Thor ter Kulve and Robert McIntyre's CanopyStair comprises modular wooden platforms made from curved birch plywood, typically used to build small aircraft.
When bound to a tree trunk with adjustable woven ratchet straps at staggered heights and orientations, the modules can be used as steps.
"Since tree trunks are all unique we had to design a system that would adapt to their uneven surfaces, whilst not harming the tree in any way," Ter Kulve told Dezeen.
One end of the step has a triangular profile, where thick neoprene pads mounted on sand-cast aluminium joints at each corner create three soft contact points with the tree.
"We have worked with the arboriculturalists at Hampstead Heath to ensure we are not damaging the tree," said McIntyre.
The curved shapes of the steps were designed to help the elements to appear straight even if they are slightly uneven when installed as a spiral set.
Ash poles attached to the end of each step can be strung together with lengths of flexible plastic to create a balustrade. Each tread also has a coarse top surface for better grip.
"As one climbs the steps, the slight curve on the top surface of the tread acts to 'cradle' your foot, adding to the sense of security," Ter Kulve said.
Kulve and McIntyre, who both studied on the RCA's Design Products course, came up with the idea for the CanopyStair while spending time on an island in the Portuguese Azores archipelago last year.
The house they stayed at was surrounded by a high wall, blocking the property's sea views, so the pair shimmied up a tree to get a better vantage point.
"Only by climbing a tree in the garden could we watch the sun setting across the ocean," McIntyre told Dezeen. "We began to discuss ways of transforming a garden tree into a staircase, allowing us to walk up and down easily and enjoy the view."
To alleviate safety issues with installing the higher treads, the designers suggest using simple rock-climbing equipment to secure whoever might be at risk of falling.
Installation times vary depending on the desired height on the staircase. "To set up a seven-metre-high staircase would take about three hours with two people," Ter Kulve said. "Taking that down would take about 30 minutes."
The duo hopes that providing an easy route up trees will encourage the exploration of their upper reaches.
"The canopies of trees are the least explored ecosystem on the planet – we know less about them than we do the deep ocean," said McIntyre. "On climbing the CanopyStair, one enters this secret world, and it is somehow mesmerising."
A prototype CanopyStair, created with the support of London architecture studio Haworth Tompkins, was successfully erected and used in Sussex. It has now been installed outside the RCA's Kensington campus as part of this year's graduate exhibition.
Photography is by Tony McIntyre.
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