As the East sweats, a growing fire threat

As the East Sweats, a Growing Fire Threat

18 July 2012

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USA –  Seventy-five years of fire suppression have brought complacency, but now extreme heat and drought are making Eastern forests vulnerable to wildfires again

Last fall scientists and foresters from more than a dozen nations gathered for the world’s first conference on the growing threat of megafires. Considering that the American West has experienced record-breaking fire seasons over the past decade, the choice of venue for the conference was a bit surprising: northern Florida.

Living in Colorado and watching as massive fires bloom across the Rocky Mountains — sparked by a combination of heat, drought, and poor decisions about forest management and housing development — it would be easy to think that the East Coast is relatively safe from smoke plumes and fireballs. Indeeed, during last year’s conference visit to Tall Timbers, a nonprofit fire research station in Tallahassee, one of the scientists in my group pulled out his phone and announced that a wildfire was threatening his home back in Nevada.

But as we learned at Tall Timbers, the humid hardwood forests of the East have their own history of fire problems, and just like out West, climate change and a century of fire suppression have primed them for danger.

Last spring, a thin snowpack, high winds, and drought — the same conditions that drove fires in the Rocky Mountains this year — also fueled fires from New England to Florida. This year, all 25 states east of the Rockies experienced their warmest recorded January-to-March periods in more than 110 years of record keeping. Many also experienced extreme drought. Last April on Long Island, wildfires threatened Brookhaven National Laboratory, destroyed three homes and nine businesses, and burned three firefighters. In Connecticut, a wildfire shut down an Amtrak line. And in New Jersey, fire spread through 1,000 acres of the state’s beloved Pine Barrens. In Virginia’s George Washington National Forest, more than 20,000 acres burned in early April — four times the previous record. Throughout the spring, much of Florida and Georgia were in extreme to exceptional drought — drier even than in 2007, when a record-setting drought brought on the Big Turnaround fire, the biggest in both states’ recorded histories.

The size of Eastern wildfires may not rival Western blazes — half a dozen of the active fires in the West this week were larger than 100,000 acres — but the East Coast is more densely populated, meaning that smaller fires can still threaten a great number of lives and property and require large resources to fight. “Even if the fires don’t look that spectacular, they can do a lot of damage,” says Kevin Robertson, the fire ecology program director at Tall Timbers.

This month authorities declared more than 1,000 counties in 26 states as natural disaster areas, in what has become the worst drought to strike the nation in decades. The conditions that have already contributed to massive wildfires across the West are bringing more fires to parts of the eastern U.S., including North Carolina, Tennessee, and Virginia, according to the federal National Climatic Data Center.

The East, in fact, has a forgotten history of big burns. In New Brunswick, Canada, the Miramichi fire of October 1825 — one of the three largest ever recorded in North America — burned over three million acres, devastating the towns of Newcastle and Fredericton and killing 190 people. Hundreds more drowned in rivers where they took shelter with their livestock. And on October 8, 1871 — the same day that the Great Chicago Fire exploded — a wildfire twice the size of the state of Rhode Island overran Peshtigo, Wisconsin, killing between 1,200 and 2,400 people, marking the greatest loss of life to a wildfire in the nation’s history. Seventy years later, British and American militaries studied the dynamics of the Peshtigo fire to plan the bombings of Dresden and Tokyo during World War II.

But while all those factors still exist, today residents of eastern forests have all but forgotten the threat — and with good cause. During the past 75 years, the Eastern U.S. has seen a steep decline in the number and size of wildfires.

Fire suppression has played a big role on both sides of the country. In the West, a century of extinguishing fires has left many forests with a heavy load of fuel. Today, that timber is helping feed more frequent, larger, and more intense fires.

In eastern forests, suppression was largely focused on who was starting the fires — first Native Americans, then settlers and farmers who regularly burned the forest to clear land for agriculture, grazing, and hunting. After the Peshtigo fire, foresters worked hard to eliminate human ignitions. From 1927 until 1931, American Forests, the nation’s oldest citizens conservation group, sent “Dixie Crusaders” through the Southeast, where they taught some 3 million people about the evils of starting fires. However, in the moister hardwood forests, once those human ignitions stopped, the woodlands thickened and filled with shade tolerant species that “fireproofed” many forest floors. (That’s different from the West, where fire-dependent conifers like lodgepole pines and Douglas-firs dominate the landscape.) Broadleaf trees shaded the ground, lowering the temperature, holding moisture in the woods, and sheltering them from winds that might drive fire. Flaccid, fallen leaves helped keep the ground wet. The increase in shade tolerant, less fire-prone trees over the past 75 years radically reduced the frequency and size of fires in eastern forests dominated by oak and pine. The amount of land burned in the eastern U.S. dropped from more than 10 million hectares annually in the early 1940s to less than one million hectares a year 50 years later.

“It’s getting more and more difficult to get these ecosystems to burn,” says Greg Nowacki, an ecologist and soil scientist with the U.S. Forest Service’s Eastern Region. “Because of fire suppression over the past 50 or 60 years, we can’t even get surface fires to burn in these forests.” Some northeastern woodlands are so fireproof that they’re called “asbestos forests.”

But that lack of fire has not been good, as once open stands have closed so tight that sunlight never reaches the forest floor, and shade-tolerant trees such as beeches and maples have pushed out some species of pine and oak that require more space, sun, and regular fires to thrive. Wildlife diversity also declines as the woods thicken; some southeastern forests have lost more than half of their wildlife species due to lack of hardwood-thinning fires.

So what changed to give the East such a fiery spring? Chalk it up to the drought, which in April led to red flag fire warnings in 20 eastern states. And there’s more to come: models predict that climate change will bring more frequent drought to much of the U.S. As that happens, rising temperatures will increase evaporation, drying timber and providing more fuel for fires in some traditionally moist woodlands. Precipitation patterns will also change. Swamps and wetlands, when stricken by drought, can burn intensely, like the Okefenokee Swamp did in Georgia and Florida during 2007’s record-setting Big Turnaround fire. Even worse, fires in such peat-rich, organic soils have the potential to release more carbon dioxide and methane than even a large forest fire, warming the climate even more.

What’s more, volatile storms like the “derecho” that pummeled 10 Eastern states last month with a line of volatile thunderstorms, knocking out power to 4.3 million homes and businesses, leave more fuel on the floors of overly dense forests, says Stephen Marien, the eastern area fire weather program manager for the National Park Service. Similarly, dead wood strewn through forests by Hurricane Irene last year was a worry for firefighters during this spring’s wildfires.

“We are moving towards generally drier conditions,” says Sam Levis at the National Center for Atmospheric Research. “The forests in the East will be more susceptible, especially in … drought years.”

Eastern foresters and firefighters are planning for the changes that the shifting climate will bring, but “it’s not actually all that easy,” says Erin D. Lane, fire planner with the White, Green, and Finger Lakes National Forests in New York state. Changing precipitation patterns, strengthening storms, and shifting seasons are all complicating factors.

Lane, who rappelled from helicopters in the Pacific Northwest, worked on a fire engine in Idaho, and was part of one of the nation’s elite forest firefighting “hotshot” crews in Oregon, moved East to plan for forest fires in New England eight years ago. She said the science and resources for fighting fires are more developed in the West — but the East needs to catch up, and quickly.

One of the places trying to do just that is Tall Timbers, which has studied the effects of wildfire on eastern forests and wildlife for more than 50 years. During my visit to the Florida facility last fall, I wandered among old-growth pine stands rising from ground that is set ablaze, under careful conditions, as often as every year. The regular fires burn off grasses, saplings, and shrubs, thus keeping fires small and less likely to spread to larger trees — an indication that regular fires are a good thing for forest health. Wildlife such as bobwhite quail and gopher tortoises, which decreased in numbers when the forests grew thick due to fire suppression, are doing well here, another positive sign of overall forest health. Regularly burned forests are also critical habitat for the endangered red-cockaded woodpecker, and Bachman sparrows tend leave the forest if it hasn’t burned within the last 18 months.

“That just gives you an idea of how important the fire frequency is for some of these native species,” says Robertson, the fire ecologist. “And why we want to burn so often, to keep these critters around.”

The critters may be seeing the benefits, but convincing humans to embrace fire near their home — as a way of staving off even bigger, future fires — is a tough sell, in both East and West. As warm, dry conditions across the country prime the forests to burn, though, we really have no other option. Fire will return to the Eastern forests one way or the other — better that we manage it, or we risk seeing it burn out of control.

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