Tree Canopy Walkway at Kirstenbosch
Mark Thomas Architects
Before you even walk upon it, the Tree Canopy Walkway at Kirstenbosch Gardens, built to celebrate the centenary of this important asset of the City, can claim three successes.
No trees were harmed in the process of its construction.
It is virtually invisible until you come upon it.
It became, almost overnight, an iconic structure which appears to be responsible for attracting an additional 200,000+ visitors to the Gardens in the year in which it opened.*
Quite exceptional for a structure that is 130m long, rises 12 meters (three-storeys) above ground at points, comprises 20 tonnes of steel, 5.5km of steel bar and was two years in the making.
Once on it, the walkway snakes through the trees and bursts above the canopy providing, literally, a completely new perspective on the sprawling Cape Flats, towering Table Mountain and most significantly, the intensely dense and variegated forest canopy of the 450 indigenous species that are Kirstenbosch Gardens.
The central spine is constructed of tubular steel supported by steel columns 12m apart. Steel ‘ribs’ and light mesh welded to this ‘skeleton’ provide cross bracing and the foundation onto which wooden trusses – which create the actual walkway – are attached. They also provide a means to encourage creepers to embrace the structure over time. The handrails are made from slender planks of Padauk, a sustainably harvested West African hardwood traditionally used to manufacture musical instruments and were laminated and finished on site.
The materials of light steel and wood combine to create a structure that is at once stable enough to walk on yet touches the earth lightly. It also is an interesting combination of industrial material and manufacturing technology with the fine detail that can only be achieved through the hand and expert craftsmanship.
Architect and engineer agree that the beauty of the completed project emanates from the essentialness of the structure – and we would add the integrity of the structure in its environment. The design of the 130m walkway was directly informed by the site. Every tree was surveyed and the structure emerged from the natural routes and paths inherent in the growth. Built on a slope it also means the structure is fairly horizontal while still achieving great height off the ground.
The success of the project lies in the painstaking integration of design, engineering and construction and the multi-disciplinary nature of the team that collaborated (Architect Mark Thomas, Engineer Henry Fagan and SANBI horticulturist Adam Harrower assisted by filmmaker Chris Bisset).
Nicknamed “The Boomslang” ironically the most deadly of South African snakes, instead, this boomslang is exceptionally benign.
While an unusual entrant amongst buildings and structures, the assessors felt it has been so expertly created and crafted and has become so quickly iconic that it deserved to be shortlisted.
* In 2014 the garden exceeded 1 million visitors for the first time in its history. An increase of 27% on the previous year, and attributed, in the main, to this new attraction.