Green walls are part of human history
Green roofs and façades are beautiful and have, over the ages, provided humanity with a plenitude of ecosystem services such as produce and shade. We have long relied on plants to create spaces for humans to thrive and prosper. However, some view green infrastructure (GI) as a recent construct, leading to a failure to understand how critical urban greening is for a healthy, sustainable, and happy urban life. Green infrastructure is integral to sustainable urban development and helps humans thrive.
Where it began
Green infrastructure has been a fundamental part of human settlements dating back to the Neolithic period (4300 BC-2000 BC). The first form of a green roof was the sod roof. Humans formed these sod roofs with a layer of peat or sod over a cave structure. While these sod structures were most prevalent in Norse countries, green infrastructure existed in parallel all over the globe, from the literary gardens in China during the Shang Dynasty (600-1046 BC) to the giant, stepped ziggurat pyramids of Mesopotamia (600 BC) on which trees and shrubs grew to provide shade and produce. In modern-day Iraq, the hanging gardens of Babylon (600-500 BC) are often mentioned as examples of Mesopotamian green infrastructure. Despite lacking direct evidence of the garden's existence, archaeological records display spectacular garden-related engineering, such as a building with a built-in irrigation system.
Ancient Greece and the Romans
The climate of ancient Greece inspired the use of vegetated trellis structures and trees to create shade in their open meeting spaces or “agoras” in order to stimulate public discourse and interaction. The trellis systems also supported grape vines for their burgeoning wine industry.
The Romans took even further steps towards cooling by using imported trees planted on and around institutional buildings. They also used climbing plants outside the villas to create shade and cool buildings.
Roman botanist Theophrastus (371-287 BC) writes about using Sempervivum (a close relative to Sedum) on roofs and walls. Sedum plants are now one of the most used plant types on extensive green roofs.
Early green roofs in America
Sod houses also played an important part in US history stemming from the Homestead Act of 1862. The act was passed by the US Congress, stating that 160 acres of land would be granted by the government to settling families after five years, with the condition that they build a house and dig a well on the land. These settlers were referred to as "soddies” due to the construction of green roof sod houses. also supported grape vines for their burgeoning wine industry.
American green innovators
The US environmental movement originated in the 19th century and was vital in developing our modern understanding of the human need for access to green spaces.
One significant figure in this movement was landscape architect Frederick Law Olmsted, well-known for his work on parks and green infrastructure, most notably Central Park and the 1,100 acres of interconnected parks and waterways known as the Emerald Necklace in Boston and Brookline, Massachusetts.
“We want a ground to which people may easily go when the day’s work is done, and where they may stroll for an hour, seeing, hearing, and feeling nothing of the bustle and jar of the streets where they shall, in effect, find the city put far away from them…”
- (Frederick Law Olmsted, 1870)
Leading architectural and public figures already recognized the link between good mental health, high work output, and green infrastructure.
Modern green infrastructure
In 1938, Professor Stanley Hart White of the University of Illinois developed and patented the first green wall system. He named the modular system "Botanical Bricks," as it allowed for a quick buildup of greened structures. However, green wall systems did not gain popularity until 1986. when French botanist Patrick Blanc successfully created a massive green wall installation at the Museum of Science and Industry in Paris.
Despite the advancements in green infrastructure, the simple and reliable trellis systems in tandem with climbing plants have always remained in fashion. Over the ages, green infrastructure has remained essential to human health and well-being, bringing great beauty and value to the built environment.
By Dr. Anna Zakrisson