Architects love to render their buildings covered and ringed in trees: trees that sprout from balconies, dot roofs, climb walls.
Even if you could design a skyscraper to withstand the weight and root-stresses of these imaginary jungles, even if you could invent seismic dampers that could account for the weird aerodynamic artifacts of tall buildings covered in questing, irregular trees, the trees themselves would die like flies. Wind and cold interfere with photosynthesis. Buildings ringed with trees would see three-quarter die-offs for the same reason mountains only have trees growing on one side of them.
It's true that there have been limited successes with treescrapers (that is, buildings that came in way overbudget, struggle with maintenance, and used so much energy creating the treescape effect that it largely offset any environmental benefit from the trees), but they look nothing like the lush treescrapers of the renderings.
However, mossy, ivy-colored buildings with grassy roofs, covered in "extensive" rather than "intensive" foliage, are very do-able, and as lovely as the ivy league.
For extensive projects, the demands are lower for water, nutrients and ongoing management than they are for intensive ones. Structural requirements are also reduced: engineers need to account for just 15 to 50 pounds additional per square foot versus 50 to 150 or more.
Yet even the thinnest green coverage requires a growing medium, filter fabric, drainage layer, insulation, waterproof membrane and more. Naturally, too, these flatter green surfaces tend to make for less attractive drawings, particularly wide-angle views at a distance.
Renderings vs. Reality: The Improbable Rise of Tree-Covered Skyscrapers
[Kurt Kohlstedt/99 Percent Invisible]
(via Dan Hon)
(Image: Vertical Cities Asia, Singapore [WOHA])