Evaluation of the composite burn index for assessing fire severity in Alaskan black spruce forests

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 (R 2 = 0.61, P < 0.0001, F = 60.3), low correlations were found between the other measures of fire severity and the CBI (R 2 = 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.

[1]  R. Hall,et al.  Using Landsat data to assess fire and burn severity in the North American boreal forest region: an overview and summary of results , 2008 .

[2]  E. Kasischke,et al.  Evaluating the potential of Landsat TM/ETM+ imagery for assessing fire severity in Alaskan black spruce forests , 2008 .

[3]  A. McGuire,et al.  Topographic influences on wildfire consumption of soil organic carbon in interior Alaska: Implications for black carbon accumulation , 2007 .

[4]  D. Greene,et al.  The reduction of organic-layer depth by wildfire in the North American boreal forest and its effect on tree recruitment by seed , 2007 .

[5]  E. Kasischke,et al.  Assessing spatial and temporal variations in surface soil moisture in fire-disturbed black spruce forests in Interior Alaska using spaceborne synthetic aperture radar imagery — Implications for post-fire tree recruitment , 2007 .

[6]  M. Turetsky,et al.  Effects of wildfire and permafrost on soil organic matter and soil climate in interior Alaska , 2006 .

[7]  D. Odion,et al.  Fire Severity in Conifer Forests of the Sierra Nevada, California , 2006, Ecosystems.

[8]  W. Shepperd,et al.  Modeling Postfire Mortality of Ponderosa Pine following a Mixed-Severity Wildfire in the Black Hills: The Role of Tree Morphology and Direct Fire Effects , 2006, Forest Science.

[9]  S. A. Lewis,et al.  Remote sensing techniques to assess active fire characteristics and post-fire effects , 2006 .

[10]  G. Wang,et al.  Are mineral soils exposed by severe wildfire better seedbeds for conifer regeneration , 2006 .

[11]  F. Chapin,et al.  Scale-dependent environmental controls over species composition in Alaskan black spruce communities , 2006 .

[12]  E. Kasischke,et al.  Recent changes in the fire regime across the North American boreal region—Spatial and temporal patterns of burning across Canada and Alaska , 2006 .

[13]  E. Knapp,et al.  Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest* , 2006 .

[14]  Peter Wallbrink,et al.  Effects of differing wildfire severities on soil wettability and implications for hydrological response , 2006 .

[15]  Yves Bergeron,et al.  Effect of fire severity on regeneration success in the boreal forest of northwest Québec, Canada , 2006 .

[16]  Sarah A. Lewis,et al.  Assessing burn severity and comparing soil water repellency, Hayman Fire, Colorado , 2006 .

[17]  E. Kasischke,et al.  Stand-level effects of soil burn severity on postfire regeneration in a recently burned black spruce forest , 2005 .

[18]  E. Kasischke,et al.  Variation in postfire organic layer thickness in a black spruce forest complex in interior Alaska and its effects on soil temperature and moisture , 2005 .

[19]  E. Schuur,et al.  Soil carbon stabilization along climate and stand productivity gradients in black spruce forests of interior Alaska , 2004 .

[20]  K. Treseder,et al.  Experimental warming and burn severity alter soil CO2 flux and soil functional groups in a recently burned boreal forest , 2004 .

[21]  A. Weaver,et al.  Detecting the effect of climate change on Canadian forest fires , 2004 .

[22]  D. V. Sandberg,et al.  Chemistry of burning the forest floor during the FROSTFIRE experimental burn, interior Alaska, 1999 , 2004 .

[23]  E. Kasischke,et al.  Environmental Controls on Soil Co2 Flux Following Fire in Black Spruce, White Spruce, and Aspen Stands of Interior Alaska , 2002 .

[24]  E. Kasischke,et al.  Analysis of the patterns of large fires in the boreal forest region of Alaska , 2002 .

[25]  K. Hirsch,et al.  Large forest fires in Canada, 1959–1997 , 2002 .

[26]  Kenji Yoshikawa,et al.  Impacts of wildfire on the permafrost in the boreal forests of Interior Alaska , 2002 .

[27]  A. DesRochers,et al.  Is ring count at ground level a good estimation of black spruce age , 1997 .

[28]  David K. Swanson,et al.  Susceptibility of Permafrost Soils to Deep Thaw after Forest Fires in Interior Alaska, U.S.A., and Some Ecologic Implications , 1996 .

[29]  R. Wein,et al.  Postfire vegetation recovery and tree establishment at the Arctic treeline: climate-change-vegetation-response hypotheses , 1993 .

[30]  C. T. Dyrness,et al.  The effects of experimental fires on black spruce forest floors in interior Alaska , 1983 .

[31]  R. A. Norum,et al.  Artificial regeneration of trees and tall shrubs in experimentally burned upland black spruce/feather moss stands in Alaska , 1983 .

[32]  R. K. Lebarron.  Adjustment of Black Spruce Root Systems to Increasing Depth of Peat , 1945 .

[33]  R. Ottmar,et al.  Forest Floor Consumption and Smoke Characterization in Boreal Forested Fuelbed Types of Alaska , 2007 .

[34]  N. Benson,et al.  Landscape Assessment: Ground measure of severity, the Composite Burn Index; and Remote sensing of severity, the Normalized Burn Ratio , 2006 .

[35]  Eric S. Kasischke,et al.  Fire, Climate Change, and Carbon Cycling in the Boreal Forest , 2000, Ecological Studies.

[36]  E. Kasischke,et al.  Controls on Patterns of Biomass Burning in Alaskan Boreal Forests , 2000 .

[37]  J. Goldammer,et al.  Fire in Ecosystems of Boreal Eurasia , 1996, Forestry Sciences.

[38]  Leslie A. Viereck,et al.  Climatic Characteristics of the Taiga in Interior Alaska , 1986 .

[39]  C. T. Dyrness,et al.  Forest Ecosystems in the Alaskan Taiga , 1986, Ecological Studies.

[40]  David A. MacLean,et al.  The Role of fire in northern circumpolar ecosystems , 1983 .

[41]  Leslie A. Viereck,et al.  The effects of fire in black spruce ecosystems of Alaska and northern Canada , 1983 .

[42]  Leslie A. Viereck,et al.  Forest Succession in Relation to Nutrient Cycling in the Boreal Forest of Alaska , 1981 .