How climate and vegetation influence the fire regime of the Alaskan boreal biome: the Holocene perspective, Mitigation and Adaptation Strategies for Global Change 11

• Main Authors: Feng Sheng Hu, Linda B. Brubaker, Daniel G. Gavin, Philip E. Higuera, Jason A. Lynch, T. Scott Rupp, Willy Tinner
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2006
• Subjects: Tundra; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.420.2483; http://www.lter.uaf.edu/pdf/968_hu_brubaker_2006.pdf

Abstract. We synthesize recent results from lake-sediment studies of Holocene fire-climatevegetation interactions in Alaskan boreal ecosystems. At the millennial time scale, the most robust feature of these records is an increase in fire occurrence with the establishment of boreal forests dominated by Picea mariana: estimated mean fire-return intervals decreased from ≥300 yrs to as low as ∼80 yrs. This fire-vegetation relationship occurred at all sites in interior Alaska with charcoal †-based fire reconstructions, regardless of the specific time of P. mariana arrival during the Holocene. The establishment of P. mariana forests was associated with a regional climatic trend toward cooler/wetter conditions. Because such climatic change should not directly enhance fire occurrence, the increase in fire frequency most likely reflects the influence of highly flammable P. mariana forests, which are more conducive to fire ignition and spread than the preceding vegetation types (tundra, and woodlands/forests dominated by Populus or Picea glauca). Increased lightning associated with altered atmospheric circulation may have also played a role in certain areas where fire frequency increased around 4000 calibrated ‡ years before present (BP) without an apparent increase in the abundance of P. mariana. When viewed together, the paleo-fire records reveal that fire histories differed