FROSTFIRE was a landscape-scale prescribed research burn in the boreal forest of interior Alaska that occurred July 8-15, 1999. Within the 2200-acre perimeter, fire mimicked natural conditions by burning 900 acres of mostly black spruce, leaving the hardwoods standing. Boreal forests account for about one-third of the carbon sequestered in terrestrial ecosystems, and this research is measuring the changes in carbon pools and fluxes that result from large fires in the boreal forest. Models are being developed that predict major feedbacks to the climate system from fires in the boreal forest. This experiment differs from previous experimental fires in the boreal forest because it is in terrain dominated by discontinuous permafrost, focuses on the large-scale ecological consequences of fire, and takes place on an Long Term Ecological Research (LTER) site, enabling long-term, experimentally-controlled research. Principal investigators are from the USDA Forest Service and the University of Alaska.