Wood

Wood is a natural organic material that has been used for many centuries for the construction of buildings, bridges, and a variety of other structures. It remains an important construction material today as research and improved technology have led to a better knowledge of the material behaviour. Timber has many important attributes. It has a warm texture and attractive appearance and is often used for internal finishing and the main structure. It is easy to work with and can be produced in a wide range of shapes and sizes. It has a high strength-to-weight ratio and has good thermal insulation properties. Timber can be used compositely with concrete and steel. It is the only construction material that does not contribute to greenhouse emissions and is a fully renewable and largely recyclable material.

Softwood – wood of coniferous tree species, generally less dense than hardwood

Hardwood – wood of broad-leaved tree species, generally more dense than softwood

Differences in wood anatomy of softwood and hardwood

Softwood anatomy

Anatomical elements (types of cells):

a) tracheids

vertical -- axial cells (length up to 5 mm); physiological function: both water transport and mechanical support

horizontal -- ray tracheids (only in some species) -- a part of ray; physiological function: water transport in horizontal direction

b) parenchyma cells

form anatomical structures:

- rays – horizontal bends of parenchyma cells (in some species with ray tracheids); physiological function: food storage

- resin ducts (only in some species) – intercellular species surrounded by parenchyma cells. Vertical and horizontal direction. Only in all species of the following genera: Picea, Pinus, Pseudotsuga, Larix.

- longitudinal parenchyma (only in some species) – axial bends of parenchyma cells; physiological function: food storage

Hardwood anatomy

Anatomical elements (types of cells):

a) vessels -- axial cells with fully or partly open endings (perforation plates); function: water transport

b) fibres – axial cells; physiological function: mechanical support

c) tracheids (not in all species) – axial cells, three types: vascular, fibrous, vasicentric

d) parenchyma cells

form anatomical structures:

- rays – horizontal bends of parenchyma cells; physiological function: food storage

- longitudinal parenchyma (only in some species) – axial bends of parenchyma cells; physiological function: food storage