How wood is made from trees
How Timber Gets From the Forest to Your Builders Merchant
Timber has played a key role in the construction industry for many years. And while it’s always been a popular material, the process of how and where it arrives from is often overlooked.
In this guide, we’ll take you through the journey of timber – how it travels from the forest and arrives in your builders merchant, ready for you to embark on your next project.
Stage One: Felling
The first stage of preparing the timber for commercial use is called ‘felling’ – the process of downing individual trees. In this case, the person cutting the tree is called the ‘feller’ – while the harvesting machine is referred to as a ‘feller buncher’.
A forestry worker will determine when and which trees should be cut down, depending on when they reach their economically ‘mature’ stages. Trees can range from 40 to 150 years old before they stop growing vigorously and are ready to be cut down. The differences in age at felling can depend on the tree species. For example, conifers grow at a much quicker rate than broad-leaved species. Environmental factors, such as soil nutrients, can also affect their growth.
Felling is normally carried out in winter, because the trees usually have less moisture content in them, compared to summer months, where they can have more than fifty percent water content.
Finally, felled trees should be replaced with saplings so that the forest has a chance to grow once again, providing a sustainable resource for future generations.
Stage Two: Storing/ Transporting
Next, the logs are stored in a clearing or in the forest until they are needed at the sawmill. This also allows some of the ‘free’ water content to evaporate, reducing the weight of the tree/log, which will result in lowering the cost of transporting and handling.
The trees are usually cut into smaller lengths on-site and then picked up by a timber lorry, which transports the timber to a processing site, such as a sawmill, paper mill, pallet, fencing or construction producer.
Stage Three: On Site
At the chosen site, the logs are debarked and bucked, or cut to the required length. Then they are cut into boards, using equipment such as circular saws and bandsaws. This is called ‘conversion’. The first stage of conversion is a process called ‘breaking down’ – which means rough sawing. The second stage is called ‘re-sawing’ and refers to more precise cutting and finishing, such as planing and further machining.
Two types of rough sawing can be used in the breaking down process – through sawn and quarter sawn.
The ends of each log is trimmed to ensure they are straight and cut into boards. Large circular saws are then used to further-process the boards, removing the curved edges. Each processed piece of wood now looks like a board.
Stage Four: Seasoning
Seasoning of natural wood is the process of removing excess water/moisture content. When a tree is felled, it still contains a large proportion of water/moisture – usually between forty to fifty per cent water content.
Water is held inside a tree in two ways:
- Free Water: Water that is held in the vessels and cells in order to distribute nutrients inside the tree.
- Cell water: Also known as ‘bound’ water, is an essential part of the tree’s cell walls.
During the seasoning process, a tree loses its free water and a high proportion of its cell water and as a result, is less likely to warp or deform.
Wood that has not been seasoned and still has a high water content is called ‘green wood’ and can be more difficult to work with because it has a tendency to change shape.
Stage Five: Preparing for Market
After turning trees into timber through saw milling, covered in stage three – also referred to as primary processing, the market value of timber can be further increased through manufacturing sawn timber products – called secondary processing. This involves the wood being made (either by man or machine) into a more refined product, such as a door, window or furniture, made to the specific size and dimensions
At this stage any preferred treatments to timber such as fire or rot resistance is added. Treated timber in sawn form is used either directly in construction or to prepare construction components, such as timber frame panels. Planed joinery components, on the other hand, are usually treated after assembly.
Finally, once all modifications are made, the timber is ready to be shipped to market.
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How Lumber is Obtained from Trees
Lumber is a term relating to various woods as a construction material. The wood is cut from tree trunks lengthwise in square or rectangular sections. Wood has been used as a construction material since before written history, with the earliest evidence is found in Nice, France using wood posts to support a hut. The oldest wooden construction still intact was built 7,300 years ago in northwest Germany. The first reference to using a sawmill dates back to around 375 B.C. in northern Europe, which was powered by running water.
Hardwood and Softwood
There are two classifications of trees that lumber is produced from, known as softwood and hardwood. The defining characteristic between the two classifications is that the softwood doesn’t shed its needles during the winter, while hardwood sheds its leaves.
Hardwood is used for cabinetry, flooring, doors, trim work, and paneling. Softwood is used for joists, planks, rafters, beams, posts, decks, wall studs, sheathing, concrete forms, and subflooring. Both types of wood are graded based on the number and size of defects such as holes, splits, wanes (missing pieces), and knots. Higher grades are called select grades and have very few defects, while lower grades are called common grades and used for general construction purposes.
Once a tree is cut down in a managed forest area owned by a lumber company, or leased by the government, the tree is transported to a lumber mill where it will be cut into various sizes and shapes.
- Felling – Trees are inspected and marked to be cut down. Two cuts are made at the base of the tree with one on each side to control the direction of the fall. Limbs are trimmed and the tree is cut into lengths suitable for transportation. A skidder (diesel-powered tractor), or yarder (self-propelled with telescoping hydraulic tower) is used to transport the tree sections to the trucks which take them to the lumber mill. The wood is stacked into piles called log decks which are sprayed with water to keep the wood from drying.
- Debarking and bucking – A rubber-tired loader picks up the logs from the log deck and places them on a conveyor which brings them into the mill. Sometimes the outer bark is removed to be used as fuel for the mill’s furnaces or sold as decoration. A circular saw called a bucking saw cuts the log into specified lengths.
- Head rig sawing large logs – Sensors scans both ends of the log to determine its diameter, length, and any defects. A computer calculates a suggested cutting pattern for maximizing the amount of lumber that can be made with the log. A head rig sawyer uses a head rig saw to cut the log based on personal experience and recommendations from the computer pattern. The first cut is made closest to the operator and is called the slab which is discarded into use as paper pulp. The log is then rotated to make additional cuts.
- Band sawing small logs – smaller diameter logs are passed through a series of band saws to cut them into smaller pieces at one time.
- Drying or seasoning – After the lumber is cut, it is moved into an area to dry or be seasoned to prevent decay and allow the wood to shrink as it dries. Lumber is dried differently based on the type of wood.
- Planing – Dried pieces of lumber pass through planers to trim them to their final size, smooth the wood, and round the edges.
- Grade stamping and banding – Every piece of lumber is visually inspected and stamped with its grading along with information on moisture content, and mill identification number. Bundles are made up according to the type of wood, grade, and moisture, then sent to lumberyards for sale.
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What kind of wood furniture is made of: types and properties of wood
Natural wood furniture is always relevant - it is beautiful, practical and serves its owners for many years without losing its visual appeal. In whatever style the interior is decorated, solid wood furniture will look great in it.
For the manufacture of furniture, various types of wood with different textures and densities are used. In the production of furniture sets, wood of medium density is mainly used, it is quite easy to process, the furniture turns out to be practical and durable.
Soft wood is also used in furniture production, facades and decorative elements are made from it.
Hard wood is the most difficult to process, which affects the price of furniture sets made from this type of wood. Such products are able to withstand high levels of humidity, temperature extremes.
- soft: pine, spruce, cedar, linden;
- medium hard and hard: larch, oak, cherry, walnut, ash, beech;
- extra hard: hornbeam, mahogany, yew, acacia, Karelian birch.
Pine, ash, beech, oak and birch are the most commonly used woods for modern furniture. These types of trees are common in our latitudes, they are well processed and have good performance characteristics. Furniture made of wood of these species looks aesthetically pleasing and has an affordable price.
Each type of wood has its own advantages and disadvantages:
- Birch - used for the production of furniture and load-bearing structures. It has a beautiful light shade, natural luster, which gives the furniture an aesthetic appeal. Birch is often used to make nursery furniture. Durable wood is resistant to damage, able to withstand heavy loads. Its disadvantage is low moisture resistance.
- Pine - well processed, contains resins that protect furniture from fungus and give the wood a pleasant smell. Allocates phytoncides, the influence of which has a beneficial effect on the atmosphere of the home, the human nervous system. The disadvantages include instability to mechanical damage.
- Beech is a popular species for furniture and decorative items. Beech wood is as durable as ash and oak. It has a beautiful shade from milky white to pinkish-beige, and the shade after processing almost does not change. Beech furniture is durable and can last for a long time, but it must be protected from moisture.
- Oak - often used in the manufacture of solid wood furniture due to its practicality, beauty and high strength. Oak wood - one of the hardest, has a beautiful pattern, the color range varies from golden to brown, depending on the age of the tree and the place of growth. Artificially aged and bog oak look original and are widely used to create stylish interiors. Oak furniture is not afraid of moisture, fungus, pests, so it retains its qualities and can be used for decades.
- Ash - wood is easy to process, easy to cut, resistant to mechanical damage. Ash furniture has a matte sheen, shades from silver-pearl to yellowish, looks good in a classic interior. Ease of processing allows you to create furniture from ash with beautiful decorative elements.
- White locust is the hardest hardwood among the hardwoods, highly resistant to abrasion. Acacia is difficult to process and is used primarily for cladding softer woods. It has an expressive texture, a beautiful yellow-brown shade, lends itself well to polishing.
- Larch among conifers has the most durable wood. It is used in the manufacture of furniture and carved parts, has an interesting reddish tint. Processing wood is difficult due to the high resin content.
Tips for choosing furniture from different types of wood:
- furniture made of light woods - ash, birch, beech, will visually make a small room larger, pastel colors make the room lighter, form an effective combination with bright decor;
- dark wood furniture creates cosiness in the room, but visually reduces the space, suitable for spacious rooms;
- The kitchen is characterized by temperature fluctuations and high levels of humidity, so it is better to choose durable wood furniture.
What is wood? Translation of an article by Eric Meyer from the Yurkov Sawmill
A little theory about wood
It is common knowledge that wood comes from trees. What may not be so obvious is the structure of the wood itself and the individual components that make it up. Unlike a homogeneous piece of styrofoam, plywood, or other artificial material, wood is an organic material and has many distinct characteristics that are worth learning.
Hardwoods and softwoods
A direct and important distinction that can be made between types of trees (and woods) is the distinction between hardwoods and softwoods. This is somewhat incorrect, as it is really just a distinction between angiosperms (flowering plants such as maple, oak, or rosewood) and gymnosperms (cone-bearing trees, such as pine, spruce, or fir).
Deciduous species (angiosperms) are broad-leaved and usually deciduous, meaning they lose their leaves in autumn. (However, there are many tropical evergreen hardwoods that retain their leaves year-round.) In addition, deciduous trees tend to form a branched or multi-pointed "dendritic" trunk.
Coniferous (gymnosperms) trees generally have needle or scaly foliage, although in some rare cases they may have rather wide flat leaves, such as the agathis (Agathis australis). Most conifers are evergreen, however some conifers such as larch or cypress lose their needles in autumn.
Conifers tend to have a single main trunk with smaller side branches - this cone-shaped growth pattern helps them to shed snow off their branches in temperate climates. Again, there are a few conifers that are exceptions to this form of growth, such as the Lebanese cedar (Cedrus libani).
Confusion in the classification arises from the fact that the wood of angiosperms is not always hard (a striking example is balsa), while the wood of gymnosperms is not always soft (an example is yew, larch). However, hardwoods tend to be harder than softwoods, and the division of wood into hardwood and softwood has a right to exist.
To begin with, let's assume that we have a tiny little seedling that is just starting its journey to become a big tree. In addition to the main root, main stem, and leaves and primordia of branches, there are growth points at the ends of the stem and root called apical meristems. These growth points are responsible for the vertical growth of the plant.
In addition, between the bark and the inner wood is a thin layer or sheath called the vascular cambium. This magical layer is responsible for almost all of the horizontal growth of the tree. The cambium is made up of reproductive cells that divide to form new bark on the outside and wood on the inside.
It is the seasonal growth activity of the cambium that causes the formation of growth rings in wood: in temperate zones, the cambium is most active in spring (this wood is sometimes called spring or early wood), its activity slows down in summer (summer or late wood is formed) and completely stops in winter. These differences in growing cycles from year to year form growth rings, which are a fairly accurate indication of the age of a tree.
In tropical areas, where temperatures and seasonal variations are minimal, the wood may not have visible rings, or may correspond to different rainy seasons, so it is more correct to call them growth rings rather than growth rings.
Sapwood and Heartwood
As the cambium forms new wood cells, they develop into different types of tissues to perform various functions such as nutrient storage, conduction function, support function, etc. When a tree is young, certain cells in wood are alive and able to conduct or store nutrients, such wood is called sapwood .
After a few years (the number can vary greatly between different tree species), the tree no longer needs the entire trunk to carry nutrients, and starting from the central part of the trunk, the cells begin to die. This dead wood that forms in the center of the trunk is called core .
Certain substances and impurities, commonly referred to as extractives, accumulate in the core. In particular, these extractives are responsible for giving the core its characteristic color: black, red, brown, and any others.
But the extractives of the heartwood are not only responsible for the color, they increase (to varying degrees) the resistance of the heartwood to rot, and also give it additional viscosity and hardness (sapwood has practically no resistance to rot). From a biological standpoint, it's easy to see the benefits that heartwood brings to a tree as it grows taller and wider - and by the way, many of these benefits also translate into benefits for woodworkers.
However, it should be noted that the transition from sapwood to heartwood, commonly referred to as sapwood demarcation, can vary from gradual to very abrupt. A clear demarcation line helps prevent accidental inclusion of sapwood and minimizes the risk of subsequent rot or damage to wood products.
Planes or surfaces of wood
When discussing treated wood and sawn timber, it is important to understand which wood surface is being discussed. Working within the already discussed growth rings and their orientation in the tree trunk, three main planes meet in treated wood.
The first plane of the wood is the transverse (or end ) cut (which is by far the most useful plane for wood identification). On the cut, semicircular growth rings are visible.
The second main plane is radial. Annual layers on the cut in the form of straight lines. It is located perpendicular to the transverse surface, stretches from the center to the cortex.
Third and last surface - tangential . The annual layers are curved on the cut. Stretches along the annual layer.
Although the radial and cross cut surfaces are named after their original sawing method, in practice these terms usually refer only to the angle of the growth rings on a piece of processed lumber, with anything between 45° and 90° being called radial sawing, and anything between 0° and 45°, usually transverse, regardless of how the log was actually milled.
Sometimes there is an intermediate angle, commonly referred to as rustic , which corresponds to growth rings angled between 30° and 60° (with an average of 45°). Although it is called rustic lumber, lumberjacks rarely cut the log on purpose to achieve this angle; usually the name simply serves as a convenient term to describe wood that is not perfectly radial.
In addition, the term face generally refers to the most dominant/widest plane of wood in any section of lumber and does not refer to any particular cut. Observing the angle of inclination of annual rings - as when looking at a stack of boards, where only the ends are visible - one can make a fairly accurate prediction of the appearance of the surface of the board. Likewise, in many cases where only the front of the board is visible, you can imagine what the end will look like. Each cut has different strengths and weaknesses and is used in different areas.
Radial boards are very uniform in appearance and good for flooring. They are resistant to deformation with changes in humidity, which is very useful in many cases, for example, when creating sleepers and beams. However, due to additional processing and a higher scrap rate, radial sawn timber tends to cost more than crosscut lumber.
Most agree that tangential sawn lumber looks more attractive due to its intricate patterns (some logs are specially cut in such a way to obtain such a pattern). Tangential lumber is lighter than radial lumber and is used more often for decorative purposes.
Rustic lumber falls somewhere between the two above. They have a uniform appearance, very similar to radial lumber, and are nearly as strong. You can read more about this here.
The discussion of radial and transverse sawing would be incomplete if we did not mention the most significant visual difference between them: the presence (or absence) of core rays;
Just like a radial cut, core rays radiate from the core of the tree to the bark; for this reason, although core rays are technically always present in wood, they become most visible and pronounced in radial cuts.
But even though almost all woods have heart rays, only woods with wide, prominent heart rays will make a good impression. Perhaps the largest rays are found in breeds such as Rupala (Roupala spp.) and Lacewood (Panopsis spp.).
Non-exotic species such as oak (Quercus spp.