Biennale ending this weekend

First published on 26 Jul 2010. Updated on 2 Aug 2010.

There's an astonishing artwork down at Circular Quay. It's like a piece of shiny tumbleweed blown in on a gust of wind - from the take-off thrusters of a spaceship maybe. As comes to an end, It's Roxy Paine's Neuron and as the 17th Biennale of Sydney ends it will leave its current site.

It's very large (nearly 11 metres high) and although tumbleweed pops into my head it's not very apt: as you get closer you notice long, tentacle-like protrusions (dendrites I think - although I'm no expert on the nervous system). These stretch outwards and skywards while lower ones seem to have burrowed into the grass. This isn't rolling anywhere without bits snapping off.

In simplistic terms this sculpture fits in exactly with what the Biennale hopes to achieve. Neuron is about communication and the exchange of ideas. It's positioned at the MCA main entrance and it's an amazing piece of construction.

Paine's tree-like sculptures (which he calls Dendroids) are based on his research of real trees but Realism isn't his aim. Industrial piping and rods mimic the language of trees but the joins are still visible. The Dendroids are only one facet of his art – which also includes art-making machines and realistic plant and fungi creations. But all his art focuses on this central issue: what is natural and what is artificial?

We are drawn by Neuron's size. The polished steel is incredibly beautiful and pulls us closer, like glinting jewellery in a shopfront. The symbol of the tree is rich in meaning - since Eve noticed the forbidden fruit looked succulent it's taken on many connotations, religious and otherwise. The Dendroids individually have their own significance: Neuron's branches fly out from its centre like cracks of current in a plasma globe - it's part of a network (as in a tree chart) but the artist has brought his own personal experiences into a work previously. Conjoined was produced at a time he was experiencing conflict; maybe Neuron is indicative of a new cerebral period in which he is spreading his influence wider. He likes his sculpture to brim over with possible metaphor without taking us by the hand in one direction only.

Paine's first Dendroid stood in a natural forest but he prefers urban settings and the tensions created by man-made surroundings. Down at the quay there's landscaping, 24-hour surveillance and fences around Neuron. This frozen explosion of polished metal glints in the sun. A few metres away the rolling flat ocean of Sydney Harbour is molten with its own reflected sunshine.

Paine is not demonising the dawn of technology but wants his art to work as a catalyst for some serious thought. Neuron's appearance is a bit sinister - cancerous and parasitic as well as space-age. Some branches twist back on themselves and snake into the soil. The brain and neurology are still areas that science doesn't fully understand; the Biennale is about pushing boundaries, but Paine might also be making reference, darkly, to mankind's limitations.

I can't help but think of trees in terms of carbon emissions. Trees have become the currency of environmental harm. Pollute, use resources and more trees will save the day! How incredibly ironic to build trees out of industrially produced materials. Lorna Johnston