15 January 2014

Canberra's leafy suburbs 7 degrees cooler than treeless hell?

| johnboy
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New Scientist has an article on Australian climate policy (no, this is not an excuse for the nutters on both sides to break free, you know who you are) which contains an interesting aside about Canberra:

In an as-yet-unpublished study, Hanna and her colleagues found that older suburbs in Canberra with more trees were up to 7 °C cooler than newer, less leafy suburbs.

There are downsides to ancient three bed ex-govvies in the inner suburbs, but there are certainly some upsides!

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wont some one think of the solar panels we love our sun

HiddenDragon2:44 pm 16 Jan 14

poetix said :

At the risk of saying ‘how about this heat?’ I would point out that my *two* bedroom house is cooler than absolutely nowhere today.

Including Mercury.

Trees can only do so much.

AIS pool is calling.

Yes – unless trees are sufficiently large, and close to the house (and in the right position) they don’t make that much difference to the heat inside – and once the sun is down, little difference at all.

Tempestas said :

The really interesting bit here is that it would suggest that using deciduous trees for street trees is the better outcome for livability of an urban environment.

Plenty of main roads and nature parks where native ever greys can be planted, suburban streets should have deciduous trees as far as possible.

The cultural cringe against exotic trees needs to end. Street trees should provide shade in summer not heavy branch’s that fall off as it’s a bit hot/dry.

Air raid siren
slap of eucalyptus
nostrils twerking

I’d like to thank ACTEW in advance for cutting my power supply on Saturday when it is expected to be 40 degrees.

Staff and customers must be thrilled you continue to go ahead with work under such temperatures rather than reschedule them for a day more suitable.

Chop

The really interesting bit here is that it would suggest that using deciduous trees for street trees is the better outcome for livability of an urban environment.

Plenty of main roads and nature parks where native ever greys can be planted, suburban streets should have deciduous trees as far as possible.

The cultural cringe against exotic trees needs to end. Street trees should provide shade in summer not heavy branch’s that fall off as it’s a bit hot/dry.

At the risk of saying ‘how about this heat?’ I would point out that my *two* bedroom house is cooler than absolutely nowhere today.

Including Mercury.

Trees can only do so much.

AIS pool is calling.

Yeah nature strips where all the nice old trees have been planted seem to be getting smaller and smaller or in many cases non-existant.

It’s a shame as many of Canberra’s new suburbs look identical to those in greater western Sydney. It’s all in the name of revenue for both the govt and developers.

GardeningGirl11:18 am 16 Jan 14

HiddenDragon said :

. . trees certainly seem to make a difference to the actual and perceived temperature. I just think it’s unfortunate that we can’t have a more balanced approach to the use of trees in this town – on the one hand, we have at times, preservation to the point of what seems like zealotry and on the other, stark, sterile brutalist developments where any token greenery is like a sprig of parsley on a baked buffalo.

+1

Wow, WTC. Not fond of Autumn leaves much huh?

Here’s what I do: some end up as mulch on garden beds (though not around the trees they came off — a disease risk). By this time of year they have pretty much all decomposed.

Some go into the chook pen as litter.

But the bulk go into a contained pile for making leaf mould, which is a great soil conditioner. I use a wire cage in a discreet corner of the yard to do this. But you can put them in a plastic garbage or yard bag with slits. Dampen them a bit when they dry out. Several months later, with very little work involved, you can dig the resulting material — which basically looks like its name, and smells pleasantly mushroomy) straight into garden beds — improves water retention in the soil enormously.

If you want to speed up this process, run a mower over the leaf pile a few times before bagging them.

I also regularly dip into the caged leaves as a carbon source for my compost bins. Why not compost the lot, I imagine you are all immediately thinking? Because leaf-mold is seriously good for improving soil water retention (better I find than compost) and is also relatively low in nutrients. So you can use it in native plant beds for example.

So: shady in summer, allows sun through in winter, provides free mulch, soil conditioner, chicken litter and kicks the compost along.

Whats not to like about a deciduous tree? (Avoiding invasive roots is a matter of choosing the site and species carefully).

c_c™ said :

Source?

That’s a very big claim, which isn’t to say it wasn’t the genuine sentiment of some perhaps back then, but certainly there were laments early on that the hills (which as distinct from the base of the plains which were naturally lacking trees, were heavily wooded) were cleared by graziers for the most part, removing some useful natural resources from both a visual and practical stand point.

They also planted heaps of imported species in those early years two, and lost a lot. An early planting of cedars, about 10,000 were killed by draught and had to be replanted. 100,000 redwods were planted and a lot failed and had to be replaced.

I don’t have it on hand, but I do remember reading about it and I’m sure that they were talking about the number of trees on the plains. I’ll keep looking for the source. I also remember a photo posted on here that showed the difference in the inner north between 1920-ish and today. Chalk and cheese.

It’s a shame the redwoods didn’t take here, and it’s sad to see them struggling out in that patch near the airport. The redwoods are an enduring memory of California and the irony is that the 12 or so species of eucalypts that grow there, grow so well! Actually, in Wunderlich Park in San Mateo, there’s this weird junction between all redwoods and all eucalypts.

I used to lament my Gungahlin view of nothing but rooftops, but in the last few years, we are starting to see the street trees grow to the height where they start to take over the view.

“In an as-yet-unpublished study, Hanna and her colleagues found that older suburbs in Canberra with more trees were up to 7 °C cooler than newer, less leafy suburbs.”
Having a number is nice, but the principles are fairly established science. Can’t wait to see Hanna’s paper when it is published.

Comic_and_Gamer_Nerd7:08 am 16 Jan 14

CLIMATE CHANGE IS CRAPPPPPPPPPP!!!!!!!!!!!

wildturkeycanoe7:07 am 16 Jan 14

Then come Autumn, the folks in the leafy suburbs are constantly raking the mess off their lawn and kerb, wondering what to do with the piles of leaves they aren’t allowed to burn or put in the bins. Rains come and due to the build up in the gutters the ceiling gets flooded, they can’t park their car on the nature strip or road because of sap and bird droppings and every few years the plumber has to be called in to unblock the roots from the aging sewer line. Everything has a downside, enjoy your 33 degree days.

HiddenDragon11:53 pm 15 Jan 14

The deciduous trees were all laid out by the Druids, according to The Secret Plan, long before it was Limestone Plains – Burley Griffin just came along and set it down on paper…..

But seriously, trees certainly seem to make a difference to the actual and perceived temperature. I just think it’s unfortunate that we can’t have a more balanced approach to the use of trees in this town – on the one hand, we have at times, preservation to the point of what seems like zealotry and on the other, stark, sterile brutalist developments where any token greenery is like a sprig of parsley on a baked buffalo.

puggy said :

johnboy said :

Not too many trees in reid and campbell in the old photos.

That’s what bugs me about people bagging out newer suburbs for the lack of trees. One of the upsides to the site for Canberra was considered to be the comparative lack of trees. The vast majority of greenery in the city’s inhabited areas was planted after settlement.

Source?

That’s a very big claim, which isn’t to say it wasn’t the genuine sentiment of some perhaps back then, but certainly there were laments early on that the hills (which as distinct from the base of the plains which were naturally lacking trees, were heavily wooded) were cleared by graziers for the most part, removing some useful natural resources from both a visual and practical stand point.

One of the very early bureaucracies established for the new capital was the Parks and Gardens Branch, and some of the earliest public works involved establishing native trees.

In 1919 they kicked graziers off Mt Majura and reserved it (I suppose a very early incarnation of the Canberra Nature Park). They planted over 20,000 trees, mainly Kurrajongs over the following 2 years.

Earlier in 1917, they’d started a massive planting program to regenerate Mt Russell, 10,000 eucalyptus trees and another 5000 on 1925.

Between 1918 and 1920, they planted over 26,000 native trees at Mugga Mugga, mainly box trees.

They also planted heaps of imported species in those early years two, and lost a lot. An early planting of cedars, about 10,000 were killed by draught and had to be replanted. 100,000 redwods were planted and a lot failed and had to be replaced.

The planting programs only grew, thousands of acres every year planned, including commercial plantations.

There was also praise for the fact that much of the natural forrest, in particular Mountain Ash to the West of the ACT, was intact, though regularly damaged by fires used by NSW graziers over the border to the chagrin of ACT planners.

The lack of trees was seen as an error to be remediated, at great effort and cost. And perhaps demonstrating this importance, Canberra was restoring native tree populations before we even had reliable drinking water established from the planned catchment.

johnboy said :

Not too many trees in reid and campbell in the old photos.

That’s what bugs me about people bagging out newer suburbs for the lack of trees. One of the upsides to the site for Canberra was considered to be the comparative lack of trees. The vast majority of greenery in the city’s inhabited areas was planted after settlement.

Queen_of_the_Bun said :

johnboy said :

Not too many trees in reid and campbell in the old photos.

What about southside? Red Hill?
Fricking inner northies drive me insane.

Pretty easy to check that one:

http://www.flickr.com/photos/canberrahouse/2708107695/

johnboy said :

They didn’t call it the limestone plains for the abundant trees. It was heavily grazed sheep country.

“Red Hill itself rises to a height of rather more than 2350 feet… an abundance of trees lend a pleasant background for the residences which are to grace the foothill.”

Canberra Times, 28 Oct 1926 (page 11)

Queen_of_the_Bun9:37 pm 15 Jan 14

johnboy said :

Not too many trees in reid and campbell in the old photos.

What about southside? Red Hill?
Fricking inner northies drive me insane.

I’m pretty sure the deciduous trees of red hill and forrest were not there before they started building the city.

Queen_of_the_Bun9:34 pm 15 Jan 14

johnboy said :

Not too many trees in reid and campbell in the old photos.

What about southside?

They didn’t call it the limestone plains for the abundant trees. It was heavily grazed sheep country.

And suddenly watering the street trees is with a few bucket a of water makes it seven times better…

http://the-riotact.com/save-the-trees-because-were-incapable-cryeth-tams/122426

Feeling seven degrees cooler here.

Queen_of_the_Bun8:02 pm 15 Jan 14

Holden Caulfield said :

Of couurse, every suburb in Canberra has been a treeless hell at some stage.

Really? So developers with bulldozers were at work in Red Hill and Campbell in the 1920s?

Not too many trees in reid and campbell in the old photos.

Holden Caulfield7:41 pm 15 Jan 14

Of couurse, every suburb in Canberra has been a treeless hell at some stage.

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