Barriers have been broken down in more ways than one for the Barbican’s latest exhibtion, Radical Nature, which brings together the visionary work of 25 artists and architects who have imagined both poetic and pioneering ways to engage with our natural environment and combat some of our planet’s ecological problems.

Aesthetically, wall dividers have been removed to create a vast space in which to house “a Frankenstein gallery made of fragments of other people’s work,” says curator Francesco Manacorda, with installation, photography, film and sculpture on display. Conceptually, the theme of bringing what should be outside inside through the displacement of nature is explored across the chronolgical scale.

From this decade, Henrik Hakansson’s presents Fallen Forest (2006), a 16-metre-square segment of rainforest flipped on its side, which serves as a comment on the unbalanced relationship between man and nature; while his predecessors Newton Harrison and Helen Mayer Harrison, have re-staged their seminal 1972 piece, Full Farm, a large-scale working allotment, “pointing to an apolyptic future in which we will have to grow our own food inside our houses,” observes Francesco.

The notion of using nature as artistic material is central to the exhibition, with other examples of historic Land Art works documented through film and imagery, such as Robert Smithson’s iconic Spiral Jetty, a monumental sculpture fashioned out of basalt in Utah’s Great Salt Lake, and Agnes Dene’s political statement Wheatfield – A Confrontation, which involved planting a field of wheat in downtown Manhattan.

Alongside these forebearers is the work of a new generation including Turner Prize winner Simon Starling who presents An Island of Weeds and architectural collective A12 who have supplied Green Room, a mirrored hut comprising of a minature garden.

Also taking up the mantle is Lara Almarcegui who produced Guide to the Wastelands of the Lea Valley, 12 Empty Spaces Await the London Olympics. The booklet and accompanying slide show document a dozen derelict sites that may soon vanish as part of the Olympic regeneration.

Telling me about the project, the Spanish artist, who now lives in Rotterdam, says: “The concept comes very much from the idea that I really love empty, derelict terrain, because of many things, but certainly because of the possibilities, every thing is possible there.

“Once these areas become a regulated natural area, or a park, or apartments, ok maybe it’s a nice project and good for the neighbourhood but freedom is gone.”

Radical Nature: Art and Architecture for A Changing Planet 1969-2009, runs until Sunday, October 18. Telephone: 0845 121 6826 www.barbican.org.uk (£4-£8)