logs as raw material) such as sawn timber, plywood, wood-based panels.

First formed phloem. In stems and roots it differentiates below the apical meristem, before a defined cambium can be recognized. It is also called “primary sieve”.

Thinner area of the intercellular layer and primary cell walls within which one or more pairs of pits generally occur.

In wood anatomy, ray originating in primary tissues and elongated by cambial growth. Note: It is commonly used for any ray that, in a cross section, is possible to trace to the pith.

Categories or wood species that command higher prices than others on the local or international market and are therefore preferred in applications.

First-formed wood differentiated by an apical meristem. It is also called “primary wood.”

Operation comprising the necessary steps (delimbing, cross cutting, strip-barking or debarking and, in some cases, stacking) to obtain the required woody assortment from the felled tree.

A machinery that performs multiple stages of the processing operation: it limbs and sections plants that have already been felled and stacks the processed logs.

Ray cell elongated in radial direction.

Attestation by an independent third party of conformity related to a particular product or service. It is based on the control of the product and its production process, which must conform to specific standards relating to that type of product or service: it is not applicable if these standards do not exist.

Checks carried out at the recycler on material that passed acceptance checks, thus becoming part of the company’s production process, and analytical checks on finished products.

Obligation on the producer or others to compensate for damage to persons or property, or other damage, caused by a product or service found to be defective. Subject of EEC Directive n. 85/374, implemented in Italy by DPR 24/5/88 n. 244.

Written authorization, given before production (or service provision), to depart from predetermined requirements for a specified quantity or for a specified period of time.

Forest managed primarily for the purpose of obtaining optimal production of woody materials or by-products.