Wood

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

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

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

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

answers: text: nutrients
question: What does wood convey to leaves, roots, and other tissues of a woody plant in addition to water?

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

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

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

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

answers: text: abundant
question: In addition to being carbon neutral, what other adjective describes wood that makes it compelling as a renewable energy source?

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

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

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

answers: text: 395 to 400
question: How many millions of years old were the plants that were discovered in New Brunswick?

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

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

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

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

answers: text: furniture
question: What category of items often constructed from wood does a chair belong to?

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

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

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

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

answers: text: annual rings
question: If a place has annual seasons, what are the growth rings on the trees there called?

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

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

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

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

answers: text: outer
question: Is summerwood the inner or outer portion of a growth ring?

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

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

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

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

answers: text: 90
question: The direction of grain in a knot can differ by as much as how many degrees from the regular wood?

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

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

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

answers: text: circular
question: Because a knot's shape is conical, what shape does a cross-section of it have?

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

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

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

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

answers: text: boards
question: A detached knot will probably drop out of the wood when someone saws it into what?

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

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

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

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

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

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

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

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

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

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

answers: text: preparation
question: In what stage of processing does knot primer need to be applied for maximum effectiveness?

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

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

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

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

answers: text: decay organisms
question: Despite being considered dead, what can heartwood have one chemical reaction to?

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

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

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

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

answers: text: sapwood
question: What is the living wood in a tree called?

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

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

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

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

answers: text: thicker
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?

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

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

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

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

answers: text: thick
question: Would a thin or a thick sapwood layer be found in a pine tree?

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

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

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

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

answers: text: age
question: Along with the smaller diameter of the upper trunk, what factor leads to thinner sapwood higher up a tree?

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

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

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

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

answers: text: sapwood
question: Since knots are defects that weaken lumber, would the heartwood or the sapwood from the same tree be stronger?

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

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

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

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

answers: text: tunnels
question: What evidence do some insect larvae leave in a tree forever?

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

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

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

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

answers: text: light
question: Along with nutrients, what do trees growing in forests have to compete for?

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

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

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

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

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

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

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

answers: text: chemical
question: Although heartwood and sapwood might be similar mechanically, if their colors are very different, what other type of difference would they have?

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

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

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

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

answers: text: kindling
question: Since it's highly flammable, what do people often use little pieces of longleaf pine tree stumps for?

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

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

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

answers: text: no indication
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?

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

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

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

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

answers: text: spalting
question: What's the name for the pretty coloring effect caused in some wood by rot-producing fungi?

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

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

answers: text: oven-dried
question: What kind of dried wood retains a small quantity of water but is considered absolutely dry?

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

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

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

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

answers: text: softening
question: What type of action does water create in cloth?

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

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

answers: text: spruce
question: What type of wood can hold four times as much of a load when dried?

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

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

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

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

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

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

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

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

answers: text: lignin
question: What substance is hemicellulose impregnated with?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

answers: text: toughness
question: Along with strength, what property do wood fibers lend to wood?

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

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

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

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

answers: text: diffuse-porous
question: Is maple wood diffuse-porous or ring-porous?

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

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

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

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

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

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

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

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

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

answers: text: hard pines
question: What kind of pines have very deep, darkly colored hardwood that stands out against the light earlywood?

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

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

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

answers: text: porous
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?

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

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

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

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

answers: text: a rule
question: While there is some relationship between where and how a tree grows, what can't anyone formulate to govern it?

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

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

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

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

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

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

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

answers: text: ring-porous
question: What is the only kind of wood that will definitely be harder and stronger when it grows faster?

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

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

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

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

answers: text: thick-walled
question: What kind of fibers are in the latewood of good oak, making it very firm?

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

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

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

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

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

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

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

answers: text: unaided
question: What adjective describes how our eyes function without a tool like a microscope to help?

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

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

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

answers: text: little
question: Does uniformity of the texture and grain of wood usually result from much or little contrast between earlywood and latewood?

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

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

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

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

answers: text: palms
question: Along with bamboo, what's the other monocot that's a major source of so-called "wood"?

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

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

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

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

answers: text: water-saturated
question: When wood is described as "green," what does "green" mean?

context: Wood density is determined by multiple growth and physiological factors compounded into “one fairly easily measured wood characteristic” (Elliott 1970).
qas: answers: text: physiological
question: Along with growth, what kind of factors determine the density of wood?

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

answers: text: Elliott
question: What author called wood's density "fairly easily measured"?

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

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

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

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

answers: text: seed
question: What tiny object's source plays a role in determining wood density?

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

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

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

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

answers: text: dicotyledons
question: What's the scientific name for trees like the oak with broad leaves?

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

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

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

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

answers: text: model building
question: What hobby is balsa wood often used for?

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

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

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

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

answers: text: magnesium
question: What element joins potassium, calcium, manganese, iron, and sodium to make a combined 1% of the chemical composition of wood?

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

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

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

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

answers: text: cellulose
question: Which of the three main components of wood is used to manufacture paper?

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

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

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

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

answers: text: Hardwood
question: Which kind of wood contains lignin derived from two main alcohol sources?

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

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

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

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

answers: text: turpentine
question: Along with tall oil and rosin, what commercial product do we get from wood's extractives?

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

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

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

answers: text: warmth
question: What benefit besides the cozy atmosphere would a wood-burning fireplace add to a home?

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

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

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

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

answers: text: houses
question: Other than boats, what do people often build with wood?

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

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

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

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

answers: text: Douglas fir
question: For modern solid wood doors, what wood is often used in addition to small-knotted pine or poplar?

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

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

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

answers: text: construction
question: What industry benefits greatly from engineered wood products?

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

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

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

answers: text: doors
question: Inside a building, what wooden things might you open to enter or leave rooms?

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

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

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

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

answers: text: veneers
question: Wood fibers from wood strands, lumber, and what other source can be glued together to make larger units?

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

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

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

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

answers: text: 100 million
question: About how many cubic meters of wood was used in 1991 to make products like glulam, LVL, and structural composite lumber?

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

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

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

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

answers: text: paper
question: What widely-used product is almost always made of wood fibers?

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

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

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

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

answers: text: chopsticks
question: What special wooden utensils do many people use to eat Chinese takeout?

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

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

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

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

answers: text: modify wood
question: In addition to extracting components from wood, what might scientist do by adding components, for example, to make innovative products?

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

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

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

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

answers: text: National Museum of Scotland
question: What museum exhibits the Millennium clock tower?

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

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

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

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

answers: text: tone
question: Along with resonance, what property of an instrument will be affected by the wood used to make it?

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

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

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

answers: text: reeds
question: What objects do musicians have to have in order to play woodwind instruments?

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

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

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

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

answers: text: fragile
question: Compared to hickory and ash, what adjective might be used for a maple baseball bat?

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

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

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

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

answers: text: fiberglass
question: What other modern material has joined composites, carbon fiber, titanium, and aluminum to replace wood in the manufacture of sporting equipment?

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

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

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

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

answers: text: Flavobacteria
question: What bacteria starting with the letter "F" were found in wood after it was underwater for more than a year?