Not since the Hanging Gardens of Babylon has there been an urban innovation…oh, hang on…
Not since the gardens of Versailles have we seen…oh, wait…
Not since ivy…
Ok, so it’s not really a new concept - but there is something enormously appealing and compelling about the vertical gardens designed by Patrick Blanc, which have transformed more than a few nondescript buildings and shopping malls across Europe.
Using a kind-of trellis system and felt impregnated with seeds, Blanc can design growing walls which live off grey water and nutrients drip-fed from the top of the structure. The system is lightweight and doesn’t damage the building, as it’s suspended a few inches out from the surface.
Here’s a local (non-Patrick Blanc) effort on a nearby street in Manhattan:
It’s a yoga studio of course, so you can get a skinny soy decaf latte with your dose of greenery.
But it doesn’t take much imagination to see the potential such structures have for transforming urban life:
Apart from the aesthetic and psychological benefits of more green-space, there are considerable energy and environmental factors to consider.
If we could re-surface the brick and concrete of the world’s largest cities with vegetation, what would this mean in terms of energy savings, environmental improvements, air quality and urban amenity?
1. Vegetation on a building has a considerable moderating effect on temperature extremes. Here in Manhattan the heat signature is around 5+ degrees centigrade above the surrounding countryside. That’s purely due to the concrete absorbing and then re-radiating ambient heat. Everyone’s air conditioners make it worse. How much could the heat signature of cities be reduced if an appreciable percentage of the concrete was surfaced with vegetation?
2. How much energy could building owners save from excess heating and cooling? How long would the energy savings take to recoup the cost of installing the vertical garden?
3. The gardens live off grey-water, reducing the overall water treatment needs of a large city. What savings and improvements in water quality could we expect?
4. What improvements in air quality could be obtained by having large areas of vertical vegetation? How much carbon dioxide could be absorbed? Could we turn cities into carbon sinks?
I lack the engineering and physics training to calculate these matters, but if anyone has a spare back of an envelope, they’d be worth investigating.
Goodonya Merc
There was a news item on ABCTV news and in “The Age” a few months back about a Brunswick lass growing veges on her roof. Pumpkins etc.
I’d advocate passion fruit, climbing beans, etc too. Then there are the undrground houses with turf on top. Not everyone’s cuppa.
Let’s keep thinking out loud. Street tree plantings are terrific and widely used in Australia, oui? The grey water is a key element. Council tree-watering trucks with signs saying they’re using recycled water to keep the trees alive in hot summer weeks. Some credit too for urban parkland and golf courses?
You are damn right about large cities being “heat islands” in he surrounding landscape - which leads of course to HIGHER use of air-con, and thence HIGHER heating of the city air.
cheerio
Estimates from Green Roofs Australia are that green roofs in themselves can improve efficiency of individual dwellings by 20% and apartment blocks by 10%. This would be increased by vertical greenery on north and west faces particularly. These things do not however add up to a carbon-sink city, sad to say, though they also play additional roles in reducing wind speeds around buildings, and the overall heat island effect, which all have knock-on benefits.
Probably the biggest single benefit would be the reduction in our peak loads in summer due to air conditioning use, and that is a big benefit. The less variability in demand for energy, the smaller the infrastructure requirements for our energy systems, as I understand it.
One additional benefit from greening of facades, apparently, is that it can improve the benefit of PV cells. As you’ll all know, these decrease in efficiency as the temperature rises (being at optimum at around 25 degrees celsius, which is somewhat hard to achieve while being in direct summer sun!). By cooling the building, the greenery keeps those PV cells generating more optimally.
The only downside I can see is the increase in embodied energy for building, as structures need to be more massive to cope with the weights of green roofs. However with lightweight substrates, and typical over-engineering of most buildings, this may not be too great a factor.
Hanging gardens aren’t new (for recent decades), nor confined to Europe. In the early 1980s, they were blooming in Singapore/ HK; Stephan (Qld’s flamboyant hair-dresser) built a roof jungle on top of his Briz penthouse; even the designers of our new Parliament House, Canberra, put a lawn on the roof.
But, as SE QLDers know, water-hungry gardens are not a good in drought periods; which, according to the more alarmist CC lobbyists, will become more of a problem in the future as warming continues. As in SEQ’s current crisis, most grey water needs to be harvested for recycling, just to keep cities & their industries going. How bad? In the gap between desperate water restrictions & legislation to re-introduce domestic rain-water tanks, we had to have 5 of our big trees removed because lack of water had made them dangerous!
This is Australia, folks! South of the Tropic, even coastal cities have water problems. Of our capital cities, Brisbane, Canberra, Melbourne, Adelaide & Perth will, in the long term, have continuing major water problems, and Sydney & Hobart will from time to time.
If those alarmist scenarios become reality, all rain water will need to go into either city aquifers or through household toilets & washing machines.
Plant Oz natives, perhaps? Gum trees do well in drought conditions - ask Canberrans! - but, highly flammable, they come as a terrible cost - ask Canberrans (& residents in Sydney’s leafy semi-rural areas and Melbourne’s Dandenongs) about that, too.
In Oz, the real “green” solution is buy-back of stations and farms in marginal areas, and reafforestation of native flora through the vast, once-treed reaches of inland Australia; but even this will be water-expensive in the short term.
That is a good find, Mercurius. The pros and cons are con water pro cooling cities and suburbs less airconditioning potentially less extreme weather events (hail). I am a fan though regardless.
Caution.
There was a famous ivied wall in Paddington, really old and beautiful. The business that owned the wall got in a contractor to clean up the pathway that the ivy wall lined. Very thorough worker cleaned away all of the undergrowth all of the way to the wall which included cutting through the main root trunks of the ivy. It is now a plain terrace wall. That’s how I heard it anyway.
Interesting, BilB. One feature of the vertical gardens is that the plants are suspended a couple of inches away from the building surface. The roots can’t invade the building, something that ivy is notorious for…
If you have to dismantle the garden for any reason, you just remove the panels and re-fill the concrete bolt-holes…
This is probably an impossible fantasy, but sometimes things start that way. How about growing eucalyptus forests on flat city rooves, and stock them with koalas, possums etc.
I can see the artguments against it - water shortage, fire danger and so on. But come on, we’re smart. There must be a way.
Paul - your biggest problem is getting any sort of ecology going. If you can’t, the effort involved in maintaining any sort of biodiversity would be cripplingly expensive.
It’s a great idea, but it’ll always be artificial nature.
DeeCee @ 3
“Gum trees do well in drought conditions - ask Canberrans”
Wish it were true but I’m not so sure. We have had two gums removed in the last few years because they died. A biggish one up the road died at the same time, the neighbors behind us lost one just a month ago and the neighbors next to us have one dieing right now. Our suburb is one of the older ones with lots of natives and I never heard more chainsaws and stumpgrinders. The guy that came to inspect our street tree said that they have never been busier and have removed thousands. In fact our street has only about 3 or four left whereas 25 years ago there were heaps.
Gum trees are also dangerous in suburban areas and I’m kind of glad ours (we had 5 at one stage) are all gone. We had one fall straight across our street quite a while back in a storm and a number of years ago we came across a motorcyclist (fortunately we weren’t the first) who had died after hitting a fallen gum
at night in one of the back streets of Canberra.
Paul - roofs can’t take that kind of weight! That’s why these gardens rely on the wall structures. The engineering is beyond me, but there are some substantial walls installations rising 7+ storeys high. They weigh several tonnes, but any building with solid foundations can handle that sort of additional force. But roofs - no…
And you would get some ecology going spontaneously in a sufficiently large area of vertical vegetation. The plant roots growing in the felt break it down and create their own soil made of root-mat, dead leaves and the degraded felt. Plenty of opportunistic birds, insects and small mammals would find a home. Most animal life in jungles and forests lives vertically…
if the plants are watered by grey water from the roof … what’s the energy cost of getting the water on the roof? rainwater might be a better bet i might guess. australian cities get good rainfall generally in the city area - just not always in the dam catchments. looks like an interesting idea … can it be done with australian native species?
Australian cities already have plenty of urban ecology. I reckon you’d have to trial it to see if it further advantages the ferals or whether other species reach pest proportions.
Also I don’t really think of Australian forests as vertical in the sense of living on cliffs. Many birds for instance, pick a level in the forest and generally stick to it. So you will find bower birds and lyrebirds in the bottom story, treecreepers on the bare trunks, pardalotes in the top story. And many small marsupials that inhabit the top stories of rainforest are all born and die 30 meters up. The ground is a completely alien space to them - they needed connected top stories to travel horizontally. Up in NQ (in the Daintree i think) they started putting wires across the roads so the forest on either side is connected up for these species.
Great point Tyro Rex. That solves the water problem. I’ll start to plan straight away. I had planned to ivy the front wall of my (ugly) factory, but attempts (half baked) to sprout the ivy in the unfriendly rubble under the tar failed several times. The next door factory was converted to a dance studio and they have planters beside the door fed with water from the air conditioner. The planters were struggling to survive the dry and cigarette buts (waiting parents) until the airconditioners were installed last summer.
Grey water, greyt idea.
Of course, people could always get of their bums and protest that forests not chopped down for arse paper, so that all the start up effort of manufacturing
artificial ones could then be applied to other problems.
Then perhaps we could move from the latest cycle of neoliberalism, that demands that the public be punished for global warning, alibiing the shifting of capitalism’s fetishist costs onto them yet again.
Never mind, so long as as Mr Gunns and Mr Cubbie Creek and MR Macbank and their attending hordes of political,press legal, and bean counting parasites are left ok.
Dee Cee (# 3 Jul 12th, 2008 at 9:37 am) has a point. Many Australian city precincts are just too close to flamable bush and, we just may have to uniformly reserve even grey water for other uses if the southern part of the continent continues to dry.
However, having said that, I am sure that there would be many large buildings across the country who could use ‘greened’ roofs and walls to mitigate energy use and bad design.
Another way to “turn cities into carbon sinks” might be to use
“Eco-Cement which absorbs C02 from the atmosphere to set and harden and can be recycled.”
I saw it on The Inventors: wouldn’t it be great if all those concrete monstrosities, such as most modern university buildings, were part of the solution, not just the problem?
By sheer coincidence, I just wrote this brief article on the Musée du quai Branly that features a Patrick Blanc living wall.
It is a great idea, along with green roofs and solar panels on buildings.
The times they are a changin’
greenery (aka plants) is not a carbon sink. great idea to beautify and give life to boring and stale architecture, but don’t think of it in greenhouse terms. plants die and release the carbon they sequester.
pete m - Greenery IS a carbonsink - that’s all that forests do, after all. Some of it is not very long-lived but it depends what happens to it as it dies. Some of it becomes carbon stored in the soil, some of it stays locked up in woody parts of the plants that hang out as mulch. It may not be enough of a carbon sink for our sad ailing world, but it is something. There is always a good reason to plant something.
BilB - Don’t plant ivy. It is a horribly invasive exotic plant with few redeeming features, except for being virtually unkillable, and able to grow in the shade (try it indoors, where it can do less harm). If you need fast-growing native species to cover a wall, try Wonga wonga vine (Pandorea pandorana) or Black Coral Pea (Kennedia Nigricans). I’ve probably got those Latin names wrong, but it’ll be enough to track them down. Neither of these get watered by me, but they love to grow. They can both cope with shade, and they have stunning flowers. Sadly, they won’t attach to your wall directly, and will need some sort of structure, but some fixed wires is usually the easiest to get them started. If you must have a plant that self-attaches, Ficus pumila (creeping fig) is an exotic that is far less offensive than ivy, IMO.
Yep, I think water supply is the only shortcoming - either availability or cost. But if there are real avoided aircon costs they could net each other out. I always liked that idea of using skyrise windows as solar panels. What happened to that idea?
As for planting passionfruit, I’m picturing them dropping from the 50th floor onto the footpath below…
Kymbos,
I quite like the idea of passionfruit dropping from 50 stories, but they would not grow that high. Something about water not being able to move up through the stem above a certain height. Though if they did, they are pretty light once ripe, and might not be too damaging…
If you mean passive solar heating, kymbos, it’s alive and well in home building and small scale commercial buildings. Free lighting, winter warming from the lower sun, etc. All through the north-facing windows, and very cheap to achieve. Design eaves to shade out the sun in hotter summer months.
Solar clothes-drying’s been around for centuries too.
cheerio
Ambigulous
There was a news item on ABCTV news and in “The Age” a few months back about a Brunswick lass growing veges on her roof. Pumpkins etc.
That was the Republic of Moreland.
More (land) here.
http://republicmoreland.wordpress.com/2007/05/10/green-roofs-could-make-more-land-in-moreland/
“It may not be enough of a carbon sink for our sad ailing world, but it is something. There is always a good reason to plant something.”
Picture this: genetically modified solid hardwood redwood trees, which have been engineered to grow into house- and building-shaped formations. An entire vertical redwood city: a vast long-lived carbon sink, solid as rocks, picturesque as all get-out, and plus you get to live in not just a treehouse, but a penthouse treehouse.
Get cracking, bio-geniuses. If you fail, we’re stuck with just bamboo and kudzu.
“In Oz, the real “green” solution is buy-back of stations and farms in marginal areas, and reafforestation of native flora through the vast, once-treed reaches of inland Australia; but even this will be water-expensive in the short term.”
Umm, I think the Aboriginals and their “fire stick farming” destroyed most of those “once treed reaches” well before white fellas showed up.
Con Little,
There is a bit of a debate about how Aboriginal people changed the landscape. I am sure they did - none of us humans are good at avoiding our impacts on the planets, there are just a lot more of us now. However as I understand it, firestick farming is mostly low temperature burns in cooler months, to burn understorey and grasses rather than established trees.
Tim Flannery suggest that perhaps Australia’s megafauna once kept this continent with something more akin to open woodland, than dense forest, and perhaps indig people had an impact on their disappearance…
Firestick farmning created some open land, but most significantly it favoured eucalypt forest over any other kind - there is no doubt biodiversity took a bit hit from Indigenous “stewardship” of the land.
“Firestick farmning created some open land, but most significantly it favoured eucalypt forest over any other kind - there is no doubt biodiversity took a bit hit from Indigenous “stewardship” of the land.”
I’ll say. Indigenous Australians caused a massive extinction event in regards to megafauna and fire sensitive plant species. Yaz may have misunderstood Tim Flannery, as Flannery has used the term “blitzkrieg” to describe the impact of Aboriginal practices on the early Australian landscape. Unfortunately the left-liberal black armband narrative has effectively stifled any disinterested discussion of such matters.
When I fly over Melbourne I’m struck by the green canopy over the city and wonder if the extant vegetation is sequestering almost as much carbon as it did circa 1770, particularly when the wood in buildings etc is taken into account.
“Unfortunately the left-liberal black armband narrative has effectively stifled any disinterested discussion of such matters.”
Bullshit. Ummm, with all due respect ‘n’ all.
There is a piddling minority of folks who simply won’t hear a word against Aboriginal culture and history, but in the fields of ecology and natural history no such stifling has occurred and nor will it.
“… but in the fields of ecology and natural history no such stifling has occurred and nor will it.”
Science is free of politics? Well may I suggest you acquaint yourself with the climate change debate and the attitudes of scientists like Fred Singer, Pat Michael etc etc etc