Visual Arts:   Rood by Alice Maher, Green on Red Gallery; It's So Hard to be a Saint in the City by Blaise Drummond at the Rubicon Gallery; Moving Statues by James Hanley at the Ashford Gallery and Eurojet Futures: An Anthology at the RHA Gallagher Gallery, all reviewed by Aiden Dunne

The current exhibitions by Alice Maher at Green on Red and Blaise Drummond at the Rubicon comprise a striking example of synchronicity. In both, it's as if Birnam Wood has been on the move, invading the gallery spaces. The Rubicon is dominated by what looks like a whole, moribund hawthorn. A startling sight in the gallery, it looks solidly planted in the floor and reaches to the ceiling, and it contains a big nest of twigs and litter in its higher branches. At Green on Red, meanwhile, a row of coppiced ashes is suspended, upside down, from a beam, bisecting the cavernous exhibition space.

This upended ash hedge recalls Spanish sculptor Cristina Iglesias's latticework sculptural screens, her Celosias. For Maher's hedge refers, as its title Rood indicates, to the rood screens, often elaborately carved with plant and animal motifs as well as crucifixes, that separated the chancel from the congregation in medieval churches. The reference is reinforced by her striking version of stained glass panels, a series of printed vinyl sheets derived from snail trails. Applied to the tall windows at Green on Red, they colour the light that falls into the gallery.

Rood might symbolically separate nature from culture. Snails, generally regarded as slimy and even disgusting, find their way into in a temple of culture, the gallery. Hundreds, perhaps thousands, are used in creating a set of four snail-shell globes, small worlds. The ash plants seem to sprout from the beam, an idea Maher introduces in the first piece, at the foot of the stairs leading up to the gallery: a wooden ladder disappears into the ceiling, twigs sprouting from its sides, inviting us into an Alice in Wonderland realm. It's a fitting prelude to a show that turns the world upside down.

Drummond's tree is also an unruly intrusion into the synthetic, fabricated space of the gallery. Like the snail shells in Maher's work, the nest is a habitation in the heart of nature, and a recognisable version of the human habitations that seem to fascinate Drummond. There is a continual play or debate in his work about our relationship with nature and whether there is any such thing as nature for us. That is, our presence changes and distorts things, de-natures nature.

As with the tree, the other pieces in Drummond's show, It's So Hard to be a Saint in the City, are a mixture of puns and meditations on the nature-culture question. An electric fan acts as a breeze for a clump of grass in a pot. A subjective camera chronicles a walk through wild, densely vegetated countryside that turns out to be a garden. It's as though Drummond is edgily unsure. He'd like to feel we can negotiate a place for ourselves without hopelessly compromising the natural world, but he's instinctively sceptical.

James Hanley, at the Ashford Gallery, takes a break from what must be a gruelling schedule of portrait commissions and lets off steam by mocking the pomposity of public monuments throughout several European cities in Moving Statues.

A mythological grouping of figures is transformed into a set of trapeze artistes, an Amazon dons a sports bra, a triumphant warrior is given a camp reworking by the addition of a simple prop. The humour is sometimes pointed but always agreeable and good natured.

The drawings are carefully and precisely made, and have a substantial quality about them. Hanley is a technical perfectionist, so much so that it is as if he is distrustful of the free flow of an organic line. He pins down contours, arranging them into angular, geometric structures in the manner of William Coldstream or Euan Uglow. Yet the tightness and precision of his method work well with, rather than against, the lightness and humour of the drawings, making for an enjoyable show.

The Eurojet Futures has been one of the best, most enlightened arts sponsorships of recent years and this year, to mark the conclusion of the scheme, the RHA features Eurojet Futures: An Anthology, showcasing the work of all 27 artists who have exhibited in the series over the past five years. It's a good idea, and it makes for a good show, one that is diverse and occasionally challenging, and very well installed. Yet perhaps it comes too soon. Maybe it would have been better to round up these particular suspects five years down the line. As it is, we see incremental developments, if that, of what we have already seen by them.

This is not to disparage what is on offer, which is generally strong, but there is an air of familiarity rather than surprise, particularly in relation to the work of the past few years' Eurojet exhibitors. Having said which, it's worth noting some of those incremental developments. Linda Quinlan, who began by being perhaps a little too indebted to Matthew Barney, has gone on to make extraordinary installations that are distinctively her own and offer a fascinating take on contemporary cultural and lifestyle preoccupations.

As though instinctively recognising that there is no point in repeating his prior Eurojet appearance, Paul Nugent shows illuminating pieces based on contact sheets of the source materials for his larger paintings. They demonstrate that he is preoccupied not so much with religious iconography as with religion as an enveloping system of signs and meaning. All the while, his interest is underwritten by a tactful, sympathetic humanism.

Jeanette Doyle's sequence of paintings inventively explore the anonymity of urban life and the cultural role of celebrity. John Gerrard's striking Horizon Line, an end-of-the-world conversation between two laid-back Americans, could well be an homage to Derek Jarman's Blue. Mary Kelly's subtle colour photographs are oblique and poignant records of the traces of human presence in extreme circumstances.

Rood, Alice Maher, Green on Red Gallery until Sept 10 01-6713414

It's So Hard to be a Saint in the City, Blaise Drummond, Rubicon Gallery until Aug 27 01-6708055

Moving Statues, James Hanley, Ashford Gallery until Aug 27 01-6612558

Eurojet Futures: An Anthology, RHA Gallagher Gallery until Aug 28 01-6612558