Cities are vulnerable to heatwaves. But green spaces can help more than we thought

[craigs]

So the article states that the MWD has compiled a list of recommendations for small, medium and large trees native to California, available on its website.

And the agency is especially encouraging residents to plant the coast live oak, which Krista Guerrero, an MWD resource specialist, describes in glowing terms: “In terms of tree superstar in Southern California, the oaks really take the top prize just in terms of their ability to sequester carbon, to cool the air around us, and they do require very little water,” she said.

[hauntedheadnc]

Originally Posted by craigs

Plant a tree, get $100 under new MWD program aimed at expanding SoCal’s tree canopy

Lila Seidman
Los Angeles Times
March 6, 2024

With many areas of Southern California starved for shade, the region’s largest water supplier has launched a rebate program offering residents and businesses up to $500 as an incentive to plant trees.

There are organizations here that will give you free trees to plant. I've gotten trees from one, TreesUpstate, and planted them only to see the brutality of nature in South Carolina unfold before my eyes. It turns out that carpenter bees, for example, upon learning there is a new redbud tree in the front yard, will gang up on it and work it over like muggers on a Kansan tourist in Times Square, circa 1986. They killed one of the free redbuds I got from TreesUpstate and left the other in tatters. It came back last year, but I haven't seen if it's coming back yet this year.

Meanwhile, when it comes to money for trees, Clemson University runs a program where they will pay you a bounty for your Bradford pear trees. For those unaware, Bradford pears are an ornamental tree that was introduced to the US in the 1960s and planted extensively across the South. They're remarkably fast growing, to the point that their weak wood splits in high winds and under the weight of snow or ice, and although they were supposed to be sterile they most decidedly are not. Once they start escaping into the wild they form dense, impenetrable thickets and can develop thorns that can puncture a tractor tire. All that, and they also have the added benefit of smelling strongly of semen when they're in bloom. With all that, who could resist their charms, but if you can resist, Clemson will pay you money to kill your Bradford pear. I can recall seeing them all over the place when I was a kid in the 80s, but it took a while before people realized what a pain in the ass they were. They are a failed street tree -- which adds another dimension to the discussion. Bradford pears aren't the only ornamental plants that turned out to be a bad idea for adding greenery to urban areas.

[Obadno]

Ive been harping on this for years. I am extremely well versed in water issues.

Water hogs in the west are AGRICULTURE 75% followed by manufacturing/industry followed by housing/golf/parks

Making people kill their lawns and trees while growing almonds and alfalfa is UTTERLYU ASININE and makes hot cities HOTTER

We should be pushing on big agg to change what they grow and be more water efficient and ENCOURAGING people to plant SHADE TREES and greenery. California, Arizona and Nevada are doing the opposite of this its so infuriating

[jmecklenborg]

Originally Posted by hauntedheadnc

The article came from ZME Science which, according to an organization that would know, knows more about the issue than you do. So you can stop being petty and harumphing about the topic like an offended old spinster any time you like. Nobody said trees were a new idea.

I own a bunch of mature trees, maybe 50 of them. Some of them overhang my houses, both of which are over 100 years old. I also own two lots with a variety of mature trees on them, one of which has been bothering me for several years as it overhangs a neighboring business and no doubt drops a ton of leaves into their gutters. They haven't complained so I haven't done anything about it.

I can tell you that modern houses with no tree cover are more comfortable during the summer than are either of these old houses. A lot of old houses are charming but they have serious problems that can't be fixed without a gut rehab, and that rehab will almost certainly ruin much of their charm.

We are also, of course, blaming the trees or buildings instead of the individuals for doing logical things like drinking water instead of pop and beer when it's hot.

People also do completely irrational things like run window AC units AND their furnace at the same time. Sometimes they leave town for the weekend with both ripping the whole time. I'm a landlord. This is the sort of crap I have to put up with my tenants doing.

[hauntedheadnc]

Redwood trees are growing almost as fast in the UK as their Californian cousins – study

... My team’s new study is the first to look at the growth of giant sequoias in the UK – and they seem to be doing remarkably well. Trees at two of the three sites we studied matched the average growth rates of their counterparts in the US, where they come from. These remarkable trees are being planted in an effort to help absorb carbon, but perhaps more importantly they are becoming a striking and much-admired part of the UK landscape.

***

So how did these trees get here? Exotic plant collecting was big business in the 18th and 19th centuries, in large part as a display of wealth and taste. Giant sequoias were first introduced in 1853 by Scottish grain merchant and keen amateur collector Patrick Matthew, who gave them to friends. Later that same year commercial nurseryman William Lobb brought many more from California, along with accounts of the giant trees from which they came.

***

UK sequoias are unlikely to grow as tall as their Californian counterparts, which tend to grow in forests, due to lightning strikes and high winds – always a risk when you’re the tallest thing in the landscape rather than one among many. More recently, there has been a resurgence in planting giant sequoias in the UK, particularly in urban settings. This is because of their carbon storage potential and perhaps because people seem to really like them.

[ocman]

Originally Posted by jmecklenborg

Breaking news: it's cooler in the woods during the summer than outside the woods.

We thought covering the whole place in concrete would do the job. We were doing it wrong all along.

[ocman]

Originally Posted by isaidso

I doubt they'd be so foolish as to plant species that aren't suited to their climate. They would surely consult with professionals that specialize in urban forestry and climate mitigation. You want trees/plants that flourish without human intervention. Many of those species don't provide as much shade as an oak tree would but there are many benefits beyond shade.

And there are trees growing in Los Angeles on city-owned sidewalks that don't get watered except for the occasional rain. The notion that you shouldn't grow trees in LA is ridiculous especially considering how many drought-tolerant trees exist in the world and LA. (Not to mention it's a myth that LA is a desert that's never seen a tree before because rain doesn't exist). Trees are the solution in LA to heating environments as well as air quality. And in terms of water, its doesn't even put a dent in actual municipal usage comparatively. So yes, LA should plant "forests" i.e public spaces with lots of trees.

[ocman]

Originally Posted by Yuri

People don't water trees in Johannesburg afaik. And their shade cool the whole urban area and decrease evaporation.

No one waters the numerous drought-tolerant or deep-rooted trees that are growing on LA sidewalks either. Which is why it's an absurd argument to be against greenspace in Meditteranean environments that already have enough rain to support trees (as they have already before human habitation despite falsehoods).

[hauntedheadnc]

Originally Posted by ocman

We thought covering the whole place in concrete would do the job. We were doing it wrong all along.

Well, surely you must agree with him though that trees are so... plebian, so... vulgar, as the poors can enjoy them without paying, and rather than take action about overheating in cities on any macro level, the more effective strategy will be to lecture, for example, the Parisians about their hydration choices.

[Gantz]

Originally Posted by iheartthed

Maybe places in Southern California should implement sun shades, which are pretty common in southern Spain:

Los Angeles has La Sombrita.

(If you know, you know...)

[hauntedheadnc]

The thrust of the gist here is that while London planetrees look nice, and do sequester carbon, provide shade, and trap pollutants, they don't support insect populations the way native trees do, and therefore don't do anything for biodiversity. Trees, like oaks, that support healthy insect populations also attract and are good for birds. London planetrees aren't good for birds. Also, Robert Moses.

This Shouldn’t Be New York City’s Most Common Tree: The London planetree is a symbol of European settlement, biodiversity collapse, and Robert Moses.

...Devoid of most critters, the London planetrees are about as sterile as trees can be. And they’re just about everywhere. You might not yet have a strong feeling about these trees, but they’re probably familiar to you. New York City is home to over 87,000 London planetrees, per the Department of Parks and Recreation’s 2015 tree census. That’s 13 percent of all the trees.
There are about 23,000 more London planes than the next most abundant species, the honeylocust.

***

In a 2021 piece for Curbed about stewarding urban nature, Stephanie Foo drew motivation from a London plane that annually sequesters an estimated 10,500 tons of carbon dioxide. As Alison Kinney wrote in a 2017 New Yorker essay romanticizing the planetree, they also help filter rainwater and provide green spaces for New Yorkers.

***

It was during Moses’ reign over the Department of Parks and Recreation that the planetree was popularized in the city’s parks and streets. Like expressways tearing through low-income neighborhoods, London planes are said to have been a personal favorite of that shrewd tyrant. Moses seemed to love this tree almost as much as he loathed poor New Yorkers, people of color, and public transit. When Moses consolidated the boroughs’ parks departments into a single citywide office in 1934, the new parks department got a now-familiar logo. That leaf, while officially unspecified, seems to depict a London plane.

[edale]

Originally Posted by ocman

And there are trees growing in Los Angeles on city-owned sidewalks that don't get watered except for the occasional rain. The notion that you shouldn't grow trees in LA is ridiculous especially considering how many drought-tolerant trees exist in the world and LA. (Not to mention it's a myth that LA is a desert that's never seen a tree before because rain doesn't exist). Trees are the solution in LA to heating environments as well as air quality. And in terms of water, its doesn't even put a dent in actual municipal usage comparatively. So yes, LA should plant "forests" i.e public spaces with lots of trees.

Los Angeles is a chaparral biome. Look at any old photos of the landscape, or even just visit one of the few undeveloped tracts of land around the Southern California region, and you'll see this place was never a forest (outside of the mountains). Chaparral consists of drought tolerant shrubs and grasses that can withstand the ~7 months of minimal rainfall the region sees between May and November. Yes, there are a few species of native trees that grow here as well, but they mostly clustered near water sources, and existed as patch habitats rather than forests. Those are just facts. Many of the trees commonly seen around LA are not native- Jacarandas, most species of palms, etc. are all imports.

I don't see why it's controversial to say LA is not a forested landscape. If someone wants to plant as many trees as they can on their private property, go for it! What I take issue with is the demand that many Angelenos make for the city to provide them with an 'urban forest' so they can walk around more comfortably in the summer. Sorry, but I don't think that's how things should work. You don't move to Buffalo and demand the city to provide heated sidewalks to make walking more pleasant in the winter. It's cold and snowy in the winter there, and you deal with it. Similarly, it's hot and relentlessly sunny in LA in the summer (especially in places like the Valley, which is where I last heard this demand for the city to provide an urban forest). It's a chaparral region, not a forest, and imo it's unreasonable to expect the city to create an artificial biome so you can be more comfortable in the summer.

Ever hear an Angeleno talk about humidity? It's incredibly common to hear some variation of "oh I could never live on the east coast/midwest/wherever, it's SO humid and gross there in the summer!" Well, humidity and rain throughout the year is what allows for urban forests to exist in Atlanta and DC and cities throughout the eastern part of the country. Wanting a forest to exist in LA is wanting to have your cake and eat it too.

[craigs]

Originally Posted by edale

Los Angeles is a chaparral biome. Look at any old photos of the landscape, or even just visit one of the few undeveloped tracts of land around the Southern California region, and you'll see this place was never a forest (outside of the mountains). Chaparral consists of drought tolerant shrubs and grasses that can withstand the ~7 months of minimal rainfall the region sees between May and November. Yes, there are a few species of native trees that grow here as well, but they mostly clustered near water sources, and existed as patch habitats rather than forests. Those are just facts. Many of the trees commonly seen around LA are not native- Jacarandas, most species of palms, etc. are all imports.

I don't see why it's controversial to say LA is not a forested landscape. If someone wants to plant as many trees as they can on their private property, go for it! What I take issue with is the demand that many Angelenos make for the city to provide them with an 'urban forest' so they can walk around more comfortably in the summer. Sorry, but I don't think that's how things should work.

How you "think things should work" is a weak argument against planting trees to cool Los Angeles in an increasingly hot climate.

You don't move to Buffalo and demand the city to provide heated sidewalks to make walking more pleasant in the winter. It's cold and snowy in the winter there, and you deal with it. Similarly, it's hot and relentlessly sunny in LA in the summer (especially in places like the Valley, which is where I last heard this demand for the city to provide an urban forest). It's a chaparral region, not a forest, and imo it's unreasonable to expect the city to create an artificial biome so you can be more comfortable in the summer.

Unlike heating the outdoors in winter in Buffalo, planting street trees in Los Angeles is practicable. We know this because there are already a multitude of street trees in parts of the region.

[edale]

Originally Posted by craigs

How you "think things should work" is a weak argument against planting trees to cool Los Angeles in an increasingly hot climate.

I'm sharing my opinion just as you're free to share yours.

[Lost Island]

Originally Posted by edale

Well, humidity and rain throughout the year is what allows for urban forests to exist in Atlanta and DC and cities throughout the eastern part of the country. Wanting a forest to exist in LA is wanting to have your cake and eat it too.

That applies to the flora of the eastern hardwood forest -- you're literally comparing apples and oranges. Many west coast trees such as coast live oak would die with too much moisture or humidity in the summer. In fact, they need the dry season like most trees that thrive in a Mediterranean climate.

[edale]

Originally Posted by Lost Island

That applies to the flora of the eastern hardwood forest -- you're literally comparing apples and oranges. Many west coast trees such as coast live oak would die with too much moisture or humidity in the summer. In fact, they need the dry season like most trees that thrive in a Mediterranean climate.

So show me an example of a non-mountain forest in Southern California. I've never said that trees don't grow in Los Angeles. I know very well about our native trees. Outside of the mountains, we don't have forests here. We have chaparral and trees that mostly cluster near water sources. So the desire for Atlanta levels of tree canopy are unrealistic and unreasonable, imo.

[craigs]

Originally Posted by edale

So the desire for Atlanta levels of tree canopy are unrealistic and unreasonable, imo.

Disagreed. First, you're the only one talking about Atlanta-level tree cover. The rest of us are talking about the understandable and reasonable desire to cool the city (or keep it from getting hotter) as the planet warms by planting more trees. And that is a reasonable and realistic goal if that is what we decide to do. IMO.

[Lost Island]

Originally Posted by edale

So show me an example of a non-mountain forest in Southern California. I've never said that trees don't grow in Los Angeles. I know very well about our native trees. Outside of the mountains, we don't have forests here. We have chaparral and trees that mostly cluster near water sources. So the desire for Atlanta levels of tree canopy are unrealistic and unreasonable, imo.

At the same time, the L.A. basin for example needn't revert to largely a savannah, either. There could be more tree lined streets, shaded yards, shopping centers, and so much the better for it.

I live in a land area east of New York City that was actually a huge grassland before the settlers came (The Hempstead Plains). Probably 10 mi X 10 mi, it was the only natural prairie east of Ohio. No one hesitates to plant a suburban tree canopy on it today, and why should they?

[hauntedheadnc]

“We Need Shade”: America’s Hottest City Rushes to Plant More Trees -- Only about 9 percent of Phoenix has canopy coverage—poor neighborhoods have less.

...Trees have multiple benefits in urban areas which include cleaner air, improved physical and mental health, water conservation, increasing wildlife habitat, CO2 storage and sequestration and lower temperatures through shade.

The city is mostly concerned with reducing the urban heat island effect and improving public health, and its 2010 shade masterplan set out a goal of achieving 25 percent citywide canopy cover by 2030. Amid little progress and rising heat mortality and morbidity, in 2021 Phoenix established the country’s first office of heat response and mitigation. Its community tree planting program is now being rolled out to public schools, churches and homes in qualifying census tracts—low-income neighborhoods with little shade.

Residents can choose from a list of 19 native and desert-adapted trees including the Texas olive, Chinese red pistache and Chilean mesquites. The trees, which are a couple of years old and pretty heavy, are planted by contracted arborists. For insurance reasons, they must be within the property—not the sidewalk—and not too close to walls or power lines. Each household also gets a tree kit—a 100 foot hose, irrigation timer, and instrument to measure the soil pH and moisture, as well as written care instructions.

[mrnyc]

Originally Posted by Lost Island

At the same time, the L.A. basin for example needn't revert to largely a savannah, either. There could be more tree lined streets, shaded yards, shopping centers, and so much the better for it.

I live in a land area east of New York City that was actually a huge grassland before the settlers came (The Hempstead Plains). Probably 10 mi X 10 mi, it was the only natural prairie east of Ohio. No one hesitates to plant a suburban tree canopy on it today, and why should they?

why should they? because it takes a lot of careful and continuous management to protect the long island aquifer, which is always in danger due to development. in long island it seems to be fairly well handled with the requirement for sumps aka recharge basins for groundwater. that keeps the poisonous stuff from sinking down. and i suppose the imported trees and plants help too. but you gotta put in the continual work to make it work out properly, that’s the lesson for others.