1. Has high reflectance in the infrared, so they reflect sunlight back to the sky before it is converted to heat. Built surfaces would absorb this radiation and heat up.
2. Reduce heat also by evaporating water.
3. Reduce ground level heat by providing shadow.
4. Remove pollution from air, such as sulfur oxide (SO2), nitrogen oxides (NOx), ozone (O3) and fine particles.
But yes, converting these to money is very indirect and involves a lot estimation.
Next time, try ice plant and jade plant, or just go with concrete.
The US Forest Service created algorithms to calculate ecological value based on rainwater each tree retains, the electricity conserved, and reduction of air pollution - that calculation just happens to be expressed in dollars. How they make that transition from ecological value to economic value is a mystery to me, but it is just something to keep in mind as you look over this. It is moreso a measure of ecological impact, not economic (though, of course, they are connected).
Improving public health and reducing e.g. lung cancer can have value for the national economy, even if individual people do not perceive tradable value in things like buying a home on a street with less polluted air, or quitting smoking.
Value is a slippery concept, and i think i'm willing to go out on a limb and say all value is subjective.
You can't expect to get in-depth, exhaustive explanations of complex concepts in a short article, but you should looks the primary sources cited therein and critique those if you feel they fall short.
There was an article I read not too long ago that showed the areas in NYC with more trees and greenery also command higher rents.
Also on a completely anecdotal level I feel more "at ease" and less anxious when I'm in parts of cities that have a lot of greenery, especially compared to areas that are barren and nearly all concrete/brick/whatever.
I imagine I can't be the only one who feels that way.
That can just be correlation though, the affluence might make it easier to keep trees or be an indicator of larger setbacks or whatever.
If the affluent find it easier to keep trees that must be because they exert power to do so, which implies they want them for some reason. Same reasons they would pay more to be around them in the first place? The affluent would find it much easier to get rid of trees, even if protected by regulation, and the land value the trees take up is worth more.
I think the causation implied by this correlation is implied pretty strongly.
When you say you're not convinced that it's possible to be really sure you've captured all of the benefits, do you mean captured their exact value? Or a hard upper bound of such? Or a soft upper bound with a given confidence interval? Or even just enumerated all of the benefits?
I think calculating an upper bound with confidence interval for the value of a tree in a city would be a really interesting exercise. To do it properly you'd have to account for everything from tangible benefits (shade, reduced CO2) to vague generalities such as residents who "feel happier living in a city with lots of trees". I think it'd be possible, but definitely not trivial.
http://www.nbclosangeles.com/news/local/LA-Expected-to-OK-Pl...
"$1.4 billion plan to repair a backlog of broken sidewalks that will allow the city to turn over the responsibility of future upkeep to property owners. City officials plan to spend the funds, which will average at least $30 million a year over the next three decades"
0.1% of LA county's budget next year will be repairing damage from trees.
I'm not going to argue whether that's a large or a small amount. Just want to put the $1.4B number into perspective.
http://time.com/money/4389722/national-parks-economic-value/
As ^green infrastructure^.
Trees->flowers->insects->pollination. Lack of pollinators can be compensated by more trees. This is but one example ~ https://www.epa.gov/green-infrastructure/what-green-infrastr...
There are two statements that I think are meaningful: "this tree costs $X to plant and maintain", and "This tree provides benefits that would otherwise cost $X". But if you want to make the latter statement, are you really sure you've captured all the benefits? Including aesthetic ones? Because I'm not really convinced that's possible.