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Holocene development of Boreal forests and fire regimes on the Kenai Lowlands of AlaskaCenter for Environmental Sciences & Education, & Quaternary Sciences Program, Box 5694, Northern Arizona University, Flagstaff AZ 86011, USA, Scott.Anderson{at}nau.edu
Center for Environmental Sciences & Education, & Quaternary Sciences Program, Box 5694, Northern Arizona University, Flagstaff AZ 86011, USA, Department of Geography and School of Environmental Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
Kenai National Wildlife Refuge, U.S. Fish & Wildlife Service, Box 2139, Soldotna AK 99669, USA
4014A Lewis Lane, Austin TX 78756, USA
Quaternary Sciences Program, Box 5644, Northern Arizona University, Flagstaff AZ 86011, USA
Department of Geology, Box 4099, Northern Arizona University, Flagstaff AZ 86011, USA
US Fish & Wildlife Service, 2800 Cottage Way, Sacramento, CA 95825, USA Several studies have noted a relationship between vegetation type and fire frequency, yet despite the importance of ecosystem processes such as fire the long-term relationships between disturbance, climate and vegetation type are incompletely understood. We analysed pollen, plant macrofossils and sedimentary charcoal from three lakes within the Kenai lowlands to determine postglacial relationships between disturbance, climate and vegetation for the Boreal forest of southwest Alaska. An herb tundra was established in the lowlands following deglaciation by 13 000 cal. BP. Salix, Alnus and probably Betula kenaica, expanded in the area after 10 700 cal. BP, followed by Picea glauca by 8500 cal. BP. Picea mariana became established by 4600 cal. BP. The early Holocene was probably the driest time during the postglacial, as determined by aquatic plant macrofossils and climate models. Lake levels reached near-modern conditions by at least 8000 cal. BP. Mean Fire Intervals (MFI) were longest during the shrub-herb tundra phase (138±65 yr), decreased after expansion of B. kenaica, Salix and Populus (77±49 yr) and Picea glauca (81±41 yr), and increased again with the arrival of P. mariana (130±66 yr). Unlike previous studies, our data demonstrate the highest fire frequencies during the early to mid-Holocene and less frequent fire during the late Holocene when P. mariana forests dominated the lowlands. Early Holocene forests of P. glauca and B. kenaica existed in summers that were longer and drier than today, while the increasingly wetter and cooler climates of the late Holocene probably hindered forest fire around Paradox Lake, perhaps because of less frequent summer drought.
Key Words: Boreal forest • charcoal analysis • climate change • fire history • vegetation history • Holocene • Alaska
The Holocene, Vol. 16, No. 6,
791-803 (2006) This article has been cited by other articles:
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