A new exhibition at Kew highlights the work of prolific sculptor David Nash RA. The exhibition will be open until April 2013. 4scapes Dr Colin Mumford went along to talk to David Nash and explains what you can expect to find.

My introduction to David Nash was slightly abstract, "I start them off and they finish themselves" he said as he spoke about his work to my peers, which I had joined in mid discussion. Faulty signals meant my train was an hour late getting to London's Liverpool Street Station and therefore I arrived at the Kew press preview of David's work a bit behind the allotted schedule.

As Kew's artist in residence until April 2013, Nash will create new sculptures from wood sourced from the grounds at Kew. He won't cut down a healthy living tree, preferring to use the wood of dead trees, or those trees that are ear-marked for removal.

Tony Kirkham, who is responsible for the Kew arboretum, explains "successional planting is important; some trees from Kew will be removed due to health and safety reasons, or because of disease. These have been set aside for David to use, and will be replaced with either a new species to Kew, or with an existing species where we have an example that is approaching its end of life."

Five trees this year will be harvested for David to sculpt; these include a 300 year old English oak (Quercus robor) that died from Acute Oak Decline, a White ash (Fraxinus americana), Common holly (Ilex aquifolium), Large-leaved lime (Tilia platyphyllos), and a Red Oak (Quercus rubra). The 300 year old English oak has already had parts selected by Nash, which have been retained for him to work on at a later date. He has also begun shaping and carving the trunk in situ. "A tree such as this is ideal as it has lots of heartwood which is the older, nonliving central wood of a tree, and is usually harder than the younger sapwood," explains Nash.

"Birch and Beech rot very quickly outside. Smaller pieces, such as branches have little heartwood, mostly sap wood which rots away after a few years, so the smaller pieces are not as durable outside."

Preparations for the exhibition began earlier this year (14th April 2012) with David's arrival and the establishment of the Wood Quarry; the site where he will carry out his work. The Wood Quarry at Kew is sited on Cedar Vista, and is within view of the Pagoda.

Life as a sculptor
With a career spanning 40 years, Nash has worked all around the world. He has always been a sculptor; his earliest recollection is from the age of three playing with wood and trying to form shapes with it.

This could be why his preferred medium is wood, which he shapes and carves with two main tools; a chainsaw and an axe. Brandishing such dangerous tools means health and safety is paramount when he is carving. To prevent himself stepping back on anyone behind him when he is using a chainsaw he maintains a clear area around him, a sort of mini exclusion zone, for his and everyone else's safety. At Kew he will be working within a cordoned off area - the Wood Quarry - so that visitors to Kew are kept at a safe distance from him while he is creating new pieces.

Nash has a third tool that he likes to use on some of his carvings; fire. He often chars outdoor pieces black, so they "start black and stay black." Charing also keeps the bugs off the pieces of work as "bugs don't like to eat carbon, plus the wood absorbs wood preservative oil better when it has been charred," explains Nash.

Some of his pieces are long term works that have evolved over time, principally from an original wood carving to an eventual bronze cast. A prime example of such a piece is 'Apple Jacob,' which can be found in Kew's Temperate House. Originally an apple tree that had been cut down, Nash cut steps into its trunk and main branches in the 1960's to form a tripod shape that can be seen in the Temperate House today. The piece on display, however, is not wood as Nash had the piece cast into bronze.

When asked how long it took to produce the sculpture Nash replied "it took 40 years for the tree to grow, the cuts were done in one day, and the casting took approximately four weeks." The casting was carried out in Germany where there is a tradition of casting wood into bronze, and therefore an expertise in casting such materials.

The works on display
The exhibition is a blend of outdoor and indoor works, with an array of wood and metal forms that Nash has created. All the works on display belong to David, none are borrowed due in part to the length of the exhibition; it would be unfair to expect someone to loan their David Nash original for up to a year, and the logistics of hauling some extremely large pieces of work across the UK or from further afield can be financially prohibitive.

To the naked eye some of the forms on display appear to defy gravity, positioned at angles that you would expect them to topple over or roll away. As Kew is open to the public the health and safety of the public is extremely high on Kew's agenda. Every step has been taken to ensure that all the displays are secure and immobile so that there is no danger of any of the works moving or falling down.

This has been achieved by laying large metal beams in a cross form under the sculptures. The beams have large metal rods rising from them; corresponding holes on the sculpture enable the works of art to be slotted over the metal rods, creating large - but hidden - stabilizers that keep the works in the correct orientation. It is this attention to detail that has a large impact on the pieces. With so many unique pieces on display the exhibition is heavily insured, and there is 24 hour security on site.

Maintenance required
As you would expect with a static object the maintenance requirements are minimal. To keep the sculptures looking their best, however, Kew's maintenance staff checks each sculpture on a daily basis, usually first thing in the morning. The main maintenance issue revolves around the wildlife at Kew, primarily the birds, as they don't discriminate between a natural perch, bush, tree or work of art, therefore the maintenance staff are looking to see if any bird mess needs to be removed from the displays. Surprisingly the staff removes more bird mess from the pieces in the Temperate House than those outside. The mess is cleaned off with warm water and a sponge within 24 hours of its arrival. Mess that stays for more than 24 hours is harder to remove and can potentially stain the display.

The other species of wildlife that can present a problem is the Fox. When fox relieve themselves on the bronze pieces, the fox's urine can eat into the bronze and turn the metal blue. Washing off the urine as soon as possible minimizes any potential change in hue or blemishes forming, but worst case scenarios can require the affected section of bronze to be recast.

The other main maintenance issue revolves around maintaining the grass that borders each display. The mowers used to cut the grass straddle the edge of the turf as the mower goes around each piece of work. This requires the cordons to be set back from the edge of the turf, so that they do not interfere with the mower. The area to be mown also needs to be checked for pieces of slate which could damage the mower. Slate has been used to encircle many of the sculptures and can be kicked onto the surrounding turf by animals or over inquisitive visitors.

What you can see
To list every item on display would be unfair, as the sculptures are laid out in such a fashion that they encourage you to explore further the grounds at Kew. But to whet your appetite here is a selection of the works you will find at the exhibition.

Two Falling Spoons: originally a wood carving which has been cast in bronze. It looks like it is called, a large tumbling spoon like shape within another spoon like shape. The 'spoons' has a drain hole to prevent water collecting in the middle.

Cube, Sphere, Pyramid: these are forms that Nash likes to use. He always makes pyramids three sided so that they have a triangular footprint, and although they do not look very big they weigh approximately 80 kg each.

Black Butt: this looks like a large charred orb, but it's actually bronze! The original wood used was an Elm which died in the 1980's. It fell down in 2006, and Black Butt is a section of its trunk. Nash originally wanted to cast the wood but couldn't afford to. When an investment matured he spent in the region of £50,000 to have it cast. It consists of 80 separate sections and would cost £180,000 to purchase.

Black Trunk: this is a Californian redwood trunk. Nash rarely imports wood, usually preferring to carry out the sculptures close to the source of the material where they remain near to where he sculptured it. The trunk weighed four tonnes originally, and when he went to move it a year later it weighed five tonnes, due to rain water that had been absorbed by the trunk. This piece hasn't been oiled, which has given the char a brighter sheen.

Oculus: Oculus is four eucalyptus trunks that have grown in close proximity to one another and have fused together. The trunk has been cut and turned upside down to form a large four columned cube with a central opening. Nash encourages people to go up to and embrace works such as this. A shaft of daylight penetrates the central opening through a small opening at the top of the sculpture, which can be viewed from inside. This piece is popular with children who like to run through the openings and hide inside it.

Some named pieces will be for sale after the exhibition. If you are considering purchasing a wood or bronze sculpture the exhibition is a good opportunity to see how large wood carvings and bronze pieces of this type will look throughout a year in different seasons, and to see how they sit within the landscape.

For more information about the David Nash exhibition at Kew, please visit www.kew.org/visit-kew-gardens/whats-on/david-nash/index.htm

To accompany the exhibition there will be a David Nash at Kew app available in early July. For more information about Kew apps, please visit www.kew.org/mobileapp