Female reporter: Another searing day baking California.

Woman: Extreme heat is the number-one weather-related killer in the United States.

Narrator: In 2023, a record-breaking 2,325 people died from heat in the United States.

In urban areas with dense roads, machinery, buildings, and a lack of ample vegetation, temperatures can measure 20 degrees or higher than in rural or underdeveloped lands, impacting the lives and health of residents, but scientists and organizations are finding a way to mitigate the impact-- trees.

♪ [Click] ♪ Announcer: This presentation is made possible in part by a grant from Anne Ray Foundation, a Margaret A. Cargill philanthropy, and the Orange County Community Foundation.

♪ de Guzman: We boiled down all of the hundreds of census tracts in the City of Los Angeles, and this led us to this particular neighborhood of Central Alameda.

Narrator: Less than 1% of Los Angeles' population lives in nearly a quarter of the total tree canopy.

Central Alameda is one of the most densely populated neighborhoods in Los Angeles County, but it has less than half the tree coverage of the citywide average.

With little shade and poor protection from the canopy, residents are exposed to higher temperatures.

Ferdman: We know that extreme heat is one of the deadliest climate impacts across the country and especially for LA County.

This is the one that's having the most impact on people's health and on people's lives.

♪ [Train horn blows] Mejilla: [Speaking Spanish] ♪ ♪ de Guzman: There are certain neighborhoods that might experience a heat wave, and it's about 102 degrees, but go a couple of miles to the east or south, and you might experience 110 degrees at the same time.

That makes a difference outdoors, and it also makes a difference indoors.

Your body itself can experience a heat wave very differently depending on whether you're in direct sun or not, whether it's breezy or not, whether it's humid or not.

All of that compounds to create an experience of heat.

This is Central Avenue and 42nd Place.

It's a historic neighborhood.

It's a historic part of Central Alameda, and what we see is that we have a lot of heat-exposed areas, so if we were to do some level of greening with probably adding just a dozen or two trees, you can see we would improve conditions.

We would provide more shade and created a space that is inviting both for cyclists and pedestrians and people who might want to linger and have a picnic or hang out in this lovely, historic area.

Narrator: Distribution of trees and vegetation is not equal across Los Angeles.

A history of redlining, where banks and governments denied loans to neighborhoods depending on their racial makeup, led to the current inequities of developing natural areas.

Pueblo Del Rio housing project, by architect Paul Revere Williams, was built in 1941.

Initially zoned as an industrial area, it was intended to provide housing for low-income factory workers and military veterans.

Ferdman: Trees are not a resource that's equitably distributed.

We know that there is inequitable access to tree canopy all across the county, and that inequity in access is not random.

Thomas: The lack of trees and the lack of green space is just one component of the inequity that exists in our society and certainly in the City of Los Angeles.

I think the term for it would probably be "environmental racism," "environmental injustice."

Ferdman: We know that those historic injustices are compounding in the same communities in the same locations over and over again.

Thomas: We know areas that historically have been more disadvantaged where there's a lack of urban greening because, very specifically, the people who live in these communities are African American, Black, Latino, often immigrant populations, and it's very apparent--for example, South Central Los Angeles, the density of population in these areas adjacent to freight train lines, adjacent to industrial areas, adjacent to freeways.

Ferdman: The same places that don't have access to trees are the same places that don't have access to other kinds of green space, clean air, or clean soil or affordable housing or fresh and healthy foods, so even though those policies are in the past, you know, the legacies of those policies are very much still present and felt by communities who live here today.

♪ Narrator: Temperatures between neighborhoods can vary drastically based on tree coverage.

Studies have measured differences of 10 degrees or more between areas with tree coverage and without, impacting not just outside temperatures, but indoor temperatures, as well.

de Guzman: We had one of our study sites, which was a home in Huntington Park with no shade, with no trees.

We had a temperature reading of 107 degrees on the hottest day recorded in Los Angeles.

To have an indoor temperature of 107 degrees over a sustained period of time, you could be among the healthiest, you could be an Olympic athlete, but that kind of exposure over a few hours is bound to have sometimes irreparable, you know, consequences on the body.

Narrator: Research has shown that LA's urban forest initiatives could reduce heat-related emergency room visits by up to 66% if the total allowable tree cover across the city is filled.

The lives and health outcomes of Los Angelenos could be drastically improved.

de Guzman: So this little sensor is a Bluetooth-enabled device that collects data continuously about different weather conditions, including temperature and relative humidity among other factors.

It's kind of neat to be able to tell what the heat signature of different surfaces is, and that's what that thermal camera does.

So this is pretty remarkable.

Just within the space of a few feet, what I'm seeing is, that shaded part of the sidewalk, surface temperature is about 86 degrees.

The portion that's in the sun right in front of us here is 110, 111, and at the same time, the street is 120 or so.

In this particular case, the grass is actually just about the same temperature, maybe even a little bit warmer than the sidewalk is that's in the shade.

♪ [Birds chirping] At UCLA, we went through a whole process that took several months of doing research, engaging with the community, understanding what residents want.

Our purpose for collecting the visual data, both thermal imagery as well as the ambient temperature data, is to be able to see what the baseline conditions are and then to be able to come back and show how we have made an impact by virtue of planting more trees and providing more shade in those neighborhoods.

♪ About 3/4 of this neighborhood is paved, which means that we have incoming solar radiation during the day to be retained which then is released at night and creates sort of an ongoing cycle of exposure to heat during heat waves, which, of course, we know are getting longer and more intense, so what we want in every corner of the city is for people to have a place to go, have a place to enjoy, have a place to get a break from the heat.

This park can be one of those places if we had shade here, if it was more inviting.

Having a pocket park that can provide that--and shade, again, is the number-one way to reduce outdoor temperatures--is a vision that we want to realize for the city.

I think there's space here for probably 10 or 12 trees, depending on what you're planting.

I would look at all of the areas that are currently not paved and think about how we can plant in those areas.

♪ How do we bring neighborhoods that have long been neglected up to par so that they enjoy as much shade and green sort of space as some of the wealthier neighborhoods around town?

We're really talking about a long-term investment in planting potentially thousands of trees per neighborhood.

Ferdman: Trees provide so many different benefits to our communities, and I think that's what makes them such a powerful symbol and tool for sustainability.

They provide multiple benefits-- everything from shade and cooling to stormwater management to providing habitat to really improving mental and physical health for people.

[Beeping] ♪ Guerrero: There's a saying in urban forestry--"Right tree, right place," and the way I pick trees from nurseries, because we are in Southern California, which is in the Mediterranean belt, so we usually try to go native.

Thomas: Southern California, or certainly the Los Angeles Basin, is not a naturally forested area.

We get very little rainfall, for one.

In the past, before we created this city, there would have been large trees in very specific areas.

For example, along the rivers and waterways, you would have found large trees; on some of the slopes of our hills, primarily the north-facing sides of the slopes that don't get too much sun all day; or in canyons, but most of the LA Basin is very dry chaparral or what we call a coastal sage scrub plant community which consists of small shrubs and grasslands.

Since people have moved here from all over the world, we brought trees, so we've planted this forest, but it's a largely human-made forest.

We don't have nearly enough rainfall or naturally occurring water in Southern California to grow these forests.

We are taking water from the Colorado River, Eastern Sierra Nevada, Owens Valley area, and from up north to water these trees.

♪ Ferdman: All right.

We're ready to go.

[Engine starts] We are in an unincorporated community of Los Angeles County which is called Athens Westmont, and this is a place in the county that has a really low canopy cover, and, as you can see sort of looking around, this is a really highly paved community, a lot of asphalt and a lot of concrete.

I'm gonna show you some different reasons why this community looks the way it does now and some plans that the county has for increasing tree canopy cover in this area.

Thomas: North East Trees was founded over 30 years ago.

I was on the original crew.

At the time, I had just come back from New York City, and a friend of mine had started North East Trees while I was away, and he described to me that this organization was planting native trees in Los Angeles and working with at-risk young people, and I thought, "What a perfect combination-- you know, help the environment and also help the social challenges of the city at the same time," so I signed up and have been with them ever since.

It could be 20 degrees hotter in the San Fernando Valley than it is in Marina del Rey, so we select trees that will do well in what we call these microclimates all over the city, and at the same time, we're trying to create diversity in our species selection.

We don't want to plant what we call monocrops or one dominant species everywhere, and that's partially because if a tree gets a disease which affects that species and you only have one species everywhere, well, you're gonna lose your entire urban forest, and this has actually happened in some towns in the United States where entire urban forests just disappeared to a disease because there was not enough diversity.

♪ Ferdman: Welcome to Gardena, all of these palm trees, and a lot of them are on private property, but here, you see palm trees in the street, a two-by-two box with palm trees.

We have a new policy at the county as part of our CFMP that we will not be planting palm trees as street trees because they're not as closely related to trees as they are to other types of plants, like grasses.

That little palm tree that's taking up that box over there, that tree well vacancy, it is not providing all of the shade and cooling that a real tree would provide.

It requires more maintenance than a regular tree.

A lot of palm trees, their fronds come down, and they can really be a nuisance, and so they need a lot of maintenance to be safe and to reduce the risks associated with all of that debris, and also a lot of palm trees, while iconic, are really rather invasive.

Those seeds can get spread by birds or by other means, and they can be really hard to eradicate, and they're not native, so they're not providing a lot of habitat.

They're not providing a lot of shade and cooling.

They're really taking up a lot of resources when it comes to the limited resources we have for planting and maintaining trees, and so going forward, we are recommending that palm trees only be planted if they're needed for sort of an ornamental basis as part of a landscaping.

♪ Really is about planting trees as infrastructure for people.

It's not so much about restoring a natural environment or conserving trees that might have naturally occurred.

It's thinking about how we think trees should be serving people while also serving, you know, other purposes that are more ecological, like supporting habitat.

♪ And so I think this neighborhood is slated for something close to 800 trees, and even that is not all of the vacancies that are available in this location.

It's just the portion that we're able to fund with the grant money that we have right now, and so eventually, we'd like to increase our stocking rate and plant as many vacancies as we can.

Thomas: There's not a lot of space for trees in these highly urbanized, low-income communities.

This space between the sidewalk and the street tends to be narrower.

The presence of overhead power lines is pretty much everywhere.

We're going for maximum benefits, but, because the physical constraints are everywhere, we have to be very mindful as we can about trees that can survive long term.

The average lifespan, at least for street trees in Los Angeles, is only about 30 years.

Now, this varies wildly.

In affluent neighborhoods where the conditions are more hospitable, trees will most likely live longer, but overall, it's a really difficult environment for a tree to live in, so we do try to put as many trees in our parks like coast live oaks that can genetically live hundreds and hundreds of years, knowing that many of the other trees that we find in our community will not be around maybe even 50 years from now.

Ferdman: You can see some typical trees here, but there is one street that is very special.

It's called Cordary Street, and--I know it's a hot day today--I bet it will feel at least a few degrees cooler.

These are Italian stone pine trees.

These trees are old.

They're big.

They're beautiful.

They're evergreen, and they are just changing the entire character of this street for people who might want to walk down the street.

Narrator: According to a study by the US Forest Service, Los Angeles' trees are estimated to reduce annual residential energy costs by $10.2 million per year, but there are some trade-offs.

While public tree maintenance is a year-round labor provided by the city, sidewalk and sewer maintenance is the property owner's responsibility.

Ferdman: You can see they're pulling up the sidewalk, and the sidewalk has been redesigned to accommodate these trees because people love them so much.

They require a lot of maintenance to keep them out of the power lines, but I think it gives you a sense of what's possible.

If you could envision a street like this, but with different species--perhaps a species that's a bit more climate-appropriate, a little bit lower infrastructure impact--then you can start to see why people might want to choose to make space for trees over trash cans or parking lots.

Thomas: We could use metrics like how many trees we planted, how much greenhouse gas those trees have captured and sequestered, and they're significant, but trees don't capture carbon dioxide and other greenhouse gases immediately or quickly.

They have to grow to maturity, and that takes decades.

We planted a few trees next to the LA River years ago, and in order to do that, we had to get the authorization of Caltrans because these trees were near the freeway.

It was a tangled web of government agencies that we were required to navigate in order to do the simple act of planting a few trees.

It requires a lot of persistence and a lot of patience, but over time, we've developed a very good, close working relationship.

We were addressing the environmental needs of Northeast LA, including naturalizing the river and planting trees in schools and streets and parks and in the public housing developments, and it was because of our work with public housing that we were invited to then work throughout the city with the Housing Authority of Los Angeles.

Narrator: Over the years, Los Angeles has undertaken significant efforts to expand its tree canopy.

In 2019, the city launched a plan to plant over 90,000 by 2021.

Due to delays from the pandemic, 65,000 trees were planted by 2022.

Today those efforts continue alongside organizations like North East Trees.

♪ Thomas: We've planted over 100,000 trees, and so if we count the regeneration that comes out of the trees that we plant, it could be in the millions.

Part of our ambition is to restore the natural ecosystems in Los Angeles.

It includes the improvement of our soils, of our air, waterways, even wildlife and animal habitat.

Ferdman: Trees are just the ultimate example of a long-term, multi-benefit investment.

So before this tree was planted here, this area probably didn't have much going on.

It might have been bare dirt.

It might have been turf grass that wasn't providing a lot of services to anyone.

It's just a little tree right now, but you can really imagine that in just a few years, this tree is going to grow.

Its canopy is going to expand, and it's going to start to provide a lot of shade and cooling for the people who live in this area.

Mejilla: [Speaking Spanish] Thomas: We were invited to plant trees here at Pueblo Del Rio in South Central LA.

I hired young people from Pueblo and trained them how to plant trees in their own community.

♪ We planted those trees very intentionally to grow big enough to actually visually give them a little bit of screening from the trains, to capture as much air pollution as possible, and to just beautify, to give the people who live in this community some joy and beauty in their lives through, you know, nature.

Mejilla: [Speaking Spanish] ♪ Ferdman: The key, especially in an area like this, is that you need funding not just to plant the tree, but you need to make sure that you have funding to water the tree until it's fully established.

The county has an interest in serving the communities that are unincorporated communities but also the incorporated cities all across the county, and there's a lot of effort that goes into using a data-informed approach to determine where we're going to be investing resources.

You really have to be able to get down to the neighborhood scale to understand whether or not people have access to those greening benefits.

[Train horn blows] Thomas: People look around the city of Los Angeles, and often they see blight.

They see neglect.

They see dysfunction.

We see potential.

We see opportunity.

We see beyond all of the blight.

We just work with the communities.

We try our best to improve them.

The communities that we work with, I have seen them improve over time, more people protecting their environment.

People feel more at ease, calmer, less stressed when they're surrounded by trees and nature.

Ferdman: When I think about the vision of a future urban forest for the county, I think about what we heard from community residents all across the county.

They talked about communities with clean air.

They talked about communities that were walkable, where they had opportunities to connect with nature and to be outside.

They talked about places that were safe and that were resilient to climate change, and so when I think about the role of trees in the future of our community, that's how I think about it.

I'm very optimistic about the future.

Surprisingly, people who work with the environment are often very concerned that the future of humanity in general is probably not very promising, but in spite of all the problems that we see around us in our urban in Los Angeles, this is where the most potential is for us to, I think, excel as human beings, socially, environmentally.

I'm very optimistic that we will be successful.

♪