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Biogeochemical impacts of wildfires over four millennia in a Rocky Mountain subalpine watershed.

Biogeochemical impacts of wildfires over four millennia in a Rocky Mountain subalpine watershed.

Authors :
Dunnette PV
Higuera PE
McLauchlan KK
Derr KM
Briles CE
Keefe MH
Source :
The New phytologist [New Phytol] 2014 Aug; Vol. 203 (3), pp. 900-12. Date of Electronic Publication: 2014 May 06.
Publication Year :
2014

Abstract

Wildfires can significantly alter forest carbon (C) storage and nitrogen (N) availability, but the long-term biogeochemical legacy of wildfires is poorly understood. We obtained a lake-sediment record of fire and biogeochemistry from a subalpine forest in Colorado, USA, to examine the nature, magnitude, and duration of decadal-scale, fire-induced ecosystem change over the past c. 4250 yr. The high-resolution record contained 34 fires, including 13 high-severity events within the watershed. High-severity fires were followed by increased sedimentary N stable isotope ratios (δ15N) and bulk density, and decreased C and N concentrations--reflecting forest floor destruction, terrestrial C and N losses, and erosion. Sustained low sediment C : N c. 20-50 yr post-fire indicates reduced terrestrial organic matter subsidies to the lake. Low sedimentary δ15N c. 50-70 yr post-fire, coincident with C and N recovery, suggests diminishing terrestrial N availability during stand development. The magnitude of post-fire changes generally scaled directly with inferred fire severity. Our results support modern studies of forest successional C and N accumulation and indicate pronounced, long-lasting biogeochemical impacts of wildfires in subalpine forests. However, even repeated high-severity fires over millennia probably did not deplete C or N stocks, because centuries between high-severity fires allowed for sufficient biomass recovery.<br /> (© 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.)

Details

Language :
English
ISSN :
1469-8137
Volume :
203
Issue :
3
Database :
MEDLINE
Journal :
The New phytologist
Publication Type :
Academic Journal
Accession number :
24803372
Full Text :
https://doi.org/10.1111/nph.12828