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101-708: Foresters work for the timber industry , government agencies, conservation groups , local authorities, urban parks boards, citizens' associations, and private landowners . The forestry profession includes a wide diversity of jobs, with educational requirements ranging from college bachelor's degrees to PhDs for highly specialized work. Industrial foresters plan forest regeneration starting with careful harvesting. Urban foresters manage trees in urban green spaces . Foresters work in tree nurseries growing seedlings for woodland creation or regeneration projects. Foresters improve tree genetics . Forest engineers develop new building systems. Professional foresters measure and model

202-428: A construction material , for making tools and weapons , furniture and paper . More recently it emerged as a feedstock for the production of purified cellulose and its derivatives, such as cellophane and cellulose acetate . As of 2020, the growing stock of forests worldwide was about 557 billion cubic meters. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as

303-454: A low-carbon economy , forestry operations will be focused on low-impact practices and regrowth. Forest managers will make sure that they do not disturb soil-based carbon reserves too much. Specialized tree farms will be the main source of material for many products. Quick maturing tree varieties will be grown on short rotations to maximize output. Brazil has a long tradition in the harvesting of several types of trees with specific uses. Since

404-485: A 7% prevalence of hearing loss. Worker noise exposures in the forestry and logging industry have been found to be up to 102 dBA. NIOSH recommends that a worker have an 8-hour time-weighted average of noise exposure of 85 dBA. Excessive noise puts workers at an increased risk of developing hearing loss. If a worker were to develop a hearing loss as a result of occupational noise exposures, it would be classified as occupational hearing loss . Noise exposures within

505-401: A heavy piece of pine is compared with a lightweight piece it will be seen at once that the heavier one contains a larger proportion of latewood than the other, and is therefore showing more clearly demarcated growth rings. In white pines there is not much contrast between the different parts of the ring, and as a result the wood is very uniform in texture and is easy to work. In hard pines , on

606-539: A high quality standard of product. Their goal is to do this efficiently and safely, at low cost, with rapid production time and high output. Once the timber has been manipulated in the required fashion, it can be shipped out for usage. There are many different purposes for wood including plywood , veneer, pulp, paper , particleboard, pallets, craft items, toys, instrument-making, furniture production, packing cases, wine barrels, cardboard, firewood, garden mulch, fibre adhesives, packaging and pet litter. Western Australia has

707-405: A large log the sapwood, because of the time in the life of the tree when it was grown, may be inferior in hardness , strength , and toughness to equally sound heartwood from the same log. In a smaller tree, the reverse may be true. In species which show a distinct difference between heartwood and sapwood the natural color of heartwood is usually darker than that of the sapwood, and very frequently

808-408: A licensing requirement for foresters, and most of those require at least a four-year degree. Foresters are often employed by private industry, federal and state land management agencies, or private consulting firms. Forester was a title used widely during Medieval times. The forester usually held a position equal to a sheriff or local law enforcer, and he could act as a barrister or arbiter. He

909-400: A log is on the outside, it is more or less knotty near the middle. Consequently, the sapwood of an old tree, and particularly of a forest-grown tree, will be freer from knots than the inner heartwood. Since in most uses of wood, knots are defects that weaken the timber and interfere with its ease of working and other properties, it follows that a given piece of sapwood, because of its position in

1010-436: A mix of molecular hydrogen (H 2 ), carbon monoxide (CO), carbon dioxide (CO 2 ), molecular nitrogen (N 2 ) and water vapor (H 2 O). This gas mixture, known as " wood gas ", "poor gas" or " syngas " is obtained after the combustion of dry wood in a reductive environment (low in oxygen ) with a limited amount of atmospheric air, at temperatures of 900 °C, and can fuel an internal combustion engine . Wood

1111-481: A pretty definite relation between the rate of growth of timber and its properties. This may be briefly summed up in the general statement that the more rapid the growth or the wider the rings of growth, the heavier, harder, stronger, and stiffer the wood. This, it must be remembered, applies only to ring-porous woods such as oak, ash, hickory, and others of the same group, and is, of course, subject to some exceptions and limitations. In ring-porous woods of good growth, it

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1212-406: A slow process involving significant manual labor. Since sawmills were traditionally located within forests, milled timber had to be transported over long distances via rough terrain or waterways to reach its destination. Logs were later transported via train and tram lines, first by steam-powered log haulers then by steam-powered locomotives , and finally diesel and petrol-powered locomotives. Even in

1313-636: A source of renewable energy. In 2008, approximately 3.97 billion cubic meters of wood were harvested. Dominant uses were for furniture and building construction. Wood is scientifically studied and researched through the discipline of wood science , which was initiated since the beginning of the 20th century. A 2011 discovery in the Canadian province of New Brunswick yielded the earliest known plants to have grown wood, approximately 395 to 400 million years ago . Wood can be dated by carbon dating and in some species by dendrochronology to determine when

1414-465: A source of weakness. In diffuse-porous woods the pores are evenly sized so that the water conducting capability is scattered throughout the growth ring instead of being collected in a band or row. Examples of this kind of wood are alder , basswood , birch , buckeye, maple, willow , and the Populus species such as aspen, cottonwood and poplar. Some species, such as walnut and cherry , are on

1515-564: A tree is first formed as sapwood. The more leaves a tree bears and the more vigorous its growth, the larger the volume of sapwood required. Hence trees making rapid growth in the open have thicker sapwood for their size than trees of the same species growing in dense forests. Sometimes trees (of species that do form heartwood) grown in the open may become of considerable size, 30 cm (12 in) or more in diameter, before any heartwood begins to form, for example, in second growth hickory , or open-grown pines . No definite relation exists between

1616-423: A type of imperfection known as a knot. The dead branch may not be attached to the trunk wood except at its base and can drop out after the tree has been sawn into boards. Knots affect the technical properties of the wood, usually reducing tension strength, but may be exploited for visual effect. In a longitudinally sawn plank, a knot will appear as a roughly circular "solid" (usually darker) piece of wood around which

1717-467: A unique substance called ‘ biochar ’, which is made from jarrah and pine and sometimes from crop and forestry residues, along with the former materials. Biochar can be used to manufacture silicone and as a soil additive. Softwoods , such as the Australian eucalyptus , are highly valued, a are used mainly for construction , paper making , and cladding . The term 'round wood' describes all

1818-492: A wooden object was created. People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses , tools , weapons , furniture , packaging , artworks , and paper . Known constructions using wood date back ten thousand years. Buildings like the longhouses in Neolithic Europe were made primarily of wood. Recent use of wood has been enhanced by

1919-443: A younger age produce smaller logs, and these can be turned into lower-value products. Factors such as location, climate conditions, species, growth rate, and silviculture can affect the size of a mature tree. The native hardwood saw-milling industry originally consisted of small family-owned mills, but has recently changed to include a small number of larger mills. Mills produce large volumes of material and aim to ensure delivery of

2020-437: Is a season check in the knot, as is often the case, it will offer little resistance to this tensile stress. Small knots may be located along the neutral plane of a beam and increase the strength by preventing longitudinal shearing . Knots in a board or plank are least injurious when they extend through it at right angles to its broadest surface. Knots which occur near the ends of a beam do not weaken it. Sound knots which occur in

2121-456: Is also greatly increased in strength thereby. Since the latewood of a growth ring is usually darker in color than the earlywood, this fact may be used in visually judging the density, and therefore the hardness and strength of the material. This is particularly the case with coniferous woods. In ring-porous woods the vessels of the early wood often appear on a finished surface as darker than the denser latewood, though on cross sections of heartwood

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2222-428: Is an important consideration. The weakening effect is much more serious when timber is subjected to forces perpendicular to the grain and/or tension than when under load along the grain and/or compression . The extent to which knots affect the strength of a beam depends upon their position, size, number, and condition. A knot on the upper side is compressed, while one on the lower side is subjected to tension. If there

2323-496: Is burned in the recovery boiler . Thus, these countries have high proportions of renewable energy use (25% in Finland, for instance). Considerable effort is directed towards increasing the value and usage of forest products by companies and by government projects. A forest product is any material derived from forestry for direct consumption or commercial use, such as lumber , paper , or fodder for livestock . Wood , by far

2424-422: Is dark colored and firm, and consists mostly of thick-walled fibers which form one-half or more of the wood. In inferior oak, this latewood is much reduced both in quantity and quality. Such variation is very largely the result of rate of growth. Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in

2525-560: Is difficult to control completely, especially when using mass-produced kiln-dried timber stocks. Heartwood (or duramen ) is wood that as a result of a naturally occurring chemical transformation has become more resistant to decay. Heartwood formation is a genetically programmed process that occurs spontaneously. Some uncertainty exists as to whether the wood dies during heartwood formation, as it can still chemically react to decay organisms, but only once. The term heartwood derives solely from its position and not from any vital importance to

2626-399: Is in the walls, not the cavities. Hence the greater the proportion of latewood, the greater the density and strength. In choosing a piece of pine where strength or stiffness is the important consideration, the principal thing to observe is the comparative amounts of earlywood and latewood. The width of ring is not nearly so important as the proportion and nature of the latewood in the ring. If

2727-486: Is known as secondary growth ; it is the result of cell division in the vascular cambium , a lateral meristem, and subsequent expansion of the new cells. These cells then go on to form thickened secondary cell walls, composed mainly of cellulose , hemicellulose and lignin . Where the differences between the seasons are distinct, e.g. New Zealand , growth can occur in a discrete annual or seasonal pattern, leading to growth rings ; these can usually be most clearly seen on

2828-431: Is laid down on the outside of the wood previously formed, it follows that unless a tree materially increases its production of wood from year to year, the rings must necessarily become thinner as the trunk gets wider. As a tree reaches maturity its crown becomes more open and the annual wood production is lessened, thereby reducing still more the width of the growth rings. In the case of forest-grown trees so much depends upon

2929-460: Is managed primarily for the production of wood and non-wood forest products. In addition, 749,000,000 ha (1.85 × 10 acres) is designated for multiple use, which often includes production. Combustion of wood is linked to the production of micro-environmental pollutants, as carbon dioxide (CO 2 ), carbon monoxide (CO) (an invisible gas able to provoke irreversible saturation of blood's hemoglobine ), as well as nanoparticles . Charcoal

3030-470: Is more complex. The water conducting capability is mostly taken care of by vessels : in some cases (oak, chestnut, ash) these are quite large and distinct, in others ( buckeye , poplar , willow ) too small to be seen without a hand lens. In discussing such woods it is customary to divide them into two large classes, ring-porous and diffuse-porous . In ring-porous species, such as ash, black locust, catalpa , chestnut, elm , hickory, mulberry , and oak,

3131-599: Is relatively light in weight, because its specific weight is less than 500 kg/m , this is an advantage, when compared against 2,000–2,500 kg/m for reinforced concrete or 7,800 kg/m for steel. Wood is strong, because the efficiency of wood for structural purposes has qualities that are similar to steel. Wood is used to build bridges (as the Magere bridge in Amsterdam), as well as water and air mills, and microhydro generators for electricity. Hardwood

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3232-465: Is the dark grey residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis , the heating of wood or other substances in the absence of oxygen . Charcoal can then be used as a fuel with a higher combustion temperature. Wood gas generator (gasogen): is a bulky and heavy device (but technically simple) that transforms burning wood in

3333-736: Is the harvest, transportation, purchase, or sale of timber in violation of laws . The harvesting procedure itself may be illegal, including using corrupt means to gain access to forests; extraction without permission, or from a protected area; the cutting down of protected species ; or the extraction of timber in excess of agreed limits. Illegal logging is a driving force for a number of environmental issues such as deforestation , soil erosion and biodiversity loss which can drive larger-scale environmental crises such as climate change and other forms of environmental degradation . Illegality may also occur during transport, such as illegal processing and export (through fraudulent declaration to customs );

3434-747: Is the main producer of wood and wooden items destined to the US, the biggest consumer of wood and its byproducts in the world. The water systems of the Great Lakes , Erie Canal , Hudson River and Saint Lawrence Seaway to the east coast and the Mississippi River to the central plains and Louisiana allows transportation of logs at very low costs. On the west coast , the basin of the Columbia River has plenty of forests with excellent timber. The agency Canada Wood Council calculates that in

3535-437: Is the most important species for tree plantations, is used for several purposes as plywood manufacture, packing boxes, paper, matches , etc. It needs good quality grounds with good drainage, but can be used to protect the cultivations if disposed in windbreak lines. More than 70% of Italian poplar cultivations are located in the pianura Padana . Constantly the extension of the cultivation is being reduced, from 650 km in

3636-431: Is the rule. Some others never form heartwood. Heartwood is often visually distinct from the living sapwood and can be distinguished in a cross-section where the boundary will tend to follow the growth rings. For example, it is sometimes much darker. Other processes such as decay or insect invasion can also discolor wood, even in woody plants that do not form heartwood, which may lead to confusion. Sapwood (or alburnum )

3737-491: Is the world leader in sustainable forest management practices. Only 120,000,000 hectares (1,200,000 km ; 463,320 sq mi) (28% of Canadian forests) are currently managed for timber production while an estimated 32,000,000 hectares (320,000 km ; 123,550 sq mi) are protected from harvesting by the current legislation. The Canadian timber industry has led to environmental conflict with Indigenous people protecting their land from logging. For example,

3838-413: Is the younger, outermost wood; in the growing tree it is living wood, and its principal functions are to conduct water from the roots to the leaves and to store up and give back according to the season the reserves prepared in the leaves. By the time they become competent to conduct water, all xylem tracheids and vessels have lost their cytoplasm and the cells are therefore functionally dead. All wood in

3939-400: Is then known as the latewood or summerwood. There are major differences, depending on the kind of wood. If a tree grows all its life in the open and the conditions of soil and site remain unchanged, it will make its most rapid growth in youth, and gradually decline. The annual rings of growth are for many years quite wide, but later they become narrower and narrower. Since each succeeding ring

4040-630: Is today the most used wood product. The wood economy was the starting point of the civilizations worldwide, since eras preceding the Paleolithic and the Neolithic . It necessarily preceded ages of metals by many millennia, as the melting of metals was possible only through the discovery of techniques to light fire (usually obtained by the scraping of two very dry wooden rods) and the building of many simple machines and rudimentary tools, as canes, club handles, bows , arrows , lances . One of

4141-518: Is transported by sea on timber carriers, subject to the IMO TDC Code . As of 2019, the top timberland owners in the US were structured as real-estate investment trusts and include: In 2008 the largest lumber and wood producers in the US were As these companies are often publicly traded, their ultimate owners are a diversified group of investors. There are also timber-oriented real-estate investment trusts . According to sawmilldatabase,

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4242-676: Is used as a material in wooden houses, and other structures with a broad range of dimensions. In traditional homes wood is preferred for ceilings, doors , floorings and windows . Wooden frames were traditionally used for home ceilings, but they risk collapse during fires. The development of energy efficient houses including the " passive house " has revamped the importance of wood in construction, because wood provides acoustic and thermal insulation , with much better results than concrete. In Japan, ancient buildings, of relatively high elevation, like pagodas , historically had shown to be able to resist earthquakes of high intensity , thanks to

4343-461: Is usually the latewood in which the thick-walled, strength-giving fibers are most abundant. As the breadth of ring diminishes, this latewood is reduced so that very slow growth produces comparatively light, porous wood composed of thin-walled vessels and wood parenchyma. In good oak, these large vessels of the earlywood occupy from six to ten percent of the volume of the log, while in inferior material they may make up 25% or more. The latewood of good oak

4444-406: Is white oak. Wood product Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants . It is an organic material  – a natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in

4545-608: The Asubpeeschoseewagong First Nation set up the Grassy Narrows road blockade for twenty years beginning in 2002 to prevent clearcutting of their land. Wood obtained from Nigeria's wood industry undergoes processing in various wood processing sectors, including furniture manufacturing, sawmill operations, plywood mills, pulp and paper facilities, and particleboard mills. Poplar : in Italy

4646-436: The avoidance of taxes and other charges, and fraudulent certification. These acts are often referred to as "wood laundering". The existence of a wood economy , or more broadly, a forest economy (in many countries a bamboo economy predominates), is a prominent matter in many developing countries as well as in many other nations with a temperate climate and especially in those with low temperatures . These are generally

4747-401: The grain of the rest of the wood "flows" (parts and rejoins). Within a knot, the direction of the wood (grain direction) is up to 90 degrees different from the grain direction of the regular wood. In the tree a knot is either the base of a side branch or a dormant bud. A knot (when the base of a side branch) is conical in shape (hence the roughly circular cross-section) with the inner tip at

4848-429: The resin which increases the strength when dry. Such resin-saturated heartwood is called "fat lighter". Structures built of fat lighter are almost impervious to rot and termites , and very flammable. Tree stumps of old longleaf pines are often dug, split into small pieces and sold as kindling for fires. Stumps thus dug may actually remain a century or more since being cut. Spruce impregnated with crude resin and dried

4949-429: The third world , but this amount can only be estimated, with wide margins of uncertainty. In 1998, the worldwide production of "Roundwood" (officially counted wood not used as firewood), was about 1,500,000,000 cubic metres (2.0 × 10  cu yd), amounting to around 45% of the wood cultivated in the world. Cut logs and branches destined to become elements for building construction accounted for approximately 55% of

5050-478: The 1960s, imported species of pine tree and eucalyptus have been grown mostly for the plywood and paper pulp industries . Currently high-level research is being conducted, to apply the enzymes of sugar cane fermentation to cellulose in wood, to obtain methanol , but the cost is much higher when compared with ethanol derived from corn costs. There is a close relation in the forestry economy between these countries; they have many tree genera in common, and Canada

5151-492: The 1980s to current 350 km . The yield of poplars is about 1,500 t/km of wood every year. The production from poplars is around 45–50% of the total Italian wood production. In Sweden, Finland and to an extent Norway, much of the land area is forested, and the pulp and paper industry is one of the most significant industrial sectors. Chemical pulping produces an excess of energy, since the organic matter in black liquor , mostly lignin and hemicellulose breakdown products,

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5252-433: The addition of steel and bronze into construction. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at the time a tree was cut. Wood, in the strict sense, is yielded by trees , which increase in diameter by the formation, between the existing wood and the inner bark , of new woody layers which envelop the entire stem, living branches, and roots. This process

5353-418: The annual rings of growth and the amount of sapwood. Within the same species the cross-sectional area of the sapwood is very roughly proportional to the size of the crown of the tree. If the rings are narrow, more of them are required than where they are wide. As the tree gets larger, the sapwood must necessarily become thinner or increase materially in volume. Sapwood is relatively thicker in the upper portion of

5454-486: The average. The Council for Higher Education Accreditation considers the Society of American Foresters as the principal accreditor for academic degree programs in professional forestry, both at a Bachelor's and Master's level. Usually a bachelor's degree is considered the minimum education required, but some individuals are able to secure a job without a college education based on their experience. Some states have

5555-449: The border between the two classes, forming an intermediate group. In temperate softwoods, there often is a marked difference between latewood and earlywood. The latewood will be denser than that formed early in the season. When examined under a microscope, the cells of dense latewood are seen to be very thick-walled and with very small cell cavities, while those formed first in the season have thin walls and large cell cavities. The strength

5656-458: The cell walls are composed of micro-fibrils of cellulose (40–50%) and hemicellulose (15–25%) impregnated with lignin (15–30%). In coniferous or softwood species the wood cells are mostly of one kind, tracheids , and as a result the material is much more uniform in structure than that of most hardwoods . There are no vessels ("pores") in coniferous wood such as one sees so prominently in oak and ash, for example. The structure of hardwoods

5757-435: The central portion one-fourth the height of the beam from either edge are not serious defects. Knots do not necessarily influence the stiffness of structural timber; this will depend on the size and location. Stiffness and elastic strength are more dependent upon the sound wood than upon localized defects. The breaking strength is very susceptible to defects. Sound knots do not weaken wood when subject to compression parallel to

5858-445: The competition of the trees in their struggle for light and nourishment that periods of rapid and slow growth may alternate. Some trees, such as southern oaks , maintain the same width of ring for hundreds of years. On the whole, as a tree gets larger in diameter the width of the growth rings decreases. As a tree grows, lower branches often die, and their bases may become overgrown and enclosed by subsequent layers of trunk wood, forming

5959-411: The construction of much more safe houses in seismic areas. One of the most enduring materials is the lumber from virginian southern live oak and white oak , specially live oak is 60% stronger than white oak and more resistant to moisture. As an example, the main component in the structure of battle ship USS  Constitution , the world's oldest commissioned naval vessel afloat (launched in 1797)

6060-433: The contrast is conspicuous (see section of yew log above). This is produced by deposits in the heartwood of chemical substances, so that a dramatic color variation does not imply a significant difference in the mechanical properties of heartwood and sapwood, although there may be a marked biochemical difference between the two. Some experiments on very resinous longleaf pine specimens indicate an increase in strength, due to

6161-446: The countries with greater forested areas so conditions allow for development of local forestry to harvest wood for local uses. The uses of wood in furniture, buildings, bridges, and as a source of energy are widely known. Additionally, wood from trees and bushes , can be used in a variety of products, such as wood pulp , cellulose in paper, celluloid in early photographic film, cellophane , and rayon (a substitute for silk). At

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6262-456: The criminals and during war time foresters were used as scouts to spy on enemy troop movement. The pay and status of foresters was usually above average, reflecting the responsibility of their role in a medieval environment and economy. Timber industry The wood industry or timber industry (sometimes lumber industry -- when referring mainly to sawed boards) is the industry concerned with forestry , logging , timber trade , and

6363-434: The distinction between softwood and hardwood . While softwood primarily goes into the production of wood fuel and pulp and paper, hardwood is used mainly for furniture, floors , etc.. Both types can be of use for building and (residential) construction purposes (e.g. log houses , log cabins , timber framing ). Lumber and wood products, including timber for framing , plywood , and woodworking , are created in

6464-692: The dominant product of forests , is used for many purposes, such as wood fuel (e.g. in form of firewood or charcoal ) or the finished structural materials used for the construction of buildings , or as a raw material, in the form of wood pulp , that is used in the production of paper . All other non-wood products derived from forest resources, comprising a broad variety of other forest products, are collectively described as non-timber forest products (NTFP). Non-timber forest products are viewed to have fewer negative effects on forest ecosystem when providing income sources for local community. Globally, about 1,150,000,000 ha (2.8 × 10 acres) of forest

6565-415: The end of a log, but are also visible on the other surfaces. If the distinctiveness between seasons is annual (as is the case in equatorial regions, e.g. Singapore ), these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are likely to be indistinct or absent. If the bark of the tree has been removed in a particular area, the rings will likely be deformed as

6666-450: The end of their normal usage, wood products can be burnt to obtain thermal energy or can be used as a fertilizer . The potential environmental damage that a wood economy could occasion include a reduction of biodiversity due to monoculture forestry (the intensive cultivation of very few trees types); and CO 2 emissions. However, forests can aid in the reduction of atmospheric carbon dioxide and thus limit climate change . Paper

6767-403: The exact mechanisms determining the formation of earlywood and latewood. Several factors may be involved. In conifers, at least, rate of growth alone does not determine the proportion of the two portions of the ring, for in some cases the wood of slow growth is very hard and heavy, while in others the opposite is true. The quality of the site where the tree grows undoubtedly affects the character of

6868-620: The forestry and logging industry can be reduced by enclosing engines and heavy equipment, installing mufflers and silencers, and performing routine maintenance on equipment. Noise exposures can also be reduced through the hierarchy of hazard controls where removal or replacement of noisy equipment serves as the best method of noise reduction. The Bureau of Labor Statistics (BLS) has found that fatalities of forestry and logging workers have increased from 2013 to 2016, up from 81 to 106 per year. In 2016, there were 3.6 cases of injury and illness per 100 workers within this industry. Illegal logging

6969-505: The grain. In some decorative applications, wood with knots may be desirable to add visual interest. In applications where wood is painted , such as skirting boards, fascia boards, door frames and furniture, resins present in the timber may continue to 'bleed' through to the surface of a knot for months or even years after manufacture and show as a yellow or brownish stain. A knot primer paint or solution (knotting), correctly applied during preparation, may do much to reduce this problem but it

7070-412: The greater the water content, the greater its softening effect. The moisture in wood can be measured by several different moisture meters . Drying produces a decided increase in the strength of wood, particularly in small specimens. An extreme example is the case of a completely dry spruce block 5 cm in section, which will sustain a permanent load four times as great as a green (undried) block of

7171-486: The greatest area of forest in Russia. By 2001 the rainforest areas of Brazil were reduced by a fifth (respect of 1970), to around 4,000,000 km ; the ground cleared was mainly destined for cattle pasture —Brazil is the world's largest exporter of beef with almost 200,000,000 head of cattle. The booming Brazilian ethanol economy based upon sugar cane cultivation, is likewise reducing forests area. Canadian forest

7272-577: The growth of forests with tools like geographic information systems . Foresters may combat insect infestation, disease, forest and grassland wildfire , but increasingly allow these natural aspects of forest ecosystems to run their course when the likelihood of epidemics or risk of life or property are low. Increasingly, foresters participate in wildlife conservation planning and watershed protection. Foresters have been mainly concerned with timber management, especially reforestation , forests at prime conditions, and fire control. Many people confuse

7373-425: The industrialized, internationalized world, there is a tendency toward huge integrated businesses that cover the complete spectrum from silviculture and forestry in private primary or secondary forests or plantations via the logging process up to wood processing and trading and transport (e.g. timber rafting , forest railways , logging roads ). Processing and products differs especially with regard to

7474-407: The larger vessels or pores (as cross sections of vessels are called) are localized in the part of the growth ring formed in spring, thus forming a region of more or less open and porous tissue. The rest of the ring, produced in summer, is made up of smaller vessels and a much greater proportion of wood fibers. These fibers are the elements which give strength and toughness to wood, while the vessels are

7575-557: The modern era, timber is dried in kilns . When the first steam railway in Australia opened in Melbourne in 1854, timber transportation changed dramatically. Trains made the transportation of lumber quicker and more affordable, making it possible for the Australian sawmill industry to move inland. Wood is transported by a variety of methods, typically by road vehicle and log driving over shorter distances. For longer journeys, wood

7676-480: The moisture content of the air) retains 8–16% of the water in the cell walls, and none, or practically none, in the other forms. Even oven-dried wood retains a small percentage of moisture, but for all except chemical purposes, may be considered absolutely dry. The general effect of the water content upon the wood substance is to render it softer and more pliable. A similar effect occurs in the softening action of water on rawhide, paper, or cloth. Within certain limits,

7777-486: The most ancient handmade articles ever found is a polished wooden spear tip ( Clacton Spear ) 250,000 years old (third interglacial period), that was buried under sediments in England, at Clacton-on-Sea . The main source of the lumber used in the world is forests, which can be classified as virgin , semivirgin and plantations . Much timber is removed for firewood by local populations in many countries, especially in

7878-542: The other hand, the latewood is very dense and is deep-colored, presenting a very decided contrast to the soft, straw-colored earlywood. It is not only the proportion of latewood, but also its quality, that counts. In specimens that show a very large proportion of latewood it may be noticeably more porous and weigh considerably less than the latewood in pieces that contain less latewood. One can judge comparative density, and therefore to some extent strength, by visual inspection. No satisfactory explanation can as yet be given for

7979-595: The overall industry sector had a prevalence of hearing loss lower than the overall prevalence of noise-exposed industries (15% v. 19%), workers within forestry and logging exceeded 21%. Thirty-six percent of workers within forest nurseries and gathering of forest products, a sub-sector within forestry and logging, experienced hearing loss, the most of any AFFH sub-sector. Workers within forest nurseries and gathering of forest products are tasked with growing trees for reforestation and gathering products such as rhizomes and barks. Comparatively, non-noise-exposed workers have only

8080-404: The plant overgrows the scar. If there are differences within a growth ring, then the part of a growth ring nearest the center of the tree, and formed early in the growing season when growth is rapid, is usually composed of wider elements. It is usually lighter in color than that near the outer portion of the ring, and is known as earlywood or springwood. The outer portion formed later in the season

8181-605: The point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud. In grading lumber and structural timber , knots are classified according to their form, size, soundness, and the firmness with which they are held in place. This firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow. Knots materially affect cracking and warping, ease in working, and cleavability of timber. They are defects which weaken timber and lower its value for structural purposes where strength

8282-458: The production of primary forest products and wood products (e.g. furniture) and secondary products like wood pulp for the pulp and paper industry . Some of the largest producers are also among the biggest owners of forest . The wood industry has historically been and continues to be an important sector in many economies. In the narrow sense of the terms, wood, forest, forestry and timber/lumber industry appear to point to different sectors, in

8383-411: The properties of the wood. Certain rot-producing fungi impart to wood characteristic colors which thus become symptomatic of weakness. Ordinary sap-staining is due to fungal growth, but does not necessarily produce a weakening effect. Water occurs in living wood in three locations, namely: In heartwood it occurs only in the first and last forms. Wood that is thoroughly air-dried (in equilibrium with

8484-468: The reverse is commonly true. Otherwise the color of wood is no indication of strength. Abnormal discoloration of wood often denotes a diseased condition, indicating unsoundness. The black check in western hemlock is the result of insect attacks. The reddish-brown streaks so common in hickory and certain other woods are mostly the result of injury by birds. The discoloration is merely an indication of an injury, and in all probability does not of itself affect

8585-575: The role of the forester with that of the logger , but most foresters are concerned not only with the harvest of timber, but also with the sustainable management of forests. The forester Jack C. Westoby remarked that "forestry is concerned not with trees, but with how trees can serve people". The median salary of foresters in the United States was $ 53,750, in 2008. Beginning foresters without bachelor's degrees make considerably less. Those with master's degrees are able to command salaries closer to

8686-453: The same size will. The greatest strength increase due to drying is in the ultimate crushing strength, and strength at elastic limit in endwise compression; these are followed by the modulus of rupture, and stress at elastic limit in cross-bending, while the modulus of elasticity is least affected. Wood is a heterogeneous , hygroscopic , cellular and anisotropic (or more specifically, orthotropic ) material. It consists of cells, and

8787-542: The stems of trees, or more broadly to include the same type of tissue elsewhere, such as in the roots of trees or shrubs. In a living tree, it performs a mechanical-support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients among the leaves , other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, woodchips , or fibers . Wood has been used for thousands of years for fuel , as

8888-420: The successive day. Paradoxically in summer oxygen created by photosynthesis in forests near to cities and urban parks, interacts with urban air pollution (from cars, etc.) and is transformed by solar beams in ozone (molecule of three oxygen atoms), that while in high atmosphere constitutes a filter against ultraviolet beams, in the low atmosphere is a pollutant, able to provoke respiratory disturbances. In

8989-466: The traditional building techniques, employing elastic joints , and to the excellent ability of wooden frames to elastically deform and absorb severe accelerations and compressive shocks. In 2006, Italian scientists from CNR patented a building system that they called " SOFIE ", a seven-storey wooden building, 24 meters high, built by the "Istituto per la valorizzazione del legno e delle specie arboree" (Ivalsa) of San Michele all'Adige . In 2007 it

9090-430: The tree, may well be stronger than a piece of heartwood from the same tree. Different pieces of wood cut from a large tree may differ decidedly, particularly if the tree is big and mature. In some trees, the wood laid on late in the life of a tree is softer, lighter, weaker, and more even textured than that produced earlier, but in other trees, the reverse applies. This may or may not correspond to heartwood and sapwood. In

9191-445: The tree. This is evidenced by the fact that a tree can thrive with its heart completely decayed. Some species begin to form heartwood very early in life, so having only a thin layer of live sapwood, while in others the change comes slowly. Thin sapwood is characteristic of such species as chestnut , black locust , mulberry , osage-orange , and sassafras , while in maple , ash , hickory , hackberry , beech , and pine, thick sapwood

9292-416: The trunk of a tree than near the base, because the age and the diameter of the upper sections are less. When a tree is very young it is covered with limbs almost, if not entirely, to the ground, but as it grows older some or all of them will eventually die and are either broken off or fall off. Subsequent growth of wood may completely conceal the stubs which will remain as knots. No matter how smooth and clear

9393-418: The wood formed, though it is not possible to formulate a rule governing it. In general, where strength or ease of working is essential, woods of moderate to slow growth should be chosen. In ring-porous woods, each season's growth is always well defined, because the large pores formed early in the season abut on the denser tissue of the year before. In the case of the ring-porous hardwoods, there seems to exist

9494-633: The wood industry from the trunks and branches of trees through several processes, commencing with the selection of appropriate logging sites and concluding with the milling and treatment processes of the harvested material. In order to determine which logging sites and milling sites are responsibly producing environmental, social and economic benefits, they must be certified under the Forests For All Forever (FCS) Certification that ensures these qualities. Mature trees are harvested from, both, plantations and native forests. Trees harvested at

9595-634: The wood removed from forests in log form and used for purposes other than fuel. Wood manufacturing residues, such as sawdust and chippings, are collectively known as "pulp". The United States industrial production index hit a 13-year high during the COVID-19 pandemic, according to a report from the Board of Governors of the Federal Reserve System. Originally, trees were felled from native forests using axes and hand-held cross-cut saws –

9696-602: The world top producers of sawn wood in 2007 were: Workers within the forestry and logging industry sub-sector fall within the agriculture, forestry, fishing, and hunting (AFFH) industry sector as characterized by the North American Industry Classification System (NAICS). The National Institute for Occupational Safety and Health (NIOSH) has taken a closer look at the AFFH industry's noise exposures and prevalence of hearing loss. While

9797-476: The world's industrial wood production . 25% became wood pulp (including wood powder and broccoli) mainly destined for the production of paper and paperboard , and approximately 20% became panels in plywood and valuable wood for furniture and objects of common use (FAO 1998). The World's largest producer and consumer of officially accounted wood are the United States, although the country that possesses

9898-519: The year 2005 in Canada, the forest sector employed 930,000 workers (1 job in every 17), making around $ 108 billion of value in goods and services. For many years products derived from trees in Canadian forests had been the most important export items of the country. In 2011, exports around the world totaled some $ 64.3 billion – the single largest contributor to Canadian trade balance. Canada

9999-428: Was often based in a forester's lodge , and was responsible for patrolling the woodlands on a lord or noble's property, hence the synonymous term 'woodward'. His duties included negotiating sales of lumber and timber and stopping poachers from illegally hunting. Frequently outlaws would take refuge in heavily wooded regions. When this occurred it was the duty of the forester to organize armed posses to capture or disperse

10100-532: Was reduced by almost 30% to 3,101,340 km over the same period. Regarding the problem of climate change, it is known that burning forests increase CO 2 in the atmosphere, while intact virgin forest or plantations act as sinks for CO 2 , for these reasons wood economy fights greenhouse effect . The amount of CO 2 absorbed depends on the type of trees, lands and the climate of the place where trees naturally grow or are planted. Moreover, by night plants do not photosynthesize , and produce CO 2 , eliminated

10201-610: Was tested with the hardest Japanese antiseismic test for civil structures: the simulation of Kobe's earthquake (7.2 Richter scale ), with the building placed over an enormous oscillating platform belonging to the NIED-Institute, located in Tsukuba science park, near the city of Miki in Japan. This Italian project, employed very thin and flexible panels in glued laminated timber , and according to CNR researchers could lead to

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