Fighting Fire With Fire
Seventy years ago, lightning started a forest fire near Little Poker Creek. The flames quickly blazed a path of charred black spruce as the muskeg below smoldered for days, creating a patchwork of burned and non-burned areas in the 2,600-acre drainage. This summer, the Little Poker Creek watershed will burn again, only this fire will be lit by man.
Scientists and fire-fighting professionals from Alaska, Canada, and as far away as Brazil and Japan will converge on interior Alaska in late July and early August to learn more about fire behavior with a controlled burn over an entire drainage. The Caribou-Poker creeks watershed, on the west side of the Chatanika River about 30 miles north of Fairbanks, has been a study area since 1969.
According to Terry Chapin, a professor of ecology at the University of Alaska Fairbanks' Institute of Arctic Biology and the head of the project, such an experiment has never been done before. Last year, fire-fighting crews from Fairbanks cut fire lines from 40-to-80 feet wide around the perimeter of the watershed. This summer, if conditions are right, those same crews will set the forest on fire. The burn, sponsored by the National Science Foundation, will provide answers for about 40 scientists--20 from Alaska and 20 from other countries.
During the past 30 years, researchers have sampled the soils, streams and plants of the watershed, documenting the character of the area before the fire. After the fire, those same researchers will compare many features of the pre- and post-burn environment, including the carbon storage of the forest. Carbon, locked up in trees, soil and moss, is released both during decay and by burning as carbon dioxide.
Other scientists will be checking stream runoff from the watershed, observing how fire affects the flow rates, chemical composition, temperature and other factors that matter to things that live in the water. Chapin said the controlled burn also will allow fire-fighting agencies in Alaska, Canada and the Lower 48 to validate computer models. The agencies regularly use computer models to predict fire behavior and develop the best plan for fighting a wildfire, but these models have never been tested for Alaska.
The burn will help scientists understand how fire modifies Alaska's climate. If Alaska gets warmer over the next few decades, as scientists predict, soils will be dryer and forest fires will occur more often. With more fires, plants will transpire less water to the atmosphere. The charred soil will be darker, so it will absorb more heat. All these factors tinker with the regional and global climate.
Jim Roessler, a fire management specialist with BLM, will make the decision to commence the Caribou-Poker creeks burn. When he does, fire-fighting crews will first burn to widen the fire line. Then, the firefighters will use hand held and helicopter-based drip torches to start fires within the fire line. "We're not just going to charge up there and burn it," Roessler said. "If critical elements of the prescription aren't in range, we won't do it." The burn prescription, a plan of action for controlled fires, states the conditions needed for the burn to happen. The wind has to be a certain speed and from a certain direction, the temperature and humidity must be right, ground moisture must be at a certain level, and BLM has to have equipment and people available.
"If we have another Carla Lake (a fire that required more than 30 fire crews in early June), we won't be able to meet that prescription," Roessler said. "It'll have to wait until next year."
