Great Work: Iron Tree (2013), Ai Weiwei, 628 x 710 x 710, Yorkshire Sculpture Park, published in the Independent, London

Andrew Welford Photography

Last autumn, John Constable's small painting of the trunk of a great elm tree – so bulky and so vividly corpulent that it was almost huggable - shouldered its way into the space above such words as these. Here is another tree, this time captured on a sullen Yorkshire afternoon in springtime, on a day when the lapwings had just returned to their old nesting grounds in a nearby field. This tree is Chinese in origin, and it sits amongst English yews, in front of an eighteenth-century chapel, in a sculpture park.

Unlike Constable's, this tree is neither more nor less than a symbol. In common with so many of the works of Ai Wei-Wei, it proceeds by stealth. It does not sloganeer. It does not bang drums. His art is not so much an art of protest as an art of life-affirmation.

In part, it has the look of a tree. And in other respects it does not, not quite. It is, for example, a vivid orange tree – and by that I do not mean that it will in time be glad-handing the fortunate few with a crop of oranges. No, I mean that it is a rusting tree, in hue and actuality, and that it will continue to rust and to rust – it had the silvery sheen of new metal in 2013, when it was first put on public display inside that nearby chapel - until it becomes too dangerous for its own good. At which point it will suffer some equivalent of felling.

Yes, here we have a tree amongst old trees which is in fact a simulacrum of a tree. It consists of 97 separate parts, and each segment is cast in iron from a Chinese tree part. Its inspiration comes from street vendors of wood in Jingdhezen, Southern China. The whole is awkward, ungainly, fistily comical and wonderfully tenacious. In order to be itself at all, each limb or part-bole has had to be bolted and screwed together to every other part, as if it were a work of human manufacture. Which it is. The elements do not quite fit – one section of its massive trunk seems to be sliding sideways, drunkenly. The limbs gesture skyward, wildly, helplessly. Rivulets of rusting iron look as if they might just taste tangy. Its characterfulness also comprehends something rather nasty and even fairy-tale-cronish too.

We try to decide whether these are cast parts from one tree or many. We fail to reach a final conclusion. It is undoubtedly a tree of sorts, but this tree is also a message, we cannot but feel, about the condition of man in the world, this awkward, bolted-together creature who is forever striving to cohere as something credible and singular, forever striving to hold his own amongst more authentic versions of himself. Ai Wei Wei is by no means the first person of great imaginative reach to extrapolate from tree parts to the nature of the human condition. Read Jonathan Swift's great Meditations Upon a Broomstick, for example. At least this tree is the right way up.

Biography

Ai Weiwei was born in Beijing in 1957. In 1958, he and his family were exiled to Xinjiang, Northwest China, his poet-father having been accused of 'rightism'. He lived in New York from 1981 to 1993. On his return to China, he co-founded Beijing East Village, an experimental artists' cooperative. His passport was confiscated in 2014.