Brigham Young University researchers were awarded a $13 million research grant from the federal Joint Fire Science Program to study ways to manage vegetation using controlled burns and other interventions in order to reduce catastrophic wildfires, said Thomas Fletcher, a BYU professor of chemical engineering leading the research. Fletcher said the research team’s initial findings show a leaf can burn even with up to 50% of its moisture present — a previously unknown fact that has serious ramifications for existing fire-spread models, which often mistakenly factor in the additional time it takes for a leaf’s moisture to evaporate.
“The Forest Service came to us and they wanted to improve their fire-spread models, especially when it came to live vegetation,” he said.
Previous fire-spread models were based on dead fuels. Instead, Fletcher’s team tested live fuels in a simulated fire in the university’s lab, where students ran a simulation by pumping a gas mixture of methane, hydrogen and oxygen into what looks like a small lunar rover. The top of the rover is covered with a square foot of porous material that steadily allows gas to escape, creating a very uniform, 1,800-degree flame when lit, Fletcher said.
A small pulley brings the flame-on-wheels toward different types of leaves and bushes to simulate an approaching wildfire. Fletcher said students can also apply environmental effects, such as wind to the flame, and take measurements using infrared cameras, oxygen sensors and — after the burn — moisture analyzers to safely predict how a wildfire will behave.
“What our experiments have shown is that … there still a lot of moisture inside the leaf even though the edges are burning,” he said. “That changes the heat transfer and how we model these fires.”
The findings will improve fire modeling by providing a more accurate description of how wildfires burn and the affect of live fuels, Fletcher said. It also will assist the wildfire chief, who often relies on available fire models to make quick and significant decisions about deploying resources, he said.
Fletcher and his team of five students, four of whom are undergraduates, hope to finish their improvements to existing models within the next two years.
“We are hoping our research gets implemented into the models current being used,” he said. “We don’t plan on reinventing the wheel. But our work can help improve those fire modeling.”