Theme: East-West Interdisciplinary Boreal Forest Fire Experiment, Part 4 Moderator: V.V. Furyaev and Eino Mälkönen 10.8.1995 9:30 Room: U16
Fuels and Fire Behavior on the Bor Forest Island Fire
Stocks, Brian J., Lawson, Bruce D., Valendik, Eric N.
A field experiment, Fire Research Campaign Asia-North (FIRESCAN), organized under the joint sponsorship of the International Boreal Forest Research Association (IBFRA) and the IGBP International Global Atmospheric Chemistry (IGAC) Project, was carried out in north-central Siberia in July 1993. The purpose of FIRESCAN was to conduct a high-intensity stand replacement fire under controlled conditions, permitting Russian and western fire scientists to compare research methodologies before, during, and after the fire. A 49-hectare site, Bor Forest Island, was selected near Bor, located on the Yenesei River approximately 600 km north of Krasnoyarsk. A pure mature stand of Scots Pine (Pinus sylvestris L.) covered the Island, with a sparse shrub understory, and ground cover dominated by Cladonia lichens.
Various techniques were used to determine preburn and postburn fuel loads. Ground fuel loads (lichen and duff layer) averaged 4.27 kg/m2 (1.39 kg/m2 for lichen and 2.88 kg/m2 for duff). Surface fuel loads (downed woody material) averaged 1.51 kg/m2, while aerial fuel loads (needles and fine shoots) were estimated to be 0.80 kg/m2.
As winds were light and variable during the burn day, the island was ignited completely along the perimeter, creating a very intense, convection-style fire that spread rapidly, accelerating toward the island centre. The average rate of spread was 25 m/min. Total fuel consumption was 3.44 kg/m2 (ground fuels 2.07 kg/m2, surface fuels 0.81 kg/m2, and aerial fuels 0.56 kg/m2). Fire residence times (above 100°C) were approximately 5 min. Overall frontal fire intensity was estimated to be 25,800 kW/m. This level of fire behavior translated into a high-intensity, stand replacement fire that crowned out over 70 % of the island, resulting in virtually 100 % mortality of the overstory trees. This high rate of energy release produced a convection column approximately 5 km high, with a well-developed capping cumulus top.