It looks as though the 21st century will be kind to the fortunes of the various wood industries. Wood is once again a fashionable material because it is renewable, recyclable and its products have low embodied energy.   Our sector must not be complacent, however, about the superiority of wood in this respect. The steel and concrete industries would point out that the elements which make their products are abundant and so renewability is irrelevant. For example, 35% of the earth is iron, 17% is silicon and 1.4% calcium. The latter two are the most important components of concrete. So there is more iron, and components for concrete, than we could ever use.   Another example is water, which is practically everywhere on earth so we do not worry that it is not renewable; it is recyclable.   From this we can learn that any material that is truly recyclable need not be renewable. The recycling of steel and glass is well developed and the recycling technologies for concrete and plastics are developing rapidly.   Therefore the unique selling point (USP) of wood may well become its low embodied energy. The embodied energy of a product is most commonly defined as the non-renewable energy required to make it - the energy needed to procure the raw materials, machining and finishing.   But will wood's low embodied energy guarantee its future success? What if there is a breakthrough in energy production, such as the development of fusion power or improvement in the efficiency of solar energy? Then the level of embodied energy will become less important and wood may lose its USP.   The concrete industry is promoting the benefits of its products by pointing out that, when combined with high thermal insulation, the high thermal mass of concrete provides thermal regulation in buildings. It is generally accepted that 80% of the energy of a building comes from its use and the other 20% is linked to its construction and demolition.   Therefore, thermal efficiency can contribute more to the environment than the choice of low-embodied-energy building materials. It would seem prudent for the wood sector to develop building systems which offer the highest thermal efficiencies; wood based panels can contribute here.   The wood sector must invest in research to develop new products so it can stay ahead of the competition from concrete and steel.