Oak and the Environment

Europe as a whole has seen its forests grow in size over the last 100 years, and much of this can be attributed mainly to improvements in forestry and silviculture. It is now estimated that the annual harvesting of timber in Europe is 25-30% lower than the net annual gain in timber volume. In Britain it is estimated that we only harvest half of the volume of hardwood that grows each year, so it would be possible to double the output without any net loss. This bodes well for the future because not only is timber a renewable resource but our home-grown supply is actual increasing. The Forestry Authority, which is part of the Forestry Commission, sets national standards for the care and management of broadleaf woodlands and also administers grants to encourage further planting. Many woodlands now produce FSC (Forestry Stewardship Council) certified timber or PEFC (Pan European Forest Certification) timber, which gives a Chain of Custody from the forest to the customer, so that you know that the timber you have bought, has been sustainably produced. Although these organisations have their critics, it is still a massive step in the right direction.

The Greenhouse Effect

Greenhouse gases increase warming in our atmosphere, which could lead to dire environmental consequences, unless its progress is checked. The main greenhouse gas is carbon dioxide, which is constantly increasing because of our use of fossil fuels. Trees on the other hand act as a carbon sink and they absorb CO2 during photosynthesis. This locks the CO2 within the tree, until the tree dies and decays, or it is burnt as fuel. This does not increase the net CO2 levels in the atmosphere because only the amount that was absorbed by the tree in the first place is released. Overall CO2 emissions in the atmosphere can be reduced by replacing fossil fuels with carbon neutral wood, but if felled timber is converted into something that has a long term use (longer than the life of the original tree) then a significant amount of carbon dioxide is removed from the atmosphere. Oak frames are a perfect example of this, because the average life of an oak tree used in a frame is between 60 and 100 years, and yet if the building is looked after properly, it will last many hundreds of years.

Embodied Energy

Manufacturing green oak frames requires less energy usage than other forms of general construction made out of alternative products because its embodied energy is so low. This is a measure of how much energy is required to extract, and/or manufacture, and/or treat and transport to where it is going to be used. For example, the approximate embodied energy of locally produced green oak is 220 kWh/m³, where as steel is 24,700 kWh/m³ and aluminium is 141,500 kWh/m³. Unlike other timber in construction, green oak does not need to be wholesale treated with preservatives, which have been known to pollute soil and watercourses.