Friendly fire: Burning in Everglades can actually be good

Friendly fire: Burning in Everglades can actually be good

9 May 2009

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USA — The wildfire that blocked Alligator Alley, the primary east-west artery across the Everglades, was a costly two-week headache for truckers, travelers and businesses.

In the blackened 30,000-acre swath left behind in the Big Cypress National Preserve, however, the fire wasn’t the destructive force it might immediately appear to be as drivers now whiz by.

For all the problems and dangers wildfires pose to settled South Florida, they’re essential to the health of its sprawling wild lands. Much of the natural mosaic — sawgrass prairies, cypress sloughs, tropical hammocks, pine forests — evolved over centuries of regular burns. They need a rejuvenating dose of flame now and then.

”It really is built to burn,” said Rick Anderson, fire management officer at Everglades National Park. “Marjory Stoneman Douglas might have called it the River of Grass, but when I look at it I call it the River of Fire.”

Within weeks — days, if rains arrive unexpectedly — what looks like wasteland along a 10-mile stretch of Interstate 75 beginning near mile marker 70 will offer a roadside ecology lesson in the cycle of fire and life in the Everglades. Scorched soil, suddenly supercharged with nutrients from ashen plants, will erupt with the green shoots of sedges and flowers, native plants that will lure back grazing wildlife and birds.

”It may look charred out there sometimes, but in the end, fire is like a spring tonic for many of Florida’s native creatures,” said Jerome Jackson, an ecology professor at Florida Gulf Coast University whose research has focused on fire effects.

In the Big Cypress, 750,000 acres of cypress swamps, pine forests and grassy wetlands bordering Everglades National Park, regular burns are so vital that managers set more acreage afire annually than in any national park — typically 50,000 to 70,000 acres a year, said preserve spokesman Bob DeGross.

Historically, the Big Cypress landscape — typically higher and drier than the Everglades — burned more often than the wetter Glades, with fires sweeping large areas every three to four years. Preserve managers, cautious about protecting campgrounds, camps and houses, shoot for a seven-year cycle.

The recent blaze, dubbed the ”Deep Fire” because it began with a lightning strike near a section south of I-75 called Deep Lake, saved fire managers some work. It blazed north across I-75 into the East Hinson Marsh, an area untouched by fire for about eight years.

While preserve managers expect much of the 30,000 acres to recover quickly, a historic dry spell exposed some normally protected pockets to damage — cypress ”domes” that are usually soggy and shady stands of trees thick with rare bromeliads, and tropical hardwood hammocks, usually steamy with humidity.

”We did see some areas burn that would typically not,” said DeGross, “but that was a very small percentage.”

Beyond fueling new growth, fire is a powerful pruner of the dead, decaying and diseased, and an exterminator of invasive pests and plants that were not — as Everglades’ Anderson puts it — “built to burn.”

Sawgrass blades go up like paper, but the roots, protected in soggy mud, can survive fast-moving prairie fires. Tough slash pine bark serves as insulation and trees lose lower branches as they grow, raising green limbs above common ground fire.

Many animals also have adapted, bolting at the first scent of smoke or even taking advantage of wildfires, Anderson said. He’s seen hawks working the edges of advancing blazes to pick off fleeing prey. In one aftermath video, he watched ravens “picking at the remains of toasted insects.”

Others, particularly slow movers, don’t fare so well.

”If you happen to be a box turtle in front of a fast-moving fire, it can be a bad thing,” he said.

Because the Everglades has been dried out by drainage canals and dikes, some fires, particularly during arid dry seasons like the current one, can leave serious and damaging scars. In the worst cases, fires burn deep into the peat or muck, creating intense burns almost impossible for firefighters to put out without help from rain.

In the 1970s and ’80s, muck fires carved huge depressions into sections of the northern Everglades and destroyed 1,500-year-old islands of hardwood trees, some of the system’s richest habitat. Cattails invaded the wounds, pushing out native sawgrass and plants.

For many decades, scientists didn’t understand the benefits of fire, and parks and national forests tried to snuff them out. That only made things worse. When brush built up, the super-fueled fires turned devastating.

The Everglades was a leader in changing that Smokey Bear, no-fire-is-good policy. It was the first park to study the role of fire in the natural system back in 1958 and conducted the first prescribed, or intentional, fire ever in a national park.

Now, national parks routinely manage wildfires for ecological benefits and intentionally set them when conditions are right. Random bolts from the blue don’t always spark blazes where, or when, they are most needed — as the Big Cypress blaze showed.

The preserve had shut its prescribed burn program down in January and, with dry conditions becoming dangerous, Superintendent Pedro Ramos had banned back-country campfires 12 days before the start of the wildfire that shut down I-75. But nature doesn’t read memos.

”It’s such an important tool,” Anderson said. “We can choose our time instead of waiting for the driest, windiest days for lighting to strike.”

Miami Herald staff writer Laura Figueroa contributed to this report.

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