Furniture designer Luke Hughes' lecture on designing with sustainable hardwood was a fascinating discussion on the benefits of this exquisite and unpredictable material - not least for the ensuing debate on responsible sourcing and deforestation.
SAFE SOURCING Timber, we are told, is back in vogue. The diversity in the grains and hues across a huge variety of species ensures that every designer can add a unique signature to their buildings.
And in an age of rapidly depleting construction resources, timber has the added benefit of being a naturally regenerating material. So rich are the planet's resources that the American Hardwood Export Council (AHEC), the primary American hardwood lobbying group, estimates that there are more than 295 million hectares of available hardwood in the USA alone.
But while few would question timber's environmental credentials, the issue of sustainable sourcing continues to rattle cages across all camps.
Luke Hughes used Greenpeace's own data to argue that only 1.01 per cent of all tropical 'forestry' is used for industrial purposes, including construction and furniture. Of this figure, only about 18 per cent (or less than 0.2 per cent of all tropical forest depletion) enters international trade. The major causes of deforestation are identified as poverty, population pressures and shifting agriculture. Persuasively, he explained that healthy markets for wood products will actually help to prevent deforestation, encouraging those countries to follow carefully monitored forest management. Suddenly it's relatively simple economics: boycotts may only serve to decrease the value of the land, thus endangering the future of those very same forests that could be a nation's economic saviour.
'And the one power that is truly irritating, ' stated an incensed-looking Hughes 'is the Forest Stewardship Council. All this drive for certification has done is to add a margin onto timber costs, making the situation worse. It's riddled with bureaucracy and anyway, certificates can always be bought.' 'So what do you suggest architects do?' piped up a slightly confused Bill Gething of Feilden Clegg Bradley Associates, who, incidentally, is also RIBA's advisor on sustainability. 'Do we just take their [the suppliers'] word for it?' Absolutely not, was Hughes' retort: 'Look at the data on websites, check sourcing by region and state, look closely at the policy and systems followed.
With European and USA sources there is a 95 per cent chance it is certified - even if it doesn't say it.' Hughes also recommended looking at guidelines set by, among others bodies, the American Tree Farm System (ATFS) and the International Tropical Timber Organisation (ITTO).
THOUGHTFUL FIT-OUT Responsible sourcing isn't the only way to follow sustainable ambitions and it didn't take Hughes long to broach the tricky subject of office refits. 'We are now in our third generation of Canary Wharf fit-outs, ' he lamented. 'That's rather extreme, but you can expect most offices to have an overhaul every 12-15 years or so, usually when a new CEO takes over or at the end of a lease. Considering timber furniture can have a life expectancy of centuries, depending on use, it's a terrible waste.' One way to avoid costly wastage is to use veneers, on table tops for example.
Although these don't take kindly to impact and are difficult to repair inconspicuously, slip matching allows boardroom table tops to achieve uniform colour and design and alleviates the heartbreak of disposing of beautifully crafted solid-timber units.
Where furniture is desired for institutional buildings, such as museums, colleges or churches, the intended life may be 50-100 years. In these cases, there really is no substitute for solid timber, especially where resistance to knocks and abuse is specified as standard.
KNOW YOUR WOOD Being able to predict how timber will behave is another good way to eliminate not just wastage but potentially destructive problems to do with distortion once the material is in use. It is important to remember that:
? Timber expands and contracts in width - not length;
? Movement is related to humidity, not temperature. An oak-top table 1m wide (if made when the moisture content is at 20 per cent), will shrink by 2cm when the moisture content is reduced to 12 per cent*; and - Boards tend to cup away from the tree's heart, so look for perpendicular rings to guarantee optimum stability (see diagram).
Hughes also explained that timber sourced from densely planted areas is less likely to distort because the trees grow straighter. So use the most appropriate cut of timber and if you do use solid sections, keep them to the most feasible dimensions.
Hughes stipulated that it is vital to know what sizes are available.
Also, be aware that all exposed timber surfaces will change colour upon exposure to light and air: light timbers tend to get darker and vice versa, while sunlight will have a dramatic bleaching effect.