The efficacy of urban ecological infrastructure is largely governed by something far simpler than many would believe — the amount of vegetation covering a given surface area. There are several nuances to this, but the general rule holds true — the more plants you have layered over a landscape, the better your environment is going to be. The key is finding enough surface area within our existing built environment to cover with appropriately designed layers of dense vegetation.
Green cities typically conjure a neo-Corbusian vision of gleaming renderings, — ultra-LEED certified, futuristic steel-and-glass buildings, laden with solar panels,- the latest technology. This mirage promises zero emissions and campuses populated with manicured green lawn punctuated occasionally with trees. Alternatively, albeit less commonly, our future is sketched as a series of green ziggurats, buildings staggering under loads of plants with but little resemblance to the urban landscapes we know. Neither vision incorporates traditional, working streetscapes at human scale. Both visions point to a reliance on high tech solutions in a society that has transcended traditional ideas of industry, supply chains, waste, and ecology. Nature looks upon these utopian landscapes with kindness, deciding to suspend the laws of biophysics in their favor in the first case, or economic realities in the latter. Futuristic visions of newly constructed ecological societies do not account for the reality of our built environments. Nature is not easily swayed by marketing pitches, instead, it is ruled only by the cold but quantifiable realities of surface area, fluid dynamics, boundary layers, and biological processes.