derek-thomas/squad-v1.1-t5-question-generation huggingface dataset:
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.

Question: What type of "ultimate" strength is one of the two types increased the most by drying wood? Question: Is strength at elastic limit in endwise compression or stress at elastic limit in cross-bending increased more by drying wood? Question: Is the strength of the modulus of rupture or elasticity increased more when wood is dried? Question: What property of wood is least affected by drying?
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%).

Question: Along with hygroscopic, cellular, and anisotropic, how is the material of wood described? Question: What does wood consist of? Question: What part of wood's cells are composed of cellulose and hemicellulose? Question: What makes up 40-50% of the cell walls in wood? Question: What substance is hemicellulose impregnated with?
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.

Question: Are hardwood or softwood species more uniform in structure? Question: What type of cells makes up most wood cells in coniferous trees? Question: What are the visible vessels in hardwoods commonly called? Question: What hardwood that starts with the letter "O" would have pores? Question: Besides oak, what's an example of a hardwood with prominent pores?
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.

Question: Is the structure of hardwood simple or complex? Question: What handles most of the water conduction in hardwoods? Question: Are the vessels in chestnut wood large or small? Question: In wood from a willow tree, what would you need to use to see the tiny vessels? Question: Besides ring-porous, what's the other class hardwoods are often divided into?
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]

Question: What species of hardwood are hickory and mulberry trees? Question: In what season do the growth-rings of ring-porous species form with larger vessels localized? Question: In what season does the part of the growth-ring with smaller vessels form in ring-porous species? Question: What fibers does the summer's section of growth-ring have more of? Question: Along with strength, what property do wood fibers lend to wood?
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]

Question: What kind of woods have pores that are uniformly sized? Question: Is maple wood diffuse-porous or ring-porous? Question: What capability is spread through the growth ring in ring-porous species? Question: What species do aspen, cottonwood, and poplar trees belong to? Question: With walnut, what's another tree in the intermediate group?
In temperate softwoods there often is a marked difference between latewood and earlywood. The latewood will be denser than that formed early in the season. When examined under a microscope the cells of dense latewood are seen to be very thick-walled and with very small cell cavities, while those formed first in the season have thin walls and large cell cavities. The strength 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.

Question: What kind of softwoods often have significant differences in their earlywood and latewood? Question: Is latewood denser or less dense than earlywood? Question: What general size are the cavities in the cells of very dense latewood? Question: Are the cell walls of earlywood thick or thin? Question: Does strength come from the walls or cavities of wood cells?
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.

Question: Comparing a heavy and a lightweight piece of wood from a pine, which would have a greater proportion of latewood? Question: What feature of a piece of pine with more latewood would be more clear and pronounced? Question: What type of tree has very little contrast between parts of its growth rings? Question: Is white pine easy or difficult to work with because of its texture? Question: What kind of pines have very deep, darkly colored hardwood that stands out against the light earlywood?
It is not only the proportion of latewood, but also its quality, that counts. In specimens that show a very large proportion of latewood it may be noticeably more porous and weigh considerably less than the latewood in pieces that contain but little. One can judge comparative density, and therefore to some extent strength, by visual inspection.

Question: Having a high proportion of latewood isn't all that matters; what else is important? 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? Question: What can we judge in wood just by looking at it? Question: What property of wood could we project some indication of by looking at its density?
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.

Question: What counterpart of earlywood are scientists still trying to explain the formation of? Question: What species of tree can be said to growth ring proportions that aren't determined just by their rate of growth? Question: What facet of wood is affected to some degree by the place where the tree grows? Question: While there is some relationship between where and how a tree grows, what can't anyone formulate to govern it? Question: If you want wood that's easy to work with, what kind of growth would you want the tree to have?
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.

Question: What kind of woods always have very clearly marked seasonal growth? Question: What size pores form early in ring-porous woods' growing season? Question: When does the denser tissue the new pores abut come from?
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.

Question: Ring-porous hardwoods have a clear relationship between their properties and what other factor? Question: If the growth rings are wider, was the growth of the tree slower or more rapid? Question: Is harder, heavier wood indicated by narrower or wider growth rings? Question: What is the only kind of wood that will definitely be harder and stronger when it grows faster? Question: What kind of wood with a name that starts with "H" is a ring-porous hardwood?
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.

Question: Which specific type of wood within ring-porous woods have more fibers to make it strong? Question: When there is less latewood, what is diminishing? Question: Does slow or rapid growth make relatively porous, light wood? Question: What kind of oak has just 6-10% volume of large vessels in the log? Question: What kind of fibers are in the latewood of good oak, making it very firm?
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:

Question: What term is sometimes used for wood with wide rings? Question: Do young trees grow more quickly in open stands or in a closed forest? Question: What property is important to manufacturers who use "second-growth" hardwood? Question: What specific kind of "second-growth" hardwood is often used to make handles and spokes? Question: What organization tested hickory to find out about its properties?
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.

Question: What kind of wood often has ring divisions that can't even be seen by looking at it? Question: What adjective describes how our eyes function without a tool like a microscope to help? Question: In diffuse-porous woods, if the demarcation between rings is obvious, what type of difference within the ring might not be?
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.

Question: What kind of wood has all similarly sized vessels? Question: The capability of diffuse-porous woods to carry what substance is spread out in the growth ring? Question: What division of trees are diffuse-porous woods more similar in growth rate to than ring-porous woods? Question: What rate of growth in a tree will make the wood from it stronger than trees that grow very slowly or very quickly? Question: Does uniformity of the texture and grain of wood usually result from much or little contrast between earlywood and latewood?
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.

Question: What's another term used for "conifer" wood? Question: What type of plants produce material that is referred to as "wood" even though it is technically not? Question: What monocot plant produces "wood" by the same name that's often used for flooring and veneer? Question: While we call bamboo "wood," what botanical family does it belong to? Question: Along with bamboo, what's the other monocot that's a major source of so-called "wood"?
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).

Question: Which property of wood reveals the most about its quality? Question: In addition to lumber strength, what important indicator of wood's quality can be determined using specific gravity? Question: What measurement is expressed in mass per unit substance? Question: When wood dries and shrinks, what happens to its density? Question: When wood is described as "green," what does "green" mean?
Wood density is determined by multiple growth and physiological factors compounded into “one fairly easily measured wood characteristic” (Elliott 1970).

Question: Along with growth, what kind of factors determine the density of wood? Question: Into how many characteristics are the factors of wood combined? Question: What author called wood's density "fairly easily measured"?
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. :)

Question: What specific type of growth has an effect on the density of wood? Question: What tiny object's source plays a role in determining wood density? Question: What should be anticipated because of the many factors that influence wood's density? Question: Variation in what measurement is sometimes greater within one tree than from one tree to another? Question: Which part of a tree can have vertical or horizontal variation in its specific gravity?
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.

Question: What term do we use for the wood that comes from pine trees? Question: What's the scientific name for trees like the oak with broad leaves? Question: What kind of wood does an oak tree have? Question: Is balsa a softwood or a hardwood? Question: What's an example of a softwood that isn't "soft," and is actually harder than a lot of hardwoods?
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.

Question: What kind of relationship exists between a tree's properties and its wood's properties? Question: What property of wood varies according to species? Question: What property of wood has a correlation to its density? Question: Is mahogany a hardwood or a softwood? Question: What hobby is balsa wood often used for?
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.

Question: What approximate percentage of carbon does wood have? Question: Which element in wood composes about 42% of its weight? Question: What element makes up about 6% of the chemical composition of wood? Question: About what percentage of wood is composed of nitrogen? Question: What element joins potassium, calcium, manganese, iron, and sodium to make a combined 1% of the chemical composition of wood?
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.

Question: How many main components make up wood, not counting water? Question: What's the name for the crystalline polymer derived from glucose? Question: After cellulose, what component is most plentiful in wood? Question: What kind of trees have about 30% hemicellulose? Question: Which of the three main components of wood is used to manufacture paper?
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.

Question: What component of wood determines whether it is hardwood or softwood? Question: Which kind of wood contains lignin derived from two main alcohol sources? Question: In addition to coniferyl alcohol, what other alcohol is in hardwood lignin? Question: Which wood has lignin that comes primarily from one type of alcohol? Question: Which type of alcohol mainly becomes softwood lignin?
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.

Question: What's the name for the low molecular weight organic compounds in wood? Question: Along with fatty acids, what kind of acids are in the extractives in wood? Question: Wood extractives include resin and fatty acids, terpenes, and what other component? Question: What do conifers use rosin to protect themselves from? Question: Along with tall oil and rosin, what commercial product do we get from wood's extractives?
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.

Question: What type of areas use more wood for fuel? Question: What type of wood is preferred as fuel? Question: What type of wood burns quickly and makes more smoke than hardwood? Question: What benefit besides the cozy atmosphere would a wood-burning fireplace add to a home?
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).

Question: What significant purpose has wood been used for as long as humans have built shelters? Question: Other than boats, what do people often build with wood? Question: Until the late 19th century, what vessels were almost always wooden? Question: What wood is decay-resistant when wet? Question: What plumbing component was once made out of elm?