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At the edge of the savanna, Robert Ausmus is waiting patiently for orders to start a fire. He has a torch fueled by diesel and gasoline at his feet, and a metal rake hoe in his hand to snuff it out. In his standard, non-flammable, yellow button-up, the firefighter is ready to light 10 acres of the Houston Arboretum and Nature Center on fire. 

And he’s not the only one. It’s a Wednesday morning in late February, and there are about 12 firefighters from the Houston Fire Department’s Wildland group lined up around the nature sanctuary’s savanna. Everyone has a specific role to play for a good fire. Some, like Ausmus, are on the burn team. Others are in charge of keeping the fire from spreading, called the hold team. There is also a burn boss who keeps an eye on all the fires at all times. There is no second chance when it comes to fires – which is part of the reason the department is here. 

“We’re always fighting fires,” said Ausmus, 41. “Now we actually get to use fire to stop fire.” 

For the past three years, the Houston Arboretum has partnered with the Houston Fire Department to conduct prescribed fires – or controlled fires – in both the nature center’s savanna and meadow. This is because controlled burns maintain the wildlife ecosystem and habitat, keeping the natural savanna from overcrowding with trees and invasive species. It also burns up the excess brush and kindling that would otherwise start an uncontrollable wildfire. 

In the case of controlled fires in urban areas, however, such as the one at the Arboretum, which sits at the edge of Memorial Park and across Loop 610 from the Uptown district, there is more to consider. Passing traffic, nearby neighborhoods and air quality all play a role in the process of burning in a city. The day of the burn, members from the Arboretum are there as well as representatives from Texas Parks and Wildlife Department and the Houston Health Department. 

For Ausmus, who has been doing prescribed burns for the Houston Fire Department since 2017 and at the Arboretum since it started, the process is standard. Around noon, the burn boss directs Ausmus and his two colleagues to begin burning the savanna. Across from them, other firefighters are starting their own fires. The hope is the fire will meet in the middle, burning from outside in. 

“It’s nice to know we’re making a difference here,” Ausmus said. “It’s a good kind of fire.”

Good fire

The Arboretum conducted its first prescribed fire in 1999, but it wasn’t until over two decades later when the nature center burned again. Before that, the savanna was covered in pines at one point, and then oak trees. Volunteers would remove invasive species regularly and maintain the trail running through the area, but nothing as intense as burning down grass. 

Today, the savanna is clearly a savanna, spreading out acres across the arboretum. However, after a year of growth, invasive species, trees and brush have sprouted and overrun certain sections of the ecosystem. 

“Historically, this spot was a savanna,” said Trevor Rubenstahl, senior natural resource specialist for the Houston Arboretum. “Over time, the natural landscape changed due to development. At one point, the area was a World War I training camp,” he said, referring to Camp Logan, the site of a 1917 Houston Riot that recently made headlines when the U.S. Army set aside some soldiers’ convictions.

Hundreds of years ago, natural fires occurred in the area due to lightning striking the savanna or Indigenous communities maintaining the ecosystem. These natural fires would prevent non-native species from overwhelming the natural habitat and maintain biodiversity in plant and animal life – part of the circle of life of natural areas. Burning plant material also returns nutrients to the soil, enriching future growth. Normally, these plants take years to decompose – leaving the ecosystem without the healthy turnover it usually needs. 

Natural burning has been especially limited in urban areas, where city and state officials work hard to keep wildfires from spreading into development. However, prescribed burns can help keep uncontrollable fires from starting by burning the particularly flammable shrubs and brush in a safe and controlled manner, said Rubenstahl. 

“By removing the fuel load in the area, if there was a wildfire in the area, that would actually make it safer,” he said. “It wouldn’t burn as much, since there wouldn’t be as much kindling.”

For this particular burn, the dozen firefighters take different spots throughout the savanna. They burn a portion of the acreage first and then move on to another section. Everyone is very watchful to keep the fire from burning any of the wooden benches or bridges that spot the burn area. 

Stephen Benigno, the conservation director at the Arboretum, keeps an eye on the fire from the trails. Every once in a while, a firefighter will ask about a specific burn area or if he has any concerns about a certain fire. When a tree stump lights on fire, billowing blackened smoke into the air, Arboretum staff let it keep burning. 

One firefighter captain, Beau Moreno, jumps into the burning thicket to rip a dangling branch from a taller tree. Climbers, as Moreno calls them, are branches or twigs that can catch fire and lead the flames up the tree canopy. Once the fire hits the canopy, it’s harder to control the spread between trees. 

“Then we have to start chopping the trees down,” Moreno said. He successfully pulls the branch down and runs out of the flaming shrubbery. He stops to rake up some plants around a wooden bench. The fire billows around the bench, but doesn’t touch it. 

His face is chalky from the smoke. 

“It really gets hot in there,” he said. “I hope I still have my eyebrows.” 

Urban burns

At the far corner of the Arboretum parking lot, staff from the Houston Health Department are checking air quality levels during the burn. They partnered with the Fire Department to monitor the smoke and send data to the burn boss on site. 

Olariche Diala, senior project manager, and Youjin Qin, operator and chemist, check levels of fine particulate matter every hour on the hour in a mobile air-monitoring lab – a sleek, white van which tests the air quality wherever it’s parked. If the air quality levels reach above regulations set by the Environmental Protection Agency, the Fire Department will have to address the issue out in the field – whether that means halting the burn or another tactic. 

The hope is the levels stay well below a concerning range. 

“It’s up to the Fire Department in the end,” Diala said. “All we do is send them the numbers and keep them as well-informed as possible. 

Prescribed burns were only approved by the city for the Arboretum in 2021. Unlike burns started in rural areas, urban fires can be spotted by far more people and could impair vision or increase levels of pollution. 

This is why the Houston Fire Department checks weather conditions the week of a prescribed burn. The wind has to be blowing the right direction. A small, portable monitor on site set up by the Fire Department team checks the wind patterns frequently. Since 610 runs right past the arboretum, wind blowing in the wrong direction could disrupt traffic visibility. 

“It’s really more cost-effective and causes less damage to the ecosystem when we manage this way,” said Justin Huddleston, the wildland fire coordinator for the Houston Fire Department. “We don’t have to get any [management] equipment in here that could disturb the natural area.”

“You really won’t even know we’ve been here,” he said. 

Still, the Fire Department and the Arboretum worked with the Texas Department of Transportation to put signs out on the freeway alerting drivers to the prescribed burn. The past few years, people have called 911 because of the smoke, which can bog down the line for actual emergencies. 

Members of the Fire Department also send a drone out to check for human life. Someone experiencing homelessness could be out in the savanna or nearby who needs to be warned. 

So far, this fire in particular is burning better than any of the burns before, according to Benigno. This is promising because the areas that were burned in previous years are faring much better in biodiversity than the areas that have never burned. 

Specifically, the red-headed woodpecker – whose habitat is generally more of a savanna and less woodlands – has made a comeback in the area. 

“This is just one of the tools we used to continue to restore the area,” said Benigno. “We want to make it as healthy as possible.”

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