Our urban tree canopy – once a novelty , now a necessity – needs to be saved from developers, NIMBYs and lesser architects, says Joseph Rykwert
Everyone loves a tree. Not many will go as far as Xerxes in Handel’s opera of the same name, and actually have an affair with a plane tree; still, few of us will admit that we actually dislike them - except for some developers. Trees get in their way, particularly if they want to dig for basement extensions.
There are also plenty of NIMBY-type complainers about trees in which crows and pigeons nest and then spatter cars with droppings. Giant lorries are scratched by protruding branches, and awkward trees obscure the views of CCTV cameras, putting those who spy on us at a disadvantage. Aged oaks have even been cut down because puppies are said to choke on their acorns.
But there are more ‘systematic’ tree-haters. Insurance companies find that when there is a tree anywhere near some subsidence, rooting it out may be the simplest (though not usually the most effective) way out of the problem. Incoherent under-asphalt public utilities excavations cut through their roots, and although there is a National Joint Utilities Group (NJUG), which provides guidelines on the right way to go about such digging, local authorities are not legally obliged to follow these recommendations. So, more and more trees are lost.
‘So what?’ some of you will say - there are plenty around our cities. Anyway, urban trees are a relative novelty in public spaces. In medieval towns, they were confined to gardens and cloisters, but when gunpowder forced the replacement of stone and brick town defences with earthworks, these bulwarks soon turned into tree-lined boulevards (or the Ring in Vienna, and, allowing for differences, London’s squares). The urban tree canopy, which had been a suburban luxury to begin with, soon turned into an urban necessity as our cities outgrew their old boundaries.
Worryingly, tree numbers are decreasing, in London particularly, as various boroughs report. And we need them. Not just in a general sort of way because they might make urban life more agreeable (an argument that most developers or even local authorities are not very interested in), but because they are essential to our wellbeing. The tree canopy is a great consumer of carbon dioxide, as well as a producer of oxygen, and therefore it is a prime resource in the battle against climate change. But it is dependent on mature trees. A fully grown ash will produce enough oxygen for 10 adults.
But the picture is not all black. Southwark Council has planted a grove of palm trees along Queen’s Road in South London’s Peckham (Peckham? Yes, Peckham - palm trees seem to flourish south of Bermondsey) as a gesture to ethnic mix as well as tree cover. But such exotic efforts are a bit isolated: a year ago the environment committee of the Greater London Assembly chastised various local authorities and busybodies for what it called the ‘chainsaw massacre’. For all that, the slaughter of urban trees goes on relentlessly, if undramatically, much as before.
And what is all this to architects? The answer is everything. Tree husbandry is a skill we still need to learn. And who better to teach us than Norwegian architect Sverre Fehn, whose death we lamented last month (AJ 26.02.09) and who, over 40 years ago, built his simple, but breathtakingly subtle Nordic Pavilion in the Venice Biennale gardens. He incorporated three existing, growing trees into the pavilion, which have flourished ever since. A lesser architect might have cut them down. As William Blake once said, ‘a fool sees not the same tree that a wise man sees’.