Wood

Wood is the name given to the compact fibrous material that forms the branches, trunk and roots of trees and bushes. The material is made up of ligneous fibres, parenchyma and vessels.
A fuller definition might look like this (from a French standardization text): "Tough complex of secondary tissues (or xylem) forming the trunks, branches and roots of ligneous plants, in which it performs support, conduction and storage functions. It is produced by the cambium (just underneath the bark) and is located between this and the pith. (This does not apply to monocotyledons such as bamboos, palms and rattan)".
The wood of gymnosperms (conifers) is structurally less complex than that of angiosperms (deciduous trees).

The chemical composition of wood is fairly constant at 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen and 1% other elements.
Its component organic compounds are primarily cellulose (about 50%) and lignin (about 20%).
Wood is an anisotropic material, meaning its properties vary with direction (i.e. parallel or perpendicular to the grain).
Wood is an organic material.

Useful resources for books giving technical and other information on wood can be found at:
www.treesource.co.uk
www.woodworkerslibrary.com

Apart from the botanical classification by species, wood can also be classified in various other ways, such as by origin:

• Woods native to France
• Tropical and other imported woods

Both categories include deciduous and coniferous species.

Wood density is another important classification criterion.

Deciduous woods native to France include:

• Very light woods (density 0.4 to 0.5): poplar, willow, lime
• Light woods (density 0.5 to 0.65): alder, birch, aspen
• Semi-heavy woods (density 0.65 to 0.8): hornbeam, chestnut, oak, maple, ash, beech, wild cherry, walnut, elm, plane, pear
• Heavy woods (density 0.8 to 0.95): box, scrub oak, dogwood, mountain ash

Native coniferous woods, in increasing order of density, include pine, cypress, spruce, fir, larch and cedar.

The European Sawmills Organization has developed a quality classification for the visual aspect of sawn timber from oak and beech sawmills. And French standards set out classification rules for dimensional qualities of conifer woods (douglas fir, spruce, pine, fir).
Visual aspect criteria include presence and distribution of singularities and alterations (caused by insects and fungus).
Other, recent, classifications include a text by the French standards organization on the structure of coniferous woods, the aim being to "optimize the use of construction timber by having wood sorted into homogeneous lots of similar strength".

Felled trees are processed to produce basic wood products in many different forms: sawn wood, laminated timbers, wood panels, finished wood parts, etc.
Wood as a material can be used either directly as a raw material in itself (as for making furniture, packaging, etc.) or in the form of derivative materials such as chipboard and plywood. Because it comes in many different varieties, having differing properties and appearances, it has uses in very many applications.
The chart below outlines some of these.