Fire emerges as ally in the fight to save Louisiana’s marsh

Fire emerges as ally in the fight to save Louisiana’s marsh

23 December 2018

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Heath Romero kills the engine on his airboat and climbs to the top of the propeller cage, the highest point in the flat expanse of marsh around this part of South Louisiana. Sitting quietly with his face tilted upward, he notes the parting clouds, the brightening sun, and the wind, just now starting to come to life.

“Feel that? Now it’s gonna happen,” he says.

A fire Romero set about a half mile away starts to crackle. Within seconds it sweeps across the marsh and splashes the sky with thick, black smoke.

“It’s rolling now,” he says. “That’s what we want.”

What he wants is a healthier marsh — a marsh that resists the triple threat of sea level rise, erosion and subsidence that robs coastal Louisiana of about an acre every hour. It may seem like a contradiction to burn what you hope to save, but recent research is showing that the Gulf coast’s longstanding tradition of controlled marsh fires not only boost the health of wetlands but may help in the fight against land loss.

“We’re seeing that burning can have multiple benefits,” said Karen McKee, a wetland scientist who studied the effects of controlled fires, known as prescribed burns, on marshlands on the Texas coast.

Her research for the U.S. Geological Survey found that regular burns reduced relative sea level rise by about a third. Relative sea level rise is the combined effect of subsidence, a process that causes land to compact or sink, and rising seas caused by climate change.

McKee tested burned and unburned sections of McFaddin National Wildlife Refuge near Port Arthur, Texas, just west of the Louisiana line. Like much of the Louisiana coast, this part of Texas is retreating at a rapid rate, losing between 15 and 45 feet of marsh each year. Marsh that underwent prescribed burning on a three- or five-year cycle offset annual elevation deficits by about a millimeter, McKee said.

“That may seem small, but as a rate it’s significant,” she said, noting that global sea level rise is increasing by about three millimeters per year. “The affects can accumulate over time. I could easily envision other sites (in Louisiana) having an even greater difference.”

Research conducted by Louisiana State University found that prescribed burns can strengthen marshes and boost wildlife abundance. Marshes that underwent prescribed burns in coastal Louisiana recovered quickly. Within a year, they had thicker, greener grasses and hosted a greater number of sparrows and other birds.

“Fires are rejuvenating and stimulating,” said Jon King, fire management officer for three coastal wildlife refuges in southwest Louisiana. “They get rid of the old, dead stuff and let better stuff grow up.”

Within two hours of lighting his first fire, Romero had burned about 50 acres. That’s a fraction of what he burns each year as the land manager for the McIlhenny Co., makers of Tabasco hot sauce.

The company owns about 30,000 acres of marsh around Avery Island. Each year, Romero burns about half of it.

“When we don’t burn, you can feel it,” he said. “The ground gets spongy. You want that firm. That’s what the burning does.”

The company has been based on Avery since its founding in 1868. Avery, less of an island and more of a hill surrounded by a sprawling maze of marshes and bayou, has been hit hard in recent decades by storms, flooding and erosion. As the buffer of marsh disappears, storms can strike deeper, damaging lands that had once been safe. In 2005, Category-3 Hurricane Rita flooded and nearly destroyed Tabasco’s production and bottling facilities. Rather than pack up and leave, the company decided to stand its ground, investing millions of dollars in a levee system and several marsh restoration projects.

The company’s land managers have burned the marshes for as long as anyone can remember, but it wasn’t for the marsh’s benefit. Romero’s uncle, Raleigh Rogers, lit up the marsh to catch more muskrat.

“He’d burn all the brush, and that’d make it easier to walk and find his traps,” said Romero, who took over the land manager job from his uncle 12 years ago. “But near the end, he started seeing the other benefits.”

Rogers noticed that neighboring lands that weren’t burned eroded faster or didn’t hold up as well to storm surges.

“That land — the waves would just peel it right up,” Romero said.

The same lesson is being learned elsewhere on the Gulf Coast.

“Before you had me, who has a graduate degree in this stuff, you had trappers and ranchers doing basically the same thing,” King said. “At first, they did it because it made it better for hunting or grazing.”

They developed a mantra: “If you don’t burn your marsh, you’re going to lose it,” King said.

“Sometimes that local wisdom is true,” he said.

That doesn’t mean all human-set fires are beneficial. A fire can burn too hot and too long or be set at the wrong time of the year. It can even exacerbate land loss if not done right, McKee said.

Fires burn around 60,000 acres per year in the cluster of three refuges — Sabine, Cameron Prairie and Lacassine — that King helps manage in Cameron and Calcasieu parishes. About half that acreage is scorched naturally, usually sparked by lightning strikes.

The marsh ecosystem on the northern Gulf Coast evolved with wildfires as a key component. Fires prevent trees and other woody species from invading marshes, and they promote the growth of grasses that birds and other wildlife prefer to eat. The seaside sparrow, for instance, tends to disappear from marshes that don’t burn regularly. Fires also produce nutrient-rich ash that fertilizes the soil, and open the ground to sunlight, allowing seeds to sprout.

King and Romero try to replicate the best attributes of wildfires. They avoid burning in summer and spring, when birds are nesting and other wildlife are fattening up on bountiful plant growth. A winter fire timed a day or two after rain is best, Romero said.

On Dec. 10, he had the right balance of conditions. Weekend rainfall had saturated the roots and muddy soil, protecting them from the fire, but the leaves and stalks had dried.

“You want the flame to just sit on top of that and not get in all that peat below,” he said. “That stuff will burn forever.”

Romero’s first fire, lit with a propane torch before noon under overcast skies, wouldn’t budge. He tried a little trick of the trade — blasting the fire with his airboat’s propeller. As the fire began to move, he raced ahead and lit more fires that dried the grass in the first fire’s path.

Just after noon, Romero got the right combination of humidity, sun and wind. The fire charged ahead, crackling loudly through clusters of indigo and making enough smoke to blot out the sun. It burned out when it reached the wetter edges of the marsh. Within 20 minutes of the fire passing, the burned stalks and soil were cool to the touch, unlike the fires in Western forests, which can burn so hot and long that tree roots deep in the soil remain scalding hot for days and spark new fires. Romero’s fire blackened the landscape but left small islands of green. This patchwork will foster re-growth and give animals a bit of cover, he said.

The fire provided an immediate benefit for hawks. Nearly a dozen gathered overhead and swooped down for mice and insects flushed out by the flames.

Within a few months, the burned area’s collection of roseau cane, needle grass and three-cornered grass will be back better and healthier than before, Romero said. In 2021, he’ll probably return to light it up again.

Louisiana’s marshes have few homes, but there’s plenty of oil and gas infrastructure that could be put at risk from prescribed burns. Romero and King say they give all wells and pipelines — both active and abandoned — a wide berth. King’s fire crew regularly fights wildfires that stray close to the many refineries and liquid natural gas plants in Cameron and Calcasieu parishes.

Keeping the fires contained in the marshes of Louisiana is helped by the dense tangle of bayous and canals. Fire lines — gashes cut in the soil to halt a fire’s spread — aren’t usually required.

The biggest fire management headache is keeping the smoke away from people.

Romero might have perfect conditions for a fire but have to call it off if the wind is blowing toward Avery’s 150 residents and dozens of Tabasco workers.

“The minute the smoke goes toward houses, I get phone calls,” he said. “They really hate this stuff,” he said, pointing at six-inch-long tufts of ash that floated through the air during his marsh burn. “Nobody wants this stuff landing on their car.”

Large fires can hurt air quality in cities and reduce visibility on roads. A wildfire in Sabine National Wildlife Refuge produced so much smoke that traffic on major roadways near Lake Charles ground to a halt and sheriff’s deputies were called to escort vehicles out of the haze.

People are especially skittish about smoke after recent wildfires that devastated communities in California and for weeks clogged the region’s air with smoke, Romero said.

He and King worry that the public could turn against prescribed burns. In other parts of the country, towns and cities are sprawling outward into natural landscapes and homes are being built in fire-prone areas. That’s not a big worry in coastal Louisiana, where many communities have declining populations due to flood and storm risk and downturns in the local fishing and oil industries. But Lake Charles and Port Arthur are growing, and liquid natural gas facilities are popping up around the Sabine refuge.

“We’ve got an LNG facility to the north of us and another planned to the south and another right across the Texas border,” King said. “They’re all around us. No matter which way I send the smoke, I’m going to have problems.”

For Romero, keeping the smoke from going north over Avery or New Iberia, nine miles away, are his main concerns. Even if the smoke does steer in the wrong direction, his fires are usually out when the complaints roll in.

“By the time people see the smoke, we’re already done,” he said.

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