Editing Wood (section)

==Physical properties==
[[File:Tree secondary growth diagram.svg|thumb|Diagram of [[secondary growth]] in a [[tree]] showing idealized vertical and horizontal sections. A new layer of wood is added in each growing season, thickening the stem, existing branches and [[root]]s, to form a [[growth ring]].]]

===Growth rings===
{{see also|Dendrochronology#Growth rings}}

Wood, in the strict sense, is yielded by [[tree]]s, which increase in [[diameter]] by the formation, between the existing wood and the inner [[Bark (botany)|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. These cells then go on to form thickened secondary cell walls, composed mainly of [[cellulose]], [[hemicellulose]] and [[lignin]].

Where the differences between the seasons are distinct, e.g. [[New Zealand]], growth can occur in a discrete annual or seasonal pattern, leading to [[growth ring]]s; these can usually be most clearly seen on the end of a log, but are also visible on the other surfaces. If the distinctiveness between seasons is annual (as is the case in equatorial regions, e.g. [[Singapore]]), these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are likely to be indistinct or absent.  If the bark of the tree has been removed in a particular area, the rings will likely be deformed as the plant overgrows the scar.

If there are differences within a growth ring, then the part of a growth ring nearest the center of the tree, and formed early in the growing season when growth is rapid, is usually composed of wider elements. It is usually lighter in color than that near the outer portion of the ring, and is known as earlywood or springwood. The outer portion formed later in the season is then known as the latewood or summerwood.<ref>[http://www.farmforestline.com.au/pages/2.1.2.1_wood.html Wood growth and structure] {{webarchive|url=https://web.archive.org/web/20091212121121/http://farmforestline.com.au/pages/2.1.2.1_wood.html |date=December 12, 2009 }} www.farmforestline.com.au</ref> There are major differences, depending on the kind of wood. If a tree grows all its life in the open and the conditions of [[soil]] and site remain unchanged, it will make its most rapid growth in youth, and gradually decline. The annual rings of growth are for many years quite wide, but later they become narrower and narrower. Since each succeeding ring 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 [[oak]]s, maintain the same width of ring for hundreds of years. On the whole, as a tree gets larger in diameter the width of the growth rings decreases.

===Knots===
<!--[[Wood knot]] and [[Knot (wood)]] redirect directly here.-->
[[File:TreeKnot.jpg|thumb|left|A knot on a tree trunk]]

As a tree grows, lower branches often die, and their bases may become overgrown and enclosed by subsequent layers of trunk wood, forming a type of imperfection known as a knot. The dead branch may not be attached to the trunk wood except at its base and can drop out after the tree has been sawn into boards. Knots affect the technical properties of the wood, usually reducing tension strength,<ref>{{cite book |last1=Everett |first1=Alan |last2=Barritt |first2=C. M. H. |title=Materials |date=12 May 2014 |publisher=Routledge |isbn=978-1-317-89327-1 |page=38 |url=https://books.google.com/books?id=ncCOAwAAQBAJ&pg=PT38 |language=en |access-date=March 20, 2023 |archive-date=September 8, 2023 |archive-url=https://web.archive.org/web/20230908234050/https://books.google.com/books?id=ncCOAwAAQBAJ&pg=PT38 |url-status=live }} "Knots, particularly edge and arris knots, reduce strength mainly in tension, but not in resistance to shear and splitting."</ref> 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 [[wood grain|grain]] of the rest of the wood "flows" (parts and rejoins). Within a knot, the direction of the wood (grain direction) is up to 90 degrees different from the grain direction of the regular wood.

In the tree a knot is either the base of a side [[branch]] or a dormant bud. A knot (when the base of a side branch) is conical in shape (hence the roughly circular cross-section) with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud.

In grading [[lumber]] and structural [[timber]], knots are classified according to their form, size, soundness, and the firmness with which they are held in place. This firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow.

[[File:Wood Knot.JPG|thumb|upright|Wood knot in vertical section]]
{{blockquote|''Knots materially affect cracking and warping, ease in working, and cleavability of timber. They are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. The weakening effect is much more serious when timber is subjected to forces perpendicular to the grain and/or [[tension (physics)|tension]] than when under load along the grain and/or [[physical compression|compression]]. The extent to which knots affect the strength of a [[beam (structure)|beam]] depends upon their position, size, number, and condition. A knot on the upper side is compressed, while one on the lower side is subjected to tension. If there is a season check in the knot, as is often the case, it will offer little resistance to this tensile stress.  Small knots may be located along the neutral plane of a beam and increase the strength by preventing longitudinal [[shear stress|shearing]]. Knots in a board or plank are least injurious when they extend through it at right angles to its broadest surface. Knots which occur near the ends of a beam do not weaken it. Sound knots which occur in the central portion one-fourth the height of the beam from either edge are not serious defects.''|Samuel J. Record|The Mechanical Properties of Wood<ref name="Record-1914">{{cite book
 |last = Record
 |first = Samuel J
 |title = The Mechanical Properties of Wood
 |publisher = J. Wiley & Sons
 |year = 1914
 |page = 165
 |url = https://www.gutenberg.org/ebooks/12299
 |asin = B000863N3W
 |asin-tld = co.uk
 |access-date = August 28, 2020
 |archive-date = October 18, 2020
 |archive-url = https://web.archive.org/web/20201018011708/http://www.gutenberg.org/ebooks/12299
 |url-status = live
 }}</ref>}}

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.

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)|primer]] paint or solution (knotting), 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.

===Heartwood and sapwood===<!-- [[Sapwood]] and [[Heartwood]] redirect here -->
{{Redirect|Heartwood}}
{{Redirect|Sapwood|the missile also called "SS-6 Sapwood"|R7 Semyorka}}
{{see also|Trunk (botany)}}
[[File:Taxus wood.jpg|thumb|right|A section of a [[Taxus|yew]] branch showing 27 annual growth rings, pale sapwood, dark heartwood, and [[pith]] (center dark spot). The dark radial lines are small knots.]]
'''Heartwood''' (or duramen<ref name="Britannica-1911">{{Cite EB1911|wstitle=Duramen|volume=8|page=692|short=y}}</ref>) is wood that as a result of a naturally occurring chemical transformation has become more resistant to decay. Heartwood formation is a genetically programmed process that occurs spontaneously. Some uncertainty exists as to whether the wood dies during heartwood formation, as it can still chemically react to decay organisms, but only once.<ref>Shigo, Alex. (1986) ''A New Tree Biology Dictionary''. Shigo and Trees, Associates. {{ISBN|0-943563-12-7}}</ref>

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 tree|ash]], [[hickory]], [[Celtis|hackberry]], [[beech]], and pine, thick sapwood is the rule.<ref>{{Cite book|url=https://archive.org/details/mechanicalprope02recogoog|page=[https://archive.org/details/mechanicalprope02recogoog/page/n70 51]|quote=The term heartwood derives solely from its position and not from any vital importance to the tree as a tree can thrive with heart completely decayed.|title=The Mechanical Properties of Wood: Including a Discussion of the Factors Affecting the Mechanical Properties, and Methods of Timber Testing|last=Record|first=Samuel James|date=1914|publisher=J. Wiley & Sons, Incorporated|language=en|df=mdy-all}}</ref> Some others never form heartwood.

Heartwood is often visually distinct from the living sapwood and can be distinguished in a cross-section where the boundary will tend to follow the growth rings. For example, it is sometimes much darker. Other processes such as decay or insect invasion can also discolor wood, even in woody plants that do not form heartwood, which may lead to confusion.

'''Sapwood''' (or alburnum<ref name="Alburnum-1911">{{Cite EB1911|wstitle=Alburnum|volume=1|page=516|short=y}}</ref>) is the younger, outermost wood; in the growing tree it is living wood,<ref>Capon, Brian (2005), Botany for Gardeners (2nd ed.), Portland, OR: Timber Publishing, p. 65 {{ISBN|0-88192-655-8}}</ref> and its principal functions are to conduct water from the [[root]]s to the [[leaf|leaves]] and to store up and give back according to the season the reserves prepared in the leaves. By the time they become competent to conduct water, all xylem tracheids and vessels have lost their cytoplasm and the cells are therefore functionally dead. All wood in 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, {{convert|30|cm|abbr=on}} or more in diameter, before any heartwood begins to form, for example, in second growth [[hickory]], or open-grown [[pine]]s.
[[File:Cross-section of an Oak Log Showing Growth Rings.jpg|thumb|Cross-section of an oak log showing growth rings]]

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 relatively 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.

When a tree is very young it is covered with limbs almost, if not entirely, to the ground, but as it grows older some or all of them will eventually die and are either broken off or fall off. Subsequent growth of wood may completely conceal the stubs which will remain as knots. No matter how smooth and clear 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.

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 of materials|strength]], and toughness to equally sound heartwood from the same log. In a smaller tree, the reverse may be true.

===Color===
[[File:Sequoia wood.jpg|thumb|The wood of [[Sequoia sempervirens|coast redwood]] is distinctively red.]]
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 variation does not imply a significant difference in the mechanical properties of heartwood and sapwood, although there may be a marked biochemical difference between the two.

Some experiments on very resinous [[longleaf pine]] specimens indicate an increase in strength, due to 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 [[termite]]s, and very flammable. [[Tree stump]]s 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.

Since the latewood of a growth ring is usually darker in color than the earlywood, this fact may be used in visually judging the density, and therefore the hardness and strength of the material. This is particularly the case with coniferous woods. In ring-porous woods the vessels of the early wood often appear on a finished surface as darker than the denser latewood, though on cross sections of heartwood the reverse is commonly true. Otherwise the color of wood is no indication of strength.

Abnormal discoloration of wood often denotes a diseased condition, indicating unsoundness. The black check in western [[Tsuga|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 [[wood-decay fungus|rot-producing fungi]] impart to wood characteristic colors which thus become symptomatic of weakness. Ordinary sap-staining is due to fungal growth, but does not necessarily produce a weakening effect.

===Water content===
Water occurs in living wood in three locations, namely:
* in the [[cell wall]]s
* in the [[protoplasm]]ic contents of the [[cell (biology)|cells]]
* as free water in the cell cavities and spaces, especially of the xylem
[[File:Hailwood-Horrobin EMC graph.svg|thumb|Equilibrium moisture content in wood.]]
In heartwood it occurs only in the first and last forms. Wood that is thoroughly air-dried (in [[Equilibrium moisture content#Equilibrium moisture content of wood|equilibrium]] with the moisture content of the air) retains 8–16% of the water in the cell walls, and none, or practically none, in the other forms. Even oven-dried wood retains a small percentage of moisture, but for all except chemical purposes, may be considered absolutely dry.

The general effect of the [[Water content#Wood moisture measurement|water content]] upon the wood substance is to render it softer and more pliable. A similar effect occurs in the softening action of water on rawhide, paper, or cloth. Within certain limits, the greater the water content, the greater its softening effect. The moisture in wood can be measured by several different [[moisture meter]]s.

[[Wood drying|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&nbsp;cm in section, which will sustain a permanent load four times as great as a green (undried) block of the same size will.

The greatest strength increase due to drying is in the ultimate crushing strength, and strength at [[yield (engineering)|elastic limit]] in endwise compression; these are followed by the modulus of rupture, and stress at elastic limit in cross-bending, while the [[elastic modulus|modulus of elasticity]] is least affected.<ref name="Record-1914"/>

===Structure===
[[File:BlkWalnut-x-section.jpg|thumb|upright|Magnified cross-section of [[Juglans nigra|black walnut]], showing the vessels, rays (white lines) and annual rings: this is intermediate between diffuse-porous and ring-porous, with vessel size declining gradually]]
Wood is a [[heterogeneous]], [[hygroscopic]], [[cell (biology)|cellular]] and [[anisotropy|anisotropic]] (or more specifically, [[Orthotropic material|orthotropic]]) 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%).<ref>{{cite web|url=http://treetesting.com/wood_properties_growth_and_structure.htm|title=Wood Properties Growth and Structure 2015|work=treetesting.com|url-status=live|archive-url=https://web.archive.org/web/20160313044617/http://treetesting.com/wood_properties_growth_and_structure.htm|archive-date=March 13, 2016|df=mdy-all}}</ref>

In coniferous or [[softwood]] species the wood cells are mostly of one kind, [[tracheid]]s, and as a result the material is much more uniform in structure than that of most [[hardwood]]s. There are no vessels ("pores") in coniferous wood such as one sees so prominently in oak and ash, for example.

The structure of hardwoods is more complex.<ref>{{cite web|url=https://nationalvetcontent.edu.au/alfresco/d/d/workspace/SpacesStore/b2f0fcee-47cb-4650-b248-f533d73d5428/13_05/toolbox13_05/unit9_selecting_timber/section2_characteristics/lesson2_hardwood.htm|title=Timber Plus Toolbox, Selecting timber, Characteristics of timber, Structure of hardwoods|work=nationalvetcontent.edu.au|url-status=dead|archive-url=https://web.archive.org/web/20140810184152/https://nationalvetcontent.edu.au/alfresco/d/d/workspace/SpacesStore/b2f0fcee-47cb-4650-b248-f533d73d5428/13_05/toolbox13_05/unit9_selecting_timber/section2_characteristics/lesson2_hardwood.htm|archive-date=August 10, 2014|df=mdy-all}}</ref> The water conducting capability is mostly taken care of by [[vessel element|vessels]]: in some cases (oak, chestnut, ash) these are quite large and distinct, in others ([[Aesculus|buckeye]], [[Populus|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''.<ref name="Sperry-1994">{{cite journal |last=Sperry |first=John S. |author2=Nichols, Kirk L. |author3=Sullivan, June E. |author4=Eastlack, Sondra E. |title=Xylem Embolism in ring-porous, diffuse-porous, and coniferous trees of Northern Utah and Interior Alaska |journal=Ecology |date=1994 |volume=75 |issue=6 |pages=1736–1752 |jstor=1939633 |doi=10.2307/1939633 |bibcode=1994Ecol...75.1736S |url=http://bioweb.biology.utah.edu/sperry/publications/Sperry%20et%20al.%201994%20Ecology.pdf |access-date=November 30, 2018 |archive-date=August 10, 2017 |archive-url=https://web.archive.org/web/20170810100919/http://bioweb.biology.utah.edu/sperry/publications/Sperry%20et%20al.%201994%20Ecology.pdf |url-status=dead }}</ref>

In ring-porous species, such as ash, black locust, [[catalpa]], chestnut, [[elm]], hickory, [[mulberry]], and oak,<ref name="Sperry-1994"/> the larger vessels or pores (as cross sections of vessels are called) are localized in the part of the growth ring formed in spring, thus forming a region of more or less open and porous tissue. The rest of the ring, produced in summer, is made up of smaller vessels and a much greater proportion of wood fibers. These fibers are the elements which give strength and toughness to wood, while the vessels are a source of weakness.<ref>{{cite book |last1=Record |first1=Samuel James |title=The Mechanical Properties of Wood, Including a Discussion of the Factors Affecting the Mechanical Properties, and Methods of Timber Testing |date=1914 |publisher=J. Wiley & sons, Incorporated |url=https://books.google.com/books?id=IbjPAAAAMAAJ&pg=PA44 |language=en |access-date=March 20, 2023 |archive-date=September 8, 2023 |archive-url=https://web.archive.org/web/20230908234053/https://books.google.com/books?id=IbjPAAAAMAAJ&pg=PA44 |url-status=live }}</ref>

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 [[Alnus|alder]],<ref name="Sperry-1994"/> [[Tilia|basswood]],<ref name="SJRecord-1914">{{cite book|author=Samuel James Record|title=The mechanical properties of wood, including a discussion of the factors affecting the mechanical properties, and methods of timber testing|url=https://archive.org/details/mechanicalprope01recogoog|year=1914|publisher=J. Wiley & sons, inc.|pages=[https://archive.org/details/mechanicalprope01recogoog/page/n63 44]–|df=mdy-all}}</ref> [[birch]],<ref name="Sperry-1994"/> buckeye, maple, [[willow]], and the ''[[Populus]]'' species such as aspen, cottonwood and poplar.<ref name="Sperry-1994"/> Some species, such as [[Juglans nigra|walnut]] and [[Prunus pumila|cherry]], are on the border between the two classes, forming an intermediate group.<ref name="SJRecord-1914"/>

===Earlywood and latewood===

====In softwood====
[[File:Wood Pseudotsuga taxifolia.jpg|thumb|left|upright|Earlywood and latewood in a softwood; radial view, growth rings closely spaced in [[Pseudotsuga menziesii var. glauca|Rocky Mountain Douglas-fir]]]]
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.

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 [[Pinus classification|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 [[Pinus classification|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.

It is not only the proportion of latewood, but also its quality, that counts. In specimens that show a very large proportion of latewood it may be noticeably more porous and weigh considerably less than the latewood in pieces that contain less latewood. One can judge comparative density, and therefore to some extent strength, by visual inspection.

No satisfactory explanation can as yet be given for 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, where strength or ease of working is essential, woods of moderate to slow growth should be chosen.

====In ring-porous woods====
[[File:Wood Fraxinus excelsior.jpg|thumb|upright|Earlywood and latewood in a ring-porous wood (ash) in a ''[[Fraxinus excelsior]]''; tangential view, wide growth rings]]
In ring-porous woods, each season's growth is always well defined, because the large pores formed early in the season abut on the denser tissue of the year before.

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

In ring-porous woods of good growth, it is usually the latewood in which the thick-walled, strength-giving fibers are most abundant. As the breadth of ring diminishes, this latewood is reduced so that very slow growth produces comparatively light, porous wood composed of thin-walled vessels and wood parenchyma. In good oak, these large vessels of the earlywood occupy from six to ten percent of the volume of the log, while in inferior material they may make up 25% or more. The latewood of good oak is dark colored and firm, and consists mostly of thick-walled fibers which form one-half or more of the wood. In inferior oak, this latewood is much reduced both in quantity and quality. Such variation is very largely the result of rate of growth.

Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in 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 [[spoke]]s. Here not only strength, but toughness and resilience are important.<ref name="Record-1914"/>

The results of a series of tests on hickory by the U.S. Forest Service show that:
:"The work or shock-resisting ability is greatest in wide-ringed wood that has from 5 to 14 rings per inch (rings 1.8-5 mm thick), is fairly constant from 14 to 38 rings per inch (rings 0.7–1.8 mm thick), and decreases rapidly from 38 to 47 rings per inch (rings 0.5–0.7 mm thick). The strength at maximum load is not so great with the most rapid-growing wood; it is maximum with from 14 to 20 rings per inch (rings 1.3–1.8 mm thick), and again becomes less as the wood becomes more closely ringed. The natural deduction is that wood of first-class mechanical value shows from 5 to 20 rings per inch (rings 1.3–5 mm thick) and that slower growth yields poorer stock. Thus the inspector or buyer of hickory should discriminate against timber that has more than 20 rings per inch (rings less than 1.3 mm thick). Exceptions exist, however, in the case of normal growth upon dry situations, in which the slow-growing material may be strong and tough."<ref name="USDA_FPL-2007">U.S. Department of Agriculture, Forest Products Laboratory. ''[http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm The Wood Handbook: Wood as an engineering material] {{webarchive|url=https://web.archive.org/web/20070315214043/http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm |date=March 15, 2007 }}''. General Technical Report 113. Madison, WI.</ref>

The effect of rate of growth on the qualities of chestnut wood is summarized by the same authority as follows:

:"When the rings are wide, the transition from spring wood to summer wood is gradual, while in the narrow rings the spring wood passes into summer wood abruptly. The width of the spring wood changes but little with the width of the annual ring, so that the narrowing or broadening of the annual ring is always at the expense of the summer wood. The narrow vessels of the summer wood make it richer in wood substance than the spring wood composed of wide vessels. Therefore, rapid-growing specimens with wide rings have more wood substance than slow-growing trees with narrow rings. Since the more the wood substance the greater the weight, and the greater the weight the stronger the wood, chestnuts with wide rings must have stronger wood than chestnuts with narrow rings. This agrees with the accepted view that sprouts (which always have wide rings) yield better and stronger wood than seedling chestnuts, which grow more slowly in diameter."<ref name="USDA_FPL-2007"/>

====In diffuse-porous woods====
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.

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.

===Monocots===
[[File:Gelugu (coconut wood) in Klaten, Java.jpg|thumb|Trunks of the [[coconut]] palm, a monocot, in [[Java]]. From this perspective these look not much different from trunks of a [[dicot]] or [[conifer]]]]
Structural material that resembles ordinary, "dicot" or conifer timber in its gross handling characteristics is produced by a number of [[monocotyledon|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 and in the manufacture of engineered flooring, panels and [[Wood veneer|veneer]]. Another major plant group that produces material that often is called wood are the [[Arecaceae|palms]]. Of much less importance are plants such as ''[[Pandanus]],'' ''[[Dracaena (plant)|Dracaena]]'' and ''[[Cordyline]].'' With all this material, the structure and composition of the processed raw material is quite different from ordinary wood.

===Specific gravity===
The single most revealing property of wood as an indicator of wood quality is [[Relative density|specific gravity]] (Timell 1986),<ref name="Timell-1986">Timell, T.E. 1986. Compression wood in gymnosperms. Springer-Verlag, Berlin. 2150 p.</ref> 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 milliliter (g/cm<sup>3</sup> 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).<ref name="Timell-1986" />

The U.S. [[Forest Products Laboratory]] lists a variety of ways to define specific gravity (G) and density (ρ) for wood:<ref>{{Cite web |title=Wood Handbook: Chapter 4: Moisture Relations and Physical Properties of Wood |url=https://www.fpl.fs.usda.gov/documnts/fplgtr/fplgtr282/chapter_04_fpl_gtr282.pdf |publisher=U.S. Forest Products Laboratory |access-date=September 10, 2023 |archive-date=December 30, 2023 |archive-url=https://web.archive.org/web/20231230131945/https://www.fpl.fs.usda.gov/documnts/fplgtr/fplgtr282/chapter_04_fpl_gtr282.pdf |url-status=live }}</ref>
{| class="wikitable"
!Symbol
!Mass basis
!Volume basis
|-
|G<sub>0</sub>
|Ovendry
|Ovendry
|-
|G<sub>b</sub> (basic)
|Ovendry
|Green
|-
|G<sub>12</sub>
|Ovendry
|12% MC
|-
|G<sub>x</sub>
|Ovendry
|x% MC
|-
|ρ<sub>0</sub>
|Ovendry
|Ovendry
|-
|ρ<sub>12</sub>
|12% MC
|12% MC
|-
|ρ<sub>x</sub>
|x% MC
|x% MC
|}
The FPL has adopted G<sub>b</sub> and G<sub>12</sub> for specific gravity, in accordance with the [[ASTM International|ASTM]] D2555<ref>{{Cite web |title=Standard Practice for Establishing Clear Wood Strength Values |url=https://www.astm.org/d2555-17a.html |access-date=2023-09-09 |website=www.astm.org |language=en |archive-date=April 1, 2023 |archive-url=https://web.archive.org/web/20230401232343/https://www.astm.org/d2555-17a.html |url-status=live }}</ref> standard. These are scientifically useful, but don't represent any condition that could physically occur. The FPL Wood Handbook also provides formulas for approximately converting any of these measurements to any other.

===Density===

{{See also|Janka hardness test}}

Wood density is determined by multiple growth and physiological factors compounded into "one fairly easily measured wood characteristic" (Elliott 1970).<ref name="Elliott-1970">Elliott, G.K. 1970. Wood density in conifers. Commonwealth For. Bureau, Oxford, U.K., Tech. Commun. 8. 44 p.</ref>

Age, diameter, height, radial (trunk) growth, geographical location, site and growing conditions, [[silviculture|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).<ref name="Timell-1986" /> Variation of specific gravity within the [[trunk (botany)|bole]] of a tree can occur in either the horizontal or vertical direction.

Because the specific gravity as defined above uses an unrealistic condition, woodworkers tend to use the "average dried weight", which is a density based on mass at 12% moisture content and volume at the same (ρ<sub>12</sub>). This condition occurs when the wood is at equilibrium moisture content with air at about 65% relative humidity and temperature at 30&nbsp;°C (86&nbsp;°F). This density is expressed in units of kg/m<sup>3</sup> or lbs/ft<sup>3</sup>.

===Tables===
The following tables list the mechanical properties of wood and lumber plant species, including bamboo. See also [[Tonewood#Mechanical properties of tonewoods|Mechanical properties of tonewoods]] for additional properties.

Wood properties:<ref>{{Cite tech report |first=D.W. |last=Green |first2=J.E. |last2=Winandy |first3=D.E. |last3=Kretschmann |chapter=4. Mechanical Properties of Wood |chapter-url=https://www.fpl.fs.usda.gov/documnts/fplgtr/fplgtr113/ch04.pdf |title=Wood handbook: Wood as an engineering material |publisher=U.S. Department of Agriculture, Forest Service, Forest Products Laboratory |year=1999 |id=FPL–GTR–113 |pages=463 |url=https://www.fs.usda.gov/research/treesearch/5734 |doi=10.2737/FPL-GTR-113|hdl=2027/mdp.39015000158041 |hdl-access=free }}</ref><ref name="pfaf-2019" />
{|class="wikitable mw-collapsible mw-collapsed sortable"
!'''Common name'''
!'''Scientific name'''
!'''Moisture content'''
!'''Density (kg/m<sup>3</sup>)'''
!'''Compressive strength (megapascals)'''
!'''Flexural strength (megapascals)'''
|-
|Red Alder
|''[[Alnus rubra]]''
|Green
|370
|20.4
|45
|-
|Red Alder
|''[[Alnus rubra]]''
|12.00%
|410
|40.1
|68
|-
|Black Ash
|''[[Fraxinus nigra]]''
|Green
|450
|15.9
|41
|-
|Black Ash
|''[[Fraxinus nigra]]''
|12.00%
|490
|41.2
|87
|-
|Blue Ash
|''[[Fraxinus quadrangulata]]''
|Green
|530
|24.8
|66
|-
|Blue Ash
|''[[Fraxinus quadrangulata]]''
|12.00%
|580
|48.1
|95
|-
|Green Ash
|''[[Fraxinus pennsylvanica]]''
|Green
|530
|29
|66
|-
|Green Ash
|''[[Fraxinus pennsylvanica]]''
|12.00%
|560
|48.8
|97
|-
|Oregon Ash
|''[[Fraxinus latifolia]]''
|Green
|500
|24.2
|52
|-
|Oregon Ash
|''[[Fraxinus latifolia]]''
|12.00%
|550
|41.6
|88
|-
|White Ash
|''[[Fraxinus americana]]''
|Green
|550
|27.5
|66
|-
|White Ash
|''[[Fraxinus americana]]''
|12.00%
|600
|51.1
|103
|-
|Bigtooth Aspen
|''[[Populus grandidentata]]''
|Green
|360
|17.2
|37
|-
|Bigtooth Aspen
|''[[Populus grandidentata]]''
|12.00%
|390
|36.5
|63
|-
|Quaking Aspen
|''[[Populus tremuloides]]''
|Green
|350
|14.8
|35
|-
|Quaking Aspen
|''[[Populus tremuloides]]''
|12.00%
|380
|29.3
|58
|-
|American Basswood
|''[[Tilia americana]]''
|Green
|320
|15.3
|34
|-
|American Basswood
|''[[Tilia americana]]''
|12.00%
|370
|32.6
|60
|-
|American Beech
|''[[Fagus grandifolia]]''
|Green
|560
|24.5
|59
|-
|American Beech
|''[[Fagus grandifolia]]''
|12.00%
|640
|50.3
|103
|-
|Paper Birch
|''[[Betula papyrifera]]''
|Green
|480
|16.3
|44
|-
|Paper Birch
|''[[Betula papyrifera]]''
|12.00%
|550
|39.2
|85
|-
|Sweet Birch
|''[[Betula lenta]]''
|Green
|600
|25.8
|65
|-
|Sweet Birch
|''[[Betula lenta]]''
|12.00%
|650
|58.9
|117
|-
|Yellow Birch
|''[[Betula alleghaniensis]]''
|Green
|550
|23.3
|57
|-
|Yellow Birch
|''[[Betula alleghaniensis]]''
|12.00%
|620
|56.3
|114
|-
|Butternut
|''[[Juglans cinerea]]''
|Green
|360
|16.7
|37
|-
|Butternut
|''[[Juglans cinerea]]''
|12.00%
|380
|36.2
|56
|-
|Black Cherry
|''[[Prunus serotina]]''
|Green
|470
|24.4
|55
|-
|Blach Cherry
|''[[Prunus serotina]]''
|12.00%
|500
|49
|85
|-
|American Chestnut
|''[[American chestnut|Castanea dentata]]''
|Green
|400
|17
|39
|-
|American Chestnut
|''[[American chestnut|Castanea dentata]]''
|12.00%
|430
|36.7
|59
|-
|Balsam Poplar Cottonwood
|''[[Populus balsamifera]]''
|Green
|310
|11.7
|27
|-
|Balsam Poplar Cottonwood
|''[[Populus balsamifera]]''
|12.00%
|340
|27.7
|47
|-
|Black Cottonwood
|''[[Populus trichocarpa]]''
|Green
|310
|15.2
|34
|-
|Black Cottonwood
|''[[Populus trichocarpa]]''
|12.00%
|350
|31
|59
|-
|Eastern Cottonwood
|''[[Populus deltoides]]''
|Green
|370
|15.7
|37
|-
|Eastern Cottonwood
|''[[Populus deltoides]]''
|12.00%
|400
|33.9
|59
|-
|American Elm
|''[[Ulmus americana]]''
|Green
|460
|20.1
|50
|-
|American Elm
|''[[Ulmus americana]]''
|12.00%
|500
|38.1
|81
|-
|Rock Elm
|''[[Ulmus thomasii]]''
|Green
|570
|26.1
|66
|-
|Rock Elm
|''[[Ulmus thomasii]]''
|12.00%
|630
|48.6
|102
|-
|Slippery Elm
|''[[Ulmus rubra]]''
|Green
|480
|22.9
|55
|-
|Slippery Elm
|''[[Ulmus rubra]]''
|12.00%
|530
|43.9
|90
|-
|Hackberry
|''[[Celtis occidentalis]]''
|Green
|490
|18.3
|45
|-
|Hackberry
|''[[Celtis occidentalis]]''
|12.00%
|530
|37.5
|76
|-
|Bitternut Hickory
|''[[Carya cordiformis]]''
|Green
|600
|31.5
|71
|-
|Bitternut Hickory
|''[[Carya cordiformis]]''
|12.00%
|660
|62.3
|118
|-
|Nutmeg Hickory
|''[[Carya myristiciformis]]''
|Green
|560
|27.4
|63
|-
|Nutmeg Hickory
|''[[Carya myristiciformis]]''
|12.00%
|600
|47.6
|114
|-
|Pecan Hickory
|''[[Carya illinoinensis]]''
|Green
|600
|27.5
|68
|-
|Pecan Hickory
|''[[Carya illinoinensis]]''
|12.00%
|660
|54.1
|94
|-
|Water Hickory
|''[[Carya aquatica]]''
|Green
|610
|32.1
|74
|-
|Water Hickory
|''[[Carya aquatica]]''
|12.00%
|620
|59.3
|123
|-
|Mockernut Hickory
|''[[Carya tomentosa]]''
|Green
|640
|30.9
|77
|-
|Mockernut Hickory
|''[[Carya tomentosa]]''
|12.00%
|720
|61.6
|132
|-
|Pignut Hickory
|''[[Carya glabra]]''
|Green
|660
|33.2
|81
|-
|Pignut Hickory
|''[[Carya glabra]]''
|12.00%
|750
|63.4
|139
|-
|Shagbark Hickory
|''[[Carya ovata]]''
|Green
|640
|31.6
|76
|-
|Shagbark Hickory
|''[[Carya ovata]]''
|12.00%
|720
|63.5
|139
|-
|Shellbark Hickory
|''[[Carya laciniosa]]''
|Green
|620
|27
|72
|-
|Shellbark Hickory
|''[[Carya laciniosa]]''
|12.00%
|690
|55.2
|125
|-
|Honeylocust
|''[[Gleditsia triacanthos]]''
|Green
|600
|30.5
|70
|-
|Honeylocust
|''[[Gleditsia triacanthos]]''
|12.00%
|600
|51.7
|101
|-
|Black Locust
|''[[Robinia pseudoacacia]]''
|Green
|660
|46.9
|95
|-
|Black Locust
|''[[Robinia pseudoacacia]]''
|12.00%
|690
|70.2
|134
|-
|Cucumber Tree Magnolia
|''[[Magnolia acuminata]]''
|Green
|440
|21.6
|51
|-
|Cucumber Tree Magnolia
|''[[Magnolia acuminata]]''
|12.00%
|480
|43.5
|85
|-
|Southern Magnolia
|''[[Magnolia grandiflora]]''
|Green
|460
|18.6
|47
|-
|Southern Magnolia
|''[[Magnolia grandiflora]]''
|12.00%
|500
|37.6
|77
|-
|Bigleaf Maple
|''[[Acer macrophyllum]]''
|Green
|440
|22.3
|51
|-
|Bigleaf Maple
|''[[Acer macrophyllum]]''
|12.00%
|480
|41
|74
|-
|Black Maple
|''[[Acer nigrum]]''
|Green
|520
|22.5
|54
|-
|Black Maple
|''[[Acer nigrum]]''
|12.00%
|570
|46.1
|92
|-
|Red Maple
|''[[Acer rubrum]]''
|Green
|490
|22.6
|53
|-
|Red Maple
|''[[Acer rubrum]]''
|12.00%
|540
|45.1
|92
|-
|Silver Maple
|''[[Acer saccharinum]]''
|Green
|440
|17.2
|40
|-
|Silver Maple
|''[[Acer saccharinum]]''
|12.00%
|470
|36
|61
|-
|Sugar Maple
|''[[Acer saccharum]]''
|Green
|560
|27.7
|65
|-
|Sugar Maple
|''[[Acer saccharum]]''
|12.00%
|630
|54
|109
|-
|Black Red Oak
|''[[Quercus velutina]]''
|Green
|560
|23.9
|57
|-
|Black Red Oak
|''[[Quercus velutina]]''
|12.00%
|610
|45
|96
|-
|Cherrybark Red Oak
|''[[Quercus pagoda]]''
|Green
|610
|31.9
|74
|-
|Cherrybark Red Oak
|''[[Quercus pagoda]]''
|12.00%
|680
|60.3
|125
|-
|Laurel Red Oak
|''[[Quercus hemisphaerica]]''
|Green
|560
|21.9
|54
|-
|Laurel Red Oak
|''[[Quercus hemisphaerica]]''
|12.00%
|630
|48.1
|87
|-
|Northern Red Oak
|''[[Quercus rubra]]''
|Green
|560
|23.7
|57
|-
|Northern Red Oak
|''[[Quercus rubra]]''
|12.00%
|630
|46.6
|99
|-
|Pin Red Oak
|''[[Quercus palustris]]''
|Green
|580
|25.4
|57
|-
|Pin Red Oak
|''[[Quercus palustris]]''
|12.00%
|630
|47
|97
|-
|Scarlet Red Oak
|''[[Quercus coccinea]]''
|Green
|600
|28.2
|72
|-
|Scarlet Red Oak
|''[[Quercus coccinea]]''
|12.00%
|670
|57.4
|120
|-
|Southern Red Oak
|''[[Quercus falcata]]''
|Green
|520
|20.9
|48
|-
|Southern Red Oak
|''[[Quercus falcata]]''
|12.00%
|590
|42
|75
|-
|Water Red Oak
|''[[Quercus nigra]]''
|Green
|560
|25.8
|61
|-
|Water Red Oak
|''[[Quercus nigra]]''
|12.00%
|630
|46.7
|106
|-
|Willow Red Oak
|''[[Quercus phellos]]''
|Green
|560
|20.7
|51
|-
|Willow Red Oak
|''[[Quercus phellos]]''
|12.00%
|690
|48.5
|100
|-
|Bur White Oak
|''[[Quercus macrocarpa]]''
|Green
|580
|22.7
|50
|-
|Bur White Oak
|''[[Quercus macrocarpa]]''
|12.00%
|640
|41.8
|71
|-
|Chestnut White Oak
|''[[Quercus montana]]''
|Green
|570
|24.3
|55
|-
|Chestnut White Oak
|''[[Quercus montana]]''
|12.00%
|660
|47.1
|92
|-
|Live White Oak
|''[[Quercus virginiana]]''
|Green
|800
|37.4
|82
|-
|Live White Oak
|''[[Quercus virginiana]]''
|12.00%
|880
|61.4
|127
|-
|Overcup White Oak
|''[[Quercus lyrata]]''
|Green
|570
|23.2
|55
|-
|Overcup White Oak
|''[[Quercus lyrata]]''
|12.00%
|630
|42.7
|87
|-
|Post White Oak
|''[[Quercus stellata]]''
|Green
|600
|24
|56
|-
|Post White Oak
|''[[Quercus stellata]]''
|12.00%
|670
|45.3
|91
|-
|Swamp Chestnut White Oak
|''[[Quercus michauxii]]''
|Green
|600
|24.4
|59
|-
|Swamp Chestnut White Oak
|''[[Quercus michauxii]]''
|12.00%
|670
|50.1
|96
|-
|Swamp White Oak
|''[[Quercus bicolor]]''
|Green
|640
|30.1
|68
|-
|Swamp White Oak
|''[[Quercus bicolor]]''
|12.00%
|720
|59.3
|122
|-
|White Oak
|''[[Quercus alba]]''
|Green
|600
|24.5
|57
|-
|White Oak
|''[[Quercus alba]]''
|12.00%
|680
|51.3
|105
|-
|Sassafras
|''[[Sassafras albidum]]''
|Green
|420
|18.8
|41
|-
|Sassafras
|''[[Sassafras albidum]]''
|12.00%
|460
|32.8
|62
|-
|Sweetgum
|''[[Liquidambar styraciflua]]''
|Green
|460
|21
|49
|-
|Sweetgum
|''[[Liquidambar styraciflua]]''
|12.00%
|520
|43.6
|86
|-
|American Sycamore
|''[[Platanus occidentalis]]''
|Green
|460
|20.1
|45
|-
|American Sycamore
|''[[Platanus occidentalis]]''
|12.00%
|490
|37.1
|69
|-
|Tanoak
|''[[Notholithocarpus densiflorus]]''
|Green
|580
|32.1
|72
|-
|Tanoak
|''[[Notholithocarpus densiflorus]]''
|12.00%
|580
|32.1
|72
|-
|Black Tupelo
|''[[Nyssa sylvatica]]''
|Green
|460
|21
|48
|-
|Black Tupelo
|''[[Nyssa sylvatica]]''
|12.00%
|500
|38.1
|66
|-
|Water Tupelo
|''[[Nyssa aquatica]]''
|Green
|460
|23.2
|50
|-
|Water Tupelo
|''[[Nyssa aquatica]]''
|12.00%
|500
|40.8
|66
|-
|Black Walnut
|''[[Juglans nigra]]''
|Green
|510
|29.6
|66
|-
|Black Walnut
|''[[Juglans nigra]]''
|12.00%
|550
|52.3
|101
|-
|Black Willow
|''[[Salix nigra]]''
|Green
|360
|14.1
|33
|-
|Black Willow
|''[[Salix nigra]]''
|12.00%
|390
|28.3
|54
|-
|Yellow Poplar
|''[[Liriodendron tulipifera]]''
|Green
|400
|18.3
|41
|-
|Yellow Poplar
|''[[Liriodendron tulipifera]]''
|12.00%
|420
|38.2
|70
|-
|Baldcypress
|''[[Taxodium distichum]]''
|Green
|420
|24.7
|46
|-
|Baldcypress
|''[[Taxodium distichum]]''
|12.00%
|460
|43.9
|73
|-
|Atlantic White Cedar
|''[[Chamaecyparis thyoides]]''
|Green
|310
|16.5
|32
|-
|Atlantic White Cedar
|''[[Chamaecyparis thyoides]]''
|12.00%
|320
|32.4
|47
|-
|Eastern Redcedar
|''[[Juniperus virginiana]]''
|Green
|440
|24.6
|48
|-
|Eastern Redcedar
|''[[Juniperus virginiana]]''
|12.00%
|470
|41.5
|61
|-
|Incense Cedar
|''[[Calocedrus decurrens]]''
|Green
|350
|21.7
|43
|-
|Incense Cedar
|''[[Calocedrus decurrens]]''
|12.00%
|370
|35.9
|55
|-
|Northern White Cedar
|''[[Thuja occidentalis]]''
|Green
|290
|13.7
|29
|-
|Northern White Cedar
|''[[Thuja occidentalis]]''
|12.00%
|310
|27.3
|45
|-
|Port Orford Cedar
|''[[Chamaecyparis lawsoniana]]''
|Green
|390
|21.6
|45
|-
|Port Orford Cedar
|''[[Chamaecyparis lawsoniana]]''
|12.00%
|430
|43.1
|88
|-
|Western Redcedar
|''[[Thuja plicata]]''
|Green
|310
|19.1
|35.9
|-
|Western Redcedar
|''[[Thuja plicata]]''
|12.00%
|320
|31.4
|51.7
|-
|Yellow Cedar
|''[[Cupressus nootkatensis]]''
|Green
|420
|21
|44
|-
|Yellow Cedar
|''[[Cupressus nootkatensis]]''
|12.00%
|440
|43.5
|77
|-
|Coast Douglas Fir
|''[[Pseudotsuga menziesii var. menziesii]]''
|Green
|450
|26.1
|53
|-
|Coast Douglas Fir
|''[[Pseudotsuga menziesii var. menziesii]]''
|12.00%
|480
|49.9
|85
|-
|Interior West Douglas Fir
|''[[Pseudotsuga menziesii|Pseudotsuga Menziesii]]''
|Green
|460
|26.7
|53
|-
|Interior West Douglas Fir
|''[[Pseudotsuga menziesii|Pseudotsuga Menziesii]]''
|12.00%
|500
|51.2
|87
|-
|Interior North Douglas Fir
|''[[Pseudotsuga menziesii var. glauca]]''
|Green
|450
|23.9
|51
|-
|Interior North Douglas Fir
|''[[Pseudotsuga menziesii var. glauca]]''
|12.00%
|480
|47.6
|90
|-
|Interior South Douglas Fir
|''[[Pseudotsuga lindleyana]]''
|Green
|430
|21.4
|47
|-
|Interior South Douglas Fir
|''[[Pseudotsuga lindleyana]]''
|12.00%
|460
|43
|82
|-
|Balsam Fir
|''[[Abies balsamea]]''
|Green
|330
|18.1
|38
|-
|Balsam Fir
|''[[Abies balsamea]]''
|12.00%
|350
|36.4
|63
|-
|California Red Fir
|''[[Abies magnifica]]''
|Green
|360
|19
|40
|-
|California Red Fir
|''[[Abies magnifica]]''
|12.00%
|380
|37.6
|72.4
|-
|Grand Fir
|''[[Abies grandis]]''
|Green
|350
|20.3
|40
|-
|Grand Fir
|''[[Abies grandis]]''
|12.00%
|370
|36.5
|61.4
|-
|Noble Fir
|''[[Abies procera]]''
|Green
|370
|20.8
|43
|-
|Noble Fir
|''[[Abies procera]]''
|12.00%
|390
|42.1
|74
|-
|Pacific Silver Fir
|''[[Abies amabilis]]''
|Green
|400
|21.6
|44
|-
|Pacific Silver Fir
|''[[Abies amabilis]]''
|12.00%
|430
|44.2
|75
|-
|Subalpine Fir
|''[[Abies lasiocarpa]]''
|Green
|310
|15.9
|34
|-
|Subalpine Fir
|''[[Abies lasiocarpa]]''
|12.00%
|320
|33.5
|59
|-
|White Fir
|''[[Abies concolor]]''
|Green
|370
|20
|41
|-
|White Fir
|''[[Abies concolor]]''
|12.00%
|390
|40
|68
|-
|Eastern Hemlock
|''[[Tsuga canadensis]]''
|Green
|380
|21.2
|44
|-
|Eastern Hemlock
|''[[Tsuga canadensis]]''
|12.00%
|400
|37.3
|61
|-
|Mountain Hemlock
|''[[Tsuga mertensiana]]''
|Green
|420
|19.9
|43
|-
|Mountain Hemlock
|''[[Tsuga mertensiana]]''
|12.00%
|450
|44.4
|79
|-
|Western Hemlock
|''[[Tsuga heterophylla]]''
|Green
|420
|23.2
|46
|-
|Western Hemlock
|''[[Tsuga heterophylla]]''
|12.00%
|450
|49
|78
|-
|Western Larch
|''[[Larix occidentalis]]''
|Green
|480
|25.9
|53
|-
|Western Larch
|''[[Larix occidentalis]]''
|12.00%
|520
|52.5
|90
|-
|Eastern White Pine
|''[[Pinus strobus]]''
|Green
|340
|16.8
|34
|-
|Eastern White Pine
|''[[Pinus strobus]]''
|12.00%
|350
|33.1
|59
|-
|Jack Pine
|''[[Jack pine|Pinus banksiana]]''
|Green
|400
|20.3
|41
|-
|Jack Pine
|''[[Jack pine|Pinus banksiana]]''
|12.00%
|430
|39
|68
|-
|Loblolly Pine
|''[[Pinus taeda]]''
|Green
|470
|24.2
|50
|-
|Loblolly Pine
|''[[Pinus taeda]]''
|12.00%
|510
|49.2
|88
|-
|Lodgepole Pine
|''[[Pinus contorta]]''
|Green
|380
|18
|38
|-
|Lodgepole Pine
|''[[Pinus contorta]]''
|12.00%
|410
|37
|65
|-
|Longleaf Pine
|''[[Longleaf pine|Pinus palustris]]''
|Green
|540
|29.8
|59
|-
|Longleaf Pine
|''[[Longleaf pine|Pinus palustris]]''
|12.00%
|590
|58.4
|100
|-
|Pitch Pine
|''[[Pinus rigida]]''
|Green
|470
|20.3
|47
|-
|Pitch Pine
|''[[Pinus rigida]]''
|12.00%
|520
|41
|74
|-
|Pond Pine
|''[[Pinus serotina]]''
|Green
|510
|25.2
|51
|-
|Pond Pine
|''[[Pinus serotina]]''
|12.00%
|560
|52
|80
|-
|Ponderosa Pine
|''[[Pinus ponderosa]]''
|Green
|380
|16.9
|35
|-
|Ponderosa Pine
|''[[Pinus ponderosa]]''
|12.00%
|400
|36.7
|65
|-
|Red Pine
|''[[Pinus resinosa]]''
|Green
|410
|18.8
|40
|-
|Red Pine
|''[[Pinus resinosa]]''
|12.00%
|460
|41.9
|76
|-
|Sand Pine
|''[[Pinus clausa]]''
|Green
|460
|23.7
|52
|-
|Sand Pine
|''[[Pinus clausa]]''
|12.00%
|480
|47.7
|80
|-
|Shortleaf Pine
|''[[Pinus echinata]]''
|Green
|470
|24.3
|51
|-
|Shortleaf Pine
|''[[Pinus echinata]]''
|12.00%
|510
|50.1
|90
|-
|Slash Pine
|''[[Pinus elliottii]]''
|Green
|540
|26.3
|60
|-
|Slash Pine
|''[[Pinus elliottii]]''
|12.00%
|590
|56.1
|112
|-
|Spruce Pine
|''[[Pinus glabra]]''
|Green
|410
|19.6
|41
|-
|Spruce Pine
|''[[Pinus glabra]]''
|12.00%
|440
|39
|72
|-
|Sugar Pine
|''[[Pinus lambertiana]]''
|Green
|340
|17
|34
|-
|Sugar Pine
|''[[Pinus lambertiana]]''
|12.00%
|360
|30.8
|57
|-
|Virginia Pine
|''[[Pinus virginiana]]''
|Green
|450
|23.6
|50
|-
|Virginia Pine
|''[[Pinus virginiana]]''
|12.00%
|480
|46.3
|90
|-
|Western White Pine
|''[[Pinus monticola]]''
|Green
|360
|16.8
|32
|-
|Western White Pine
|''[[Pinus monticola]]''
|12.00%
|380
|34.7
|67
|-
|Redwood Old Growth
|''[[Sequoia sempervirens]]''
|Green
|380
|29
|52
|-
|Redwood Old Growth
|''[[Sequoia sempervirens]]''
|12.00%
|400
|42.4
|69
|-
|Redwood New Growth
|''[[Sequoia sempervirens]]''
|Green
|340
|21.4
|41
|-
|Redwood New Growth
|''[[Sequoia sempervirens]]''
|12.00%
|350
|36
|54
|-
|Black Spruce
|''[[Picea mariana]]''
|Green
|380
|19.6
|42
|-
|Black Spruce
|''[[Picea mariana]]''
|12.00%
|460
|41.1
|74
|-
|Engelmann Spruce
|''[[Picea engelmannii]]''
|Green
|330
|15
|32
|-
|Engelmann Spruce
|''[[Picea engelmannii]]''
|12.00%
|350
|30.9
|64
|-
|Red Spruce
|''[[Picea rubens]]''
|Green
|370
|18.8
|41
|-
|Red Spruce
|''[[Picea rubens]]''
|12.00%
|400
|38.2
|74
|-
|Sitka Spruce
|''[[Picea sitchensis]]''
|Green
|330
|16.2
|34
|-
|Sitka Spruce
|''[[Picea sitchensis]]''
|12.00%
|360
|35.7
|65
|-
|White Spruce
|''[[Picea glauca]]''
|Green
|370
|17.7
|39
|-
|White Spruce
|''[[Picea glauca]]''
|12.00%
|400
|37.7
|68
|-
|Tamarack Spruce
|''[[Larix laricina]]''
|Green
|490
|24
|50
|-
|Tamarack Spruce
|''[[Larix laricina]]''
|12.00%
|530
|49.4
|80
|}
Bamboo properties:<ref>{{Cite web|title=What are the mechanical properties of bamboo|url=https://doorstain.com/blog/news/what-are-the-mechanical-properties-of-bamboo/|access-date=2023-08-22|website=www.DoorStain.com|date=August 22, 2023 |archive-date=August 22, 2023|archive-url=https://web.archive.org/web/20230822211225/https://doorstain.com/blog/news/what-are-the-mechanical-properties-of-bamboo/|url-status=live}}</ref><ref name="pfaf-2019">{{Cite web|url=https://pfaf.org/user/Default.aspx|title=PFAF|website=pfaf.org|access-date=2019-11-03|archive-date=October 24, 2019|archive-url=https://web.archive.org/web/20191024204115/https://pfaf.org/user/default.aspx|url-status=live}}</ref>
{|class="wikitable mw-collapsible mw-collapsed sortable"
!'''Common name'''
!'''Scientific name'''
!'''Moisture content'''
!'''Density (kg/m<sup>3</sup>)'''
!'''Compressive strength (megapascals)'''
!'''Flexural strength (megapascals)'''
|-
|Balku bans
|''[[Bambusa balcooa]]''
|green
|
|45
|73.7
|-
|Balku bans
|''[[Bambusa balcooa]]''
|air dry
|
|54.15
|81.1
|-
|Balku bans
|''[[Bambusa balcooa]]''
|8.5
|820
|69
|151
|-
|Indian thorny bamboo
|''[[Bambusa bambos]]''
|9.5
|710
|61
|143
|-
|Indian thorny bamboo
|''[[Bambusa bambos]]''
|
|
|43.05
|37.15
|-
|Nodding Bamboo
|''[[Bambusa nutans]]''
|8
|890
|75
|52.9
|-
|Nodding Bamboo
|''[[Bambusa nutans]]''
|87
|
|46
|52.4
|-
|Nodding Bamboo
|''[[Bambusa nutans]]''
|12
|
|85
|67.5
|-
|Nodding Bamboo
|''[[Bambusa nutans]]''
|88.3
|
|44.7
|88
|-
|Nodding Bamboo
|''[[Bambusa nutans]]''
|14
|
|47.9
|216
|-
|Clumping Bamboo
|''[[Bambusa pervariabilis]]''
|
|
|45.8
|
|-
|Clumping Bamboo
|''[[Bambusa pervariabilis]]''
|5
|
|79
|80
|-
|Clumping Bamboo
|''[[Bambusa pervariabilis]]''
|20
|
|35
|37
|-
|Burmese bamboo
|''[[Bambusa polymorpha]]''
|95.1
|
|32.1
|28.3
|-
|
|''[[Bambusa spinosa]]''
|air dry
|
|57
|51.77
|-
|Indian timber bamboo
|''[[Bambusa tulda]]''
|73.6
|
|40.7
|51.1
|-
|Indian timber bamboo
|''[[Bambusa tulda]]''
|11.9
|
|68
|66.7
|-
|Indian timber bamboo
|''[[Bambusa tulda]]''
|8.6
|910
|79
|194
|-
|dragon bamboo
|''[[Dendrocalamus giganteus]]''
|8
|740
|70
|193
|-
|Hamilton's bamboo
|''[[Dendrocalamus hamiltonii]]''
|8.5
|590
|70
|89
|-
|White bamboo
|''[[Dendrocalamus membranaceus]]''
|102
|
|40.5
|26.3
|-
|String Bamboo
|''[[Gigantochloa apus]]''
|54.3
|
|24.1
|102
|-
|String Bamboo
|''[[Gigantochloa apus]]''
|15.1
|
|37.95
|87.5
|-
|Java Black Bamboo
|''[[Gigantochloa atroviolacea]]''
|54
|
|23.8
|92.3
|-
|Java Black Bamboo
|''[[Gigantochloa atroviolacea]]''
|15
|
|35.7
|94.1
|-
|Giant Atter
|''[[Gigantochloa atter]]''
|72.3
|
|26.4
|98
|-
|Giant Atter
|''[[Gigantochloa atter]]''
|14.4
|
|31.95
|122.7
|-
|
|''[[Gigantochloa macrostachya]]''
|8
|960
|71
|154
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|42
|53.5
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|63.6
|144.8
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|86.3
|46
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|77.5
|82
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|15
|
|56
|87
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|63.3
|
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|28
|
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|56.2
|
|-
|American Narrow-Leaved Bamboo
|''[[Guadua angustifolia]]''
|
|
|38
|
|-
|Berry Bamboo
|''[[Melocanna baccifera]]''
|12.8
|
|69.9
|57.6
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|
|
|51
|
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|8
|730
|63
|
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|64
|
|44
|
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|61
|
|40
|
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|9
|
|71
|
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|9
|
|74
|
|-
|Japanese timber bamboo
|''[[Phyllostachys bambusoides]]''
|12
|
|54
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|
|
|44.6
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|75
|
|67
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|15
|
|71
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|6
|
|108
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|0.2
|
|147
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|5
|
|117
|51
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|30
|
|44
|55
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|12.5
|603
|60.3
|
|-
|Tortoise shell bamboo
|''[[Phyllostachys edulis]]''
|10.3
|530
|
|83
|-
|Early Bamboo
|''[[Phyllostachys praecox]]''
|28.5
|827
|79.3
|
|-
|Oliveri
|''[[Thyrsostachys oliveri]]''
|53
|
|46.9
|61.9
|-
|Oliveri
|''[[Thyrsostachys oliveri]]''
|7.8
|
|58
|90
|}