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Solid Timber

WOODS
The strength and lightness of solid timber have been exploited for millennia. The qualities of wood are the result of natural growth and the influence of the elements. Each species of tree produced timber with particular strengths, weaknesses and visual characteristics. Some grow fast, tall and straight; others are slow growing with interlocking grain.

Properties
Wood is a naturally springy, resilient and durable material. It is a natural composite material made up of xylem tissue, which is a fibrous material consisting mostly of elongated, rigid walled cells that provide trees and shrubs with an upwards flow of water and mechanical support.

Wood is a sensual material that is warm to the touch. As a natural, edible and biodegradable material, it is prone to disease, insect attack and decay. An in famous example is Dutch elm disease, which wiped out much of Europe and North America's elm population and is still active today.

Softwoods are coniferous and typically evergreen trees, and include pine, spruce, fir and cedar. Hardwoods are typically broad leaved and deciduous trees. The terms hardwood and softwood are misleading. For example, balsa is very soft and light but is classified as a hardwood, while certain softwoods are dense and hardwearing like certain hardwoods.

Bamboo is a fast growing grass that is harvested and used as a hardwood-like material. It is lighter and harder than many hardwoods. There are many different species of bamboo, which have different rates of growth. Certain species grow up to 1m per day and reach heights of 30m or more. Demand for bamboo is increasing because it is proving to be an economic, environmental alternative to wood in many applications.

Processing
Wood is available for manufacturing as a sheet material, solid lumber, and as chips, particles and shavings. Most timber can be purchased as solid lumber. Limiting factors are price and availability such as in the case of decorative burled wood. Planks more than 150 mm wide are typically stabilised by cutting the wood into strips and bonding them back together alternating directions of growth. This means that as it shrinks and expands the wood works against itself and is less likely to buckle, bow or twist.

Solid timber parts are typically joined by mechanical fixings (rivets or bolts) and adhesive bonding. Suitable finishing processes include polishing and spray painting. For indoor applications no protective coatings are necessary and in such cases solid timbers are often left 'exposed' to maintain their visual appearance. Certain woods can be left 'exposed' outdoors and will gradually turn silvery or grey with exposure to sunlight and the atmosphere. Of the softwoods, cedar and larch produce natural oils that protect them from decay: they can be used untreated outdoors. Hardwoods that are suitable for use outdoors untreated include oak, walnut, iroko and certain exotic species.

Relevant Applications
Bike Frames
Solid timber and bamboo bike frames do exist. However, these materials are inevitably heavier than composites and cannot be designed and engineered to the same precise requirements. The use of wood and bamboo tends to be driven by fashion and a desire to produce a more sustainable product.

Bike Furniture
Solid timbers are suitable for bike furniture in both the domestic and public environments, except in security applications due to the ease with which they can be cut through.