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Marking-out
Bending, shaping & forming woods
Wasting processes
Jointing methods
Testing materials
What is wood?
What is wood?
Wood is the name given to a class of very unique material which is naturally sourced mainly from trees, however it can also be obtained from shrubs and bushes, in smaller quantities and in processed form.
Wood is fibrous (contains natural fibres) and it is also porous (full of micro-holes). The structure of wood is unique in that it is orthotropic. This means that its properties are unidirectional - the are unique in one direction.
The anatomy of a tree
The anatomy of a tree
What is wood made of?
What is wood made of?
The chemistry of timber
The chemistry of timber
Wood is composed of cellulose fibres (about 40%), hemicellulose (about 25%), lignin (about 25%), and about 10% organic/inorganic other materials (such as calcium, sodium, magnesium and other elements).
Cellulose is a complex carbohydrate, and unbelievably also a naturally occurring polymer (think plastic). It is used to form the cell walls of a plant. Lignin is also a naturally occurring polymer. Its function in wood is to help provide rigidity. In other words, it helps stop the wood from being 'floppy' and retain its shape/form.
What are the advantages and disadvantages of wood?
What are the advantages and disadvantages of wood?
Advantages
It's a renewable material. ...
It lasts a long time. ...
It can be recycled and reused. ...
It absorbs carbon dioxide. ...
It's great at retaining heat. ...
Its waste is 100 per cent biodegradable. ...
It has a positive effect on your physical and mental health.
Disadvantages
Disadvantages
The main disadvantages of wood are:
It is porous and attracts moisture. Where moisture and warmth exist, bacteria, fungi and mould can grow and thrive. These feed off of the wood and attack it, breaking it down. To prevent this, wood must be sealed and preserved.
In some climates it is attractive to certain 'pests' such as termites, beetles, ants and bees. These attack the wood as in 1 above.
It has irregular properties. Every tree (and therefore trunk, branch, plank and strip) is different. This means the mechanical properties of wood are inconsistent, and therefore unreliable. Trees are also susceptible to changes in climate and environmental conditions. For example changes in sunlight and water availability (e.g. drought) can drastically affect timber reliability.
It can be heavy. Sometimes this is undesirable in certain uses.
Is wood an old material?
Is wood an old material?
Because wood has been used since the early days of mankind as a structural material, there is a temptation to think of it as an old material, no longer relevant in today's world, where things like plastics and composites exist.
This could not be further from the truth. Nowadays, there are many modern wood derivative materials and engineered timbers available.
An example of a modern wooden structure, the 'Metropol Parasol', a wooden sunshade for pedestrians in Seville, Spain.
Wood and its impact on our environment
Why we need trees?
Why we need trees?
Deforestation
Deforestation
Environmental impact of wood
Environmental impact of wood
Wood Revison Help Videos
How is wood made?
How is wood made?
What's the difference?
What's the difference?
Properties of common woods
Properties of common woods
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