Wood

qas: question: In addition to being used to build things, what has wood been used for over thousands of years?
answers: text: fuel

question: What kind of strong fibers are part of the composite of wood?
answers: text: cellulose

question: What's the matrix in wood made up of?
answers: text: lignin

question: What one word describes the function wood provides to a tree or plant?
answers: text: support

question: What does wood convey to leaves, roots, and other tissues of a woody plant in addition to water?
answers: text: nutrients
context: It has been used for thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers (which are strong in tension) embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs.[citation needed] In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between 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, or wood chips or fiber.

qas: question: How many cubic meters of growing stock forest are there on the planet?
answers: text: 434 billion

question: What percentage of the Earth's stock forest is commercial?
answers: text: 47%

question: In addition to buildings, what is wood often used to make?
answers: text: furniture

question: About how many cubic kilometers of the vast stock forest's wood were harvested in 1991?
answers: text: 3.5

question: In addition to being carbon neutral, what other adjective describes wood that makes it compelling as a renewable energy source?
answers: text: abundant
context: The Earth contains about 434 billion cubic meters of growing stock forest, 47% of which is commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991, approximately 3.5 cubic kilometers of wood were harvested. Dominant uses were for furniture and building construction.

qas: question: What year were the earliest plants that grew wood discovered?
answers: text: 2011

question: In which Canadian province were the oldest woody plants found?
answers: text: New Brunswick

question: If dendrochronology can't be used, what method would scientists employ to date wood?
answers: text: carbon dating

question: How many millions of years old were the plants that were discovered in New Brunswick?
answers: text: 395 to 400
context: A 2011 discovery in the Canadian province of New Brunswick uncovered 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 make inferences about when a wooden object was created.

qas: question: What has been the primary purpose of wood for millennia other than fuel?
answers: text: construction material

question: What is often made of wood that provides shelter to people?
answers: text: houses

question: For clues about the climate of a place, we can look at variation in isotopic abundances or what other thing?
answers: text: tree-ring widths

question: What could be made out of wood that could be used to fight off attackers?
answers: text: weapons

question: What category of items often constructed from wood does a chair belong to?
answers: text: furniture
context: People have used wood for millennia for many purposes, primarily as a fuel or as a construction material for making houses, tools, weapons, furniture, packaging, artworks, and paper. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at that time.

qas: question: Where does wood come from?
answers: text: trees

question: What forms in a tree to increase its diameter?
answers: text: woody layers

question: What is the process of trees growing out to get bigger around called?
answers: text: secondary growth

question: What do many places have four of that would cause growth rings in a tree?
answers: text: seasons

question: If a place has annual seasons, what are the growth rings on the trees there called?
answers: text: annual rings
context: 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 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. Where there are clear seasons, growth can occur in a discrete annual or seasonal pattern, leading to growth rings; these can usually be most clearly seen on the end of a log, but are also visible on the other surfaces. If these seasons are annual these growth rings are referred to as annual rings. Where there is no seasonal difference growth rings are likely to be indistinct or absent.

qas: question: If a growth ring has differences over one season, would the part nearest the tree's center be narrower or wider?
answers: text: wider

question: What name, besides springwood, is used for the part of a growth ring formed in the beginning of the growing season?
answers: text: earlywood

question: If the opposite of springwood is summerwood, what's the opposite of earlywood?
answers: text: latewood

question: Is earlywood usually lighter or darker than the part of the growth ring that forms later in the season?
answers: text: lighter

question: Is summerwood the inner or outer portion of a growth ring?
answers: text: outer
context: 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 is then known as the latewood or summerwood. However, there are major differences, depending on the kind of wood (see below).

qas: question: What is the sort of circular imperfection in a piece of wood called?
answers: text: knot

question: What property of wood does a knot usually reduce in the wood around it?
answers: text: strength

question: In what direction is wood often sawn so that a knot appears as a solid circle that the grain flows around?
answers: text: longitudinally

question: Are knots usually lighter or darker than the surrounding wood?
answers: text: darker

question: The direction of grain in a knot can differ by as much as how many degrees from the regular wood?
answers: text: 90
context: A knot is a particular type of imperfection in a piece of wood; it will affect the technical properties of the wood, usually reducing the local strength and increasing the tendency for splitting along the wood grain, 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 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.

qas: question: Other than the base of a side branch, what tree feature causes a knot?
answers: text: a dormant bud

question: What shape is the knot formed by a side branch's base?
answers: text: conical

question: What measurement of a stem determines a knot's inner tip placement?
answers: text: diameter

question: Because a knot's shape is conical, what shape does a cross-section of it have?
answers: text: circular
context: 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 the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud.

qas: question: What will the lower limbs of a tree usually do during development?
answers: text: die

question: For what length of time can a dead lower limb stay attached to a tree?
answers: text: years

question: Rather than being joined to the limb that died, where do subsequent layers grow?
answers: text: around it

question: Are the knots that dead tree limbs form attached or not attached?
answers: text: not attached

question: A detached knot will probably drop out of the wood when someone saws it into what?
answers: text: boards
context: During the development of a tree, the lower limbs often die, but may remain attached for a time, sometimes years. Subsequent layers of growth of the attaching stem are no longer intimately joined with the dead limb, but are grown around it. Hence, dead branches produce knots which are not attached, and likely to drop out after the tree has been sawn into boards.

qas: question: What's the process in which knots are classified called?
answers: text: grading

question: Along with firmness, soundness, and form, what property of a knot is classified?
answers: text: size

question: What property of knots does the amount of time a branch stayed on a tree while the stem kept growing affect?
answers: text: firmness
context: 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.

qas: question: What is wood's breaking strength susceptible to? 
answers: text: defects

question: Depending on the placement and size of a knot, what property of structural timber can be affected?
answers: text: stiffness

question: What do stiffness and elastic strength depend on more than defects?
answers: text: sound wood

question: What direction of compression in relation to its grain won't weaken wood with sound knots in it?
answers: text: parallel
context: 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 the grain.

qas: question: What positive visual component can knots sometimes add to decorative pieces?
answers: text: interest

question: What term is used to describe what knots can do to affect the finish of things made from wood even when they've been painted?
answers: text: bleed

question: Is bleed easy or difficult to control?
answers: text: difficult

question: The stain from a knot bleeding is usually brownish or what other color?
answers: text: yellow

question: In what stage of processing does knot primer need to be applied for maximum effectiveness?
answers: text: preparation
context: 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, correctly applied during preparation, may do much to reduce this problem but it is difficult to control completely, especially when using mass-produced kiln-dried timber stocks.

qas: question: What's another word for "duramen"?
answers: text: Heartwood

question: What is heartwood naturally resistant to?
answers: text: decay

question: How does heartwood formation occur due to its being genetically programmed?
answers: text: spontaneously

question: What adjective describes fully formed heartwood?
answers: text: dead

question: Despite being considered dead, what can heartwood have one chemical reaction to?
answers: text: decay organisms
context: Heartwood (or duramen) is wood that as a result of a naturally occurring chemical transformation has become more resistant to decay. Heartwood formation occurs spontaneously (it is a genetically programmed process). Once heartwood formation is complete, the heartwood is dead. Some uncertainty still exists as to whether heartwood is truly dead, as it can still chemically react to decay organisms, but only once.

qas: question: In what part of a tree's cross-section is heartwood visible?
answers: text: growth rings

question: What simple color distinction can heartwood have that makes it stand out from living wood in a tree?
answers: text: darker

question: Along with insect infestation, what process can discolor wood and make it look like heartwood?
answers: text: decay

question: What kind of plants never form heartwood?
answers: text: woody

question: What is the living wood in a tree called?
answers: text: sapwood
context: 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. However, 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.

qas: question: What term is interchangeable with "sapwood"?
answers: text: alburnum

question: Is sapwood the younger or older wood in a tree?
answers: text: younger

question: What essential liquid is the sapwood tasked with carrying around a tree?
answers: text: water

question: How much of the wood in a tree is sapwood at some point in its life?
answers: text: All

question: Does a tree growing quickly out in the open have thinner or thicker sapwood for its size than the same kind of tree in a dense forest?
answers: text: thicker
context: Sapwood (or alburnum) 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. However, 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 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 or more in diameter, before any heartwood begins to form, for example, in second-growth hickory, or open-grown pines.

qas: question: If a tree starts forming heartwood right away, will its sapwood layer be thin or thick?
answers: text: thin

question: What property of heartwood that has nothing to do with how important it is to trees got it its name?
answers: text: position

question: Does a beech tree usually have thin or thick sapwood?
answers: text: thick

question: Does a sassafras tree typically have a thin or thick sapwood layer?
answers: text: Thin

question: Would a thin or a thick sapwood layer be found in a pine tree?
answers: text: thick
context: The term heartwood derives solely from its position and not from any vital importance to 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 is the rule. Others never form heartwood.

qas: question: What part of a tree is the cross-sectional area of the sapwood approximately proportional to?
answers: text: crown

question: Are more rings necessary if they're narrow or wide?
answers: text: narrow

question: As a tree grows bigger, if the sapwood layer doesn't increase in volume, what will it become?
answers: text: thinner

question: In what part of the tree trunk is the sapwood layer thinnest?
answers: text: near the base

question: Along with the smaller diameter of the upper trunk, what factor leads to thinner sapwood higher up a tree?
answers: text: age
context: No definite relation exists between 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 thicker in the upper portion of the trunk of a tree than near the base, because the age and the diameter of the upper sections are less.

qas: question: What usually covers the whole trunk of a very young tree?
answers: text: limbs

question: What evidence of the stubs of the limbs a tree loses can always be seen in the wood?
answers: text: knots

question: In a very old tree, are you more likely to find a lot of knots in the heartwood or the sapwood?
answers: text: heartwood

question: What hides the stubs of a tree's lost limbs from being visible later in its life?
answers: text: Subsequent growth

question: Since knots are defects that weaken lumber, would the heartwood or the sapwood from the same tree be stronger?
answers: text: sapwood
context: 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 however remain as knots. No matter how smooth and clear 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 the tree, may well be stronger than a piece of heartwood from the same tree.

qas: question: What do broken limbs and deep wounds open a door for in a tree?
answers: text: decay

question: Decay can spread to all of what part of a tree?
answers: text: the trunk

question: What growth stage of insects bore holes into trees?
answers: text: larvae

question: What part of a tree often stays impressively sound even when hundreds or thousands of years old?
answers: text: inner heartwood

question: What evidence do some insect larvae leave in a tree forever?
answers: text: tunnels
context: It is remarkable that the inner heartwood of old trees remains as sound as it usually does, since in many cases it is hundreds, and in a few instances thousands, of years old. Every broken limb or root, or deep wound from fire, insects, or falling timber, may afford an entrance for decay, which, once started, may penetrate to all parts of the trunk. The larvae of many insects bore into the trees and their tunnels remain indefinitely as sources of weakness. Whatever advantages, however, that sapwood may have in this connection are due solely to its relative age and position.

qas: question: In what stage of its life does a tree usually grow the fastest?
answers: text: youth

question: As a tree ages, do its growth rings usually get wider or narrower?
answers: text: narrower

question: What part of a tree opens and spreads out more as it matures?
answers: text: crown

question: Is wood production of a tree lessened or increased as it ages?
answers: text: lessened

question: Along with nutrients, what do trees growing in forests have to compete for?
answers: text: light
context: 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 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 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. Upon the whole, however, as a tree gets larger in diameter the width of the growth rings decreases.

qas: question: When a big tree is cut up, will the pieces of wood differ or all be the same?
answers: text: differ

question: In a large log, will the heartwood or sapwood usually be stronger and tougher?
answers: text: heartwood

question: If you need really hard, strong wood from a small tree, would it likely be better to use the heartwood or sapwood?
answers: text: sapwood

question: Besides big trees, what trees are more likely to have a range of different kinds of wood?
answers: text: mature
context: 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 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.

qas: question: When trees have a visible difference in color between sapwood and heartwood, which is darker?
answers: text: heartwood

question: What is deposited naturally in heartwood that changes its color?
answers: text: chemical substances

question: Is the color difference between heartwood and sapwood usually very subtle or conspicuous?
answers: text: conspicuous

question: What type of properties of heartwood and sapwood is often the same even if their colors are very different?
answers: text: mechanical

question: Although heartwood and sapwood might be similar mechanically, if their colors are very different, what other type of difference would they have?
answers: text: chemical
context: 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 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 difference does not mean a dramatic difference in the mechanical properties of heartwood and sapwood, although there may be a dramatic chemical difference.

qas: question: What type of tree has resin that makes it stronger when it dries?
answers: text: Longleaf Pine

question: What's the funny name for resin-saturated heartwood?
answers: text: fat lighter

question: What is fat lighter practically impervious to in addition to termites?
answers: text: rot

question: If spruce is shot full of crude resin and dried, which of its properties is increased?
answers: text: strength

question: Since it's highly flammable, what do people often use little pieces of longleaf pine tree stumps for?
answers: text: kindling
context: Some experiments on very resinous Longleaf Pine specimens indicate an increase in strength, due to 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; however they are very flammable. 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 is also greatly increased in strength thereby.

qas: question: Which of the wood in a growth ring is usually darker?
answers: text: latewood

question: Which property of a tree's wood that gives clues about its strength and hardness can be judged by it's color?
answers: text: density

question: What category of trees show this difference greatly?
answers: text: coniferous

question: What type of woods might sometimes appear to have darker earlywood on a finished surface?
answers: text: ring-porous

question: With the exception of earlywood/latewood difference in some types of trees, how much of an indication of strength is a wood's color?
answers: text: no indication
context: Since the latewood of a growth ring is usually darker in color than the earlywood, this fact may be used in 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 not infrequently appear on a finished surface as darker than the denser latewood, though on cross sections of heartwood the reverse is commonly true. Except in the manner just stated the color of wood is no indication of strength.

qas: question: What condition does an abnormal color usually indicate in wood?
answers: text: diseased

question: What other property can you assume of wood that is diseased?
answers: text: unsoundness

question: What causes the black checked pattern in the wood of western hemlocks?
answers: text: insect attacks

question: What animals cause the reddish-brown streaks of color in hickory wood?
answers: text: birds

question: What's the name for the pretty coloring effect caused in some wood by rot-producing fungi?
answers: text: spalting
context: 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 the properties of the wood. Certain rot-producing fungi impart to wood characteristic colors which thus become symptomatic of weakness; however an attractive effect known as spalting produced by this process is often considered a desirable characteristic. Ordinary sap-staining is due to fungal growth, but does not necessarily produce a weakening effect.

qas: question: What does wood retain in its cell walls despite being air-dried?
answers: text: water

question: Air-dried wood keeps up to what percentage of the water in its cell walls?
answers: text: 16

question: What kind of dried wood retains a small quantity of water but is considered absolutely dry?
answers: text: oven-dried
context: In heartwood it occurs only in the first and last forms. Wood that is thoroughly air-dried 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.

qas: question: Often the water in wood makes it more pliable and what else?
answers: text: softer

question: What material sometimes used for dog chews reacts similarly to wood because of its water content?
answers: text: rawhide

question: What material we use to write or print on, like wood, becomes softer and more pliable when wet?
answers: text: paper

question: When water content increases within certain limits in wood, does is have a less or greater softening effect?
answers: text: greater

question: What type of action does water create in cloth?
answers: text: softening
context: The general effect of the water content upon the wood substance is to render it softer and more pliable. A similar effect of common observation is in the softening action of water on rawhide, paper, or cloth. Within certain limits, the greater the water content, the greater its softening effect.

qas: question: What will drying often increase in wood?
answers: text: strength

question: What color is also used interchangeably with "undried" for wood?
answers: text: green

question: What type of wood can hold four times as much of a load when dried?
answers: text: spruce
context: 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 the same size will.

qas: question: What type of "ultimate" strength is one of the two types increased the most by drying wood?
answers: text: crushing

question: What property of wood is least affected by drying?
answers: text: elasticity

question: Is strength at elastic limit in endwise compression or stress at elastic limit in cross-bending increased more by drying wood?
answers: text: strength at elastic limit in endwise compression

question: Is the strength of the modulus of rupture or elasticity increased more when wood is dried?
answers: text: modulus of rupture
context: 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.

qas: question: Along with hygroscopic, cellular, and anisotropic, how is the material of wood described?
answers: text: heterogeneous

question: What does wood consist of?
answers: text: cells

question: What part of wood's cells are composed of cellulose and hemicellulose?
answers: text: walls

question: What makes up 40-50% of the cell walls in wood?
answers: text: cellulose

question: What substance is hemicellulose impregnated with?
answers: text: lignin
context: Wood is a heterogeneous, hygroscopic, cellular and anisotropic material. It consists of cells, and the cell walls are composed of micro-fibrils of cellulose (40% – 50%) and hemicellulose (15% – 25%) impregnated with lignin (15% – 30%).

qas: question: What type of cells makes up most wood cells in coniferous trees?
answers: text: tracheids

question: Are hardwood or softwood species more uniform in structure?
answers: text: softwood

question: What are the visible vessels in hardwoods commonly called?
answers: text: pores

question: What hardwood that starts with the letter "O" would have pores?
answers: text: oak

question: Besides oak, what's an example of a hardwood with prominent pores?
answers: text: ash
context: 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.

qas: question: Is the structure of hardwood simple or complex?
answers: text: complex

question: What handles most of the water conduction in hardwoods?
answers: text: vessels

question: Are the vessels in chestnut wood large or small?
answers: text: large

question: In wood from a willow tree, what would you need to use to see the tiny vessels?
answers: text: a hand lens

question: Besides ring-porous, what's the other class hardwoods are often divided into?
answers: text: diffuse-porous
context: The structure of hardwoods 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.

qas: question: What species of hardwood are hickory and mulberry trees?
answers: text: ring-porous

question: In what season do the growth-rings of ring-porous species form with larger vessels localized?
answers: text: spring

question: In what season does the part of the growth-ring with smaller vessels form in ring-porous species?
answers: text: summer

question: What fibers does the summer's section of growth-ring have more of?
answers: text: wood fibers

question: Along with strength, what property do wood fibers lend to wood?
answers: text: toughness
context: In ring-porous species, such as ash, black locust, catalpa, chestnut, elm, hickory, mulberry, and oak, the larger vessels or pores (as cross sections of vessels are called) are localised 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 a source of weakness.[citation needed]

qas: question: What kind of woods have pores that are uniformly sized?
answers: text: diffuse-porous

question: What species do aspen, cottonwood, and poplar trees belong to?
answers: text: Populus

question: With walnut, what's another tree in the intermediate group?
answers: text: cherry

question: What capability is spread through the growth ring in ring-porous species?
answers: text: water conducting

question: Is maple wood diffuse-porous or ring-porous?
answers: text: diffuse-porous
context: 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,[citation needed] birch, buckeye, maple, willow,and the Populus species such as aspen, cottonwood and poplar. Some species, such as walnut and cherry, are on the border between the two classes, forming an intermediate group.[citation needed]

qas: question: What kind of softwoods often have significant differences in their earlywood and latewood?
answers: text: temperate

question: Is latewood denser or less dense than earlywood?
answers: text: denser

question: Does strength come from the walls or cavities of wood cells?
answers: text: walls

question: Are the cell walls of earlywood thick or thin?
answers: text: thin

question: What general size are the cavities in the cells of very dense latewood?
answers: text: very small
context: 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 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.

qas: question: Comparing a heavy and a lightweight piece of wood from a pine, which would have a greater proportion of latewood?
answers: text: heavy

question: What feature of a piece of pine with more latewood would be more clear and pronounced?
answers: text: growth rings

question: What type of tree has very little contrast between parts of its growth rings?
answers: text: white pines

question: Is white pine easy or difficult to work with because of its texture?
answers: text: easy

question: What kind of pines have very deep, darkly colored hardwood that stands out against the light earlywood?
answers: text: hard pines
context: If 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 the other hand, the latewood is very dense and is deep-colored, presenting a very decided contrast to the soft, straw-colored earlywood.

qas: question: Having a high proportion of latewood isn't all that matters; what else is important?
answers: text: quality

question: What can we judge in wood just by looking at it?
answers: text: comparative density

question: What property of wood could we project some indication of by looking at its density?
answers: text: strength

question: What could we call some specimens with a high proportion of latewood that explains why they weigh less than specimens with much less latewood?
answers: text: porous
context: 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 but little. One can judge comparative density, and therefore to some extent strength, by visual inspection.

qas: question: What facet of wood is affected to some degree by the place where the tree grows?
answers: text: character

question: If you want wood that's easy to work with, what kind of growth would you want the tree to have?
answers: text: moderate to slow

question: What species of tree can be said to growth ring proportions that aren't determined just by their rate of growth?
answers: text: conifers

question: What counterpart of earlywood are scientists still trying to explain the formation of?
answers: text: latewood

question: While there is some relationship between where and how a tree grows, what can't anyone formulate to govern it?
answers: text: a rule
context: No satisfactory explanation can as yet be given for 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 the wood formed, though it is not possible to formulate a rule governing it. In general, however, it may be said that where strength or ease of working is essential, woods of moderate to slow growth should be chosen.

qas: question: What kind of woods always have very clearly marked seasonal growth?
answers: text: ring-porous

question: What size pores form early in ring-porous woods' growing season?
answers: text: large

question: When does the denser tissue the new pores abut come from?
answers: text: the year before
context: 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.

qas: question: Ring-porous hardwoods have a clear relationship between their properties and what other factor?
answers: text: rate of growth

question: Is harder, heavier wood indicated by narrower or wider growth rings?
answers: text: wider

question: What kind of wood with a name that starts with "H" is a ring-porous hardwood?
answers: text: hickory

question: If the growth rings are wider, was the growth of the tree slower or more rapid?
answers: text: more rapid

question: What is the only kind of wood that will definitely be harder and stronger when it grows faster?
answers: text: ring-porous
context: In the case of the ring-porous hardwoods there seems to exist 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.

qas: question: Which specific type of wood within ring-porous woods have more fibers to make it strong?
answers: text: latewood

question: When there is less latewood, what is diminishing?
answers: text: breadth of ring

question: Does slow or rapid growth make relatively porous, light wood?
answers: text: slow

question: What kind of oak has just 6-10% volume of large vessels in the log?
answers: text: good

question: What kind of fibers are in the latewood of good oak, making it very firm?
answers: text: thick-walled
context: In ring-porous woods of good growth it 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 6 to 10 percent of the volume of the log, while in inferior material they may make up 25% or more. The latewood of good oak 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.

qas: question: What term is sometimes used for wood with wide rings?
answers: text: second-growth

question: Do young trees grow more quickly in open stands or in a closed forest?
answers: text: open stands

question: What property is important to manufacturers who use "second-growth" hardwood?
answers: text: strength

question: What specific kind of "second-growth" hardwood is often used to make handles and spokes? 
answers: text: hickory

question: What organization tested hickory to find out about its properties?
answers: text: U.S. Forest Service
context: 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 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:

qas: question: What kind of wood often has ring divisions that can't even be seen by looking at it?
answers: text: diffuse-porous

question: In diffuse-porous woods, if the demarcation between rings is obvious, what type of difference within the ring might not be?
answers: text: structure

question: What adjective describes how our eyes function without a tool like a microscope to help?
answers: text: unaided
context: In the diffuse-porous woods, the demarcation between rings is not always so clear and in some cases is almost (if not entirely) invisible to the unaided eye. Conversely, when there is a clear demarcation there may not be a noticeable difference in structure within the growth ring.

qas: question: What kind of wood has all similarly sized vessels?
answers: text: diffuse-porous

question: What rate of growth in a tree will make the wood from it stronger than trees that grow very slowly or very quickly?
answers: text: medium

question: The capability of diffuse-porous woods to carry what substance is spread out in the growth ring?
answers: text: water

question: What division of trees are diffuse-porous woods more similar in growth rate to than ring-porous woods?
answers: text: conifers

question: Does uniformity of the texture and grain of wood usually result from much or little contrast between earlywood and latewood?
answers: text: little
context: In diffuse-porous woods, as has been stated, the vessels or pores are even-sized, so that the water conducting capability is scattered throughout the ring instead of collected in the earlywood. The effect of rate of growth is, therefore, not the same as in the ring-porous woods, approaching more nearly the conditions in the conifers. In general it may be stated that such woods of medium growth afford stronger material than when very rapidly or very slowly grown. In many uses of wood, total strength is not the main consideration. If ease of working is prized, wood should be chosen with regard to its uniformity of texture and straightness of grain, which will in most cases occur when there is little contrast between the latewood of one season's growth and the earlywood of the next.

qas: question: What's another term used for "conifer" wood?
answers: text: dicot

question: What type of plants produce material that is referred to as "wood" even though it is technically not?
answers: text: monocot

question: What monocot plant produces "wood" by the same name that's often used for flooring and veneer?
answers: text: bamboo

question: While we call bamboo "wood," what botanical family does it belong to?
answers: text: grass

question: Along with bamboo, what's the other monocot that's a major source of so-called "wood"?
answers: text: palms
context: Structural material that resembles ordinary, "dicot" or conifer wood in its gross handling characteristics is produced by a number of monocot plants, and these also are colloquially called wood. Of these, bamboo, botanically a member of the grass family, has considerable economic importance, larger culms being widely used as a building and construction material in their own right and, these days, in the manufacture of engineered flooring, panels and veneer. Another major plant group that produce material that often is called wood are the palms. Of much less importance are plants such as Pandanus, Dracaena and Cordyline. With all this material, the structure and composition of the structural material is quite different from ordinary wood.

qas: question: Which property of wood reveals the most about its quality?
answers: text: specific gravity

question: In addition to lumber strength, what important indicator of wood's quality can be determined using specific gravity?
answers: text: pulp yield

question: What measurement is expressed in mass per unit substance?
answers: text: density

question: When wood dries and shrinks, what happens to its density?
answers: text: increases

question: When wood is described as "green," what does "green" mean?
answers: text: water-saturated
context: The single most revealing property of wood as an indicator of wood quality is specific gravity (Timell 1986), as both pulp yield and lumber strength are determined by it. Specific gravity is the ratio of the mass of a substance to the mass of an equal volume of water; density is the ratio of a mass of a quantity of a substance to the volume of that quantity and is expressed in mass per unit substance, e.g., grams per millilitre (g/cm3 or g/ml). The terms are essentially equivalent as long as the metric system is used. Upon drying, wood shrinks and its density increases. Minimum values are associated with green (water-saturated) wood and are referred to as basic specific gravity (Timell 1986).

qas: question: Along with growth, what kind of factors determine the density of wood?
answers: text: physiological

question: Into how many characteristics are the factors of wood combined?
answers: text: one

question: What author called wood's density "fairly easily measured"?
answers: text: Elliott
context: Wood density is determined by multiple growth and physiological factors compounded into “one fairly easily measured wood characteristic” (Elliott 1970).

qas: question: What should be anticipated because of the many factors that influence wood's density?
answers: text: Variation

question: What specific type of growth has an effect on the density of wood?
answers: text: radial

question: Which part of a tree can have vertical or horizontal variation in its specific gravity?
answers: text: bole

question: Variation in what measurement is sometimes greater within one tree than from one tree to another?
answers: text: density

question: What tiny object's source plays a role in determining wood density?
answers: text: seed
context: Age, diameter, height, radial growth, geographical location, site and growing conditions, silvicultural treatment, and seed source, all to some degree influence wood density. Variation is to be expected. Within an individual tree, the variation in wood density is often as great as or even greater than that between different trees (Timell 1986). Variation of specific gravity within the bole of a tree can occur in either the horizontal or vertical direction. :)

qas: question: What term do we use for the wood that comes from pine trees?
answers: text: softwood

question: What kind of wood does an oak tree have?
answers: text: hardwood

question: Is balsa a softwood or a hardwood?
answers: text: hardwood

question: What's an example of a softwood that isn't "soft," and is actually harder than a lot of hardwoods?
answers: text: yew

question: What's the scientific name for trees like the oak with broad leaves?
answers: text: dicotyledons
context: It is common to classify wood as either softwood or hardwood. The wood from conifers (e.g. pine) is called softwood, and the wood from dicotyledons (usually broad-leaved trees, e.g. oak) is called hardwood. These names are a bit misleading, as hardwoods are not necessarily hard, and softwoods are not necessarily soft. The well-known balsa (a hardwood) is actually softer than any commercial softwood. Conversely, some softwoods (e.g. yew) are harder than many hardwoods.

qas: question: What kind of relationship exists between a tree's properties and its wood's properties?
answers: text: strong

question: What property of wood varies according to species?
answers: text: density

question: What property of wood has a correlation to its density?
answers: text: strength

question: Is mahogany a hardwood or a softwood?
answers: text: hardwood

question: What hobby is balsa wood often used for?
answers: text: model building
context: There is a strong relationship between the properties of wood and the properties of the particular tree that yielded it. The density of wood varies with species. The density of a wood correlates with its strength (mechanical properties). For example, mahogany is a medium-dense hardwood that is excellent for fine furniture crafting, whereas balsa is light, making it useful for model building. One of the densest woods is black ironwood.

qas: question: What approximate percentage of carbon does wood have?
answers: text: 50%

question: What element makes up about 6% of the chemical composition of wood?
answers: text: hydrogen

question: About what percentage of wood is composed of nitrogen?
answers: text: 1%

question: Which element in wood composes about 42% of its weight?
answers: text: oxygen

question: What element joins potassium, calcium, manganese, iron, and sodium to make a combined 1% of the chemical composition of wood?
answers: text: magnesium
context: The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements (mainly calcium, potassium, sodium, magnesium, iron, and manganese) by weight. Wood also contains sulfur, chlorine, silicon, phosphorus, and other elements in small quantity.

qas: question: How many main components make up wood, not counting water?
answers: text: three

question: What's the name for the crystalline polymer derived from glucose?
answers: text: Cellulose

question: After cellulose, what component is most plentiful in wood?
answers: text: hemicellulose

question: What kind of trees have about 30% hemicellulose?
answers: text: conifers

question: Which of the three main components of wood is used to manufacture paper?
answers: text: cellulose
context: Aside from water, wood has three main components. Cellulose, a crystalline polymer derived from glucose, constitutes about 41–43%. Next in abundance is hemicellulose, which is around 20% in deciduous trees but near 30% in conifers. It is mainly five-carbon sugars that are linked in an irregular manner, in contrast to the cellulose. Lignin is the third component at around 27% in coniferous wood vs. 23% in deciduous trees. Lignin confers the hydrophobic properties reflecting the fact that it is based on aromatic rings. These three components are interwoven, and direct covalent linkages exist between the lignin and the hemicellulose. A major focus of the paper industry is the separation of the lignin from the cellulose, from which paper is made.

qas: question: What component of wood determines whether it is hardwood or softwood?
answers: text: lignin

question: Which wood has lignin that comes primarily from one type of alcohol?
answers: text: Softwood

question: Which type of alcohol mainly becomes softwood lignin?
answers: text: coniferyl

question: In addition to coniferyl alcohol, what other alcohol is in hardwood lignin?
answers: text: sinapyl

question: Which kind of wood contains lignin derived from two main alcohol sources?
answers: text: Hardwood
context: In chemical terms, the difference between hardwood and softwood is reflected in the composition of the constituent lignin. Hardwood lignin is primarily derived from sinapyl alcohol and coniferyl alcohol. Softwood lignin is mainly derived from coniferyl alcohol.

qas: question: What's the name for the low molecular weight organic compounds in wood?
answers: text: extractives

question: Along with fatty acids, what kind of acids are in the extractives in wood?
answers: text: resin

question: Wood extractives include resin and fatty acids, terpenes, and what other component?
answers: text: waxes

question: What do conifers use rosin to protect themselves from?
answers: text: insects

question: Along with tall oil and rosin, what commercial product do we get from wood's extractives?
answers: text: turpentine
context: Aside from the lignocellulose, wood consists of a variety of low molecular weight organic compounds, called extractives. The wood extractives are fatty acids, resin acids, waxes and terpenes. For example, rosin is exuded by conifers as protection from insects. The extraction of these organic materials from wood provides tall oil, turpentine, and rosin.

qas: question: What type of wood is preferred as fuel?
answers: text: Hardwood

question: What type of wood burns quickly and makes more smoke than hardwood?
answers: text: softwood

question: What type of areas use more wood for fuel?
answers: text: rural

question: What benefit besides the cozy atmosphere would a wood-burning fireplace add to a home?
answers: text: warmth
context: Wood has a long history of being used as fuel, which continues to this day, mostly in rural areas of the world. Hardwood is preferred over softwood because it creates less smoke and burns longer. Adding a woodstove or fireplace to a home is often felt to add ambiance and warmth.

qas: question: What wood is decay-resistant when wet?
answers: text: Elm

question: What plumbing component was once made out of elm?
answers: text: water pipe

question: Until the late 19th century, what vessels were almost always wooden?
answers: text: boats

question: What significant purpose has wood been used for as long as humans have built shelters?
answers: text: construction material

question: Other than boats, what do people often build with wood?
answers: text: houses
context: Wood has been an important construction material since humans began building shelters, houses and boats. Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction. Elm in particular was used for this purpose as it resisted decay as long as it was kept wet (it also served for water pipe before the advent of more modern plumbing).

qas: question: What term is used in North America for wood used in construction?
answers: text: lumber

question: Outside of North America, if someone said "lumber," to what would they be referring?
answers: text: felled trees

question: What do people outside of North America call the sawn boards used for building?
answers: text: timber

question: What was the preferred wood for construction in Medieval Europe?
answers: text: oak

question: For modern solid wood doors, what wood is often used in addition to small-knotted pine or poplar?
answers: text: Douglas fir
context: Wood to be used for construction work is commonly known as lumber in North America. Elsewhere, lumber usually refers to felled trees, and the word for sawn planks ready for use is timber. In Medieval Europe oak was the wood of choice for all wood construction, including beams, walls, doors, and floors. Today a wider variety of woods is used: solid wood doors are often made from poplar, small-knotted pine, and Douglas fir.

qas: question: What type of construction is often used now to build homes in much of the world?
answers: text: timber-framed

question: In addition to residential applications, what type of buildings often have engineered wood components?
answers: text: commercial

question: Along with decorative components, what type of building materials can be engineered from wood?
answers: text: structural

question: What industry benefits greatly from engineered wood products?
answers: text: construction
context: New domestic housing in many parts of the world today is commonly made from timber-framed construction. Engineered wood products are becoming a bigger part of the construction industry. They may be used in both residential and commercial buildings as structural and aesthetic materials.

qas: question: What might wood be used for in a building made from brick or other materials?
answers: text: supporting material

question: What crucial part of a house is often constructed from wood?
answers: text: roof

question: Wood might be used to construct what exterior component of a building?
answers: text: cladding

question: Inside a building, what wooden things might you open to enter or leave rooms?
answers: text: doors
context: In buildings made of other materials, wood will still be found as a supporting material, especially in roof construction, in interior doors and their frames, and as exterior cladding.

qas: question: What holds together an engineered wood product?
answers: text: glue

question: Engineered wood products are often used in construction, but what other major type of applications do they have?
answers: text: industrial

question: What requirements do engineered wood products meet?
answers: text: application-specific performance requirements

question: What efficient type of unit does the process of "engineering" wood result in?
answers: text: composite structural unit

question: Wood fibers from wood strands, lumber, and what other source can be glued together to make larger units?
answers: text: veneers
context: Engineered wood products, glued building products "engineered" for application-specific performance requirements, are often used in construction and industrial applications. Glued engineered wood products are manufactured by bonding together wood strands, veneers, lumber or other forms of wood fiber with glue to form a larger, more efficient composite structural unit.

qas: question: What category do composite panels, strand board, and plywood all fit into?
answers: text: wood structural panels

question: What's another word for glued laminated timber?
answers: text: glulam

question: What does LVL stand for?
answers: text: laminated veneer lumber

question: If current building trends continue, what material will be replaced by particle and fiber board?
answers: text: plywood

question: About how many cubic meters of wood was used in 1991 to make products like glulam, LVL, and structural composite lumber?
answers: text: 100 million
context: These products include glued laminated timber (glulam), wood structural panels (including plywood, oriented strand board and composite panels), laminated veneer lumber (LVL) and other structural composite lumber (SCL) products, parallel strand lumber, and I-joists. Approximately 100 million cubic meters of wood was consumed for this purpose in 1991. The trends suggest that particle board and fiber board will overtake plywood.

qas: question: What material results from chemically breaking down wood?
answers: text: cellulose

question: What's the abbreviation for medium-density fiberboard?
answers: text: MDF

question: How is wood broken down into chips and fibers?
answers: text: mechanically

question: What type of flooring can be made from wood derivatives?
answers: text: laminate

question: What widely-used product is almost always made of wood fibers?
answers: text: paper
context: Wood unsuitable for construction in its native form may be broken down mechanically (into fibers or chips) or chemically (into cellulose) and used as a raw material for other building materials, such as engineered wood, as well as chipboard, hardboard, and medium-density fiberboard (MDF). Such wood derivatives are widely used: wood fibers are an important component of most paper, and cellulose is used as a component of some synthetic materials. Wood derivatives can also be used for kinds of flooring, for example laminate flooring.

qas: question: What category of products usually made from wood includes chairs?
answers: text: furniture

question: What wooden utensil could you stir a pot of soup with?
answers: text: wooden spoon

question: Which parts of tools are sometimes made out of wood?
answers: text: handles

question: What pieces of furniture that most people use every night can be made out of wood?
answers: text: beds

question: What special wooden utensils do many people use to eat Chinese takeout?
answers: text: chopsticks
context: Wood has always been used extensively for furniture, such as chairs and beds. It is also used for tool handles and cutlery, such as chopsticks, toothpicks, and other utensils, like the wooden spoon.

qas: question: What could we monitor electronically that could help inform new methods of wood protection?
answers: text: Moisture content

question: Development in the wood manufacturing industry include using lignin to make what substance?
answers: text: glue

question: Instead of rubber, what important part of a car might someday be replaced by components of wood?
answers: text: tire

question: What material might be developed from wood that could make clothes that resist wear and tear?
answers: text: high strength fabrics

question: In addition to extracting components from wood, what might scientist do by adding components, for example, to make innovative products?
answers: text: modify wood
context: Further developments include new lignin glue applications, recyclable food packaging, rubber tire replacement applications, anti-bacterial medical agents, and high strength fabrics or composites. As scientists and engineers further learn and develop new techniques to extract various components from wood, or alternatively to modify wood, for example by adding components to wood, new more advanced products will appear on the marketplace. Moisture content electronic monitoring can also enhance next generation wood protection.

qas: question: Along with sculptures, what type of art have people been making out of wood for centuries?
answers: text: carvings

question: What did indigenous people in North America make out of the trunks of conifers?
answers: text: totem poles

question: What type of tree was often used for totem poles?
answers: text: Western Red Cedar

question: What city in Scotland would you visit to see the Millennium clock tower?
answers: text: Edinburgh

question: What museum exhibits the Millennium clock tower?
answers: text: National Museum of Scotland
context: Wood has long been used as an artistic medium. It has been used to make sculptures and carvings for millennia. Examples include the totem poles carved by North American indigenous people from conifer trunks, often Western Red Cedar (Thuja plicata), and the Millennium clock tower, now housed in the National Museum of Scotland in Edinburgh. It is also used in woodcut printmaking, and for engraving.

qas: question: What kind of wood are clarinet bodies made from?
answers: text: african blackwood

question: What expensive wood with a prized color is used to make the backs of violins?
answers: text: ripple sycamore

question: What category of wood is often used for musical instruments?
answers: text: tonewoods

question: What's the common name for Picea abies?
answers: text: European spruce

question: Along with resonance, what property of an instrument will be affected by the wood used to make it?
answers: text: tone
context: Certain types of musical instruments, such as those of the violin family, the guitar, the clarinet and recorder, the xylophone, and the marimba, are traditionally made mostly or entirely of wood. The choice of wood may make a significant difference to the tone and resonant qualities of the instrument, and tonewoods have widely differing properties, ranging from the hard and dense african blackwood (used for the bodies of clarinets) to the light but resonant European spruce (Picea abies), which is traditionally used for the soundboards of violins. The most valuable tonewoods, such as the ripple sycamore (Acer pseudoplatanus), used for the backs of violins, combine acoustic properties with decorative color and grain which enhance the appearance of the finished instrument.

qas: question: What type of instruments with a misleading name aren't always made completely out of wood?
answers: text: woodwind instruments

question: What are woodwind instrument's reeds often made out of?
answers: text: Arundo donax

question: Is the Arundo donax a monocot or dicot cane plant?
answers: text: monocot

question: What objects do musicians have to have in order to play woodwind instruments?
answers: text: reeds
context: Despite their collective name, not all woodwind instruments are made entirely of wood. The reeds used to play them, however, are usually made from Arundo donax, a type of monocot cane plant.

qas: question: What wood is usually used for cricket bats?
answers: text: white willow

question: Ash and hickory are often used for baseball bats to comply with the rules of what organization?
answers: text: Major League Baseball

question: What is commonly used for the basketball courts the NBA plays on?
answers: text: parquetry

question: What wood has recently started being used to make baseball bats in addition to hickory and ash?
answers: text: maple

question: Compared to hickory and ash, what adjective might be used for a maple baseball bat?
answers: text: fragile
context: Many types of sports equipment are made of wood, or were constructed of wood in the past. For example, cricket bats are typically made of white willow. The baseball bats which are legal for use in Major League Baseball are frequently made of ash wood or hickory, and in recent years have been constructed from maple even though that wood is somewhat more fragile. NBA courts have been traditionally made out of parquetry.

qas: question: What pieces of equipment for shooting arrows used to be wooden?
answers: text: archery bows

question: Which pieces of ice hockey equipment were once made out of wood?
answers: text: sticks

question: When the golf club called the "wood" was actually made out of it, what type of wood was used?
answers: text: persimmon

question: What is the golf club known as the "wood" usually made out of today?
answers: text: synthetic materials

question: What other modern material has joined composites, carbon fiber, titanium, and aluminum to replace wood in the manufacture of sporting equipment?
answers: text: fiberglass
context: Many other types of sports and recreation equipment, such as skis, ice hockey sticks, lacrosse sticks and archery bows, were commonly made of wood in the past, but have since been replaced with more modern materials such as aluminium, fiberglass, carbon fiber, titanium, and composite materials. One noteworthy example of this trend is the golf club commonly known as the wood, the head of which was traditionally made of persimmon wood in the early days of the game of golf, but is now generally made of synthetic materials.

qas: question: What component of wood is degraded by bacteria that scientists are still trying to learn about?
answers: text: cellulose

question: What type of bacteria are present in Xylophaga?
answers: text: Symbiotic

question: What type of wood is it possible the bacteria in Xylophaga help break down?
answers: text: sunken

question: How long was the wood submerged in water in the study that discovered the types of bacteria in it?
answers: text: over a year

question: What bacteria starting with the letter "F" were found in wood after it was underwater for more than a year?
answers: text: Flavobacteria
context: Little is known about the bacteria that degrade cellulose. Symbiotic bacteria in Xylophaga may play a role in the degradation of sunken wood; while bacteria such as Alphaproteobacteria, Flavobacteria, Actinobacteria, Clostridia, and Bacteroidetes have been detected in wood submerged over a year.