• Addison Lentz

The important resurgence of green walls

Addison, studying Landscape Architecture at UC Berkeley, discusses the numerous benefits of green walls, or vertical gardens.

The current urban environment is rather bland. Smog from cars, the constant hum of traffic, relatively poor air quality, and most street-level sunlight being blocked by skyscrapers contribute to the most unpleasant characteristic of all: unhappy people. In cities, the principle that architecture affects quality of life was neglected up until around the mid-nineties. By then, dissatisfaction with the urban environment had just become the ‘way things were,’ an immutable characteristic of the ‘concrete jungle,’ from which inhabitants sought escape, even if just for the weekend.

Today, we see efforts to reclaim urban space, through public empowerment, reconnection with nature, and more flexible ‘programming’ of designed spaces such as parks, plazas, and public courtyards. One of the most important efforts, in my opinion, is the resurgence of the green wall, or ‘vertical garden.’ I call it a ‘resurgence’ because this principle is not new; green walls have existed for thousands of years, albeit in a more natural setting. Vertical gardens are scalable, and can be installed on building exteriors or interiors. On the interior, they serve the residents of the specific space. On the exterior, they benefit all who use the space on a day-to-day basis: commuters, neighbors, and tourists.

"One of the most important efforts, in my opinion, is the resurgence of the green wall"

While the benefits of a green wall are numerous, there are several that are still up for debate. Some benefits that we can be sure of are:

● An increase in feelings of wellbeing; this is in large part due to biophilia, which has been defined by Merriam-Webster as “a desire or tendency to commune with nature.”

● Decreased stress levels and blood pressure, also attributable to biophilia.

● Reductions in ambient noise; living walls absorb 41% more sound than a traditional facade and result in a reduction of up to 8 decibels.

● Reduced energy costs; in summer, through evapotranspiration, the ambient air temperature is reduced -- in winter, the systems function as additional insulation, reducing heating costs. Depending on the placement of the system relative to windows, the plants can also function as additional shading on sun-exposed windows.

● Reduction in urban heat island effects; heat islands are defined by the U.S. Environmental Protection Agency as “urbanized areas that experience higher temperatures than outlying areas," because they re-emit the sun's heat more than natural landscapes. Urban areas, where structures like buildings, roads, and other infrastructure are highly concentrated and greenery is limited, become ‘islands’ of higher temperatures relative to outlying areas.”

Cities need to install green walls because the benefits far outweigh the costs; while the monetary costs of installing green walls are short-term, the benefits to quality of life, worker productivity, human health, and overall wellbeing are long-term. Given that convincing corporate America to do anything can be difficult without some monetary incentive, large cities should consider offering tax incentives for green wall installation, with the incentive amount directly correlated to the amount of facade covered with greenery.

While this is not a perfect solution, it is a proposition that more cities should take seriously, given the worsening trajectory of human satisfaction with urban spaces, urban heat island effects, and climate-change-induced migration.