A NEW LEAF

SOMETIMES WHAT’S RIGHT IN FRONT OF US WE NOTICE LEAST. HELEN BABBS URGES US TO TAKE TIME TO WONDER AT THE TREES STANDING SENTRY ON OUR STREET CORNERS

When I first moved, aged 18, from the suburbs to the inner city, nature wasn’t the thing that drew me in. But, 18 years later, it has strangely become one of things that has made me stay. The juxtaposition of the natural and the artificial intensifies the pleasure, and I love the fact that there’s more to urban areas than just the human-made.

Trees are some of the most obvious examples of what’s wild in the city. Massive but static, they line the streets I walk, sprout up along my rail routes and cycle paths, and furnish the parks where I eat my lunch. They’re what I stare at through the office window. In a hermetically sealed workplace, watching leaves brighten, darken and dance helps bring the outside in.

In contemporary cities, trees do an awful lot of good. They limit the impact of heavy weather, be it intense sun or torrential rain, reduce air and water pollution, and improve the soil. Regular access to nature also improves our physical and mental health, whether we purposely seek it out or swallow it by accident.

While a forest in the traditional sense is a geographical entity, the urban forest is a patchwork of different, unconnected landscapes and individuals. Urban forestry recognises that trees have spiritual worth as well as practical value, and it’s about people as much as it’s about plants. The trees in a city have amenity value. The point of them is to please you and me, and to improve our quality of life.*

Many of us welcome the presence of these quiet colossi into our lives without knowing them by name. But, as with human relationships, an unnamed tree essentially remains a stranger. Why not get closer to the trees around you this summer by learning a bit more about who they are?

SILVER BIRCH

One of the most common trees in central London, the birch is small and fast-growing, with decorative catkins and pale, papery skin. Its black and white bark has a graphic quality that makes it a design favourite, but this tree gives city dwellers more than aesthetic pleasure: it offers us protection too. While all trees are imagined to improve the air, studies show that birch is one of the best. The tree’s loose, spumy canopy allows air to circulate and flow freely through it, while its leaves are covered in microscopic hairs and ridges that help trap passing particles. When it rains, this trapped particulate matter washes away, freeing the foliage to catch more. So, while birch is in leaf, it acts as an excellent pollution filter.

COMMON ELDER

The elder is in the habit of growing on the edges of things, often where it’s not supposed to, and »

is sometimes accused of being a weed. You might spot one sprouting up on a neglected patch between buildings, a railway siding, in a car park or your neighbour’s unkempt backyard. A plant revered by medical herbalists, the elder is one of the first trees to come back into leaf after winter, and is covered with cheerful, strong-smelling flowers in spring. This blossom can be dried, then made into tinctures and teas, as well as cordial and champagne (see The

Simple Things issue 83), all of which are good for treating hayfever, colds and flu. In summer those dense, cream blooms will sun-ripen into bunches of vitamin-rich black berries that droop on crimson stems.* Freshly harvested elderberries can be simmered to make tea, baked into pies, or dried and used like raisins.

COMMON FIG

The fig has a domed and wide-spreading crown, with branches that twist and turn, and lobed dark leaves that are large and leather-like. It’s one of the world’s most common rainforest plants but it’s found in urban jungles too. In fact, in Sheffield you’ll find numerous figs growing wild along the chilly River Don, which is remarkable considering the tree’s preference for balmy weather. Local ecologist Oliver Gilbert discovered that the trees had established themselves back when river water was used by the steel industry for cooling and the Don ran at a constant 20C as a result. Sewage was also flowing into the river. Fig seeds found in the sewage germinated along the riverbank, fooled by the warm water into thinking they were somewhere hot. But my favourite explanation for the presence of the seeds is local people’s partiality for fig biscuits.

HORSE CHESTNUT

The horse chestnut is one of our largest urban trees, and one of the most easily recognisable because of its autumnal nuts. Conkers – which are rumoured to have once been used medicinally to treat hoarse horses suffering from coughs – are unmistakable. A spiky green jacket conceals a beige bellied, mahogany-brown nut, which is always appealingly smooth and glossy when it’s first prised out of its protective coat. Although I love conkers, I enjoy the horse chestnut more in summer these days. It’s an ideal tree to seek out if you’re craving a pool of deep shade. Its large leaves are palmate (meaning hand-like) with five to seven fat fingers radiating out in a circle from a central point. Brought over to the UK from Turkey in the late 1500s, the horse chestnut has since proved a popular planting choice for grand boulevards across Europe, particularly in Paris.

COMMON ALDER

The common alder has distinctive foliage and fruit, making it easy to pick out. Its leaves are dark green, leathery and round; never pointed but sometimes indented at the tip. Green female catkins ripen into small, woody brown cones that are stuffed with seeds. The alder tree is celebrated for its ability to improve soil quality, and landscape architects call on it when they have contaminated land to reclaim. ‘Phytoremediation’ is a way of using plants to restore balance, and an abandoned urban site might be planted with alders as part of its transformation from industrial to recreational. It’s not only in life that alder is useful – once it is felled for timber, alder wood is soft and porous and is only durable when kept wet. Rather than rotting, this timber is most effective when it’s waterlogged, which is why much of Venice is built on alder piles cut from strong tree trunks. Alder is part of Venice’s strength and support. It helps hold the city in place.

MAIDENHAIR TREE

The maidenhair tree – better known by its botanical name, Ginkgo – is the sole surviving member of a family that thrived during the time of dinosaurs, between 250 and 65 million years ago, during the Mesozoic Era. Once mostly found in botanic gardens, where it would have been one of the more noteworthy and prized specimens, ginkgo is most likely to be spotted growing along city streets, selected for its capacity to survive pretty much anything the world cares to throw at it. In polluted cities facing up to a climate emergency, and the extreme conditions it is bringing, the ginkgo seems to be a tree we can rely on to cope. It’s easy to spot because its leaves have a shape unlike any other you’ll find in the urban forest. They look like the half-unfolded wings of a butterfly, with the outline of an outspread fan.

MARITIME PINE

As its name suggests, the maritime pine is a tree of coastal areas. This pine grows tall and usually poker straight, but sometimes at a wild angle. Low branches are rare, and its canopy balances high up its bare trunk like a bird’s nest atop a ship’s mast. Despite being most frequently encountered in the Mediterranean, it has such a strong association with one English seaside town that it’s also known in the UK as the ‘Bournemouth pine’.

COMMON YEW

Sharing a city with something more than 1,000 years old is positively mind bending. Often living to be 600 or more, with Britain’s oldest thought to be somewhere between 2,000 and 3,000 years old, it is the yew’s longevity more than anything else that has secured its place as one of our best loved trees. It’s not of the streets – you’re most likely to find yew growing in a churchyard or park. Multi-stemmed and shrubby, low-growing branches strive up and out, while thicker limbs gradually fuse into an ever-expanding central trunk. It’s notorious for being poisonous but potent: a source of taxol, a cancer-fighting drug.

Helen Babbs is the author of Sylvan Cities: An Urban Tree Guide (Atlantic Books).