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12-3-01-3
2012
06/01/2012
09/29/2013
Is Spatial Heterogeneity of Burn Severity Changing With Warming Climate and Increasing Wildfire?
Spatial heterogeneity of burn severity greatly influences the resiliency of forested ecosystems. Fire activity is increasing in most parts of the world and especially in the Northern Rocky Mountains (N. Rockies). Although studies have begun to examine temporal trends in severity, surprisingly little is known about how the spatial configuration of within-fire burn severity may be changing with increasing wildfire. Broad-scale studies of trends in fire activity thus far have not characterized the ecologically significant spatial complexity within fire perimeters. In addition to temporal trends in burn severity, it is critical to understand how the spatial configuration of within-fire patterns of burn severity may be changing under a warming climate to anticipate changes in forested ecosystems and services they provide. I will address this knowledge gap by examining recent (1984-2010) temporal trends in spatial patterns of burn severity in over 1000 large wildfires (> 200 ha) across the N. Rockies to address two questions. (1) How has spatial heterogeneity of burn severity changed during the last 25 years in the N. Rockies, and where are these landscape patterns changing most rapidly? A trend towards more extreme burning conditions under a warming climate suggests that spatial heterogeneity could be decreasing and burn severity increasing. I hypothesize that trends in spatial metrics will indicate decreases in burn heterogeneity while the proportion of area burned at high severity will increase. I will map fire severity using established methods derived from Landsat TM imagery and calibrate these indices with existing postfire data (n = 1730 plots) and new postfire data (n = 350 plots) to be collected in 2012 using Composite Burn Index (CBI) protocols. Landscape metrics and statistical distributions of burn severity will be computed for each large fire in the study period and evaluated for potential changes in burn heterogeneity over this period of warming climate and increased fire. Region-wide maps will be produced to identify locations where the rate of change in spatial heterogeneity of burn severity is most rapid and thus the risk of landscapes shifting to alternative states may be high. (2) Do changes in spatial heterogeneity of burn severity vary (a) among forest types, (b) with topographic position or levels of complexity, (c) under different land management scenarios, and (d) with climate? Trends of decreasing heterogeneity and increasing severity are expected to be strongest in low-elevation conifers that historically burned with mixed-severity regimes vs. high-elevation and high-latitude mesic forests that historically burned under high-severity regimes. Depending on which factor(s) are most influential in generating heterogeneity, climate change in the N. Rockies may be altering spatial patterns of burn severity, but such connections have not been examined to date. I will develop statistical relationships between downscaled (12 km x 12 km) climate variables and measures of spatial heterogeneity of burn severity for all large forest fires in the N. Rockies during the period 1984-2010 in different topographic contexts, forest types, and management settings. The proposed research will leverage my existing dissertation data, along with existing field and climate data for the region; substantially broaden the geographic scope of my dissertation research; and allow me to develop and apply state-of-the-art remote sensing methods and landscape metrics for regional fire assessment. Results will be presented at a professional fire conference and lead to two manuscripts for submission to refereed journals. Because spatial configuration of within-fire patterns of burn severity affects postfire successional trajectories, carbon storage, wildlife habitat, and nutrient cycling, the proposed research will generate new understanding that is directly relevant for managing fire-prone forested landscapes in the face of climate change.
Monica G. Turner
University of Wisconsin-Madison
Department of Integrative Biology

Other Project Collaborators

Other Project Collaborators

Type

Name

Agency/Organization

Branch or Dept

Agreements Contact

Kim L. Moreland

University of Wisconsin-Madison

Research & Sponsored Programs

Budget Contact

Kim L. Moreland

University of Wisconsin-Madison

Research & Sponsored Programs

Student Investigator

Brian J. Harvey

University of Washington

School of Environmental and Forest Sciences

Project Locations

Project Locations

Fire Science Exchange Network

Northern Rockies

Level

State

Agency

Unit

REGIONAL

Interior West

MULTIPLE

Final Report

Project Deliverables

Title
 
Causes and consequences of spatial patterns of fire severity in Northern Rocky Mountain forests: theView
Landscape EcologyView
EcologyView
Global Ecology and BiogeographyView
Postfire subalpine forest regeneration varies with climate in patches of stand-replacing wildfireView
Are spatial patterns of burn severity changing with warming climate and increasing wildfire?View
Landscape patterns and disturbance legacies: Is a warming climate altering spatial patterns of wildfView

Supporting Documents