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Engineered wood

Engineered wood, also called mass timber, composite wood, human-made wood, or manufactured board, includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles, fibres, or veneers or boards of wood, together with adhesives, or other methods of fixation to form composite material. The panels vary in size but can range upwards of 64 by and in the case of cross-laminated timber (CLT) can be of any thickness from a few inches to 16 in or more. These products are engineered to precise design specifications, which are tested to meet national or international standards and provide uniformity and predictability in their structural performance. Engineered wood products are used in a variety of applications, from home construction to commercial buildings to industrial products. The products can be used for joists and beams that replace steel in many building projects. The term mass timber describes a group of building materials that can replace concrete assemblies.

Typically, engineered wood products are made from the same hardwoods and softwoods used to manufacture lumber. Sawmill scraps and other wood waste can be used for engineered wood composed of wood particles or fibers, but whole logs are usually used for veneers, such as plywood, medium-density fibreboard (MDF), or particle board. Some engineered wood products, like oriented strand board (OSB), can use trees from the poplar family, a common but non-structural species. Alternatively, it is also possible to manufacture similar engineered bamboo from bamboo; and similar engineered cellulosic products from other lignin-containing materials such as rye straw, wheat straw, rice straw, hemp stalks, kenaf stalks, or sugar cane residue, in which case they contain no actual wood but rather vegetable fibers.

Flat-pack furniture is typically made out of human-made wood due to its low manufacturing costs and its low weight.

Types of products
There are a wide variety of engineered wood products for both structural and non-structural applications. This list is not comprehensive, and is intended to help categorize and distinguish between different types of engineered wood.

Wood-based panels
Wood structural panels are a collection of flat panel products, used extensively in building construction for sheathing, decking, cabinetry and millwork, and furniture. Examples include plywood and oriented strand board (OSB). Non-structural wood-based panels are flat-panel products, used in non-structural construction applications and furniture. Non-structural panels are usually covered with paint, wood veneer, or resin paper in their final form. Examples include fiberboard and particle board.

Plywood
Plywood, a wood structural panel, is sometimes called the original engineered wood product. Plywood is manufactured from sheets of cross-laminated veneer and bonded under heat and pressure with durable, moisture-resistant adhesives. By alternating the grain direction of the veneers from layer to layer, or "cross-orienting", panel strength and stiffness in both directions are maximized. Other structural wood panels include oriented strand boards and structural composite panels.

Oriented strand board
Oriented strand board (OSB) is a wood structural panel manufactured from rectangular-shaped strands of wood that are oriented lengthwise and then arranged in layers, laid up into mats, and bonded together with moisture-resistant, heat-cured adhesives. The individual layers can be cross-oriented to provide strength and stiffness to the panel. Similar to plywood, most OSB panels are delivered with more strength in one direction. The wood strands in the outermost layer on each side of the board are normally aligned into the strongest direction of the board. Arrows on the product will often identify the strongest direction of the board (the height, or longest dimension, in most cases). Produced in huge, continuous mats, OSB is a solid panel product of consistent quality with no laps, gaps, or voids. OSB is delivered in various dimensions, strengths, and levels of water resistance.

OSB and plywood are often used interchangeably in building construction.

Fibreboard
Medium-density fibreboard (MDF) and high-density fibreboard (hardboard or HDF) are made by breaking down hardwood or softwood residuals into wood fibers, combining them with wax and a resin binder, and forming panels by applying high temperature and pressure. MDF is used in non-structural applications.

Particle board
Particle board is manufactured from wood chips, sawmill shavings, or even sawdust, and a synthetic resin or another suitable binder, which is pressed and extruded. Research published in 2017 showed that durable particle board can be produced from agricultural waste products, such as rice husk or guinea corn husk. Particleboard is cheaper, denser, and more uniform than conventional wood and plywood and is substituted for them when the cost is more important than strength and appearance. A major disadvantage of particleboard is that it is very prone to expansion and discoloration due to moisture, particularly when it is not covered with paint or another sealer. Particle board is used in non-structural applications.

Structural composite lumber
Structural composite lumber (SCL) is a class of materials made with layers of veneers, strands, or flakes bonded with adhesives. Unlike wood structural panels, structural composite lumber products generally have all grain fibers oriented in the same direction. The SCL family of engineered wood products are commonly used in the same structural applications as conventional sawn lumber and timber, including rafters, headers, beams, joists, rim boards, studs, and columns. SCL products have higher dimensional stability and increased strength compared to conventional lumber products.

Laminated veneer
Laminated veneer lumber (LVL) is produced by bonding thin wood veneers together in a large billet, similar to plywood. The grain of all veneers in the LVL billet is parallel to the long direction (unlike plywood). The resulting product features enhanced mechanical properties and dimensional stability that offer a broader range in product width, depth, and length than conventional lumber.

Parallel-strand
Parallel-strand lumber (PSL) consists of long veneer strands laid in parallel formation and bonded together with an adhesive to form the finished structural section. The length-to-thickness ratio of strands in PSL is about 300. A strong, consistent material, it has a high load-carrying ability and is resistant to seasoning stresses so it is well suited for use as beams and columns for post and beam construction, and for beams, headers, and lintels for light framing construction.

Laminated strand
Laminated strand lumber (LSL) and oriented strand lumber (OSL) are manufactured from flaked wood strands that have a high length-to-thickness ratio. Combined with an adhesive, the strands are oriented and formed into a large mat or billet and pressed. LSL and OSL offer good fastener-holding strength and mechanical-connector performance and are commonly used in a variety of applications, such as beams, headers, studs, rim boards, and millwork components. LSL is manufactured from relatively short strands—typically about 1 ft long—compared to the 2 to(-) strands used in PSL. The length-to-thickness ratio of strands is about 150 for LSL and 75 for OSL.

I-joists
I-joists are "I"-shaped structural members designed for use in floor and roof construction. An I-joist consists of top and bottom flanges of various widths united with webs of various depths. The flanges resist common bending stresses, and the web provides shear performance. I-joists are designed to carry heavy loads over long distances while using less lumber than a dimensional solid wood joist of a size necessary to do the same task. As of 2005, approximately half of all wood light framed floors were framed using I-joists.

Mass timber
Mass timber, also known as engineered timber, is a class of large structural wood components for building construction. Mass timber components are made of lumber or veneers bonded with adhesives or mechanical fasteners. Certain types of mass timber, such as nail-laminated timber and glue-laminated timber, have existed for over a hundred years. Mass timber enjoyed increasing popularity from 2012 to 2022, due to growing concern around the sustainability of building materials, and interest in prefabrication, off site construction, and modularization, for which mass timber is well suited. The various types of mass timber share the advantage of faster construction times as the components are manufactured off-site, and pre-finished to exact dimensions for simple on-site fastening. Mass timber has been shown to have structural properties competitive with steel and concrete, opening the possibility to build large, tall buildings out of wood. Extensive testing has demonstrated the natural fire resistance properties of mass timber – primarily due the creation of a char layer around a column or beam which prevents fire from reaching the inner layers of wood. In recognition of the proven structural and fire performance of mass timber, the International Building Code, a model code that forms the basis of many North American building codes, adopted new provisions in the 2021 code cycle that permit mass timber to be used in high-rise construction up to 18 stories.

Cross-laminated timber
Cross-laminated timber (CLT) is a versatile multi-layered panel made of lumber. Each layer of boards is placed perpendicular to adjacent layers for increased rigidity and strength. It is relatively new and gaining popularity within the construction industry as it can be used for long spans and all assemblies, e.g. floors, walls, or roofs.

Glued laminated timber
Glued laminated timber (glulam) is composed of several layers of dimensional timber glued together with moisture-resistant adhesives, creating a large, strong, structural member that can be used as vertical columns or horizontal beams. Glulam can also be produced in curved shapes, offering extensive design flexibility.

Dowel-laminated timber
Dowel laminated timber (DLT) is a less known type of mass timber product. It is made by placing multiple boards of softwood lumber next to each together, each with a hole so that a hardwood dowel can be friction fitted through all of them. As the hardwood dowel dries to reach an equilibrium moisture content with the softwood lumber, it expands into the surrounding boards creating a connection. The use of a dowel connection eliminates the need for any metal fasteners or adhesives.

Nail-laminated timber
Nail laminated timber (NLT) is a mass timber product that consists of parallel boards fastened with nails. It can be used to create floors, roofs, walls, and elevator shafts within a building. It is one of the oldest types of mass timber, being used in warehouse construction during the Industrial Revolution. Like DLT, no chemical adhesives are used, and wood fibers are oriented in the same direction.

Engineered wood flooring
Engineered wood flooring is a type of flooring product, similar to hardwood flooring, made of layers of wood or wood-based composite laminated together. The floor boards are usually milled with a tongue-and-groove profile on the edges for consistent joinery between boards.

Lamella
The lamella is the face layer of the wood that is visible when installed. Typically, it is a sawn piece of timber. The timber can be cut in three different styles: flat-sawn, quarter-sawn, and rift-sawn.

Types of core/substrate

 * 1) Wood ply construction ("sandwich core"): Uses multiple thin plies of wood adhered together. The wood grain of each ply runs perpendicular to the ply below it. Stability is attained from using thin layers of wood that have little to no reaction to climatic change. The wood is further stabilized due to equal pressure being exerted lengthwise and widthwise from the plies running perpendicular to each other.
 * 2) Finger core construction: Finger core engineered wood floors are made of small pieces of milled timber that run perpendicular to the top layer (lamella) of wood. They can be 2-ply or 3-ply, depending on their intended use. If it is three-ply, the third ply is often plywood that runs parallel to the lamella. Stability is gained through the grains running perpendicular to each other, and the expansion and contraction of wood are reduced and relegated to the middle ply, stopping the floor from gapping or cupping.
 * 3) Fibreboard: The core is made up of medium or high-density fibreboard. Floors with a fibreboard core are hygroscopic and must never be exposed to large amounts of water or very high humidity - the expansion caused by absorbing water combined with the density of the fibreboard, will cause it to lose its form. Fibreboard is less expensive than timber and can emit higher levels of harmful gases due to its relatively high adhesive content.
 * 4) An engineered flooring construction that is popular in parts of Europe is the hardwood lamella, softwood core laid perpendicular to the lamella, and a final backing layer of the same noble wood used for the lamella. Other noble hardwoods are sometimes used for the back layer but must be compatible. This is thought by many to be the most stable of engineered floors.

Other types of modified wood
New techniques have been introduced in the field of engineered wood in recent years. Natural wood is being transformed in laboratories through various chemical and physical treatments to achieve tailored mechanical, optical, thermal, and conduction properties, by influencing the wood's structure.

Densified wood
Densified wood can be made by using a mechanical hot press to compress wood fibers, sometimes in combination with chemical modification of the wood. These processes have been shown to increase the density by a factor of three. This increase in density is expected to enhance the strength and stiffness of the wood by a proportional amount. Studies published in 2018 combined chemical processes with traditional mechanical hot press methods. These chemical processes break down lignin and hemicellulose that are found naturally in the wood. Following dissolution, the cellulose strands that remain are mechanically hot compressed. Compared to the three-fold increase in strength observed from hot pressing alone, chemically processed wood has been shown to yield an 11-fold improvement. This extra strength comes from hydrogen bonds formed between the aligned cellulose nanofibers.

The densified wood possessed mechanical strength properties on par with steel used in building construction, opening the door for applications of densified wood in situations where regular strength wood would fail. Environmentally, wood requires significantly less carbon dioxide to produce than steel.

Delignified wood
Removing lignin from wood has several other applications, apart from providing structural advantages. Delignification alters the mechanical, thermal, optical, fluidic and ionic properties and functions of the natural wood and is an effective approach to regulating its thermal properties, as it removes the thermally conductive lignin component, while generating a large number of nanopores in the cell walls which help reduce temperature change. Delignified wood reflects most incident light and appears white in color. White wood (also known as nanowood) has high reflection haze, as well as high emissivity in the infrared wavelengths. These two characteristics generate a passive radiative cooling effect, with an average cooling power of $53 W⋅m^{−2}$ over a 24-hour period, meaning that this wood does not "absorb" heat and therefore only emits the heat embedded in it. Moreover, white wood not only possesses a lower thermal conductivity than natural wood, and it has better thermal performance than most commercially available insulating materials. The modification of the mesoporous structure of the wood is responsible for the changes in wood performance.

White wood can also be put through a compression process, similar to the process mentioned for densified wood, which increases its mechanical performance compared to natural wood (8.7 times higher in tensile strength and 10 times higher in toughness). The thermal and structural advantages of nanowood make it an attractive material for energy-efficient building construction. However, the changes made in the wood's structural properties, like the increase in structural porosity and the partially isolated cellulose nanofibrils, damage the material's mechanical robustness. To deal with this issue, several strategies have been proposed, with one being to further densify the structure, and another to use cross-linking. Other suggestions include hybridizing natural wood with other organic particles and polymers to enhance its thermal insulation performance.

Moldable wood
Using similar chemical modification techniques to chemically densified wood, wood can be made extremely moldable using a combination of delignification and water shock treatment. This is an emerging technology and is not yet used in industrial processes. However, initial tests show promising advantages in improved mechanical properties, with the molded wood exhibiting strength comparable to some metal alloys.

Transparent wood composites
Transparent wood composites are new materials, currently only made at the laboratory scale, that combines transparency and stiffness via a chemical process that replaces light-absorbing compounds, such as lignin, with a transparent polymer.

Environmental benefits
New construction is in high demand due to growing worldwide population. However, the main materials used in new construction are currently steel and concrete. The manufacturing of these materials creates comparatively high emissions of carbon dioxide into the atmosphere. Engineered wood has the potential to reduce carbon emissions if it replaces steel and/or concrete in the construction of buildings.

In 2014, steel and cement production accounted for about 1320 megatonnnes (Mt) and 1740 Mt  respectively, which made up about 9% of global  emissions that year. In a study that did not take the carbon sequestration potential of engineered wood into account, it was found that roughly 50 Mt e (carbon dioxide equivalent) could be eliminated by 2050 with the full uptake of a hybrid construction system utilizing engineered wood and steel. When considering the added effects that carbon sequestration can have over the lifetime of the material, the emissions reductions of engineered wood is even more substantial, as laminated wood that is not incinerated at the end of its lifecycle absorbs around 582 kg of /m3, while reinforced concrete emits 458 kg /m3 and steel 12.087 kg /m3.

There is not a strong consensus for measuring the carbon sequestration potential of wood. In life-cycle assessment, sequestered carbon is sometimes called biogenic carbon. ISO 21930, a standard that governs life cycle assessment, requires the biogenic carbon from a wood product can only be included as a negative input (i.e. carbon sequestration) when the wood product originated in a sustainably managed forest. This generally means that wood needs to be FSC or SFI-certified to qualify as carbon sequestering.

Advantages
Engineered wood products are used in a variety of ways, often in applications similar to solid wood products:

 * Mass timber (MT) is lightweight allowing the wood to be easily handled, manufactured, and transported. This contributes to it being cost effective and easy to use on site.
 * MT offers greater strength and stiffness (based on its strength to weight ratio), increased dimensional stability, and uniformity in structures.
 * When compared to steel/concrete, MT built buildings use up to 15% less energy because of the reduced energy needed to create these wood products.
 * MT buildings on average save 20-25% in time when compared to conventional steel/concrete buildings and 4.2% on capital cost.
 * MT products sequester carbon and store it within themselves over their lifespan.  Using this instead of concrete and steel in buildings will reduce the embodied emissions in buildings.
 * Using MT has an estimated savings of around 20% in embodied carbon when compared to steel or concrete.  This is because MT is a lot lighter when compared to these two materials, so it is less intensive for the machinery to transport both to site and once delivered.
 * MT products also have high levels of airtightness and low coefficients of thermal conductivity meaning that the air inside cannot escape, and heat is not lost easily.
 * MT built buildings perform very well in seismic events because they are roughly half the mass and half the stiffness when compared to reinforced concrete buildings which properties that are desirable.  Having half the stiffness allows MT buildings to be ductile which leads to it being able to resist lateral distortion without compromising the structural integrity of the building.
 * MT is fire resistant to an extent.  Although it is considered a combustible material, MT burns slowly and in a predictable manner.  When it is burned, a charred layer is formed on the outside that protects the inner layers of the wood.  However, once the charred layer falls off, the inner layers will be exposed which can compromise the integrity of the material.

All mass timber products offer different types of advantages, and they can be seen in the following:

 * CLT: Offers high dimensional stability, high strength and stiffness and is easy to manufacture.
 * Glulam: Offers high strength and stiffness, is structurally efficient, and can be manufactured into complex shapes.
 * NLT: Does not require any specialized equipment to manufacture, is cost effective, and easy to handle.
 * DLT: Offers high dimensional stability, is easy and safe to manufacture, and no metal fasteners or adhesive is required.
 * SCL: Is able to withstand greater loads compared to solid timber and is not prone to shrinking, splitting or warping.

Engineered wood products may be preferred over solid wood in some applications due to certain comparative advantages:
 * Because engineered wood is human-made, it can be designed to meet application-specific performance requirements. Required shapes and dimension do not drive source tree requirements (length or width of the tree)
 * Engineered wood products are versatile and available in a wide variety of thicknesses, sizes, grades, and exposure durability classifications, making the products ideal for use in unlimited construction, industrial, and home project application.
 * Engineered wood products are designed and manufactured to maximize the natural strength and stiffness characteristics of wood. The products are very stable and some offer greater structural strength than typical wood building materials.
 * Glued laminated timber (glulam) has greater strength and stiffness than comparable dimensional lumber and, pound for pound, is stronger than steel.
 * Engineered wood panels are easy to work with using ordinary tools and basic skills. They can be cut, drilled, routed, jointed, glued, and fastened. Plywood can be bent to form curved surfaces without loss of strength. Large panel sizes speeds up construction by reducing the number of pieces that need to be handled and installed.
 * Engineered wood products are a more efficient use of wood as they can be made from wood that has defects, underutilized species or smaller pieces of wood which also enables the use of smaller trees
 * Wooden trusses are competitive in many roof and floor applications, and their high strength-to-weight ratios permit long spans offering flexibility in floor layouts.
 * Sustainable design advocates recommend using engineered wood, which can be produced from relatively small trees, rather than large pieces of solid dimensional lumber, which requires cutting a large tree.

Disadvantages

 * Like solid wood, when exposed to high moisture conditions or termites, biodeteriorations and/or fungi decay will occur which reduces the structural integrity and durability of the wood product; essentially the wood will start to rot.
 * Raises concerns about potential widespread deforestation but can be mitigated with a sustainable forestry management plan.
 * MT buildings are susceptible to wind driven oscillation because of the relative flexibility of the MT material which may cause discomfort to people in the building.

All mass timber products have different disadvantages, and they can be seen in the following:

 * CLT and Glulam: They both have high cost.
 * NLT: It is labor intensive to make and there is significant potential for human error.
 * DLT: It has limited panel sizing and thickness.
 * SCL: It has limited panel sizing and thickness and is more suitable for low rise buildings.

When compared to solid wood the following disadvantages are prevalent:
 * They require more primary energy for their manufacture than solid lumber.
 * The adhesives used in some products may be toxic. A concern with some resins is the release of formaldehyde in the finished product, often seen with urea-formaldehyde bonded products.

Properties
Plywood and OSB typically have a density of 35 - 40 lb/ft3. For example, 3/8 in plywood sheathing or OSB sheathing typically has a surface density of 1 - 1.2 lb/ft2. Many other engineered woods have densities much higher than OSB.

Adhesives
The types of adhesives used in engineered wood include:
 * Urea-formaldehyde resins (UF): most common, cheapest, and not waterproof.
 * Phenol formaldehyde resins (PF): yellow/brown, and commonly used for exterior exposure products.
 * Melamine-formaldehyde resins (MF): white, heat, and water-resistant, and often used in exposed surfaces in more costly designs.
 * Polymeric methylene diphenyl diisocyanate (pMDI) or polyurethane (PU) resins: expensive, generally waterproof, and does not contain formaldehyde, notoriously more difficult to release from platens and engineered wood presses.

A more inclusive term is structural composites. For example, fiber cement siding is made of cement and wood fiber, while cement board is a low-density cement panel, often with added resin, faced with fiberglass mesh.

Health concerns
While formaldehyde is an essential ingredient of cellular metabolism in mammals, studies have linked prolonged inhalation of formaldehyde gases to cancer. Engineered wood composites have been found to emit potentially harmful amounts of formaldehyde gas in two ways: unreacted free formaldehyde and the chemical decomposition of resin adhesives. When excessive amounts of formaldehyde are added to a process, the surplus will not have any additive to bond with and may seep from the wood product over time. Cheap urea-formaldehyde (UF) adhesives are largely responsible for degraded resin emissions. Moisture degrades the weak UF molecules, resulting in potentially harmful formaldehyde emissions. McLube offers release agents and platen sealers designed for those manufacturers who use reduced-formaldehyde UF and melamine-formaldehyde adhesives. Many OSB and plywood manufacturers use phenol-formaldehyde (PF) because phenol is a much more effective additive. Phenol forms a water-resistant bond with formaldehyde that will not degrade in moist environments. PF resins have not been found to pose significant health risks due to formaldehyde emissions. While PF is an excellent adhesive, the engineered wood industry has started to shift toward polyurethane binders like pMDI to achieve even greater water resistance, strength, and process efficiency. pMDIs are also used extensively in the production of rigid polyurethane foams and insulators for refrigeration. pMDIs outperform other resin adhesives, but they are notoriously difficult to release and cause buildup on tooling surfaces.

Mechanical fasteners
Some engineered wood products, such as DLT, NLT, and some brands of CLT, can be assembled without the use of adhesives using mechanical fasteners or joinery. These can range from profiled interlocking jointed boards, proprietary metal fixings, nails or timber dowels.

Building codes and standards
Throughout the years mass timber was used in buildings, codes were added to and adopted by the International Building Code (IBC) to create standards for them for the proper use and handling. For example, in 2015, CLT was incorporated into the IBC. The 2021 IBC is the latest issue of building codes, and has added three new codes regarding construction with timber material. The new three construction types go as follows, IV-A, IV-B, and IV-C, and they allow mass timber to be used in buildings up to 18, 12, and nine stories respectively.

The following technical performance standards are related to engineered wood products: The following product category rules can be used to create environmental product declarations for engineered wood products:
 * EN 300 - Oriented Strand Boards (OSB) — Definitions, classification, and specifications
 * EN 309 - Particleboards — Definition and classification
 * EN 338 - Structural timber - Strength classes
 * EN 386 - Glued laminated timber — performance requirements and minimum production requirements
 * EN 313-1 - Plywood — Classification and terminology Part 1: Classification
 * EN 313-2 - Plywood — Classification and terminology Part 2: Terminology
 * EN 314-1 - Plywood — Bonding quality — Part 1: Test methods
 * EN 314-2 - Plywood — Bonding quality — Part 2: Requirements
 * EN 315 - Plywood — Tolerances for dimensions
 * EN 387 - Glued laminated timber — large finger joints - performance requirements and minimum production requirements
 * EN 390 - Glued laminated timber — sizes - permissible deviations
 * EN 391 - Glued laminated timber — shear test of glue lines
 * EN 392 - Glued laminated timber — Shear test of glue lines
 * EN 408 - Timber structures — Structural timber and glued laminated timber — Determination of some physical and mechanical properties
 * EN 622-1 - Fibreboards — Specifications — Part 1: General requirements
 * EN 622-2 - Fibreboards — Specifications — Part 2: Requirements for hardboards
 * EN 622-3 - Fibreboards — Specifications — Part 3: Requirements for medium boards
 * EN 622-4 - Fibreboards — Specifications — Part 4: Requirements for soft boards
 * EN 622-5 - Fibreboards — Specifications — Part 5: Requirements for dry process boards (MDF)
 * EN 1193 - Timber structures — Structural timber and glued laminated timber - Determination of shear strength and mechanical properties perpendicular to the grain
 * EN 1194 - Timber structures — Glued laminated timber - Strength classes and determination of characteristic values
 * EN 1995-1-1 - Eurocode 5: Design of timber structures — Part 1-1: General — Common rules and rules for buildings
 * EN 12369-1 - Wood-based panels — Characteristic values for structural design — Part 1: OSB, particleboards, and fibreboards
 * EN 12369-2 - Wood-based panels — Characteristic values for structural design — Part 2: Plywood
 * EN 12369-3 - Wood-based panels — Characteristic values for structural design — Part 3: Solid wood panels
 * EN 14080 - Timber structures — Glued laminated timber — Requirements
 * EN 14081-1 - Timber structures - Strength graded structural timber with rectangular cross-section - Part 1: General requirements
 * EN 15804 - Sustainability of construction works - Environmental product declarations - Core rules for the product category of construction products
 * EN 16485 - Round and sawn timber - Environmental Product Declarations - Product category rules for wood and wood-based products for use in construction (complementary-PCR to EN 15804)
 * ISO 21930 - Sustainability in buildings and civil engineering works - Core rules for environmental product declarations of construction products and services

Plyscrapers
Plyscrapers are skyscrapers that are either partially made of wood or entirely made of wood. Around the world, there have been many different plyscrapers built including Ascent MKE building and the Stadthaus building.

The Ascent MKE building was built in 2022 in Milwaukee, Wisconsin, and is the tallest high-rise building using different mass timber components in combination with some steel and concrete. This plyscraper is 87 meters tall and has 25 stories.

The Stadthaus building is a residential building built in 2009 in Hackney, London. It has 9 stories reaching 30 meters tall. It uses CLT panels as load-bearing walls and floor 'slabs'.

The Black & White Building is an office building topped out in 2023 in Shoreditch, London. It has 6 stories reaching 17.8 meters tall. It uses CLT panels, glulam curtain walling and LVL columns and beams.

Bridges
The Mistissini Bridge built in Quebec, Canada, in 2014 is a 160-meter-long bridge that features both glulam beams and CLT panels. The bridge was designed to cross over the Uupaachikus Pass.

The Placer River Pedestrian Bridge built in Alaska, United States, in 2013. It spans 280 ft long and is located in the Chugach National Forest. This bridge features glulam as it was used create the trusses.

Parking structures
The Glenwood CLT Parking Garage in Springfield, Oregon, is going to be a 206,000 sqft garage that features CLT. It will be 4 stories tall and hold 360 parking spaces. The parking garage however is under construction, and the year of completion is not yet known.

title: Engineered wood


text:
User:Haukurth

Latest work

 * Rigveda 1.32 - One of the most notable hymns in the Rigveda so it is surprising that an article was not created on it until 2024. The issue may be that the hymn has no conventional name, only the designation by number of mandala and sukta. Names attract articles.

da:Bruger:Haukur de:Benutzer:Haukur fo:Brúkari:Haukur fr:Utilisateur:Haukur is:Notandi:Haukurth no:Bruker:Haukur nn:Brukar:Haukur sv:Användare:Haukurth

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title: User:Haukurth


text:
Talk:Pointy-haired Boss

Proposal to reinstate section:

-Section title: Other fictional characters with some PHB traits

 * John Armstrong (The Armstrongs)
 * Henry Blake (M*A*S*H)
 * David Brent (The Office, BBC original)
 * Julius C. Dithers (Blondie (comic strip))
 * Jack Donaghy (30 Rock)
 * Gordon Jump as Arthur 'Big Guy' Carlson (WKRP in Cincinnati)
 * Bill Lumbergh (Office Space)
 * Mr. Poe (A Series of Unfortunate Events)
 * Alan Roy (Made in Canada)
 * Michael Scott (The Office, NBC adaptation)
 * Frank Waturi (Joe Versus the Volcano)

-History of article and questionable removal
After researching the history of this article and all relevant inclusions, the section approximately looked as above until it was removed on 2007-04-07 T06:01:58 by TKD for the reason "rm comparison list involving other unrelated characters; such analytical comparisons are original research unless sourced" While we may understand his sentiments, I respectfully contend it was overly strict adherence to a guideline. I further believe this resulted in a seemingly snap decision which was out of sync with the nature of this and other useful articles. In any case, such a section deletion should have gone through discussion and allowed other editors to weigh in.

-Proposed reinstatement
For that matter, I propose reinstating it. It was a long-running and helpful section in this article. By the same token, I think the floor should stay open for a little discussion, first. I personally do not believe the very minor "analytical comparisons" were over-reaching for the scope of wiki editors. Additionally, any sources to support the list (in whole or in part) would be appreciated. grubbmeister 21:07, 30 July 2007 (UTC)

-Discussion

 * Add any additional comments, then sign with "~" .

 * A few points here: No original research isn't merely a guideline; it's a policy. Part of it states that original research includes the introduction of "an argument, without citing a reputable source for that argument, that purports to refute or support another idea, theory, argument, or position." Giving a list of PHBs, without citing a source that calls them such, advances an unsupported argument/position. Character trait analysis and comparisons are not exactly incontrovertible material. The fact that another article does something isn't necessarily reason to follow suit in other articles. Indeed, in addition to the policy against original researrch, there is a guideline that exhorts editors to avoid trivia, which these lists of comparisons tend to bem, especially without reliable sources and eithout further context. As far as prcedure, this article wasn't very heavily edited, so I was being WP:BOLD and tried to improve it. It really wasn't a source of ongoing controversy at the time, and there's no reason to discuss every single edit to articles that don't otherwise receive a lot of attention from editors. — TKD::Talk 07:11, 1 August 2007 (UTC)

-Voting

 * Indicate whether you support or oppose reinstating the section. Indicate *Support or *Oppose followed by an optional one-sentence explanation, then sign your vote with "~" .

Example: Votes:
 * Support - the section was relevant and helpful grubbmeister 21:07, 30 July 2007 (UTC)
 * Oppose - Though I'm not sure why we even need this formalized template and such for a discussion that, for now, involves only the two of us. — TKD::Talk 07:11, 1 August 2007 (UTC)
 * Oppose - While it may be worthwhile having a section that draws some comparisons with the Bill Lumbergh and Michael Scott characters (who are examples of the same office management phenomenon), the rest should go. But regardless of whether the section gets added, the list is useless and should be cut. - Kingnosis 16:58, 24 August 2007 (UTC)
 * Oppose - This is original research, it's trivia, and it's stupid. For example, Henry Blake had no relation to the PHB whatsoever -- he was a nice, fair-minded guy, beloved by his subordinates, who didn't make the them work any harder than they had to, and was competent in the same field as them (surgery; as if the PHB was a capable engineer).  He was virtually the opposite of the PHB.  Damn.  Leave other characters out of this.  Don't try to compare the rest of the universe to Dilbert.  Believe it or not, the rest of the universe doesn't fit.  --63.25.252.165 (talk) 04:52, 15 September 2008 (UTC)
 * Support/Oppose -
 * Support/Oppose -
 * Support/Oppose -

Disputed claim
"In the Dilbert TV series, in which he was voiced by comedian Larry Miller, the character was notably smarter..."
 * IMHO he is every bit as stupid in the TV series, if not more so. Lee M 19:10, 19 April 2007 (UTC)
 * As a big fan who owns the DVD boxsets, I agree that the TV version of PHB was as stupid as the cartoon strip version. Should be removed as it's incorrect. Notorious Biggles 12:24, 20 April 2007 (UTC)

Lists and Their Evils
This page is a perfect example of why we shoudn't use lists: every other person that comes along feels the need to add to it. Someone needs to reformat it (Read: delete half of it) into a coherent paragraph.the1physicist 19:40, 16 December 2005 (UTC)

I disagree. That list was very helpful. In fact, I had a boss who fit 17 of the traits perfectly. That is a perfect example of why we SHOULD use lists. (64.228.222.141 (talk) 23:11, 27 July 2008 (UTC))

I VOTE we reinstate the list. —Preceding unsigned comment added by 64.228.222.141 (talk) 23:11, 27 July 2008 (UTC)

Nah, leave it out. --63.25.252.165 (talk) 04:59, 15 September 2008 (UTC)

Requested move

 * No longer relevant; article was moved in December 2005. æ² ✆ 2006‑12‑25t04:39z

The name should have a hyphen to be grammatically correct, but Pointy-Haired Boss has an edit history reflecting changing name of this article itself. æle ✆ 22:35, 18 December 2005 (UTC)

Voting

 * Add *Support or *Oppose followed by an optional one-sentence explanation, then sign your vote with ~

 * Support per nom. Goyston 20:47, 24 December 2006 (UTC)

Discussion

 * Add any additional comments

"Heck" link
At the time I found this, "Heck" redirected to "Hell". Since a few words down "Hell" already has it's own wikilink and a few words above "Phil" already has his own link I have changed the link portion to Heck(Dilbert) as the natural place if such an article is created. Jon 19:24, 15 June 2007 (UTC)

Mauve has the most RAM
I've deleted this section. The text of the strip as recounted is completely incorrect. There is no citation proving that the joke is a reference to Douglas Adams. I very much doubt the strip has anything whatsoever to do with SGI workstations. If you want to put it back you'll have to rewrite it.

Picture?
I understand Wikipedia needs to use free images, but surely there's a picture we can use for this article. NoobixCube (talk) 09:13, 24 July 2008 (UTC)

I have since added a picture--CornfieldMannequin (talk) 18:38, 6 January 2009 (UTC)

Never mind. We need a picture again.--CornfieldMannequin (talk) 19:08, 15 August 2009 (UTC)

Removed the weaselly-named "Related Acronyms".
After staring blankly at the "Related Acronyms" section for a bit, I realized was was bugging me about it. It's about stuff that really isn't related to Dilbert at all, except in the "If you enjoy Dilbert, Amazon recommends the following: ________" sense. It repeatedly used weasel words to build an after-the-fact connection when no real, verifiable connection ever existed. It was entirely about another strip/cartoon/whatever, by another artist, with no connection with Scott Adams's work. It was as if you put a whole section about Radiohead, and only Radiohead, in the Pink Floyd article. Oh, and on top of all that, it was purely original research. At first, I thought about rewriting it. . . but then, I realized I couldn't figure out any good reason for it being in the article at all. As if we need help recognizing when one acronym is reminscent of another? Or that we needed to be told the PHB is a "suit"?!? Can anyone justify this section's reinstatement? I think the article's much better without it. --63.25.252.165 (talk) 05:13, 15 September 2008 (UTC)

Book Covers
The following images can be used in the article, showing the Pointy-Haired Boss's portrayal on Dilbert book covers:
 * Here
 * and Here

These images show relevance in the article. With the first one, management itself is portrayed as a bald person with pointy-hair, regardless of gender. And with the second one, the symbol of pointy-hair is referred to negatively as a pile of manure. (Hence the term "Don't Step In It," as well as the shovel.) I feel that these images should be shown in the article, and that someone should add Non-Free Use Rationales to them, permitting them to be used in this article. Please comment.--CornfieldMannequin (talk) 17:42, 21 April 2009 (UTC)

Jowly boss
actually last appeared Sunday 1st December, 1991. How sad am I ;) Calum (talk) 16:11, 16 July 2009 (UTC)

Not entirely incompetent
There was a strip in the past year where he stated something that was actually a good idea in terms of business but was once again shot down by the pompous ass that Dilbert is - and this was all supposed to be funny because Dilbert is never wrong (even if he's an idiot in terms of business sometimes). 99.240.141.220 (talk) 16:19, 10 September 2010 (UTC)

new section on the description of people as "pointy haired bosses"
due to the popularity of the comic strip, describing people as "pointy haired bosses" as a reference to the characteristics of the original is becoming more common.

am i right in thinking their should be a section on this? Magicalbendini (talk) 15:10, 23 July 2014 (UTC)

Is he called PHB in the strip?
Is he referred to as Pointy-haired Boss in the Dilbert world, or is that just what fans have decided to call him? the article doesn't say 74.108.54.119 (talk) 13:05, 30 July 2016 (UTC)

title: Talk:Pointy-haired Boss


text:
Leopard cat

The leopard cat (Prionailurus bengalensis) is a small wild cat native to continental South, Southeast, and East Asia. Since 2002 it has been listed as Least Concern on the IUCN Red List as it is widely distributed although threatened by habitat loss and hunting in parts of its range.

Historically, the leopard cat of continental Asia was considered the same species as the Sunda leopard cat. As of 2017, the latter is recognised as a distinct species, with the taxonomic name Prionailurus javanensis.

Leopard cat subspecies differ widely in fur colour, tail length, skull shape and size of carnassials. Archaeological evidence indicates that the leopard cat was the first cat species domesticated in Neolithic China about 5,000 years ago in Shaanxi and Henan Provinces.

Characteristics

A leopard cat is about the size of a domestic cat, but more slender, with longer legs and well-defined webs between its toes. Its small head is marked with two prominent dark stripes and a short and narrow white muzzle. There are two dark stripes running from the eyes to the ears and smaller white streaks running from the eyes to the nose. The backs of its moderately long and rounded ears are black with central white spots. Body and limbs are marked with black spots of varying size and colour, and along its back are two to four rows of elongated spots. The tail is about half the size of its head-body length and is spotted with a few indistinct rings near the black tip. The background colour of the spotted fur is tawny, with a white chest and belly. However, in their huge range, they vary so much in colouration and size of spots as well as in body size and weight that initially they were thought to be several different species. The fur colour is yellowish brown in the southern populations, but pale silver-grey in the northern ones. The black markings may be spotted, rosetted, or may even form dotted streaks, depending on subspecies. In the tropics, leopard cats weigh 0.55 - 3.8 kg, have head-body lengths of 38.8 - 66 cm, with long 17.2 - 31 cm tails. In northern China and Siberia, they weigh up to 7.1 kg, and have head-body lengths of up to 75 cm; generally, they put on weight before winter and become thinner until spring. Shoulder height is about 41 cm.

Taxonomy

Felis bengalensis was the scientific name proposed by Robert Kerr in 1792 for a leopard cat from Bengal. In the subsequent decades, 20 more leopard cat specimens were described and named, including:

In 1939, Reginald Innes Pocock subordinated them to the genus Prionailurus. The collection of the Natural History Museum, London comprised several skulls and large numbers of skins of leopard cats from various regions. Based on this broad variety of skins, he proposed to differentiate between a southern subspecies P. bengalensis bengalensis from warmer latitudes to the west and east of the Bay of Bengal, and a northern P. bengalensis horsfieldi from the Himalayas, having a fuller winter coat than the southern. His description of leopard cats from the areas of Gilgit and Karachi under the trinomen Prionailurus bengalensis trevelyani is based on seven skins that had longer, paler and more greyish fur than those from the Himalayas. He assumed that trevelyani inhabits more rocky, less forested habitats than bengalensis and horsfieldi.
 * Felis nipalensis (Horsfield & Vigors, 1829) from Nepal
 * Felis chinensis (Gray, 1837) from Canton Province, China
 * Leopardus ellioti (Gray, 1842) from the area of Bombay Presidency
 * Felis horsfieldi (Gray, 1842) from Bhutan
 * Felis wagati (Gray, 1867) and Felis tenasserimensis (Gray, 1867) from Tenasserim
 * Felis microtis (Milne-Edwards, 1872) from the Peking area; and also from Tsushima Island.
 * Felis euptilura (Elliot, 1871) based on two skins from Siberia. One was depicted in Gustav Radde's illustration cum description of a wild cat; the other was part of a collection at the Regent's Park Zoo. The ground colour of both was light brownish-yellow, strongly mixed with grey and covered with reddish-brown spots, head grey with a dark-red stripe across the cheek. The initial binomial euptilura given by Elliott has been incorrectly changed to "euptilurus" by some later authors, but under the International Code of Zoological Nomenclature Article 31.2.1, nouns and noun phrases are not subject to gender agreement; at present, both terms appear in use, but only the spelling "euptilura" is correct.
 * Felis manchurica (Mori, 1922) from the vicinity of Mukden in Manchuria was a light grey spotted skin.

Two more subspecies were proposed and described:

 * P. b. alleni (Sody, 1949) from Hainan Island
 * Iriomote cat P. b. iriomotensis (Imaizumi, 1967) from the island of Iriomote, one of the Ryukyu Islands in the Japanese Archipelago; Initially, the Iriomote cat was recognised as a distinct species, but following mtDNA analysis in the 1990s was considered a leopard cat subspecies.

In the 1970s and 1980s, the Russian zoologists Geptner, Gromov and Baranova disagreed with this classification. They emphasized the differences of skins and skulls at their disposal and the ones originating in Southeast Asia, and coined the term Amur forest cat, which they regarded as a distinct species. In 1987, Chinese zoologists pointed out the affinity of leopard cats from northern China, Amur cats and leopard cats from southern latitudes. In view of the morphological similarities they did not support classifying the Amur cat as a species.

Molecular analysis of 39 leopard cat tissue samples clearly showed three clades: a northern lineage and southern lineages 1 and 2. The northern lineage comprises leopard cats from Tsushima Islands, the Korean Peninsula, the continental Far East, Taiwan, and Iriomote Island. Southern lineage 1, comprising Southeast Asian populations, showed higher genetic diversity. Southern lineage 2 is genetically distant from the other lineages.

Following a revision of Felidae taxonomy in 2017, two leopard cat species are now recognised, based on molecular analyses, morphological differences, and biogeographic separation:

 * the mainland leopard cat (P. bengalensis) is widely distributed on mainland Asia, from Pakistan to Southeast Asia, China, and the Russian Far East.
 * the Sunda leopard cat (P. javanensis) is native to Java, Bali, Borneo, Sumatra, Palawan, Negros, Cebu, Panay, and possibly the Malay Peninsula.

Two mainland leopard cat subspecies are currently recognised:

 * P. b. bengalensis (Kerr, 1792) ranges in South and East Asia, from Pakistan to China, and probably the Malay Peninsula; and
 * P. b. euptilura (Elliott, 1871) is native to the Russian Far East, Manchuria, Korea, Taiwan, Iriomote and Tsushima Islands.

Phylogeny
Phylogenetic analysis of the nuclear DNA in tissue samples from all Felidae species revealed that the evolutionary radiation of the Felidae began in Asia in the Miocene around. Analysis of mitochondrial DNA of all Felidae species indicates a radiation at around.

The Prionailurus species are estimated to have had a common ancestor between, and. Both models agree in the rusty-spotted cat (P. rubiginosus) having been the first cat of this evolutionary lineage that genetically diverged, followed by the flat-headed cat (P. planiceps) and then the fishing cat (P. viverrinus). It is estimated to have diverged together with the leopard cat between and.

The following cladogram shows the phylogenetic relationships of the leopard cat as derived through analysis of nuclear DNA:

Distribution and habitat
The leopard cat is the most widely distributed Asian small wild cat. Its range extends from the Amur region in the Russian Far East over the Korean Peninsula, China, Indochina, the Indian Subcontinent to northern Pakistan. It lives in tropical evergreen rainforests and plantations at sea level, in subtropical deciduous and coniferous forests in the foothills of the Himalayas at elevations above 1000 m. It is able to tolerate human-modified landscapes with vegetation cover to some degree, and inhabits agriculturally used areas such as oil palm and sugar cane plantations.

In 2009, a leopard cat was recorded by a camera trap in Nepal's Makalu-Barun National Park at an altitude of 3254 m. At least six individuals inhabit the survey area, which is dominated by associations of rhododendron, oak and maple. The highest elevation record was obtained in September 2012 at 4474 m in the Kanchenjunga Conservation Area.

In the northeast of its range it lives close to rivers, valleys and in ravine forests, but avoids areas with more than 10 cm of snowfall. It is rare in Pakistan's arid treeless areas. In Afghanistan, it was reported in the 1970s from Jalalkot and Norgul in the Kunar Valley, and the Waygul forest of Dare Pech.

In Thailand's Phu Khiao Wildlife Sanctuary, 20 leopard cats were radio-collared between 1999 and 2003. Home ranges of males ranged from 2.2 km2 to 28.9 km2, and of the six females from 4.4 km2 to 37.1 km2. In China, it was recorded in the Changqing National Nature Reserve in the Qinling Mountains, in the Tangjiahe National Nature Reserve in the Min Mountains, in Wolong Nature Reserve and other protected areas in the Qionglai Mountains and Daliang Mountains between 2002 and 2008.

In the Japanese archipelago, the leopard cat is currently restricted to the islands of Iriomote and Tsushima. Fossils excavated dating to the Pleistocene period suggest a broader distribution in the past.

Ecology and behaviour

Leopard cats are solitary, except during the breeding season. Some are active during the day, but most hunt at night, preferring to stalk murids, tree shrews and hares. They are agile climbers and quite arboreal in their habits. They rest in trees, but also hide in dense thorny undergrowth on the ground. There, leopard cats feed on a large proportion of rats compared to forested areas.

Leopard cats can swim, but seldom do so. They produce a similar range of vocalisations to the domestic cat. Both sexes scent mark their territory by spraying urine, leaving faeces in exposed locations, head rubbing, and scratching.

Diet
Leopard cats are carnivorous, feeding on a variety of small prey including mammals, lizards, amphibians, birds and insects. In most parts of their range, small rodents such as rats and mice form the major part of their diet, which is often supplemented with grass, eggs, poultry, and aquatic prey. They are active hunters, dispatching their prey with a rapid pounce and bite. Unlike many other small cats, they do not "play" with their food, maintaining a tight grip with their claws until the animal is dead. This may be related to the relatively high proportion of birds in their diet, which are more likely to escape when released than are rodents.

Reproduction and development
The breeding season of leopard cats varies depending on the climate. In tropical habitats, kittens are born throughout the year. In colder habitats farther north, females give birth in spring. Their gestation period lasts 60–70 days. Litter size varies between two and three kittens. Captive-born kittens weighed 75 to 130 g at birth and opened their eyes by 15 days of age. Within two weeks, they doubled their weight and were four times their birth weight at the age of five weeks. At the age of four weeks, their permanent canines break through, and they begin to eat meat. Captive females reach sexual maturity earliest at the age of one year and have their first litter at the age of 13 to 14 months. Captive leopard cats have lived for up to thirteen years.

The estrus period lasts five to nine days.

Threats

In China, leopard cats are hunted mainly for their fur. Between 1984 and 1989, about 200,000 skins were exported yearly. A survey carried out in 1989 among major fur traders revealed more than 800,000 skins on stock. Since the European Union imposed an import ban in 1988, Japan has become the main importing country, and received 50,000 skins in 1989. Although commercial trade is much reduced, the leopard cat continues to be hunted throughout most of its range for fur, food, and for sale as a pet. It is widely viewed as a poultry thief and killed in retribution.

In Myanmar, 483 body parts of at least 443 individuals were observed in four markets surveyed between 1991 and 2006. Numbers were significantly larger than non-threatened species. Three of the surveyed markets are situated on international borders with China and Thailand, and cater to international buyers, although the leopard cat is completely protected under Myanmar's national legislation. Implementation and enforcement of CITES is considered inadequate.

Conservation
The leopard cat is listed in CITES Appendix II. In Hong Kong, it is protected under the Wild Animals Protection Ordinance Cap 170. The population is well over 50,000 individuals and, although declining, the cat is not endangered.

The Tsushima leopard cat is listed as Critically Endangered on the Japanese Red List of Endangered Species, and has been the focus of a conservation program funded by the Japanese government since 1995. It is threatened by habitat loss, including from logging in the 1950s and 1960s, and a growing deer population which removes undergrowth that the Tsushima cat hunts for rodents in. The historical population has been split into two by the dividing of Tsushima island by a canal, and the southern population was thought extinct until a sighting in 2007. A recorded 122 individuals were killed by cars from 1992 to 2022. A captive breeding program has been initiated, but has not led to any successful reintroductions.

In the United States, the leopard cat is listed as Endangered under the Endangered Species Act since 1976; except under permit, it is prohibited to import, export, sell, purchase and transport leopard cats in interstate commerce. A permit is required for the import or exportation of the Asian Leopard cat. Those who import/export without a CITES permit face large fines.

Leopard cats and hybrids as pets
Fossil remains of leopard cats were excavated at Neolithic villages in Central China in 2001. Radiometric dating of these bones showed that they are at least 5,000 years old. These findings indicate that the leopard cat was a human commensal or domesticated in Neolithic China. They were later replaced with domestic cats that originated in the Middle East, some time before the Tang dynasty.

The Bengal cat is a cross breed between the leopard cat and the domestic cat. It was introduced to cat shows in the 1970s. The fifth generation is marked like a leopard cat. This hybrid is usually permitted to be kept as a pet without a license. The founding parents from the F1–F3 generations of breeding are usually reserved for breeding stock purposes or the specialty-pet home environment.

title: Leopard cat


text:
Definitive stamp

A definitive stamp is a postage stamp that is part of the regular issue of a country's stamps, available for sale by the post office for an extended period of time and designed to serve the everyday postal needs of the country. The term is used in contrast to a "provisional stamp", one that is issued for a temporary period until regular stamps are available, or a "commemorative stamp", a stamp "issued to honor a person or mark a special event" available only for a limited time. Commonly, a definitive issue or series includes stamps in a range of denominations sufficient to cover current postal rates. An "issue" generally means a set that is put on sale all at the same time, while a "series" is spread out over several years, but the terms are not precise. Additional stamps in a series may be produced as needed by changes in postal rates; nevertheless some values may be permanently available, regardless of prevailing rates; examples include 1c or 1p and $1 or £1.

Range
The range of values varies by era and country, but the focus is on coverage; the values should be sufficient to make up all possible charges using as few stamps as possible. Generally the smallest value will be the smallest unit of currency, or smallest fractional postal rate; for instance, the 1925 regular issue of the United States included a $1/2$-cent stamp because some rates were expressed in fractions of a cent per ounce. The highest value of the series is generally quite large, typically from 50 to 100 times the normal letter rate; typical values include one pound, five dollars, etc. Not often seen by the average person, they are most common for parcels.

The in-between values are usually chosen to "make change" efficiently, for instance 1, 2, 5, 10, 20, 50 in a decimal currency. It is common to include all values between 1 and 10, multiples of 5 from 10 to 50, and multiples of 10 from 50 to 100. Additional "oddball" values may reflect specific common rates, and if the series lasts for a period of time, there may be a number of such unusual values as in the UK QE II Machin series below.

Definitives are the workhorse stamps of a country, and as such, they tend to be small, with designs reflecting local culture and history. The definitives of poorer countries will often be very plain and cheaply printed, unlike the large and decorative commemoratives, which are almost pure profit if bought by foreign collectors and never used for postage.

Frequency of issue
Since postal administrations know that many stamp collectors want to own every stamp of a definitive series, and a complete series can be quite expensive, there is always the temptation by governmental bureaucrats to make extra money by frequently issuing new definitive sets, as well as including stamps with very high face values in a set. Collectors' organizations have recommended that administrations only bring out new definitive issues no more often than every five years, and most administrations of the world follow this policy. An exception would be the death of a monarch, or other prominent leader, necessitating a new definitive series for the new ruler. Sometimes merely the portrait is changed, and the outer design (known as the frame) remains the same throughout several issues. Countries that ignore frequency of issue guidelines and issue volumes of stamps that have little to no practical usage produce what many collectors refer to as wallpaper.

Collecting
Since definitive series are issued over a period of time and are reprinted to meet postal demand, they often contain more variation than is typically found in stamps that have a single print run. Switching printing methods and experimenting with phosphors is a common source of variation in modern stamps, while differences in watermarks and perforation are also prevalent, especially in older stamps. Many philatelists study these differences as part of their hobby and try to collect all the varieties of each stamp. Some varieties are particularly rare and can be more valuable than others of the same stamp that may look the same to the casual observer. One notable example of this variation is the Machin stamps of the UK, where philatelists have identified over 1,000 varieties of the same basic design.

Special stamps, such as the Christmas stamps issued annually by various countries, are sometimes regarded as definitives because they are not commemoratives, but they typically only include a limited range of denominations relating specifically to the mail seen on the occasion for which they are issued.

Notable definitive stamp series

 * Argentina
 * 1935-1951 Patriots and Natural Resources Issue
 * Australia
 * Kangaroo and Map
 * King George V series
 * Canada
 * Scroll issue
 * Queen Elizabeth II issue
 * Arch and maple leaf issue
 * War issue
 * France
 * Ceres series
 * Navigation and Commerce issue
 * Germany
 * Germania
 * Women in German history series
 * Greece
 * Hermes Heads
 * Norway
 * , issued since 1872
 * Portugal
 * Ceres series
 * Russia
 * Gold Standard issue, produced by the USSR in 1923–1927
 * United Kingdom
 * Wilding series
 * Machin series
 * United States
 * 1869 Pictorial Issue
 * Series of 1902
 * Washington-Franklin Issues
 * Presidential Issue
 * Liberty issue
 * Prominent Americans series
 * Americana series
 * Great Americans series
 * Transportation coils
 * Distinguished Americans series

title: Definitive stamp


text:
User talk:Mandark~enwiki

Welcome to Wikipedia! I hope you'll find this an enjoyable and valuable resource, both as a reader and writer. I'm glad we have another expert to help us expand the coverage and correctness of our articles on mental health topics.

You might be interested in joining the WikiProject Psychopathology. -- The Anome 17:41 24 Jul 2003 (UTC)

Hi Mandark,

I'm also a research scientist (from the UK) working on the neuropsychology of psychosis. We're just discussing your changes to the schizophrenia article over at Talk:Schizophrenia and we'd be grateful if you could join us.

Thanks! -- Vaughan

Your account will be renamed
Hello,

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Unfortunately, your account clashes with another account also called Mandark. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Mandark~enwiki that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name. If you think you might own all of the accounts with this name and this message is in error, please visit Special:MergeAccount to check and attach all of your accounts to prevent them from being renamed.

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Renamed
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title: User talk:Mandark~enwiki