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Persistent Effects of Fire Severity on Early Successional Forests in Interior AlaskaThere has been a recent increase in the frequency and extent of wildfires in interior Alaska, and this trend is predicted to continue under a warming climate. Although less well documented, corresponding increases in fire severity are expected. Previous research from boreal forests in Alaska and western Canada indicate that severe fire promotes the recruitment of deciduous tree species and decreases the relative abundance of black spruce (Picea mariana) immediately after fire. Here we extend these observations by (1) examining changes in patterns of aspen and spruce density and biomass that occurred during the first two decades of post-fire succession, and (2) comparing patterns of tree composition in relation to variations in post-fire organic layer depth in four burned black spruce forests in interior Alaska after 10-20 years of succession.Wefound that initial effects of fire severity on recruitment and establishment of aspen and black spruce were maintained by subsequent effects of organic layer depth and initial plant biomass on plant growth during post-fire succession. The proportional contribution of aspen (Populus tremuloides) to total stand biomass remained above 90% during the first and second decades of succession in severely burned sites, while in lightly burned sites the proportional contribution of aspen was reduced due to a 40- fold increase in spruce biomass in these sites. Relationships between organic layer depth and stem density and biomass were consistently negative for aspen, and positive or neutral for black spruce in all four burns. Our results suggest that initial effects of post-fire organic layer depths on deciduous recruitment are likely to translate into a prolonged phase of deciduous dominance during post-fire succession in severely burned stands. This shift in vegetation distribution has important implications for climate-albedo feedbacks, future fire regime, wildlife habitat quality and natural resources for indigenous subsistence activities in interior Alaska.
Document ID
20110002896
Document Type
Reprint (Version printed in journal)
Authors
Shenoy, Aditi (Alaska Univ. Fairbanks, AK, United States)
Johnstone, Jill F. (Alaska Univ. Fairbanks, AK, United States)
Kasischke, Eric S. (Alaska Univ. Fairbanks, AK, United States)
Kielland, Knut (Alaska Univ. Fairbanks, AK, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2011
Publication Information
Publication: Forest Ecology and Management
Volume: 261
Issue: 3
ISSN: 0378-1127
Subject Category
Earth Resources and Remote Sensing
Funding Number(s)
CONTRACT_GRANT: NSF DEB-0620579
CONTRACT_GRANT: NNG04GR24G
CONTRACT_GRANT: PNW01-JV11261952-231
CONTRACT_GRANT: NNX06AF85G
Distribution Limits
Public
Copyright
Other