Theme: East-West Interdisciplinary Boreal Forest Fire Experiment, Part 3 Moderator: A. Granström and G. Ivanova 8.8.1995 16:30 Room: U16
Prefire Vegetation, Forest Stand and Site Characteristics of Bor Forest Island, Krasnoyarsk Region, Siberia
Ivanova, Gallina A., Mälkönen, Eino
The experimental site (60°45’N, 89°25’E) is on the Dubches plain in the Western Siberian Lowland. Vegetation is typical of central taiga forests of Western Siberia. The study site is a nearly level, slightly elevated, sandy island surrounded by bogs, which are dominated by mixed-grass/sphagnum and tall sedge. Soils are homogeneous across the island. The soil is a ferric podsol, with a coarse sand texture. The A horizon, of mixed mineral and organic matter, is very thin. Occasional weakly cemented patches occur in the B horizon. The humus layer contains 34.6 t/ha of organic matter and 19.9 kg/ha of carbon, with 18.1 kg/ha of carbon in the mineral soil (070 cm).
Before the experimental fire, the forest island supported a pure stand of Scotch pine (Pinus sylvestris L.), well-stocked and even-aged (130 years old). The pine stand was of fire origin. The canopy cover was relatively high (0.60.7), and average density was 1470 trees/ha. Average tree diameter and height were 18 cm and 17 m, respectively. The volume of standing living trees, snags and downed wood were 248, 14.6, 17.3 m3/ ha, respectively. Downed wood was in various stages of decomposition. Conifer regeneration was sparse, and included Pinus sibirica Ledeb. and Pinus sylvestris L. Understory shrub cover was low, with scattered patches of Rosa acicularis and Salix caprea. The edge of the island and depressions were covered by Spiraea salicifolia. The ground cover was of mosaic character, dominated by a dense mat of Cladonia lichens (Cladonia stellaris, C. sylvatica, C. rangiferina, and C. uncialis). Green moss (Pleurozium schreberi) and low shrub plants (Vaccinium vitis-idaea, V. myrtillus, V. uliginosum and Ledum palustre) were found in shallow depressions.
The heights of the moss, lichen, and low shrub layers were 35, 57, and 1235 cm respectively. The total biomass of living ground cover was 15.9 t/ha. Litter and forest floor organic layer load was 17.6 t/ha. Pine-lichen stands are remarkable for their rapid development of flammability and the ability to maintain high flammability during the fire season. The considerable load of ground fuels on the forest island was conducive to the occurrence of high-intensity crown fire. The prefire research allowed us to estimate fuel loads and biomass consumption in the fire, and provides a baseline for studying processes of post-fire forest recovery in this area.
Key words: Pinus sylvestris, ground cover, soil.
Correspondence: Gallina A. Ivanova, Institute of Forests, Russian Academy of Sciences, Siberian Branch, Forest Fire Laboratory, Akademgorodok, RUS-Krasnoyarsk, 660036