Greening our concrete jungles: how trees heal a city

With reforesting on the rise across Britain, Joe Shute looks at the ways greenery can help our urban areas

There is very little art to planting an oak sapling: dig a decentsized hole and back-fill it with mud, ensure that the base of the trunk is level to the ground and surround it with a ring of wood mulch. In Lostock Park in south-west Manchester, at this time of year, you don’t even need to add water: the glowering skies above will make sure of that.

It may take mere moments to plant, but high hopes rest on this small tree. Should it survive urban vandals and wayward footballs booted from the playing fields opposite, it will become part of a new woodland being planted in this urban scrub on the edge of the park by the Manchester organisation City of Trees. Since 2015, the group has planted more than 750,000 trees across Greater Manchester and aims to soon plant more than three million – one for every citizen at least – creating a vast canopy across the city.

Nearby, traffic hums along the M60 and over the ring road is the sprawling behemoth of Manchester’s Trafford Centre. It is far from the most bucolic location for a new woodland but that, explains Beth Kelsall, a 32-year-old delivery manager for City of Trees, is exactly the point.

“More than anything it is the connection between trees and people that make them really valuable,” Kelsall says. “We are in a concrete landscape basically, so it is really important that trees have a place.”

For years tree-planting has been hailed by successive politicians as a key tool in abating the worst impacts of climate change. Though in rural areas this is proving something of a difficulty – the pledge by former prime minister Boris Johnson to plant 30,000 hectares of new woodland every year by 2024 is currently languishing around 14,000 hectares at the most recent count, with concerns that vital habitat such as peat bog and ancient grassland may be grubbed up by ill-planned forest planting.

Meanwhile, Britain’s towns and cities have embarked on something of a reforesting revolution, with trees increasingly seen as vital to keep our cities liveable. Earlier this year, the UK registered a record 19 entries in the Arbor Day Foundation’s Tree Cities of the World programme, which recognises urban areas that are creating and maintaining community green spaces. During next week’s national tree week, planting of urban trees will play a starring role.

Not all cities are equal, of course. According to a report by scientists from the University of Sheffield and Flinders University in Australia, the UK’S least green city – with tree population a key factor – is Glasgow. In contrast, Exeter is the British city with the most green space, beating Islington, Bristol, Bournemouth and Cambridge – all in the south – to claim the top spot as Britain’s greenest urban area.

And it is increasingly obvious how badly we need them. As Britain sweltered in record 40C temperatures this summer, street trees helped cool city pavements. In the increasingly severe winter floods trees act as sponges soaking up surface water and helping prevent the sewers becoming deluged (parts of the south-east have in recent days recorded half a month’s rainfall in a matter of hours). Urban trees can also help improve air quality by trapping toxic particles on their leaves and provide vital habitat for wildlife.

Experts say the current treeplanting revolution is on a par with the grand planting schemes of the Edwardian and Victorian era, which created many of the avenues still lining our cities today. But with a key difference. Today’s urban trees are being planted in increasingly innovative locations and with a far more diverse mix of native and non-native species to enable them to survive. In short, a new urban forest is rapidly taking shape around us that will transform our towns and cities in the process.

London’s 1960s-built Blackfriars Crown Court, for example, is currently the subject of a planning application to repurpose the building into an office and community space with a 1.4-acre urban forest on the roof – something the developer claims is the first of its kind in the capital. In 2020, Earthwatch partnered with Witney Town Council in Oxfordshire to plant what it described as the UK’S first ever “tiny forest”. The forests are based on a 1970s Japanese planting method to pack 600 trees on top of a tenniscourt-sized patch of land, making them highly suitable for urban areas. Over the past two years the forests have been planted in dozens of urban locations across the UK.

Trees are also being incorporated into larger sustainable urban drainage schemes which are designed to hold vast amounts of rainfall and prevent sewers being flooded and, in turn, reduce the amount of sewage being discharged into rivers. Back in Greater Manchester, City of Trees has recently installed such designs in Salford, Prestwich and Bury.

They don’t come cheap. The installation on Howard Street in Salford, for example, cost between £7,000 and £10,000 per tree spanning a 20-metre long pit. But the scheme has reduced the speed at which rainfall enters the sewer by 81 per cent. Plus it is estimated that every £1 spent on trees saves the UK £7 in healthcare, energy and environmental costs. “This isn’t a luxury thing to have but an essential thing to make cities more resilient to extreme heat, rain and poor air,” insists Pete Stringer, green infrastructure resilience manager at City of Trees.

And yet cost remains a prohibitive factor in expanding urban forests, with many cash-strapped local authorities unable or unwilling to fund large-scale planting. Increasingly community sponsorship schemes are being adopted to help counter this with streets or local groups raising money themselves to fund new planting.

The Uk-wide organisation Trees for Cities has created a new platform called Trees for Streets which partners up with local authorities to match-fund neighbourhood planting schemes. Chief executive David Elliott says it already covers one third of London local authorities and is expanding out to Bristol, Cambridge and Leeds among other cities. Over the next decade, it plans to help fund 250,000 urban trees.

An obvious downside of communityfunded planting is that it could lead to richer areas becoming greener and more deprived neighbourhoods missing out. Trees for Streets says its scheme can help free up council funding for more deprived areas while the Woodland Trust is currently embarking on a “tree equity” research programme in Birmingham to map the link between urban canopy cover and housing density.

According to Elliott, we are shifting from the single species avenues planted by Victorians and Edwardians to an “urban arboretum” of smaller, more mixed trees. “We are creating this fascinating cocktail where rather than fewer, bigger trees there is lots of space to put in smaller growing species,” he says. “There are so many opportunities in really creative spaces to see our streets covered in trees.”

A similar community planting scheme has been implanted in Sheffield following the felling scandal which led to thousands of healthy trees being removed across the city prompting massive protests and global headlines. The trees were cut down after the council signed a £2.2 billion PFI contract with highways provider Amey to manage its roads which included a controversial target to fell 17,500 trees in a city which last year was voted England’s greenest.

The felling was ultimately halted following a wave of protests; an independent inquiry into the disastrous saga is currently ongoing. A street tree partnership has also been established enabling community groups to fund their own planting across the city.

Catherine Nuttgens, who previously worked as a tree officer and community woodland manager at Sheffield Council and is now urban programme lead for the Woodland Trust, says ultimately the protests demonstrated the strength of feeling people have for their street trees. “Doing a Sheffield” has now become a common phrase, meaning many local authorities are now increasingly aware of the importance of preserving street trees.

“People are still very connected to their trees and the trees ultimately are what gives that urban pride,” says Nuttgens. “They are living monuments in the landscape.”

‘More than anything it is the connection between trees and people that make them so valuable’