Methods: Experimental Burn (FROSTFIRE)

On July 8-15, 1999, an experimental burn at the Caribou-Poker Creeks Research Watershed burned about one third of the C4 watershed (365 ha). It was ignited using a helitorch that dropped ping-pong balls of jellied gasoline from a helicopter. Some hand-firing from handheld drip torches also occurred. Narrow strips of vegetation, where fire could be contained, were lit from the top to the bottom of the watershed. Although this fire was artificially ignited, it behaved very much like a natural wildfire, changing from a ground fire to a crown fire at times of low humidity. As with a natural wildfire, a range of burn severities developed from irregular burning patterns. The majority of the relatively flammable black spruce vegetation in the watershed burned, whereas the less flammable deciduous birch and aspen stands and the wetter Sphagnum-dominated valley bottoms did not burn.

Extensive pre-fire surveys and studies made it possible to compare environmental conditions and ecological processes before, during, and after the fire. FROSTFIRE is the most thoroughly documented fire in history, with more than 50 research projects examining a wide range of processes, including fire behavior, long and short-term impacts to ecology, hydrology, surface energy balance, and trace-gas fluxes. The extensive pre-burn and post-burn documentation permit accurate and quantitative analysis of long-term impacts and recovery from wildfire.