Why wood shaped, and still shapes our world
Timber’s beauty, strength and suppleness means it remains a crucial ingredient within contemporary architecture
Does wood still have a place within our modern thickets of building? Yes, believe the environmental writer and broadcaster Richard Mabey, because timber can possess so many different physical properties.
“Wood is a smart material,” writes Mabey in the introduction to our new architectural title, Wood. “Its complex internal structure and ageing processes mean a single piece can behave quite differently as circumstances change. A section cut across the grain will be brittle, and a blow can split it along the channels of the annual growth rings. Cut along the grain, it will be supple and springy. It won’t snap under pressure, but it may splinter along the fibres. As it ages and dries out, wood moves towards the toughness and density of stone, but never entirely loses the ‘give’ provided by its cellular structure.”
In Britain, a tree’s life span imposed certain restrictions on earlier domestic architecture. “Most sixteenth to eighteenth-century timber-framed cottages and farmhouses constructed in this region are 5.5 – 6 m (18 – 20 ft) wide – the length of usable timber in a tree thirty to seventy years old,” Mabey writes. “These dimensions were dictated by the way oak timber was grown in historic times.”
Yet dimensions have since been greatly surpassed thanks to modern building techniques, which exploit the material’s strengths. Indeed, trees themselves can offer engineers structural guidance, as Maybe explains.
“Immobile trees have a special trick that helps them to cope with stresses: they grow what is called reaction wood,” he writes. “Reaction wood forms wherever a stress has to be countered or the sinews of a tree strengthened. In deciduous trees it’s called tension wood, as it forms on one side of a limb to pull it back into position. In conifers what’s called compression wood pushes the wood back. Compression wood is denser than ordinary wood, reddish in colour and has thicker cell walls. Tension wood is paler and more elastic. Both types create bulging and asymmetrical grain patterns, rather like the cross-section of a bicep. It’s perfectly reasonable to see an analogy between reaction wood and permanently clenched muscle. I’ve seen living trees, tilted by as much as forty degrees from the vertical, respond by growing great hawsers of tension wood on the back of the trunk, hauling it back, or at least attempting to prevent any further tilting.”
These physical properties means architects will still favour timber for decades to come, while we can enjoy the way, unlike glass and polished steel, wood also ages with remarkable elegance.
“Patterns of use are progressively revealed, while the narrative of the seasonal rings is more clearly exposed and the logic of the structure emerges into plain sight,” writes Mabey. “Flat surfaces become conciliatory, corners turn equivocal, straight lines curve, the continuous becomes fractured and the whole built structure shifts towards the organic fuzziness of the growing tree. In the end the timbers decompose, return to earth and are recycled as new trees, and the ultimate virtue of wooden architecture – sustainability – is confirmed.”
For greater insight into the place of this most natural of materials in the built environment order a copy of Wood here.