By Eric MeierOutline.,.:,.:,.:,In sharp contrast to the simple, the hardwoods of the world exhibit a dazzling array of endgrain patterns and intricate motifs; and it’s in this complexity that the challenge (and joy) of wood identification really comes alive. An unknown hardwood sample could be just about anything under the sun, yet as each anatomical feature is considered, anything is narrowed down to something.That is to say, throughout the identification process, the more observations that can be made and classified about a hardwood sample, the more and more the field of possible candidates narrows. Ultimately, the point is reached where no further refinements can be recorded, and either a clear identification emerges, or a handful of possibilities remain.As discussed on the page, a positive identification down to the species level isn’t always possible, but generally, anything can be narrowed down to a more descriptive something, and in many cases, the genus or family of the wood can usually be ascertained. To begin this process, the largest and most conspicuous anatomical elements are examined first.
Vessel elementsWhen viewed from the endgrain, vessels simply appear to be holes in the wood—what are commonly referred to as pores. In a live tree, vessels serve as the pipelines within the trunk, transporting sap within the tree.( completely lack vessels, and instead rely on tracheids for sap conduction.) Vessel elements are the largest type of cells, and unlike the other hardwood cell types, they can be viewed individually—oftentimes even without any sort of magnification.For simplicity’s sake, vessel elements will simply be referred to as pores throughout this website.Hardwoods are initially divided into three main categories according to the arrangement of their pores, commonly called its porosity. In temperate zones, it’s not unusual for hardwood pores to correspond to the annual growing season, with larger pores forming a band or ring along the earlywood zone.
This category of porosity is called ring-porous.The second category—common in many tropical species—occurs when the pores are distributed evenly throughout the wood. (Growth rings may still be discernible through other cell types, such as parenchyma bands, or a change of color in the wood fibers, but the largest elements—the pores—will be spread out and diffused throughout the wood.) This category of porosity is called diffuse-porous.Additionally, a third, intermediate arrangement is also seen, which is sometimes difficult to define.
It includes wood that has pores that are generally evenly spaced but grade from large to small between growth rings, subtly suggesting growth boundaries. (Wood species with pores of a uniform size that are arranged in weak or broken bands are considered by some sources to be a part of this intermediate category as well.) This intermediate category of porosity is interchangeably called either semi-ring-porous or semi-diffuse-porous; for simplicity’s sake, this group will be referred to as semi-ring-porous throughout this website.In addition to the foundational three-fold categorization of the pores, there’s also a few other factors pertaining to pores to consider in hardwood identification. Pore sizeTechnically, wood pore diameters are measured in micrometers (sometimes called microns), but the scope and scale of such minute scientific measurements can be hard to grasp. Pore frequencyPore frequency is generally only measured on diffuse-porous woods; if noted, it’s indicated in comparative terms, such as few, or numerous, rather than by precise microscopic terms such as quantity per square millimeter.FrequencyVessels/mm 2Very Few 100In some instances, considering the pore frequency can prove to be an important distinguishing factor in identification.
In the case of, one species (D. Nigra) has much more infrequent pores, which proves to be a reasonably good discriminator. Pore contentsBesides simply considering the size or arrangement of the pores, sometimes it pays to observe what’s actually in them. As sapwood becomes heartwood, certain substances and structures are deposited in the wood cells.In some cases, pores can become filled with colored gums, resins, or other deposits that can aid in identification. In most species, heartwood deposits tend to be somewhat sporadic, so it shouldn’t be relied upon as a primary identifying feature.
The frequency of pore contents, if present, are described using the relative terms, sparse, common, and abundant.Another common by-product of the conversion of sapwood to heartwood is the appearance of tyloses. Tyloses (singular, tylosis) appear as bubble-like structures that grow into open pores, and in some cases, completely stop-up the pores of the heartwood. Black locust (endgrain 10x)is a superb example of a wood with pores that are abundantly packed with tyloses.Some species lack tyloses altogether, while many others have an intermediate distribution ranging from sparse to common, while some species have tyloses in abundance, to the point that nearly every heartwood pore is filled with tyloses.
This blockage has the beneficial effect of rendering the pores essentially watertight: a well known example of this is found in (Quercus alba), whose packed pores are commonly used for barrel-making (also known as cooperage). ParenchymaIn a living tree, the parenchyma contained in the sapwood consists of living tissue that serves as storage cells. Technically, there are a few different types of parenchyma cells seen in wood, (such as those occurring radially in the rays), but far and away the most common type of cells that are designated specifically as parenchyma refer to longitudinal or axial parenchyma, which are oriented along the length of the tree-trunk. All references to parenchyma in this website will be describing axial parenchyma.Single parenchyma cells are typically too small to be seen individually, but when viewed as a whole, patterns and shapes emerge. Very infrequently, parenchyma is absent or hardly observable, but in most hardwood species, parenchyma forms unique and telling patterns that greatly aid in the identification process.
In describing parenchyma, there are two main classifications. Apotracheal parenchymaIn order to understand this somewhat intimidating scientific term, it may help to consider the English word “trachea,” which refers to a tube or pipe (in this case, a wood pore).
Combine this with the Greek prefix “apo,” which means away from or separate, and the meaning becomes clearer.Apotracheal refers to parenchyma cells that occur separate from the pores. Apotracheal parenchyma can occur as single scattered cells, classified as diffuse parenchyma. These cells are too small to be seen without a microscope. However, in some wood species, several apotracheal parenchyma cells are joined or aggregated together, forming thin but visible tangential lines.
This formation is known as diffuse-in-aggregates parenchyma. Paratracheal parenchymaThe counterpart to apotracheal parenchyma is paratracheal parenchyma. The Greek prefix “para” means beside or near, and the classification of paratracheal describes parenchyma that occurs in association with the wood’s pores. Of the two classifications, paratracheal parenchyma exhibits a much wider range of patterns and variations.Paratracheal parenchyma can occur as single cells bordering a pore, called scanty parenchyma. These cells are too small to be seen individually without a microscope, and along with diffuse parenchyma, will not be given further consideration in this website.
Difference Between Hardwood And Softwood Cell Structures
The most basic paratracheal parenchyma formation is a ring or circle of cells surrounding the pore, which is termed vasicentric parenchyma. The term vasicentric is simply a combination of the words vase (suggesting a vessel or pore), and centric, which simply indicates that the parenchyma is centered around the pore. It should be noted that vasicentric parenchyma isn’t always visible with a hand lens. If the pores of a wood species are especially small, (with the parenchyma being even smaller), or if the parenchyma ring is only one cell thick, it may not be clearly visible with a hand lens. When horizontal (tangential) bands of parenchyma occur either as (apotracheal) diffuse-in-aggregates, and/or as extensions of aliform or confluent (paratracheal) parenchyma, it is known as banded parenchyma. Banded parenchyma can be in continuous bands, or it can occur in interrupted or discontinuous bands. The bands can be very thick—constituting over half of the wood’s overall volume in some species—or they can be very thin and hardly visible with a hand lens. The bands can be very numerous and evenly spaced, or they can be very sparse and sporadic. Ray widthWhen viewed under a microscope, ray width can be measured in perfect precision by the number of cells across the ray.
Wood species with the thinnest rays measure only one or two cells wide, (called uniseriate, and biseriate, respectively), while some of the widest rays can measure well over a dozen cells wide.However, when viewed with a hand lens, individual ray cells cannot be counted, and more generic comparative terms, such as narrow, medium, or wide are used to describe the ray width. WidthNumber of CellsNarrow1-3 seriateMedium3-5 seriateWide5-10 seriateVery Wide 10 seriateHowever, using these generic terms are an imperfect compromise, as the individual rays cells can vary in width, so a narrow uniseriate ray with large cells may visually appear just as wide as a medium-width ray that’s made up of smaller cells.In addition to noting the average width of the rays, some species also have two distinct sizes of rays present. In the case of hard maple (Acer saccharum), its combination of wide and narrow ray widths can help. Ray spacingIn addition to their width, rays are also measured by their spacing, usually expressed as a quantity per millimeter. However, because of the impracticality of obtaining precise counts per millimeter using only a hand lens, comparative terms will be used.SpacingRays/mmWide 21(It should be noted that in cases where the rays are spaced extremely close together, the rays tend to be so small and narrow that they can’t always be discerned with a hand lens.).
Aggregate raysOccasionally, some species will have intermittent rays that are many times wider than the rest. These mega-rays are essentially a collection of a number of normal-sized rays grouped together and appearing as one large ray. They are known as aggregate rays.Perhaps the most well-known commercial lumber in the United States that features aggregate rays is (Alnus rubra). In addition to alder, only a handful of other genera and species exhibit these rays: (Carpinus spp.), and some species of (Allocasuarina and Casuarina spp.) and (Quercus spp.) also feature aggregate rays. Storied raysOne final characteristic of rays involves examining the flatsawn (tangential) surface of the wood. In some wood species, (particularly those in tropical regions), the rays tend to be aligned in horizontal or diagonal tiers, also referred to as stories. This pattern is called storied rays, and it produces a visual phenomenon known as ripple marks.Even though there’s technically no unevenness in the wood, to the unaided eye, (and at low levels of magnification), storied rays appear as minute stripes of wood alternating between light and dark.
In addition to the rays, other anatomical features (such as the parenchyma or the fibers) can also form stories, and therefore produce ripple marks. Wood fibersIn a living tree, hardwood fibers have strong, thick cell walls that mainly serve to support and strengthen the trunk. When viewed from the endgrain, fibers are very small and can’t be seen individually.
Instead, fibers can only be distinguished in a broader sense as colored areas which form the backdrop of the wood’s endgrain.Occasionally, the wood fibers will change in color in correlation with the growing season, providing a means to distinguish the growth ring boundaries in instances where it may not be apparent in the arrangement of pores or marginal parenchyma. Monocots: a special caseHardwoods are classified as dicotyledons, (or “dicots” for short) because they have two cotyledons (embryonic leaves). That is to say, when a dicot first emerges from its seed, the seedling will have two leaves. Most of the world’s fruits, vegetables, and fibers are dicots.However, within the division of Angiosperms (flowering plants) there are also plants that only have one embryonic leaf, called monocotyledons, or “monocots” for short. This important group contains corn, wheat, rice, and all true grasses. In the woodworking world, the most notable monocots are palm and bamboo.Anatomically, the “wood” of monocots is diverse from both hardwoods and softwoods, and can usually be spotted easily, even without magnification.
Viewing the endgrain reveals a fairly simple structure of darker-colored fibrovascular bundles embedded throughout a mass of lighter-colored parenchyma cells. Growth rings, sapwood/heartwood, and rays are all completely absent.Narrowing most monocots down to even the genus level (let alone to a precise species) is essentially impossible—at least when limited to the anatomical features of the wood itself.
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There just aren’t enough distinguishing features present to discern between different species. Fortunately, in woodworking and lumber applications, there are generally only a few types of monocots encountered. PalmThese tropical monocots have no growth rings, and when viewed on end, a palm log will appear as a circular gradient between the darker (and stronger) fibrovascular bundles along the outer edge, and the lighter (and softer) parenchyma structure in the center. Toward the outer wall of the trunk, the density of the wood is the greatest, and gradually becomes lighter, softer, and weaker towards the soft core.Palm lumber is typically divided into two general categories: red, and black. Is commonly harvested from the coconut palm (Cocos nucifera), but other genera and species are also used. As the name implies, the fibrovascular bundles have a reddish hue. Is harvested from at least five different genera, and is identified by its darker, nearly black fibrovascular bundles, which contrast with the pale grayish brown parenchyma.
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BambooThese fast growing members of the grass family (Poaceae) are very diverse, with hundreds of species encompassing dozens of genera. Unlike trees, bamboo initially grows at full width, with no tapering or horizontal growth.Much like palm, bamboo has fibrovascular bundles that are more concentrated near the edge of the stem—also called the culm—with softer parenchyma grading in toward the inner wall.
Bamboo culms are hollow in the center, with closed “nodes” generally occurring every few feet or so. Hello,I make outdoor hammocks made from wooden dowels.Originally I was using asian birch and treated them with 3 coats of Sikkens HLS (Cetol 1 in North America).This seems to have worked well if there is a re-coat every 2 or 3 years. I am now living in Indonesia, and I want to use teak dowels. Im trying to use scrap pieces from other manufacturers to make the dowel, so they cannot guarantee me premium grade teak. As long as it’s dried 8% – 12% do you think I would have a problem with splitting or cracking with the lower grade teak if exported to other countries?Any advice would be greatly appreciated.Thanks and regards,Kyle.
Hardwood is not necessarily a harder material (more dense) and a softwood is not necessarily a softer material (less dense).Different types of construction projects call for different kinds of timber, both hardwood and softwood are used for everything from structural to decorative.Softwood and hardwood are distinguished botanically in terms of their reproduction, not by their end use or appearance. All trees reproduce by producing seeds, but the seed structure varies.In general, hardwood comes from a deciduous tree which loses its leaves annually and softwood comes from a conifer, which usually remains evergreen.
Hardwoods tend to be slower growing, and are therefore usually more dense.Softwood trees are known as a gymnosperm. Gymnosperms reproduce by forming cones which emit pollen to be spread by the wind to other trees. Pollinated trees form naked seeds which are dropped to the ground or borne on the wind so that new trees can grow elsewhere. Some examples of softwood include pine, redwood, douglas-fir, cypresses and larch. (more information visit our )A hardwood is an angiosperm, a plant that produces seeds with some sort of covering such as a shell or a fruit.
Angiosperms usually form flowers to reproduce. Birds and insects attracted to the flowers carry the pollen to other trees and when fertilized the trees form fruits or nuts and seeds.
Hardwoods include eucalypts, beech and blackwood.The hardwood/softwood terminology does make some sense. Evergreens do tend to be less dense than deciduous trees, and therefore easier to cut, while most hardwoods tend to be more dense, and therefore sturdier. In practical terms, this denseness also means that the wood will split if you pound a nail into it. Thus you need to drill screw or bolt holes to fasten hardwood together. But structural lumber is soft and light, accepts nails easily without splitting and thus is great for general construction. Post navigation.
In reality, the technical distinction has to do with the reproductive biology of the species. Informally, trees categorized as hardwoods are usually — meaning they lose their leaves in the autumn. Softwoods are, which have needles rather than traditional leaves and retain them through the winter.
And while generally speaking the is a good deal harder and more durable than the average softwood, there are examples of deciduous hardwoods that are much softer than the hardest softwoods. An example is balsa, a hardwood that is quite soft when compared to the wood from yew trees, which is quite durable and hard. Definition and Taxonomy: Hardwoods are woody-fleshed plant species that are (the seeds are enclosed in ovary structures). This might be a fruit, such as an apple, or a hard shell, such as an acorn or. These plants also are not monocots (the seeds have more than one rudimentary leaf as they sprout). Definition and Taxonomy: Softwoods, on the other hand, are gymnosperms (conifers) with 'naked' seeds not contained by a fruit or nut., and, which grow seeds in cones, fall into this category.
In conifers, seeds are released into the wind once they mature. This spreads the plant's seed over a wide area, which gives an early advantage over many hardwood species. Softwoods do not have pores but instead have linear tubes called tracheids that provide nutrients for growth.
Softwood
Commercial Timbers for use in Construction, Joinery, and FurnitureWe have more than 1500 commercial timber species available to use in the Construction, Joinery and Furniture sectors this is ever increasing with the addition of modified timbers. We narrowed down to appx 100 species in the Gallery – to help the wood enthusiasts make an informed decision with some of the more readily available wood types available in Europe and Worldwide. To see the list of species we have considered visit sections- Hardwoods, Softwoods and Modified sections.There are two main classifications of wood – Softwoods and Hardwoods a new classification that has been added i.e. Modified woods. There are a number of features in wood structure and properties that need to be considered so you can say you know the differences between the two main classifications.
The physical structure of the wood, as well as its makeup, should be considered to know in what classification a certain type stands. One might think that it is as simple as defining hardwood as anything hard and durable while softwood as soft and flexible made from softwood timber. This might be the simplest way to classify in some degree, but there are exceptions to every rule such as yew trees which are considered to be softwood but are hard and balsa trees which are known hardwood but actually softer compared to softwood. Softwoods have the smallest diversity making them easier to identify in their anatomical features compared to hardwoods. To identify hardwoods, a number of features need to be considered in the cell structure such as vessel elements unique to hardwoods their- porosity, arrangement, size, frequency, contents; Parenchyma or storage cells- apotracheal, paratracheal and Rays- width, spacing, aggregate, noded, storied etcHardwood is sourced from flowering plants that are not monocots called angiosperm with common examples such as walnut, oak, and maple. The hardwood family includes Convolvulaceae (morning glory family), Fabaceae (legume family) Rosaceae (rose family) Sapindaceae (soapberry).Softwood is sourced from softwood timber of gymnosperm trees such as evergreen conifers.
The coniferous family includes, Araucariaceae, Cupressaceae, Pinaceae, Podocarpaceae and Taxaceae, The most popular description of conifers is spruce and pine.Here are some of the general differences between the two:. The trees of hardwood have usually broad leaves while the softwood trees have needles and cones for leaves. Most Softwoods tend to have resin canals and long fibers, e. Longitudinal tracheids.
With hardwood trees, water is transported through vessels or pores elements while softwood trees have medullary rays as well as tracheids. Hardwood has pore-like elements when viewed using a microscope while softwood does not have any pores. It is easy to identify the difference quickly by looking at the end grain; hardwoods will have prominent pores.The pores that are present in hardwoods are the ones responsible for giving the wood its prominent grain while softwood has a lighter grain in comparison. It is easier to make things out of softwoods. This is the reason why many of the wood used all over the globe are softwoods, making up 80 percent of the total timber used.
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Hardwoods are usually used in furniture with high quality, flooring, constructions built to last and decks. Softwoods, on the other hand, are used in building components such as doors and windows, furniture, paper, fiberboard with medium density and Christmas trees. Common examples of hardwood trees are Ash, oak, alder, walnut, balsa, maple, beech, teak, hickory and mahogany.
Tree Wuchs - Hardwood/SoftwoodTree trunks and branches grow thicker as new cells are added beneath the bark. These cells make up vessels, called xylem and phloem, that carry water and food throughout the tree. Xylem carries water and nutrients from the roots up to longer carries water. It forms the heartwood of the tree and may be a different color from the sapwood.
List Of Hardwood And Softwood
Phloem, also called inner bark, carries food from the leaves to the branches, trunk and roots. Outside the phloem is the outer bark, which protects the tree from injury.The cambium is found between the phloem and xylem. If you looked at a tree stump, you could not see the cambium, because it is only one cell layer thick. The cambium’s job is to make new xylem and phloem cells.Tree roots grow from specialized tissue at their tips. Roots anchor a tree in the soil and absorb the water and nutrients a tree needs.
Most of a tree’s roots are found in the top two feet of soil, even when the tree is very large. Root hairs near the growing tips take in water from the soil. You’d need a microscope to see these tiny, tubelike hairs; yet, in a large tree, they can absorb hundreds of gallons of water each day. Surprisingly, only a small amount of this water is used in photosynthesis. The rest is released from the leaves in a process called transpiration.Wood begins as a natural resource and passes along the production chain until it is converted into end user products.Wood construction is common for many single-family houses throughout the world. Inareas where timber and wood materials are easily accessible, timber construction is oftenconsidered to be the cheapest and best approach for residential housing structures.
Timber framing is a versatile, environmentally sustainable method of construction.The design of residential timber framed construction must comply with AS1684. For other timber engineering stuctures the design code AS1720 is applicable.1 Pith2 Hartwood3 Sapwood4 Cambuim Layer5 Bast6 Bark7 Annual Rings8 Sping growth9 Autumn growth10 Medullary RaysHow a Tree works.
The Bark is thetree's protection from the outside world. It keeps moisture out during rain,prevents loss of moisture. The Bast is the pipeline through which the when the air is dry,insulates against cold and heat, and wards off insects food (Elaborated Sap)produced in the leaves is passed down to the tree. It lives for only a shorttime then dies and turns to Bark. The Cambium layeris the growing part of the tree trunk. It annually produces new Sapwood on theinside and some Bast on the outside.
Sapwood is thetree's pipeline for moving water and minerals up the tree trunk to the leaves.Sapwood is new wood; as newer rings of Sapwood are produced, its inner cellslose their vitality and turn into Heartwood. Heartwood is thecentral, supporting pillar of the tree. Although dead, it will not decay orlose strength while the outer layers are intact.Softwood - HardwoodThe terms ‘softwood’ and ‘hardwood’ do not indicate softness or hardness of particular timbers. In fact, some hardwoods are softer and lighter than softwoods.
The main differences between hardwoods and softwoods are botanical, and relate to the way the tree grows. Cell Structure of Softwood and HardwoodWood, instead of being arelatively solid material like steelor concrete, is basically composedof many tubular fiber units, orcells, cemented together. Manyproperties of wood are relateddirectly to its structure. FIGURE 2The essential difference between the wood from hardwoods and softwoods is the presence of vessels in hardwoods as shown in the above diagrams.
These are continuous pipes running the length of the tree and serve as conduits for water and nutrients in the outer layers of wood in a growing tree. In hardwoods, the cells are closed and cannot function as conduits. In softwoods, the cells have openings to other cells.
This means the cells are the nutrient conduits. The actual cells in the softwood species have the same function as the vessels in hardwoods. The open cell structure of softwoods makes them generally more receptive than hardwoods to preservative treatments to enhance durability.Strength and Stiffness (Example straw model)As can be seen in Figure 1 & 2 the wood structure is dominated by longitudinal cells, with only a few transverse cells bundling them together, one can model the microstructure of wood using the using drinking straw bound loosely together by elstic bands (class demonstration). As has been demonstrated timber has a good longitudinal tensile strength and very low tensile strength to the grain as shown in the picture below.FIGURE 3ShrinkageShrinkage is a defect, and generally a natural defect, occurring during the seasoning process. When timber is seasoning it dries below its fibre-saturation point, it shrinks.
However, the loss in dimension is not the same in all directions. Timber shrinks in three directions:. Longitudinally, along the grain of the timber. Radially, across the growth rings and. Tangentially, along the line of the growth rings.These differential rates of shrinkage have considerable effect on the performance of timber in service. When it's moisture content (MC) is reduced below the Fibre Saturated Point (FSP) continued drying will cause dramatic change such as increase in strength but also distortion and shrinkage.
Shrinkage is the greatest tangentially over the radial direction with little loss along the grain length. However, when the amount of shrinkage takes place in an uncontrolled way, the risk of splitting the timber increases significantly.(see Figure 4)FIGURE 4close page if not needed.