Peat-rich soil feeds Pocosin Lakes fire

Peat-rich soil feeds Pocosin Lakes fire

21 June 2008

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NC, USA — The fire in Pocosin Lakes National Wildlife Refuge in Eastern North Carolina has burned more intensely and spread more widely because of changes to the land in earlier decades to promote farming.

Much of the swampy land blackened by the Evans Road fire is crosshatched with ditches and canals that lower the water level and make the ground suitable for growing crops. The drainage ditches also allow the carbon-rich peat soil to dry and become fuel for a fire.

“That is why this has become the fire that it has become,” said Bonnie Strawser, a spokeswoman for the U.S. Fish and Wildlife Service.

Strawser said the dry peat — dried even more by the prolonged drought — was ripe for a wildfire, which lightning ignited June 1 on private land. The fire spread quickly onto the refuge.

As of late Friday, the fire had burned about 41,000 acres — 64 square miles — two-thirds of that on the wildlife refuge. The fire is now 75 percent contained at a cost of $5.4 million, but the peat soils will burn until significant rain falls, according to a spokesman for the North Carolina incident team fighting the fire.

Fires that scorch the ground are part of the natural cycle in this wetland area, but fires hot enough to ignite the soil have been rare, Strawser and others said.

Doug Rader, a scientist with the Environmental Defense Fund, an advocacy group, said the area’s wetlands need to be restored, and that might involve buying out private landowners.

Wildlife officials regularly conduct controlled burns on parts of the 110,000-acre refuge to create a more varied habitat for wildlife and to reduce the amount of undergrowth vegetation that could fuel wildfire. But refuge managers never conducted a controlled burn where the fire occurred, deeming it too risky — precisely because of the dry peat soil.

“We didn’t have the hydrologic conditions to create a safe prescribed burn,” Strawser said.

Since 1994, Fish and Wildlife officials have been slowly trying to restore some semblance of the natural water levels on about 27,500 acres of the refuge by damming ditches and controlling drainage. That work is still in the initial stages.

Betting on farming

Much of the land that makes up the refuge was carved into grids of ditches and canals decades ago.

Paul Lilly, a retired associate professor of soil science at N.C. State University, said the area had a long history of land speculation. Companies built networks of ditches in anticipation of selling off the land as farms

“The area that is actually being burned was mostly ditched in the 1950s and 1960s, primarily on speculation,” Lilly said.

Starting in the early 1970s, First Colony Farms acquired 376,000 acres in Washington, Tyrrell, Hyde and Dare counties with plans to develop it into farmland, pasture, forest and wildlife areas. Lilly said the land was difficult to develop for large-scale agriculture, and eventually the company sold or traded most of it. It formed the basis of the Alligator River National Wildlife Refuge and Pocosin Lakes National Wildlife Refuge.

Lilly said the ecology of the area included fires, and cross-sections of the layers of peat contain ash.

“There are records of big fires in the exact area back to the 1700s and 1800s,” Lilly said. “The bottom line is it is inevitable that it will burn again.”

Curtis Richardson, director of the Duke University Wetland Center, said fire is part of the natural system in such environment, but fires typically wouldn’t have been as severe or burned deeply into the soil.

“When you have as many ditches as have been put out there, those areas that were ditched have dropped the water table 1 to 3 feet,” Richardson said. “Those turn really dry. Peat is pre-coal. It’s very good fuel.”

He said a third of the world’s carbon is stored in peat.

“This is one of the real worries with global warming,” Richardson said. “If these areas dry out like the Everglades and northern pocosins, it will potentially release millions of metric tons of carbon.”

Strawser noted that as the fire moved eastward, it stopped spreading when it reached an area of undisturbed wetlands where deeper peat soil held more moisture.

“That area has not been ditched and drained,” Strawser said. “That has been sort of a saving grace in that area.”

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