On the morning of the burn, the nerves set in. Even months of planning does not guarantee that the weather conditions will be perfect. The team starts with a small fire, monitoring the flame to determine if it can continue.
For Heidi Holman, the start of a prescribed burn is disconcerting even with her years of experience. Holman is a wildlife biologist with the New Hampshire Department of Fish and Game who uses prescribed burns to support ecosystems across the state that rely on fire to survive.
Species like the Karner blue butterfly, frosted pixie butterfly and roseate tern are in play, as are rare habitats like pine forests. That’s why this fall, Holman and his team have planned a series of prescribed burns across the state – starting small, controlled fires on the Isle of Shoals, a group of islands about 7 miles offshore. Atlantic Ocean, and on the pine barrens surrounding Concord’s airport.
These fires also help clear shrubs and downed branches that can fuel wildfires.
During a prescribed burn, the crew will burn 2 to 15 acres of land. At least six to eight people participate in each burn, but sometimes up to 15 people are on site. The burns can last anywhere from 40 minutes to four hours, depending on the wind and whether the path of the burn is straight or requires the team to make lots of turns.
“You’re very nervous and (full of) excited stress that morning,” Holman said. “And then as it starts to progress, and you expand that fire more, it creates black.”
Black is good because it means there is no more vegetation to burn; this creates a safe zone. “As you get more black on the floor, you start to feel a little better,” Holman said. “You know your edges are secure and you can start shooting more, and the rhythm starts to happen.”
Holman said prescribed burns are critical to the survival of Karner’s blue butterfly. Wild lupine is the butterfly’s host plant, allowing it to complete its caterpillar life stage and become an adult. But without fire, trees encroach on these open fields, shading the lupine and killing it.
“The directed fire just keeps those openings going and it also gives that burst of nutrients,” she said. After a year of fire, butterfly populations explode because there are more nutrients available to the lupine, which means better nutrition for the caterpillars that eat the lupine. When the caterpillars become adults, they in turn lay more eggs.
Beyond these established benefits, Holman believes fire is important to this ecosystem for reasons science has yet to fully understand, including its role in nutrient cycling or its impact on a type of bacteria that grows on lupine and can play a crucial role in how it competes with other plants. These relationships haven’t been studied or understood, Holman said, “and so it’s easier to just mimic a natural process and hope it all happens.”
“These systems support so many other unique species that we haven’t even had the ability to begin research,” she said. “Imagine the relationships.”
The pine barrens are a unique habitat, like an archipelago stretching across the region; other moors are found on the coast of Maine, Cape Cod, Massachusetts, and Albany, New York. In Concord, Holman learned that the sand is between 60 and 80 feet deep. It is nutrient-poor and porous, so water passes through it, creating a hot, dry environment where fire can easily occur. Fires would naturally occur here, but are avoided due to nearby houses.
Steve Sherman, chief of the New Hampshire Division of Forestry and Lands Office of Forest Protection, works with Holman’s team on prescribed burns.
“I’ve been with the state since 1997, and we’ve been burning ever since and before,” he said.
Wildfires have been worse than usual this summer due to drought conditions across the state, and prescribed burns may also be contributing.
“We mitigate the potential for large, out-of-control wildfires by having these small fires controlled,” Holman said. “Once that fuel is used up, that big catastrophic fire is less likely to happen.”
She said large wildfires occurred in Concord well into the 1980s in the Steeplegate Mall area.
But the fear of wildfires can prejudge people against any kind of fire, no matter how beneficial. Holman said in her experience, residents were understanding and she thinks most people are used to fires. “Everyone is aware. They got the message for 20 years,” she said. “We try to keep burning to make our presence known.”
A prescribed burn ends once the crew has ensured that all fire is completely extinguished. It may take about an hour to go through the burn and check for any remaining hot spots.
The blackened ground seems lifeless, but in its wake the fire has left the exact conditions needed to sustain it.
