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Countering climate change with cool pavements

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Re: Countering climate change with cool pavements

#41

Post by bcrosby95 »

clairity wrote: post #34
moonchrome wrote: post #31

Earlier quoted context omitted.

How do you get trees to avoid destroying concrete/pavement with roots ? We have a lot of old trees around and the pavement around them is bulged, cracked and deformed.

primarily by choosing an appropriate tree that doesn't do that. countersinking the tree can work in some cases too (often with a metal grating around the base of the tree so people don't fall in and hurt themselves). i don't know that you can "fix" the roots once the tree has become well established, without seriously damaging the tree and potentially creating additional hazard.

You also have to be careful of mainlines and turning that into swiss cheese with the root system. Ultimately it takes a fair amount of research to pick the right location and tree.

Re: Countering climate change with cool pavements

#42

Post by nl »

koolba wrote: post #28
BurningFrog wrote: post #21

Earlier quoted context omitted.

One logical answer is "Artificial trees". That is, constructed shade structures that provides shade without being unpredictable living things. There are probably real problems with that approach too. What are they?

Artificial plants are like synthetic plastic grave stones, superior in almost every way to the traditional approach yet considered incredibly tacky.

Except for the transpiration and reduction of CO2.

Re: Countering climate change with cool pavements

#43

Post by harmmonica »

stackbutterflow wrote: post #40
harmmonica wrote: post #13

Earlier quoted context omitted.

from one LA resident to another, amen to that. we were just walking down our street this morning and discussing, for the umpteenth time, whether our neighbors would actually be willing to take care of trees if we went out and bought them and planted them. the problem, as other commenters have pointed out, is that they do require upkeep, but since they're living/breathing things the more hardy ones can really be abuse…

I've never been to LA so let me try. Rolling hills, Park estates, coastal san Pedro? That's all I got after 5 minutes on Google maps.

ha! i’m glad you tried it! only one of those (san pedro) is in the city of LA, which i should’ve been more clear about. but those places do indeed appear to have more trees than the vast urban expanse. sadly san pedro does not rate as an above average area (rolling hills would). that said if you want to waste another 5 minutes of your life on this go to google maps again, look at the area between “downtown los angeles” and “santa monica” and find the green areas. really love that you actually tried to do it once already though!

Re: Countering climate change with cool pavements

#44

Post by harmmonica »

bcrosby95 wrote: post #41
clairity wrote: post #34

Earlier quoted context omitted.

primarily by choosing an appropriate tree that doesn't do that. countersinking the tree can work in some cases too (often with a metal grating around the base of the tree so people don't fall in and hurt themselves). i don't know that you can "fix" the roots once the tree has become well established, without seriously damaging the tree and potentially creating additional hazard.

You also have to be careful of mainlines and turning that into swiss cheese with the root system. Ultimately it takes a fair amount of research to pick the right location and tree.

like parent commenter said LA actually has a list of acceptable “street trees” that they’ve approved so they don’t kill the sidewalks. some of the most glorious trees you’ll see here are ficus, but those are not on the list because they do blow away sidewalks, streets, utilities. unbelievable shade trees though that require very little water.

Re: Countering climate change with cool pavements

#45

Post by barsonme »

berikv wrote: post #8

Why wouldn’t you just plant some trees. You don’t need any fancy pavement if it is below a tree.. European cities are filled with trees to cool the streets below them. Obviously, you’d need smaller streets that fit pedestrians and bicycles instead of massive urban highways for trees to be effective.

US cities have trees, too. One downside, though, is the roots can grow and break up the sidewalk. There are some sidewalks in Seattle that are completely inaccessible to wheelchairs or even folks with walkers.

Re: Countering climate change with cool pavements

#46

Post by hisyam »

barsonme wrote: post #45
berikv wrote: post #8

Why wouldn’t you just plant some trees. You don’t need any fancy pavement if it is below a tree.. European cities are filled with trees to cool the streets below them. Obviously, you’d need smaller streets that fit pedestrians and bicycles instead of massive urban highways for trees to be effective.

US cities have trees, too. One downside, though, is the roots can grow and break up the sidewalk. There are some sidewalks in Seattle that are completely inaccessible to wheelchairs or even folks with walkers.

You can plant trees that doesn't have pavement-breaking roots.

Re: Countering climate change with cool pavements

#47

Post by robocat »

harmmonica wrote: post #13
clairity wrote: post #3

> “Conversely, by reflecting light — called incident radiation — onto nearby buildings, cool pavements can warm structures up, which can increase AC usage in the summer and lower heating demand in the winter.” this is one of the reasons why i'm an advocate for street trees, and urban foliage in general (cuts down both incident and reflective radiation), and why i'm maddened when i see urban trees cut down or cut back…

from one LA resident to another, amen to that. we were just walking down our street this morning and discussing, for the umpteenth time, whether our neighbors would actually be willing to take care of trees if we went out and bought them and planted them. the problem, as other commenters have pointed out, is that they do require upkeep, but since they're living/breathing things the more hardy ones can really be abuse…

> people who have never been here can point out the expensive neighborhoods because they are the greener ones

This is normal in many cities.

Trees can mean high status because

(a) you need excess land to have trees.

(b) old wealthy suburbs often have old trees (a massive old oak tree implies something).

(c) single dwelling houses that are near the city often have very old trees due to the age of the location, and can have high value because the location has now become central (due to city outskirt growth).

(d) maintaining trees costs time and money, as mentioned, so that also implies wealth (and status).

Aside: lawns are another status symbol - that is why so many people care about them so much! Think of a huge old English estate with manicured lawns, and why that is a strong symbol of wealth.

Edit: and I should say I love trees and I think they are really worthwhile, independent of any associated status!

Re: Countering climate change with cool pavements

#48

Post by sk2020 »

burlesona wrote: post #4

It's interesting that the effects are so complex and nuanced. I also wonder - they didn't specify - just how reflective these surfaces need to be, and how "bright" they are to look at. I could see glare being a potential safety hazard if the surface is reflective enough, but I'm assuming that any surface rough enough to make good pavement won't be _too_ bad to look at.

I would doubt they went far enough to get meaningful measurements. I think this is just more of the Ivy League enriching itself at the bottomless climate feeding trough. The discovery that light colors absorb less heat isn’t remarkable. I would be embarrassed to see this if I were an MIG alumnus. Statements about replacing all pavement in a metropolitan area (that doesn’t even patch its potholes) are so out of touch that they discredit the whole article. Just replace all that asphalt with concrete filled with, I guess, prismatic beads which would be like staring at the sun? Brilliant! Oh, or use “lighter colored aggregates”? Right. We I never thought to just ask the local geology to rearrange itself a bit so my local quarries can produce a different color product. I’ll give it a go!

Several here have made the much more obvious observation: just use plants.

Re: Countering climate change with cool pavements

#49

Post by wruza »

clairity wrote: post #3

> “Conversely, by reflecting light — called incident radiation — onto nearby buildings, cool pavements can warm structures up, which can increase AC usage in the summer and lower heating demand in the winter.” this is one of the reasons why i'm an advocate for street trees, and urban foliage in general (cuts down both incident and reflective radiation), and why i'm maddened when i see urban trees cut down or cut back…

I would add that city people underestimate or simply do not know about the ability of vegetation to cool off its environment. My city has areas (few abandoned plots) with a wild high grass and bushes on them. When it’s hot and you walk nearby, like 2-3m close, it is as if you went from the street to under AC. I don’t know how they do it, but my guess is that photosynthesis is a hell of an endothermic process. And you’re right, modern “city trimming” is just a disgusting non-functional nonsense.

Re: Countering climate change with cool pavements

#50

Post by burnished »

clairity wrote: post #34
moonchrome wrote: post #31

Earlier quoted context omitted.

How do you get trees to avoid destroying concrete/pavement with roots ? We have a lot of old trees around and the pavement around them is bulged, cracked and deformed.

primarily by choosing an appropriate tree that doesn't do that. countersinking the tree can work in some cases too (often with a metal grating around the base of the tree so people don't fall in and hurt themselves). i don't know that you can "fix" the roots once the tree has become well established, without seriously damaging the tree and potentially creating additional hazard.

Ooooh, countersinking a tree to get its roots below the pavement, with a metal grating to keep people out.. thanks, I used to wonder about this and had no idea why some one would do that.
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