It is 100 years since Barbara Hepworth was born in Wakefield in the West Riding of Yorkshire. The house where she was brought up - a less than prepossessing terrace in an unprestigious postcode - belies the fact that she enjoyed a relatively comfortable lifestyle, and recordings of her voice suggest a plumminess not normally associated with this former coal-mining area. Hepworth was the daughter of the county surveyor, and some of her first recollections were of the hills and peaks of the Yorkshire skyline, as seen from the window of her father's car - here was an artist who would not be confined by her immediate circumstances, whose future lay above and beyond the horizon. An education at Wakefield Girls' High School indulged her interest in many of the arts, including poetry, dance, music and painting, and led to her enrolling, at the age of just 15, at Leeds College of Art. There she came into contact with Henry Moore, and by this time her destiny was decided. She went on to study at the Royal College of Art, and then to Italy. Not surprisingly, the sight of classical sculpture basking in Mediterranean light came as something of a revelation to a young woman more used to the smog of London and the soot-blackened buildings of her hometown. With her imagination thoroughly sandblasted by the experience, she returned to England, eventually settling in the small Cornish town of St Ives.
It is said that the intensity of light in St Ives is the highest in the country (now a scientifically proven fact). It has also been said that the smell of fish in the once-thriving pilchard port was strong enough to stop the church clock. Today, the aroma of marine life is more likely to come from the kitchen windows of the town's many fine restaurants and trendy cafes. The trawlermen may be few and far between, but the narrow streets of St Ives's quirky "downalong" area are jammed for many months of the year by holidaymakers lured into this geographical bottleneck not just by its promise of ultraviolet rays, but by its standing as an artists' colony. Patrick Heron, Alfred Wallace and Ben Nicholson (Hepworth's second husband) are just a few of the local legends. The Tate St Ives acts as a kind of emporium of their reputations, and also as an important venue, attracting international exhibitions to one of Britain's most far-flung regions.
A couple of hundred yards across the isthmus is another shrine of sorts, the Barbara Hepworth Museum, the garden of which is a suntrap, so much so that many of Hepworth's pieces are to be found lurking beneath the fringes of robust-looking palm trees or competing for glory alongside exotic plants. Through the glass of the wooden conservatory, visitors can peer into the ordered chaos of Hepworth's Trewyn studio, untouched since her working days or painstakingly recreated where needed. If nothing else, the chisels, hammers and great slabs of stone are a reminder of the sheer physicality of the art form, giving the impression of a builder's yard rather than the workspace of a sensitive artist. She died there in a fire in 1975.
In almost total contrast is the Yorkshire Sculpture Park, where the Hepworth Centenary Exhibition has recently opened. To the east of the park, the M1 can be seen and heard, and the cluster of buildings on the southern horizon is Barnsley. The contrast with St Ives, however, is not one of urban versus rural, or even north versus south, but one of space. Among Britain's most enlightened tourist attractions, Yorkshire Sculpture Park is actually a country estate comprising more than 500 acres of managed land - a virtual community, in fact, where dry-stone wallers, lumberjacks and members of many trades coexist with artists and art. So, when visiting the Hepworth, wear decent footwear and a coat, and begin with the bronzes. Start with Oval Form (Trezion), whose elliptical curves act as a portal for the whole exhibition, looking out towards the formal terrace where Two Forms (Divided Circle) and Dual Form can be viewed along the same plane. As with most of Hepworth's "pierced" works, the holes themselves are not simply gaps in the material but shaped interiors, suggestive of anatomy or physiology because of their resemblance to sockets and joints. Being concave rather than convex, they also invite further inquiry, either from the eye or the hand, and are a natural pocket for warmth, rain, shadow and even insects.
Most of the vertical pieces have what can roughly be described as a front and a back. And the uprightness of most of the bronzes is another reflection of Hepworth's enduring preoccupation with placing the human form within the surface geography of the world. There can be few better examples of this than the exquisite Single Form (Antiphon) - a figurine, almost, slender and tall. Originally carved in wood, the bronze casting has made for a more durable version and demonstrates Hepworth's commitment to presenting sculpture in the open air. The patina that has covered one hemisphere of the work is reminiscent of moss growth on the north-facing bark of trees, reminding us of the prototype.
In the Pavilion, with its newly painted (white) canopy, under brilliant (white) lights, the retina needs time to adjust before the display of single forms carved in (white) marble can be properly seen, let alone appreciated. Smaller and raised on plinths, the pieces are predominantly abstract, and yet are unashamedly imbued with some human element. One has the smoothness of skin. Another the fluted curve of a tear, another the suggestion of the foetal position. Perhaps it's just the warmth in this room, but there is a definite sense of incubation. And in the Bothy, maquettes, models and patterns are arranged with some of Hepworth's "strung" works. Being in such sympathy and accord by this time, the temptation is to reach out and pluck the twine, so it is as well that these works are housed within glass cases.
Finally, visit The Family of Man. This permanent exhibition has to be the highlight of the show. Viewed from the bottom of the slope, the nine figures seem to turn their attention on the spectator with a sense of innocence and inquiry. Family members, their similarities can be traced backwards, a sort of genetic coding of colour and form. Totemic in shape, they are naive - like boxes stacked by a child - and appear uncorrupted, full of beautiful possibility. Seen from behind, however, The Family of Man is a ghostly crew. Like gravestones planted in the earth, they suggest departure rather than approach, and have the sad demeanour of the dispossessed or the lost. Perhaps this is a deliberate misinterpretation, but any configuration of humanity must surely allow for such a reading.
It has been interesting over the past few months to watch television journalists queuing up to file reports in front of Hepworth's massive bronze sculpture Single Form. Why there? Because of its position outside the United Nations building in New York, and to quote Hepworth at the unveiling of that piece in 1964: "The United Nations is our conscience. If it succeeds it is our success. If it fails it is our failure." In light of recent events, Hepworth's very human work has found a new importance and a disturbing, perhaps unexpected, resonance.
"Barbara Hepworth" is at the Yorkshire Sculpture Park, WF4 (01924 832 515) until 14 September, and the Barbara Hepworth Centenary is at Tate St Ives (01736 796 226) until 12 October
Simon Armitage's most recent volume of poetry is The Universal Home Doctor (Faber and Faber)