WOODS

DESIGN AND TECHNOLOGY

2º ESO

TREES, A LIVING RESOURCE Wood is one of the most abundant

and versatile natural material on earth.

Wood comes from trees. Wood is made up of cellulosecellulose grains

(fibras). Trees contain other substances such

as water, oils, resins, mineral salts...

What is sapsap?It’s a solution of water and nutrients that circulates in the tree from

roots to trunk, branches and leaves.

WOODS GIVE US... HEAT. TOOLS AND

WEAPONS. CONSTRUCTION

MATERIALS. RELATED PRODUCTS:

paper, cardboard…

PARTS OF A TRUNK

1.1. BARK (BARK (cortezacorteza):): it is the most external layer of the tree and protects tree from damage (extreme temperatures, bad weather, insects).

2.2. CAMBIUMCAMBIUM ( (llííberber): it takes the sap from the roots to the various parts of the tree.

3.3. SAPWOOD (SAPWOOD (alburaalbura): ): the youngest part of a trunk, which has a clear colour.

4.4. HEARTWOOD (duramen):HEARTWOOD (duramen): it is the part of a trunk that gives harder and more consistent wood. It is the wood used for making things.

PARTS OF A TRUNKHow old is a treeHow old is a tree?

It’s possible to know how old a tree is thanks to the annual rings are seen when a trunk is cut.

The clear rings represent the tree´s growth in spring and the dark ones are related to autumn, when its growth is lower.

THE PROCESS TO GET SOLID WOOD

TO FELL (TALAR): It is carried out in winter. Bark and branches are all removed from the tree and they are used for gardens or like a combustible.

TIMBER TRANSPORTATION (TRANSPORTE): To carry timber to sawmill by lorry, train or fluvial/maritime transport.CUTTING UP (CORTE): Timber is cut in different pieces and sizes in the sawmill.

THE PROCESS TO GET SOLID WOOD

DRYING (SECADO): It consists of removing natural moisture from timber. This can be done in two ways:

NNaturalatural (slower and cheaper) and with kilns orkilns or air-driedair-dried (quicker but more expensive)

WOOD PROPERTIES How does it feel?: Color, texture, brightness… Hardness: Can tools, nails, screws...make holes in it?

Does it wear or scratch by other objects? Density: It depends on mass and volume. Let us know if it

is a heavy or light wood. Moisture content (grado de humedad): Different woods

have different mass of water and their properties and durability depend on it.

Thermal and electric conductivity: Woods are not a good conductor of heat and electricity.

Strength: The ability to resist forces without breaking and bending depends on the type of wood. It´s very good when forces act along the grain (fibra).

Renewable.

TYPES OF WOODROBLE

HAYA

PINO ABETO

HARDWOODHARDWOOD

Deciduous (hoja caduca) trees which drop their leaves in winter and are the typical round top tree shape.

SOFTWOODSOFTWOOD

Coniferous (coníferas), which are cone bearing evergreen (hoja perenne) trees which generally have the typical Christmas tree triangle shape.

Softwoods are cheaper than hardwoods and easier to work.

Hardwoods are attractive woods but they are not easy to work.

PINE

OAKWALNUT

BEECH

FIR

MAN MADE WOODSMan-made wood has been made up of bits of

wood which originally came from a tree.

CHIPBOARD

AGLOMERADO

PLYWOOD

CONTRACHAPADO

HARDBOARD

TABLEROS DE FIBRA

WORKING WITH WOODTo make a wood object we must follow the next steps :

MEASURE, MARK AND DRAW

HOLD

CUT AND SAW

DRILL

PLANE AND SAND

JOIN PIECES

FINISH

COMMERCIAL WOODSNatural woods can be sold with different shapes:

Thick plank Wood sheet Strip

Frame PlankBoard