Tussock Replacement as a Means of Stabilizing Fire Breaks in Tundra Vegetation

Fire generally is not considered an important factor in tundra ecosystems. Cool, moist summer weather, low plant productivity resulting in a minimum amount of fuel, and low human population densities combine to deter fires. Northwestern Alaska, and the Seward Peninsula in particular, may be exceptions to this generality. Periodic summer droughts and frequent thunderstorms during the snowfree period produced several major tundra fires in this area during the last decade (Wein, 1976; Racine and Racine, 1978). Because these fires threatened local native villages and their associated reindeer range, the U.S. Bureau of Land Management pursued an active policy of fire containment. The use of bulldozers to scrape away surface accumula- tions of organic matter generally is considered an impor- tant tactic in tundra fire suppression. Narrow firebreaks are constructed ahead of advancing flames and often are successful in blocking the progress of such fires. The construction of firebreaks may, however, severely dam- age tundra landscapes. Removal of the protective and thermally insulating vegetative cover exposes the under- lying mineral soil to increased depth of thawing and water- caused erosion. When firebreaks lie more or less on the line of fall of long slopes, channelization of runoff in the more deeply thawed soil can quickly result in formation of deep gullies. DeLeonardis (1971), for example, reported that within two years following the construction of cat-