As the opportunities for new territories become more limited, the only way is up.
Mitchell Schwarzer explores the dizzying heights of the 'last biotic frontier' of arboreal architecture with its high platforms, walkways and canopy craft.
[Image: The human butterfly embracing the forest, lightly touching down on the forest's crown and walking on the leaves.]
[Image: Marks Barfield Architects, Treetop Walkway and Rhizotron, Kew Gardens, London, 2008]
[Image: SeARCH, Tower Power treetop observation platform, Schovenhorst Estate, Putten, the Netherlands, 2009]