Wood is the main substance in the stems and roots of trees and other woody plants. It is mainly formed by the xylem vessels which transport substances that plants need to live. Substances that xylem transports include water and minerals obtained through the plant's roots, as xylem runs from the roots to the stems and leaves.
Different trees make different wood (see picture below): 1. Pine 2. Common Beech 3. Sycamore 4. Oak 5. Birch 6. Sugar Maple 7. Microberlinia 8. African Rosewood 9. Okoumé 10. Common Walnut 11. Brazilian Rosewood 12. Ebony.
People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses. Buildings like the European Neolithic long house were made primarily of wood.
For certain building projects, like Solomon's temple, wood from the cedar of Lebanon was prized above all other woods. This warm, red wood is free of knots and has a fragrance, which is pleasant to humans, but repels insects, It was in every way an ideal wood for large buildings.
Wood has long been used as an artistic medium. It has been used to make sculptures and carvings for millennia.
The phrase "chip off the block" means a person who resembles their parent, especially in character. A chip is the same wood as the block from which it comes. The expression dates back to 270 BC when it appeared in Theocritus' Idylls.
The phrase by hook or crook dates from around the 14th century. It refers to a time when the poor were allowed to gather as much firewood from their lord's land as they could rake up from undergrowth with a hook or pull down from trees with a shepherd's crook. It was first recorded in the Middle English Controversial Tracts of John Wyclif in 1380.
Grinling Gibbons (April 4, 1648 – August 3, 1721) is widely regarded as the finest-ever woodcarver working in England. Most of his work was in lime (tilia) wood, especially decorative Baroque garlands made up of still-life elements at about life size, made to frame mirrors and decorate the walls of churches and palaces. His exquisite cascades of leaves, flowers and fruit adorn Hampton Park Palace, St Paul's Cathedral and countless other stately homes and churches.
Wood is the hard tissue beneath the bark of many perennial plants. It is composed of water conducting cells, or secondary xylem, and gains its hardness and strength from deposits of lignin. The secondary xylem is laid down by the vascular cambium which forms a new layer of wood annually, on the outside of the existing wood and visible when a tree is felled as an annual ring.
The central wood in a branch or stem is known as heartwood and is generally darker and harder than the outer wood; it consists only of dead cells. As well as providing structural support, heartwood often contains gums, tannins, or pigments which may impart characteristic color and increased durability. The surrounding sapwood is the functional part of the xylem that conducts water.
Woods are usually divided into softwood (from conifers) and hardwood (from flowering plants). Softwood makes up about 80% of the world's production of lumber.
Although in general softwoods are softer than hardwoods, this is not always the case. The difference between hardwood and softwood has to do with how they reproduce, not the hardness of the wood. Pitch pine, for instance, which is very dense and hard, is a softwood.
Cuipo wood is classified as a hardwood. However, according to the Janka test, the softest wood in the world belongs to the Cuipo tree, which has a rating of just 22 lbf (pounds-force) making it is drastically softer than Balsa wood which has a higher, but still very low rating.
The hardest wood is said to come from the Australian Buloke (pronounced "Bull-oak") tree, with a huge rating of 5060 lbf. (For reference, a commonly worked with type of wood that is generally considered very hard is Hickory, which has a1820 lbf rating).
Wood has been an important construction material since humans began building shelters and, houses. Carpenters make houses of mostly soft wood such as pine.
Wood has always been used extensively for furniture, such as cabinets, chairs and beds. For many kinds of furniture carpenters use harder wood such as maple or oak.
Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction.
Wood has a long history of being used as fuel, which continues to this day, mostly in rural areas of the world. Hardwood is preferred over softwood because it creates less smoke and burns longer.
Wood pulp is wood that has been processed in into a pulpy mass of fibres. Its main use is for making paper, but it's also used to make rayon and other cellulose fibres and plastics. There are two methods of making wood pulp - mechanical and chemical. In the former, debarked logs are ground with water (to prevent charring) by rotating grindstones. The wood fibres are physically torn apart. In the latter, log chips are digested with chemicals (such as sodium sulphite). The chemicals dissolve the material holding the fibres together.
Most paper is made from pine, spruce and eucalyptus.
Sources Hutchinson Encyclopedia, Gizmodo
Different trees make different wood (see picture below): 1. Pine 2. Common Beech 3. Sycamore 4. Oak 5. Birch 6. Sugar Maple 7. Microberlinia 8. African Rosewood 9. Okoumé 10. Common Walnut 11. Brazilian Rosewood 12. Ebony.
HISTORY
People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses. Buildings like the European Neolithic long house were made primarily of wood.
For certain building projects, like Solomon's temple, wood from the cedar of Lebanon was prized above all other woods. This warm, red wood is free of knots and has a fragrance, which is pleasant to humans, but repels insects, It was in every way an ideal wood for large buildings.
Wood has long been used as an artistic medium. It has been used to make sculptures and carvings for millennia.
 |
| Prayer Bead with the Adoration of the Magi and the Crucifixion, Gothic boxwood miniature |
The phrase "chip off the block" means a person who resembles their parent, especially in character. A chip is the same wood as the block from which it comes. The expression dates back to 270 BC when it appeared in Theocritus' Idylls.
The phrase by hook or crook dates from around the 14th century. It refers to a time when the poor were allowed to gather as much firewood from their lord's land as they could rake up from undergrowth with a hook or pull down from trees with a shepherd's crook. It was first recorded in the Middle English Controversial Tracts of John Wyclif in 1380.
Grinling Gibbons (April 4, 1648 – August 3, 1721) is widely regarded as the finest-ever woodcarver working in England. Most of his work was in lime (tilia) wood, especially decorative Baroque garlands made up of still-life elements at about life size, made to frame mirrors and decorate the walls of churches and palaces. His exquisite cascades of leaves, flowers and fruit adorn Hampton Park Palace, St Paul's Cathedral and countless other stately homes and churches.
PHYSICAL PROPERTIES
Wood is the hard tissue beneath the bark of many perennial plants. It is composed of water conducting cells, or secondary xylem, and gains its hardness and strength from deposits of lignin. The secondary xylem is laid down by the vascular cambium which forms a new layer of wood annually, on the outside of the existing wood and visible when a tree is felled as an annual ring.
The central wood in a branch or stem is known as heartwood and is generally darker and harder than the outer wood; it consists only of dead cells. As well as providing structural support, heartwood often contains gums, tannins, or pigments which may impart characteristic color and increased durability. The surrounding sapwood is the functional part of the xylem that conducts water.
Woods are usually divided into softwood (from conifers) and hardwood (from flowering plants). Softwood makes up about 80% of the world's production of lumber.
Although in general softwoods are softer than hardwoods, this is not always the case. The difference between hardwood and softwood has to do with how they reproduce, not the hardness of the wood. Pitch pine, for instance, which is very dense and hard, is a softwood.
Cuipo wood is classified as a hardwood. However, according to the Janka test, the softest wood in the world belongs to the Cuipo tree, which has a rating of just 22 lbf (pounds-force) making it is drastically softer than Balsa wood which has a higher, but still very low rating.
 |
| Cuipo Tree |
The hardest wood is said to come from the Australian Buloke (pronounced "Bull-oak") tree, with a huge rating of 5060 lbf. (For reference, a commonly worked with type of wood that is generally considered very hard is Hickory, which has a1820 lbf rating).
USES
Wood has been an important construction material since humans began building shelters and, houses. Carpenters make houses of mostly soft wood such as pine.
Wood has always been used extensively for furniture, such as cabinets, chairs and beds. For many kinds of furniture carpenters use harder wood such as maple or oak.
Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction.
Wood has a long history of being used as fuel, which continues to this day, mostly in rural areas of the world. Hardwood is preferred over softwood because it creates less smoke and burns longer.
Wood pulp is wood that has been processed in into a pulpy mass of fibres. Its main use is for making paper, but it's also used to make rayon and other cellulose fibres and plastics. There are two methods of making wood pulp - mechanical and chemical. In the former, debarked logs are ground with water (to prevent charring) by rotating grindstones. The wood fibres are physically torn apart. In the latter, log chips are digested with chemicals (such as sodium sulphite). The chemicals dissolve the material holding the fibres together.
Most paper is made from pine, spruce and eucalyptus.
Sources Hutchinson Encyclopedia, Gizmodo
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