There are 7 ways of improving our lives in cities.
Let’s start today by looking at vegetation.
The Urban Heat Island (UHI) effect is well documented, I don’t believe we do not need more studies to confirm it, nor do we need more awareness - we can feel it. It's the feeling of walking your neighbourhood and feeling the marked difference between a shady tree-lined street, and a urbanised, building-centric area. How much does it contribute? Reducing the UHI effect improves Outdoor Thermal Comfort (OTC), which is critical for a functional community and economy. I draw my content from a report published by Cooling Singapore, specifically their catalogue of measures of cooling strategies.
Future buildings must consider improving the UHI effect. We’ve seen the plans for the Atlassian tower; it will have a green roof which effectively works by reducing the surface temperature by 15-45ºC (depending on location and time of year), which can lead to nearby air being reduced by 2-5ºC. A reasonable estimate of the reduction of energy consumption is about 10%. This is just the start.
What about vertical greenery adjacent to a building? Growing plants or trees on the side of buildings to cover the external facade. This has a similar, albeit lower effect, to a green roof and is entirely dependent on the thickness of the greenery. However, this planting style would also benefit pedestrians and could reduce energy consumption by about 10-30%.
This leads to a person asking, if greenery is good adjacent to a building, why not make a green facade? A green facade as a vegetation implementation of thermal insulation has been studied and results suggest that nearby outdoor temperature is also reduced by 0.5-4ºC.
Finally, we come to selectively planting trees to create shade on the nearby street. Studies have shown that overwhelmingly people feel a positive effect from the mere visual of trees on the street. Selecting native trees means that they will require less intervention and they will benefit the local fauna. However, it was found in a study that foliage density had the greatest contribution to surface-soil cooling, followed by leaf thickness, leaf texture, and leaf colour lightness in that order. Well-selected trees can lead to an air temperature reduction of 2ºC.
The purpose of this post is to show how this information is already understood, catalogued, and readily available. Next week I will focus on Transport.
