Designers Thor te Kulve and Robert McIntyre have devised a clever system that allows anyone to build a spiral staircase up the trunk of a tree without actually hurting it and without using tools.

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Their innovative staircase is made of birch steps that hold on to the tree trunk with straps and grip its side with thick neoprene pads. Attaching a series of these steps, along with an accompanying handrail, creates a spiral staircase.

“We have worked with the arboriculturalists at Hampstead Heath to ensure we are not damaging the tree,” McIntyre told Dezeen. Trees can still be harmed by girdling after long after sustained friction, so we assume these steps are a temporary setup. According to the designers, a 7m staircase would take 2 people 3 hours to build but only 30min. to take apart.

More info: (h/t: treehugger, dezeen)