Evaluation of the composite burn index for assessing fire severity in Alaskan black spruce forests
Eric S. Kasischke A F , Merritt R. Turetsky B C , Roger D. Ottmar D , Nancy H. F. French E , Elizabeth E. Hoy A and Evan S. Kane BA Department of Geography, University of Maryland, 2181 LeFrak Hall, College Park, MD 20742, USA.
B Departments of Plant Biology, and Fisheries & Wildlife, Michigan State University, East Lansing, MI 48824, USA.
C Present address: Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
D USDA Forest Service, Pacific Northwest Research Station, 400 N 34th St, Seattle, WA 98103, USA.
E Michigan Tech Research Institute, Michigan Technological University, 3600 Green Court, Suite 100, Ann Arbor, MI 48113-4001, USA.
F Corresponding author. Email: ekasisch@umd.edu
International Journal of Wildland Fire 17(4) 515-526 https://doi.org/10.1071/WF08002
Submitted: 5 January 2008 Accepted: 15 January 2008 Published: 6 August 2008
Abstract
We evaluated the utility of the composite burn index (CBI) for estimating fire severity in Alaskan black spruce forests by comparing data from 81 plots located in 2004 and 2005 fire events. We collected data to estimate the CBI and quantify crown damage, percent of trees standing after the fire, depth of the organic layer remaining after the fire, depth of burning in the surface organic layer (absolute and relative), and the substrate layer exposed by the fire. To estimate pre-fire organic layer depth, we collected data in 15 unburned stands to develop relationships between total organic layer depth and measures of the adventitious root depth above mineral soil and below the surface of the organic layer. We validated this algorithm using data collected in 17 burned stands where pre-fire organic layer depth had been measured. The average total CBI value in the black spruce stands was 2.46, with most of the variation a result of differences in the CBI observed for the substrate layer. While a quadratic equation using the substrate component of CBI was a relatively strong predictor of mineral soil exposure as a result of fire (R2 = 0.61, P < 0.0001, F = 60.3), low correlations were found between the other measures of fire severity and the CBI (R2 = 0.00–0.37). These results indicate that the CBI approach has limited potential for quantifying fire severity in these ecosystems, in particular organic layer consumption, which is an important factor to understand how ecosystems will respond to changing climate and fire regimes in northern regions.
Acknowledgements
The research in the paper was supported by NASA through Grants NNG04GD25G and NNG04GR24G, the Joint Fire Science Program (JFSP Project No. 03-1-3-08 to the USA Forest Service), and the Bonanza Creek Long-Term Ecological Research program (USFS grant number PNW01-JV11261952–231 and NSF grant number DEB-0080609). The authors thank Gordon Shetler, Evan Ellicott, Luz Silverio, Lucas Spaete, Sam Upton, and Richard Powell for assisting in the collection of field data. We thank Scott Rupp for providing CBI data for 8 plots in the Tors fire event and for carrying out the analyses of tree rings to estimate stand ages. The authors also thank the two anonymous reviewers whose constructive comments and suggestions helped improve the manuscript.
Bergner B, Johnstone J , Treseder KK (2004) Experimental warming and burn severity alter CO2 flux and soil functional groups in recently burned boreal forest. Global Change Biology 10, 1996–2004.
| Crossref | GoogleScholarGoogle Scholar |
Greene DF, Macdonald SE, Hauessler S, Domenicano S, Noel J, Jayen K, Charron I, Guathier S, Hunt S, Gielau ET, Bergeron Y , Swift L (2007) The reduction of organic-layer depth by wildfire in the North American boreal forest and its effect on tree recruitment by seed. Canadian Journal of Forest Research 37, 1012–1023.
| Crossref | GoogleScholarGoogle Scholar |
Hollingsworth TN, Walker MD, Chapin FS , Parsons AL (2006) Scale-dependent environmental controls over species composition in Alaskan black spruce communities. Canadian Journal of Forest Research 36, 1781–1796.
| Crossref | GoogleScholarGoogle Scholar |
Johnstone JF , Kasischke ES (2005) Stand-level effects of burn severity on post-fire regeneration in a recently-burned black spruce forest. Canadian Journal of Forest Research 35, 2151–2163.
| Crossref | GoogleScholarGoogle Scholar |
Kasischke ES , Turetsky MR (2006) Recent changes in the fire regime across the North American boreal region – spatial and temporal patterns of burning across Canada and Alaska. Geophysical Research Letters 33, L09703..
| Crossref | GoogleScholarGoogle Scholar |
Kasischke ES, Williams D , Barry D (2002) Analysis of the patterns of large fires in the boreal forest region of Alaska. International Journal of Wildland Fire 11, 131–144.
| Crossref | GoogleScholarGoogle Scholar |
Keyser TL, Smith KW, Lentile LB , Sheppard WD (2006) Modeling postfire mortality of ponderosa pine following a mixed-severity wildfire in the Black Hills: The role of tree morphology and direct fire effects. Forest Science 52, 530–539.
Stocks BJ, Mason JA, Todd JB, Bosch EM, Wotton BM, Amiro BD, Flannigan MD, Hirsch KG, Logan KA, Martell DL , Skinner WR (2002) Large forest fires in Canada, 1959–1997. Journal of Geophysical Research 108, 8149..
| Crossref | GoogleScholarGoogle Scholar |
Yoshikawa K, Bolton WR, Romanovsky VE, Fukuda M , Hinzman LD (2002) Impacts of wildfire on the permafrost in the boreal forests of Interior Alaska. Journal of Geophysical Research 107, 8148.
| Crossref | GoogleScholarGoogle Scholar |
Zasada JC, Norum RA, Van Veldhuizen RM , Teutsch CE (1983) Artificial regeneration of trees and shrubs in experimentally burned upland black spruce/feathermoss stands in Alaska. Canadian Journal of Forest Research 13, 903–913.
| Crossref | GoogleScholarGoogle Scholar |
