How METRO officials could plant a tree at every bus stop in Houston

A pilot study from Houston Public Media found that bus shelter shade was on average half as effective at cooling riders as tree shade — a potential solution for METRO and the City of Houston as climate change makes the heat worse for transit riders.

By Sara Willa Ernst & Katie Watkins, Houston Public MediaSeptember 22, 2023 12:44 pm, ,

From Houston Public Media:

This is the second of a two-part investigation into the impact of extreme heat on Metro riders. Read part one of the investigation or listen to the podcast, Hot Stops: How Houston Bus Stops Get Dangerously Hot.

Barbara Quattro has been planting trees in Alief for over 20 years.

Down the street from her house is a METRO bus stop — a pole with a sign attached. There was no bus shelter or tree offering shade nearby. She noticed riders waiting in the sun.

“People are standing out there in this god-awful heat all the time, my God it’s miserable,” Quattro said. “That’s why I decided to plant (a tree) because it makes a difference.”

Quattro is now planning to plant five more trees to develop a larger shade canopy for riders.

This is one of the ways that trees show up at bus stops in Houston — community members stepping up to address the problem. METRO, the public transit agency in Houston, is not systematically planting trees along its transit lines and more than 9,000 bus stops, according to interviews with officials.

Sara Willa Ernst / Houston Public Media

Alief resident Barbara Quattro stands next to the tree she planted to help shade people from the heat at a bus stop.

A pilot study, conducted by Houston Public Media, shows that tree shade is an effective and consistent form of cooling for transit riders. After taking temperatures at 21 bus stops in July and August, we found that bus shelters inconsistently provided protection against the heat:

• They often reached temperatures that pose an “extreme threat” of heat illness.

• In some cases, bus shelters were hotter than standing in direct sunlight.

Tree shade on the other hand was on average twice as cool as bus shelter shade, and tree shade never made the heat worse.

“I really think that the tree part is very, very important, especially in an urban city like Houston,” said Matt Lanza, a meteorologist at Space City Weather. “You’ve just taken extreme heat and made it more tolerable. That’s a very big deal.”

On average, tree shade was twice as effective at cooling as bus shelters, according to temperature readings from the pilot study.

Climate change is exacerbating the impact of extreme heat on bus riders. Trees are increasingly being looked at by cities as a way to mitigate heat. Cities like Tempe, Arizona and Brisbane, Australia have programs dedicated to planting trees at bus stops. Other cities like Los Angeles and Miami have pursued smaller-scaled solutions that increase the number of trees near bus stops.

The main way that METRO is trying to shade riders is through bus shelters. The agency is investing millions of dollars into new shelters and rolling out 2,000 over the next five years.

The new designs are based on the most common shelter type in Houston, which has clear panels on three sides. These types of shelters are where we observed hotter temperatures inside than in direct sunlight.

We asked METRO whether they were aware of this greenhouse-like effect. In a statement, Spokesperson Tracy Jackson didn’t acknowledge the findings of our study. She wrote:

“Without independent verification that your findings are accurate, it wouldn’t be prudent to comment on the temperature readings you provided in an email. Because we don’t know what kind of device was used to measure the climate inside a shelter or any of the other variables that could impact the readings, your methodology and spreadsheet would not bear any significance.”

Urban Planner Bonnie Richardson said it’s common knowledge in the architecture world that clear panels on three sides creates this greenhouse-like effect.

“It’s pretty well known by people who design bus shelters,” said Richardson, who works in the transportation department for the City of Tempe. “If you have heat, those become an oven when the sun is shining on any kind of glass or transparent-type solid enclosure. You’re cooking people in there.”

METRO says the new shelters cost around $22,000 each. Planting a tree costs around $400. This estimate includes buying and planting a 15-gallon tree, as well as watering it for two years and pruning it for 10 years, according to Trees for Houston.

Lucio Vasquez / Houston Public Media

METRO’s standard bus shelter design has clear panels on three sides.

We reached out to METRO to ask if the agency would support an effort to plant trees near bus stops and on major transit streets. METRO failed to respond to this email before our deadline.

In a previous interview, agency officials said METRO doesn’t often plant trees because they can damage the concrete and sidewalks.

“I don’t know that we have planted trees on our local route corridors,” said Kenneth Brown, METRO’s Director of Service Enhancements. “We usually try to avoid them as much as possible because they can have an impact on the (bus) pad.”

Officials pointed to METRO’s Urban Design Manual, which includes recommendations for planting street trees near bus stops when executing new projects. However, Metro officials gave no details about specific plans in place and emphasized that the Urban Design Division is in its “infancy.”

Press Officer Tracy Jackson said the agency is “looking at all opportunities to provide a better walk, a better stop and a better ride” to customers.

Planting trees near bus stops is something that cities across the world are looking into. Since launching a program in 2021, Brisbane, Australia has planted more than 1,200 trees next to roughly 550 bus stops.

“Providing tree shade is actually better than a bus shelter in some ways because it cools the surrounding area,” said Bonnie Richardson with the city of Tempe, Arizona.

Tempe has pledged to have a tree or a different form of shade at every bus stop in their system.

“We are at a stage where we really need to have every possible implementation in place to cool the environment around a bus stop,” said Richardson.

Houston Public Media

There’s not currently an initiative in place to systematically plant trees along bus lines and stops in Houston.

A tree planting initiative

Carrying out a countywide tree planting initiative at bus stops and key transit streets is possible, according to urban planners and tree experts. The biggest challenges are finding space for trees, getting funding, and overcoming bureaucracy.

The first step is to make a map identifying all the bus stops with enough nearby space to support a tree.

“That would be pretty easy to do,” said Mac Martin, an urban forester with Texas A&M Forest Service. “We’re foresters not rocket scientists,” he said.

Martin and a team of five people did an inventory of potential tree-planting spaces in Gulfton this March. It took them about half a day.

He said his team would train anybody – city workers, community groups, volunteers – who want to do this work. Ultimately it comes down to using a tape measure and writing down how big the public right of way is. A tree needs around 3 to 5 feet of planting space. There also can’t be utility lines overhead.

Once a map is made of where trees can be planted, the next step is to get funding for the trees. After reading our investigation, Barry Ward with the non-profit Trees for Houston said it’s an initiative he would be willing to fund.

“I will pay for every one. I will put a tree at no cost to the city or METRO at every bus stop in the city of Houston,” he said. “Doesn’t mean it would be easy. Doesn’t mean I could do it overnight.”

However, the next step, which Ward argues is the most difficult one, is getting public officials all on the same page working towards a shared goal.

“It’s gonna take a certain amount of will,” he said. “There just has to be the bureaucratic willpower to say, ‘how do we make this work’? Instead of saying, ‘no, that’s too hard.’ It really is that simple.”

This type of initiative would require buy-in and coordination between METRO and the city of Houston.

Houston Parks and Recreation indicated that it would support a tree inventory and planting initiative, after we shared the temperature readings from the pilot study. This city department is responsible for granting permits for any tree planted on public property, such as bus stops.

“We would need additional staff to perform the inventory ourselves, but if METRO has an opportunity to inventory potential planting spaces, the Parks & Recreation Department will provide as much support as we can,” Jeremey Burkes, the City Forester, wrote in an email.

Burkes implied that METRO would need to take the lead.

Other departments like Public Works, The Planning Department and the Mayor’s Office of Sustainability and Resilience may need to step in as partners too.

This wouldn’t be the first time that METRO and the city have worked on a big project together, said Christof Spieler, a transportation expert and former METRO board member. He pointed to a recent program to make all bus stops compliant with federal disability standards as an example of successful coordination.

“The fact that METRO has been able to make so many stops accessible in a relatively quick period of time was only possible because the City played a big role in streamlining that process,” Spieler said.

He said agencies failing to collaborate and address the issue of heat means riders will continue to suffer.

“Ultimately, riders shouldn’t have to care about that,” Spieler said. “It’s not fair to say it’s too much work to have them work with each other. That’s utterly irrational. They all ought to get their act together and work together.”

Millions and millions of trees

The City of Houston already has a massive tree planting initiative underway, as part of its plans to address climate change. In 2020, officials set the goal of planting 4.6 million trees in the next decade, as a way to offset carbon emissions and cool the neighborhoods most affected by heat.

A city-wide heat mapping in 2020 study found that Gulfton, in Southwest Houston, was the hottest neighborhood by up to 17 degrees. Temperatures were the highest in neighborhoods with more concrete and fewer trees.

A big motivation behind this city-led tree goal is to reduce these heat inequities, also known as the urban heat island effect. The city is 1.5 million trees into the goal, which includes trees planted by outside organizations and government partners. These trees have largely been planted in parks, bayous and medians, according to interviews with partner organizations and a records request from the Parks & Recreation Department.

Partner organizations, like Trees for Houston, are a big part of the city’s goal to plant 4.6 million trees by 2030.

However, these trees are sorely needed on sidewalks, major transit streets and bus stops — areas where pedestrians are walking or transit riders are waiting.

The mayor’s office is coordinating the tree planting, but three years into the goal and there’s still no heat strategy. Only this year did the city launch an online tool to track where trees are planted.

Priya Zachariah, the Chief Resilience and Sustainability Officer, said developing a strategy around where to plant trees is the next step.

“We’re in the process of doing that outreach and education to all of our partners to have those conversations on where does it make sense when you’re thinking about heat impacts and heat islands,” she said.

Deborah January-Bevers with Houston Wilderness, one of the major planting partners, said she isn’t aware of these conversations happening yet.

“I don’t know anyone that’s trying to facilitate a Harris County region-wide urban heat plan,” she said.

For a mass tree planting initiative to be an effective tool to reduce heat, it needs the right strategy and resources behind it, according to Brian Stone, an urban climate researcher at Georgia Tech. When it comes to a goal of this magnitude, he said officials need to think of trees as crucial city infrastructure.

“It’s like a storm sewer system, and if you don’t treat it and fund it like a storm sewer system, you’re not serious about it,” Stone said. “I hope Houston is serious about it.”

Making space for trees

Even if METRO and the city do work together to plant trees, there are other barriers to shading riders. A sizable number of bus stops don’t have enough space to accommodate trees or bus shelters.

About a third of stops are next to stormwater ditches, according to METRO. On top of that, there are often competing utility lines both overhead and underground, and frequently, the public right of way isn’t big enough to plant a tree.

There always is the possibility of expanding the public right of way to make more room for trees and pedestrians. Several experts said there’s an opportunity to do that when streets are repaved or redevelopment occurs.

“We can make streets narrower, not even less (car) lanes, but narrower lanes, and by doing that you can make some spaces for trees,” said Donna Kacmar, an architect and professor at the University of Houston. “You think that the built environment is fixed, but it is evolving and changing.”

Houston Public Media

A lot of bus stops don’t currently have the right environment for a tree to grow.

Former METRO Board Member Christof Spieler agreed that making less room for cars, which can be a controversial issue, means more shade is possible.

“If you put the curb six feet from the property line, you will never have good shade in that space,” said Spieler. “If you have a 15-foot sidewalk, now you’ve got room for a whole row of street trees and you’ve got plenty of room for your bus shelter. That’s what we ought to be designing streets for.”

City officials have also been working on initiatives to make Houston more walkable.

“We need to make sure that transit riders have, in addition to shade, good ways to get to and from the bus stop itself,” said City Council Member Sallie Alcorn.

Two new ordinances – the Walkable Places Ordinance and Transit Oriented Development – require that some new projects and redevelopments include larger sidewalks and a bigger buffer where trees can go.

Building a better bus shelter

With plans to roll out thousands of shelters in the coming years, METRO has an opportunity to rethink its bus shelter design with a focus on shade.

Tempe, Arizona has redesigned its bus shelter with heat as the number one priority.

“Designing bus shelters has been one of the hardest things I’ve ever had to do,” said Bonnie Richardson, who is heading the redesign.

Unlike METRO shelters in Houston, this design did undergo heat tests that ensured the structures were helping cool riders.

The design is notable for its ability to provide shade regardless of the angle of the sun and the time of day. The new bus shelters will have seating on all sides, providing somewhere shaded to sit at all times.

Courtesy of Tempe

Cities around the world are updating their bus shelters to better protect riders from heat as climate change is warming the planet. This shelter in Tempe, Arizona has vines growing on an open screen to allow air flow and transpiration to cool the shelter.

Beyond trees and bus shelters, other solutions are being piloted in cities across the world.

Several municipalities, including Tempe, are testing out a film developed by 3M that penetrates the ozone layer and reflects heat into deep space. Bangkok and Miami have launched air-conditioned bus stops at key transit hubs. METRO in Houston has also developed a prototype for a shelter with a solar-powered fan.

Riders will be increasingly affected by extreme heat as climate change makes longer heatwaves and hotter temperatures the new normal in Houston.

“I think (heat) has become such a serious challenge during climate change,” Richardson said. “As we see the foreseeable future presenting more and more problems, the cost of not preparing is big as well.”

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