How is wood made


The ways in which wood is processed are extremely varied, because the wood must be prepared accordingly for the many different uses. You can't tell from some products that they contain wood, as is the case with paper, for example. This example shows that wood is by no means always left in its original shape. The beginning of the use of wood, the felling of trees, is explained in the subchapter wood harvest with the help of many illustrations. We would like to take a closer look at the further path of wood and processing variants here:

Wood gas and wood spirit:
If wood is heated to 300 - 800 ° C in the absence of air, a combustible gas is produced, the wood gas. It consists largely of carbon dioxide and carbon monoxide and to a lesser extent methane, ethylene and hydrogen. This gas is no longer used for heating, as the calorific value is nowhere near as high as that of town gas. Wood gas can also be used as fuel for cars and trucks.
In addition to the wood gas, the process of dry distillation also produces a liquid called wood spirit and organic compounds such as methanol, acetone and some org. Contains acids. In the past, this process was used to produce methanol.

Papermaking:

Paper is probably one of the most important products made from wood. The production of paper has a long history and has been gradually modernized. The manufacturing process consists of several steps, starting with the cutting and chipping of the trunks, through the extraction of cellulose and the further processing of the fibers. It would be going too far to describe the whole paper-making process here. The papermaking process is explained in more detail under the following links:

Wikipedia

Hamburger-Spremberg paper mill

Firewood:
Heating with wood is becoming increasingly important. Not only because it is cozy to sit in front of a fireplace or tiled stove, but also because of the economic and ecological advantages. Wood is a renewable resource, which means that if the rate of deforestation is properly determined and growth is not impaired, the resource will never run out. Fossil fuels such as crude oil or natural gas will one day become scarce. As a result, the prices for fossil fuels are also rising faster than those for wood. In the case of wood pellets, the release of CO2 is roughly the same as the CO2 uptake of the tree; one speaks of a neutral ratio. Wood pellets are small pieces of wood that are 6-8 mm thick and 5-45 mm long and are produced in special systems. Residual wood (chips, sawdust, etc.) is pressed under high pressure.

Wood fuels: from left to right: grill briquette, bark briquette, wood chips, wood pellets



Construction and utility wood:
A large amount of the felled tree trunks are transported to a sawmill and there the wood is processed to obtain beams, boards, veneers, etc.
If the wood is not dismantled and reassembled, it is called solid wood. First of all, a distinction can be made between construction timber and sawn timber. Construction logs simply consist of debarked and delimbed trunk sections. Making this wood is very easy and inexpensive. It is used e.g. for posts.
Sawn timber can be divided into the following categories, depending on the size:

There are also grading classes for sawn timber. A distinction is made between low load-bearing capacity, normal load-bearing capacity and above-average load-bearing capacity.
In addition to solid wood, there is also glued laminated wood, which consists of several layers of glued boards. The advantages are greater resistance to moisture and the structure, as knots and cracks can be avoided.

Plywood:
Plywood is made by gluing thin layers of wood on top of each other, with the grains crossed between two boards. Plywood panels are assembled from veneers or strips.


Chipboard:
Wood waste, sawdust and waste paper are used to manufacture chipboard. With the addition of binding agents such as synthetic resin or plaster of paris, the chips are pressed into panels. Chipboard is very inexpensive and is used as blind wood. This means that, e.g. for furniture production, veneers are glued onto chipboard in order to make the piece of furniture look appealing.

The sawmill collects chips that are used to produce chipboard

 

Veneers:
Veneers are thin sheets of wood that are between 0.05 and 8 mm thick. They are peeled from tree trunks and can be over 5 m long. Because veneers are so thin, large quantities can be extracted from one tree trunk. Panels can be made from veneers by gluing them together. However, they are often used in furniture production. They are glued to chipboard or plywood and the piece of furniture gets its typical look, even though it is not made of solid wood. Other possible uses are cladding and wooden floors.

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