August 7, 2019

Summer in the city isn’t all it’s cracked up to be. Your colleagues have gone to the beach and left you holding the fort. It’s hot, humid and crowded. Bin lorries trail waves of stink behind them. On the pavements, dried-up rivulets of urine add to the urban bouquet. Roads are choked with locals trying to get out and tourists trying to get in. Sunlight meets vehicle exhaust and the atmosphere takes a photochemical dive.

But one thing can make it all better – the common grace of greenery. Foliage has many proven benefits – it not only shades and cools, but also improves aesthetics, acoustics and air quality.

It’s ironic that, despite all our advances in civil engineering, the force we rely on most to re-civilise the city is what we design our buildings to keep out: nature.

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In quite the turnaround, we’re now using technology to make room for nature on every available surface – and not just the horizontal ones. Writing for The Guardian, Harriet Sherwood looks at the increasing popularity of the vertical garden or ‘living wall’:

“Living walls range from simple wire structures to support climbing plants to sophisticated modular systems, using soil or hydroponic manmade substrate, and solar-powered irrigation. The cost ranges from £200 to £800 per square metre.”

These had a bad reputation for a while – thanks to to some very visible failures when expensively installed living walls (and green roofs) died off. However, maintenance systems are improving – and will only get better. Indeed, here’s a prediction: one of the most visible signs that a society has truly reached ‘the Robot Age’ will be that its cities turn green – an army of little climbing drones weeding and watering vertical gardens everywhere.

Of course, we already have a widely available system for maintaining large amounts of foliage several storeys up in the air – it’s called a tree.

On phys.org website, Ben Long describes a recent study from the University of Wollongong. The researchers found that urban tree cover had a measurable impact on physical and mental health:

“In neighbourhoods with a tree canopy of 30 percent or more, adults had 31 percent lower odds of developing psychological distress, and 33 percent lower odds of rating their general health as ‘fair’ or ‘poor’ over six years…

“The longitudinal study tracked the changes in health of around 46,000 people aged 45 and older living in Sydney, Newcastle and Wollongong. Statistical analyses took into account other possible explanations, including differences in age, sex, income, education, employment status, and relationship status.”

However, not all green space is equal:

“Urban green spaces with open grass rather than a tree canopy did not deliver the same benefits.”

Why the difference? Ben Long mentions the shading and cooling that trees provide, but also “sensory relief in urban areas dominated by hard surfaces, right angles, glass and concrete, and intrusive, attention-seeking advertising.”

The cynic might observe that trees make the urban environment better because they cover it up. Certainly, one can discern a philosophical difference between the ‘tree-lined avenue’ of traditional urban architecture and the ‘towers-in-the-park’ ideal of the modernists. With the former there is a subtle interplay between the natural and built environments; with the latter, nature is pared back to give the artificial a position of unchallenged dominance.

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One could go even deeper and go with the theory that traditional architecture is arborial in origin and inspiration. The pillars and arches of our buildings; the perpendicular framing of their doors and windows; their vaulted ceilings and the tracery of their ornamentation: all are echoes of the forest.

Indeed, the fundamentals of a pleasing streetscape – texture, colour, variation in a pattern, the fractal order of form and structure – are essentially natural.

Modernist architecture is a rejection of those qualities – and thus of nature itself. I’m not surprised that our bodies and minds suffer in the impoverished environment thus constructed.

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Repairing the damage we’ve done is the work of many generations, but there are things we can do to start making a difference right now. Writing for The Conversation, Olivia Norfolk explains that councils up and down the country could do something important by not doing something:

“Plantlife, a British conservation charity, has called on councils to turn their road verges into wildflower meadows by cutting just once in late summer, between mid-July and September. Cutting late gives flowers time to be pollinated, produce fruit and then set their seeds in the soil, so that the meadow can grow back year after year.”

Cutting less often and later would produce real benefits for biodiversity at no financial cost – indeed, it would save money.

According to Dr Norfolk, the UK road network is 246,000 miles long – so presumably that means nearly half a million miles of verges. Obviously, not all are suitable for wildflower meadows, while others have them already. But it’s a reminder of just how extensive the built environment is in this country and its potential significance as a habitat for wildlife.

Almost everywhere we look we have opportunities to welcome nature back into our lives. And it’s not only biodiversity that would flourish, but also human wellbeing.

If our new government is looking for a post-Brexit national mission, then the greening of our towns and cities would be a wonderful place to start.