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Lumber

Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). Lumber has many uses beyond home building. Lumber is referred to as timber in the United Kingdom, Europe,[1] Australia, and New Zealand, while in other parts of the world (mainly the United States and Canada) the term timber refers specifically to unprocessed wood fiber, such as cut logs or standing trees that have yet to be cut.

For other uses, see Lumber (disambiguation).

Lumber may be supplied either rough-sawn, or surfaced on one or more of its faces. Rough lumber is the raw material for furniture-making, and manufacture of other items requiring cutting and shaping. It is available in many species, including hardwoods and softwoods, such as white pine and red pine, because of their low cost.[2]


Finished lumber is supplied in standard sizes, mostly for the construction industry – primarily softwood, from coniferous species, including pine, fir and spruce (collectively spruce-pine-fir), cedar, and hemlock, but also some hardwood, for high-grade flooring. It is more commonly made from softwood than hardwoods, and 80% of lumber comes from softwood.[3]

History[edit]

The basic understanding of lumber, or "sawn planks", came about in North America in the seventeenth century.[8] Lumber is the most common and widely used method of sawing logs. Plain sawn lumber is produced by making the first cut on a tangent to the circumference of the log. Each additional cut is then made parallel to the one before. This method produces the widest possible boards with the least amount of log waste.[9]


Lumber manufacturing globally is determined by the preferred style of building; areas with a "wood building culture" (homes were built from wood rather than other materials like brick) are the countries with significant sawmilling industries. Historical wood-frame home building regions are: Europe, North America, Japan.[10] Different areas of the world are recognized as significant timber suppliers; however, these areas (Indonesia, Sarawak, New Guinea, etc.) are exporters of raw logs and do not have a significant domestic lumber producing industry.


The largest lumber manufacturing regions in the world are: China (18%); United States (17%); Canada (10%); Russia (9%); Germany (5%); Sweden (4%).[11]


In early periods of society, to make wood for building, the trunks of trees were split with wedges into as many and as thin pieces as possible. If it was necessary to have them still thinner, they were hewn, by some sharp instrument, on both sides, to the proper size.[12] This simple but wasteful manner of making boards is still continued in some places.


Otherwise, logs were sawn using a two-person whipsaw, or pit-saw, using saddleblocks to hold the log, and a pit for the pitman who worked below.


In 1420 the island of Madeira – an archipelago comprising four islands off the northwest coast of Africa and an autonomous region of Portugal – was discovered. King Henry VI sent settlers to Madeira and the settlers started clearing the huge expanses of forest in order to grow crops. Felled trees were made into planks by water-powered mills and the timber (cedar and yew) was shipped to Portugal and Spain.[13] About 1427, the first sawmill in Germany was built.[12]


Cornelis Corneliszoon (or Krelis Lootjes) was a Dutch windmill owner from Uitgeest who invented the first mechanical sawmill, which was wind-powered, on December 15, 1593. This made the conversion of log timber into planks 30 times faster than previously.[14]


The circular saw, as used in modern sawmills, was invented by an Englishman named Miller in 1777. It was not until the nineteenth century, however, that it was generally applied, and its great work belongs to that period. The first insertable teeth for this saw were invented by W. Kendal, an American, in 1826.[15]


Logging in the American colonies began in 1607 when the Jamestown settlers cut timber to build the first settlement in the new world.[16] America's first sawmill was built at the Falls of Piscatauqua, on the line between the Province of Maine and the Province of New Hampshire, in 1634. Unauthenticated records, however, claim that as early as 1633 several mills were operating in New Netherland.[12]


The American colonies were essential to England in the role of supplier of lumber for the British fleet. By the 1790s, New England was exporting 36 million feet of pine boards and at least 300 ship masts per year to the British Empire.[16] The timber supply began to dwindle at the start of the twentieth century due to significant harvest volumes, so the logging industry was forced to seek timber elsewhere; hence, the expansion into the American West.[17]

Plain sawn (flat sawn, through and through, bastard sawn) – A log sawn through without adjusting the position of the log and the grain runs across the width of the boards.

and rift sawn – These terms have been confused in history but generally mean lumber sawn so the annual rings are reasonably perpendicular to the sides (not edges) of the lumber.

Quarter sawn

Boxed heart – The remains within the timber, post or beam, with some allowance for exposure.

pith

Heart center – the center core of a log.

Free of heart center (FOHC) – A side-cut timber, post or beam without any pith.

Free of knots (FOK) – No knots are present.

Logs are converted into lumber by being sawn, hewn, or split. Sawing with a rip saw is the most common method, because sawing allows logs of lower quality, with irregular grain and large knots, to be used and is more economical. There are various types of sawing:

C14, used for and formwork

scaffolding

C16 and C24, general construction

C30, prefab roof trusses and where design requires somewhat stronger than C24 can offer. TR26 is also a common trussed rafter strength class in long standing use in the UK.[29][30]

joists

C40, usually seen in

glulam

Chip mark: this defect is indicated by the marks or signs placed by chips on the finished surface of timber

Diagonal grain: improper sawing of timber

Torn grain: when a small dent is made on the finished surface due to falling of some tool

Wane: presence of original rounded surface in the finished product

Controlling moisture using design techniques to avoid decay

Providing effective control of termites and other insects

Using durable materials such as pressure-treated or naturally durable species of wood where appropriate

Providing quality assurance during design and construction and throughout the building's service life using appropriate maintenance practices

Fire performance: In the case of fire, the outer layer of mass timber will tend to char in a predictable way that effectively self-extinguishes and shields the interior, allowing it to retain structural integrity for several hours, even in an intense fire.

Reduction of carbon emissions: Building materials and construction make up 11% of global greenhouse gas emissions. Though the exact amount will depend on tree species, forestry practices, transportation costs, and several other factors, that one cubic meter of lumber sequesters roughly one tonne of CO2.

[49]

Natural insulation: lumber is a natural insulator which makes it particularly good for windows and doors.

Less construction time, labor costs, and waste: it is easy to manufacture prefabricated lumber, from which pieces can be assembled simultaneously (with relatively little labor). This reduces material waste, avoids massive on-site inventory, and minimizes on-site disruption. According to the softwood lumber industry, "Mass timber buildings are roughly 25% faster to construct than concrete buildings and require 90% less construction traffic".

[50]

Lumber is a sustainable and environmentally friendly construction material that could replace traditional building materials (e.g. concrete and steel) given its structural performance, capacity to fixate CO2 and low energy demand during the manufacturing process.[47]


Substituting lumber for concrete or steel avoids the carbon emissions of those materials. Cement and concrete manufacture is responsible for around 8% of global GHG emissions while the iron and steel industry is responsible for another 5% (half a ton of CO2 is emitted to manufacture a ton of concrete; two tons of CO2  are emitted in the manufacture of a ton of steel).[48]


Advantages of lumber:

End-of-life[edit]

An EPA study showed the typical end-of-life scenario for wood waste from municipal solid waste (MSW), wood packaging, and other miscellaneous wood products in the US. Based on the 2018 data, about 67% of wood waste was landfilled, 16% incinerated with energy recovery, and 17% recycled.[51]


A 2020 study conducted by Edinburgh Napier University demonstrated the proportional waste stream of recovered lumber in the UK. The study showed that timber from municipal solid waste and packaging waste made up 13 and 26% of waste collected. Construction and demolition waste made up the biggest bulk of waste collectively at 52%, with the remaining 10% coming from industry.[52]

Davis, Richard C. Encyclopedia of American forest and conservation history (1983) see also 2 online, 871pp. See online review of this book

vol 1 online

Sathre, R; O'Conner, J (2010). (PDF) (2nd ed.). FPInnovations. ISBN 978-0-86488-546-3. Archived from the original (PDF) on 21 March 2012.

A Synthesis of Research on Wood Products and Greenhouse Gas Impacts

(Rules for Grading Hardwood Lumber – Inspector Training School)

National Hardwood Lumber Association

– Australia

Timber Development Association of NSW

– UK

TDA: Timber Decking Association

TRADA: Timber Research And Development Association

The Forest Products Laboratory. U.S. main wood products research lab. Madison, WI (E)

June 20–24, 2010, Riva del Garda, Trentino, Italy

WCTE, World Conference on Timber Engineering

Forest Products data in Canada since 1990