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86-459: Splinters are primarily made of wood , but there are many other types, for example, other common types of splinters are, hair , glass , plastic , metal , and spines of animals . As with any wound that breaks the skin, splinters can lead to infection , which if left untreated could develop into more serious complications. If a splinter is in the body for more than 2–3 days, or if the wound shows signs of inflammation or tenderness (whether

172-474: A buffer in aqueous solutions to maintain a neutral pH in the environment. The buffer acting component has been proposed to be relevant for neutralizing acid rain . Some organic matter not already in the soil comes from groundwater . When the groundwater saturates the soil or sediment around it, organic matter can freely move between the phases. Groundwater has its own sources of natural organic matter including: Organisms decompose into organic matter, which

258-428: 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

344-489: A trigger such as the FOM inputs. The cause of this increase in decomposition has often been attributed to an increase in microbial activity resulting from higher energy and nutrient availability released from the FOM. After the input of FOM, specialized microorganisms are believed to grow quickly and only decompose this newly added organic matter. The turnover rate of SOM in these areas is at least one order of magnitude higher than

430-856: A 0.45 micrometre filter (DOM), and that which cannot (POM). Organic matter is important in water and wastewater treatment and recycling, natural aquatic ecosystems, aquaculture, and environmental rehabilitation. It is, therefore, important to have reliable methods of detection and characterisation, for both short- and long-term monitoring. Various analytical detection methods for organic matter have existed for up to decades to describe and characterise organic matter. These include, but are not limited to: total and dissolved organic carbon, mass spectrometry , nuclear magnetic resonance (NMR) spectroscopy , infrared (IR) spectroscopy , UV-Visible spectroscopy , and fluorescence spectroscopy . Each of these methods has its advantages and limitations. The same capability of natural organic matter that helps with water retention in

516-488: A closed forest, and in the manufacture of articles where strength is an important consideration such "second-growth" hardwood material is preferred. This is particularly the case in the choice of hickory for handles and spokes . Here not only strength, but toughness and resilience are important. The results of a series of tests on hickory by the U.S. Forest Service show that: Organic matter Organic matter , organic material , or natural organic matter refers to

602-401: 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

688-405: 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

774-400: 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

860-503: A much higher risk of infection. Simply the easiest way to avoid infection is to completely remove the splinters or foreign body as soon as possible. Though infection is generally the largest complication encountered with splinters, ranging from 1.1 to 12 percent presence, the use of antibiotics in non-bite cases is generally deemed unnecessary by the medical community. Though cases are rare, infection of foreign body wounds can result in cases of tetanus. One case of tetanus contraction through

946-481: 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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1032-636: 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

1118-465: 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

1204-434: A splinter being made of organic matter, it makes it much more difficult for the body to get rid of it. Wood 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

1290-434: A splinter has entered one's body. If manual detection and localization fail, the main methods for medical imaging of splinters are: Small wooden splinters (1–4 mm) distant from bones are most easily detected by ultrasonography, while CT scan and magnetic resonance imaging have higher sensitivity for those near bones. There are many medical techniques to remove splinters safely. Common medical techniques include

1376-591: A splinter was seen in Ohio in 1993. An 80-year-old woman was presented to an ED with dysphagia and a stiff jaw. Not long after a preliminary checkup, a wood splinter was found to have been lodged in her chin for approximately 1 week; the area was erythematous with active purulent drainage. The woman was diagnosed with tetanus, admitted to the hospital, and begun on a regimen of 3,000 units of tetanus immune globulin, tetanus toxoid, and intravenous clindamycin. Despite aggressive treatment, including assisted mechanical ventilation,

1462-564: 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

1548-423: 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

1634-492: 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

1720-437: 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

1806-456: 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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1892-428: 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

1978-443: Is called soil organic matter. When the organic matter has broken down into a stable substance that resists further decomposition it is called humus . Thus soil organic matter comprises all of the organic matter in the soil exclusive of the material that has not decayed. An important property of soil organic matter is that it improves the capacity of a soil to hold water and nutrients, and allows their slow release, thereby improving

2064-529: Is crucial to all ecology and to all agriculture , but it is especially emphasized in organic farming , where it is relied upon especially heavily. The priming effect is characterized by intense changes in the natural process of soil organic matter (SOM) turnover, resulting from relatively moderate intervention with the soil. The phenomenon is generally caused by either pulsed or continuous changes to inputs of fresh organic matter (FOM). Priming effects usually result in an acceleration of mineralization due to

2150-422: 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

2236-560: 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

2322-399: 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

2408-486: 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

2494-431: 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

2580-470: 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,

2666-405: Is one of many organic compounds that can be synthesized without any biological activity. Organic matter is heterogeneous and very complex. Generally, organic matter, in terms of weight, is: The molecular weights of these compounds can vary drastically, depending on if they repolymerize or not, from 200 to 20,000 amu. Up to one-third of the carbon present is in aromatic compounds in which

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2752-596: Is sometimes defined as only the secondary xylem in 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

2838-431: 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 )

2924-413: 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

3010-400: 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

3096-426: Is then transported and recycled. Not all biomass migrates, some is rather stationary, turning only over the course of millions of years. The organic matter in soil derives from plants, animals and microorganisms. In a forest, for example, leaf litter and woody materials fall to the forest floor. This is sometimes referred to as organic material. When it decays to the point in which it is no longer recognizable, it

3182-461: 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

3268-443: Is very important in the movement of nutrients in the environment and plays a role in water retention on the surface of the planet. Living organisms are composed of organic compounds. In life, they secrete or excrete organic material into their environment, shed body parts such as leaves and roots and after organisms die, their bodies are broken down by bacterial and fungal action. Larger molecules of organic matter can be formed from

3354-526: The bone . Some splinters will remain in place, but most will continue to migrate through the body (eg. hair splinters), further damaging their surroundings. According to the American Academy of Family Physicians , the most common foreign bodies contracted by people fall into two official classes: biological splinters, and nonbiological splinters. In the biological class, splinters include bone, fish spines , teeth , hair and wood . Although, in

3440-463: The decomposition of organic matter including its chemical properties and other environmental parameters. Metabolic capabilities of the microbial communities play a crucial role on decomposition since they are highly connected with the energy availability and processing. In terrestrial ecosystems the energy status of soil organic matter has been shown to affect microbial substrate preferences. Some organic matter pools may be energetically favorable for

3526-401: 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

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3612-460: The microbial communities resulting in their fast oxidation and decomposition, in comparison with other pools where microbial degraders get less return from the energy they invest. By extension, soil microorganisms preferentially mineralize high-energy organic matter, avoiding decomposing less energetically dense organic matter. Measurements of organic matter generally measure only organic compounds or carbon , and so are only an approximation of

3698-429: 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

3784-543: The Elliptical Technique and the String Technique. In the elliptical technique the surrounding area of the splinter is sliced in an elliptical formation. From there the flesh in the elliptical area is cut (in the shape of an upside-down cone) and the whole chunk of flesh containing the splinter is removed. The Needle Cover Technique is limited to fishhook removal. A string is looped around the base of

3870-499: The acceleration of mineralization while a negative priming effect results in immobilization, leading to N unavailability. Although most changes have been documented in C and N pools, the priming effect can also be found in phosphorus and sulfur, as well as other nutrients. Löhnis was the first to discover the priming effect phenomenon in 1926 through his studies of green manure decomposition and its effects on legume plants in soil. He noticed that when adding fresh organic residues to

3956-433: 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

4042-418: 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

4128-546: The body. It is strongly encouraged for the removal of a splinter before falling victim to an infection . Infection is usually determined by the duration of time that the foreign object remains lodged in the human body. Objects that have included poison, deep penetration, dirt, or bite injuries generally result in a shorter time until infection is notable. According to the AAFP, patients that are older, or have diabetes, or have wounds that are longer, wider, more jagged or deeper, have

4214-449: 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

4300-431: The bulk soil. Other soil treatments, besides organic matter inputs, which lead to this short-term change in turnover rates, include "input of mineral fertilizer, exudation of organic substances by roots, mere mechanical treatment of soil or its drying and rewetting." Priming effects can be either positive or negative depending on the reaction of the soil with the added substance. A positive priming effect results in

4386-488: The by-products are larger than membrane pore sizes. This clogging problem can be treated by chlorine disinfection ( chlorination ), which can break down residual material that clogs systems. However, chlorination can form disinfection by-products . Water with organic matter can be disinfected with ozone -initiated radical reactions. The ozone (three oxygens) has powerful oxidation characteristics. It can form hydroxyl radicals (OH) when it decomposes, which will react with

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4472-452: The carbon atoms form usually six-membered rings. These rings are very stable due to resonance stabilization , so they are challenging to break down. The aromatic rings are also susceptible to electrophilic and nucleophilic attacks from other electron-donating or electron-accepting material, which explains the possible polymerization to create larger molecules of organic matter. Some reactions occur with organic matter and other materials in

4558-458: 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

4644-435: 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

4730-445: 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

4816-422: The concept of the priming effect was widely disregarded until about the 1980s-1990s. The priming effect has been found in many different studies and is regarded as a common occurrence, appearing in most plant soil systems. However, the mechanisms which lead to the priming effect are more complex than originally thought, and still remain generally misunderstood. Although there is a lot of uncertainty surrounding

4902-586: The conditions for plant growth. Another advantage of humus is that it helps the soil to stick together which allows nematodes , or microscopic bacteria, to easily decay the nutrients in the soil. There are several ways to quickly increase the amount of humus. Combining compost, plant or animal materials/waste, or green manure with soil will increase the amount of humus in the soil. These three materials supply nematodes and bacteria with nutrients for them to thrive and produce more humus, which will give plants enough nutrients to survive and grow. Soil organic matter

4988-433: 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

5074-415: 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

5160-403: 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

5246-505: 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

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5332-412: 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

5418-425: The hook, and as the hook is pressed further into the skin, the string is pulled, allowing the barbs to be unhooked from muscle and follow the path of the rest of the hook out of the body without snagging any additional flesh. Since the splinter has penetrated through a physical barrier of the body it allows for an individual to get an infection. The opening from the splinter will make it easier for bacteria to get into

5504-504: The large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals . Organic molecules can also be made by chemical reactions that do not involve life. Basic structures are created from cellulose , tannin , cutin , and lignin , along with other various proteins , lipids , and carbohydrates . Organic matter

5590-407: 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

5676-542: The level of once living or decomposed matter. Some definitions of organic matter likewise only consider "organic matter" to refer to only the carbon content or organic compounds and do not consider the origins or decomposition of the matter. In this sense, not all organic compounds are created by living organisms, and living organisms do not only leave behind organic material. A clam's shell, for example, while biotic , does not contain much organic carbon , so it may not be considered organic matter in this sense. Conversely, urea

5762-480: 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,

5848-448: The nonbiological class, common splinters contracted are glass , metal , aluminum , fishhooks , pencil graphite , and plastic . Rarely, people may become infected with splinters from more unusual sources. Common cases of exotic foreign bodies include sea urchins , insect stings , stingray spines , and even grenade shrapnel . Splinters are often first detected by the person with the splinter in their body. There are many signs that

5934-542: 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

6020-453: The patient died 15 days later from the effects of her primary infection. The woman had no history of previous tetanus vaccinations despite previous care for a wound and ongoing medical attention for hypertension. Since most splinters are made of organic matter , they are much more dangerous than other types of things puncturing the body. Splinters are usually infected with many bacteria which then turn into an infection such as tetanus . Due to

6106-404: 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

6192-605: 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

6278-605: The polymerization of different parts of already broken down matter. The composition of natural organic matter depends on its origin, transformation mode, age, and existing environment, thus its bio-physicochemical functions vary with different environments. Organic matter is common throughout the ecosystem and is cycled through decomposition processes by soil microbial communities that are crucial for nutrient availability. After degrading and reacting, it can move into soil and mainstream water via waterflow. Organic matter provides nutrition to living organisms. Organic matter acts as

6364-485: The process of decaying or decomposing , such as humus . A closer look at the biological material in the process of decaying reveals so-called organic compounds ( biological molecules ) in the process of breaking up (disintegrating). The main processes by which soil molecules disintegrate are by bacterial or fungal enzymatic catalysis . If bacteria or fungi were not present on Earth, the process of decomposition would have proceeded much slower. Various factors impact

6450-411: 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

6536-401: The reason for the priming effect, a few undisputed facts have emerged from the collection of recent research: Recent findings suggest that the same priming effect mechanisms acting in soil systems may also be present in aquatic environments, which suggests a need for broader considerations of this phenomenon in the future. One suitable definition of organic matter is biological material in

6622-468: 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

6708-453: 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

6794-508: The soil creates problems for current water purification methods. In water, organic matter can still bind to metal ions and minerals. The purification process does not necessarily stop these bound molecules but does not cause harm to any humans, animals, or plants. However, because of the high reactivity of organic matter, by-products that do not contain nutrients can be made. These by-products can induce biofouling , which essentially clogs water filtration systems in water purification facilities, as

6880-592: The soil to create compounds never seen before. Unfortunately, it is challenging to characterize these because so little is known about natural organic matter in the first place. Research is currently being done to determine more about these new compounds and how many are being formed. Aquatic organic matter can be further divided into two components: (1) dissolved organic matter (DOM), measured as colored dissolved organic matter (CDOM) or dissolved organic carbon (DOC), and (2) particulate organic matter (POM). They are typically differentiated by that which can pass through

6966-455: The soil, it resulted in intensified mineralization by the humus N. It was not until 1953, though, that the term priming effect was given by Bingeman in his paper titled, The effect of the addition of organic material on the decomposition of an organic soil . Several other terms had been used before priming effect was coined, including priming action, added nitrogen interaction (ANI), extra N and additional N. Despite these early contributions,

7052-442: The splinter was removed or not), advice should be sought from a doctor. Generally, a splinter causes an initial feeling of pain as the sharp object makes its initial penetration through the body. Through this penetration, the object cuts through the cutaneous layer of the skin, and settles in the subcutaneous layer of the skin, and can even penetrate further down, breaking the sub-cutaneous layer, settling in muscle tissue, or even

7138-430: 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

7224-445: 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

7310-416: 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

7396-418: 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

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