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Methods for mapping fire hazard and risk across multiple spatial scales.

Severe fire seasons of the past decade in the western United States have spurred many government agencies to manage lands to reduce fire intensity and severity to ultimately protect human life and property.

However, seven decades of fire exclusion policies have resulted in the dense forest canopies, high surface fuel accumulations, and increased fuel continuity across large regions where fires were historically frequent. These abnormal fuel conditions may foster abnormally severe wildfires that are projected to increase with global warming. The western US has also experienced a marked increase in human development in areas surrounding public wildlands thereby creating and expanding a “wildland urban interface”. With this expansion comes an increased risk to human life and property as severe wildfires become increasingly common. In response, federal agencies have advocated fuels reduction treatments to mitigate the risk and hazard of severe wildfires, particularly in the wildland urban interface. With limited available funding and the cost of fuel treatments continually increasing, fire managers have been charged with developing a detailed methodology for identifying and prioritizing which federal lands are in the greatest need for fuels reduction treatments. A quantification of fire hazard and risk is critical for identifying and prioritizing areas for fuel fuels treatments, and comprehensive fire models are an important first step towards providing spatially explicit estimates of fire risk and hazard over a range of spatial and temporal scales.

This project involves the development of a research computer model called FIREHARM (FIRE HAzard and Risk Model) that computes common measures of fire behavior, fire danger, and fire effects over space to use as variables to portray fire hazard spatially, and then computes fire risk by simulating daily fuel moistures over 18 years to compute fire measures over time. The digital hazard and risk maps can then be used for fire management planning and real-time wildfire operations. Extensive validation of six FIREHARM output variables is being conducted to estimate model accuracy and precision to aid in the interpretation of results.

The objective of this study is to develop methods of computing fire hazard and risk that minimize the limitations and drawbacks of previous efforts. To accomplish this we created the FIREHARM computer model that 1) increased consistency across hazard and risk layers, 2) standardized weather inputs, 3) employed a multiple scale analysis into its structure, 4) included some spatial effects, and 5) expanded the number of fire hazard and risk variables. The audience for this effort is managers and researchers interested in describing and evaluating fire hazard and risk across multiple spatial scales. This research may lead to new methods of prioritizing fuel treatments after major insect, disease, or fire events and it will provide important parameters and values for future efforts.

Image: 1. FIREHARM hazard assessment for a Montana landscape

Photo: Fireharm hazard assessment
Modified: May 28, 2014

Select Publications & Products

Keane, R.E., Drury, S., Karau, E., Hessburg, Paul F., Reynolds, K. 2010. A method for mapping fire hazard and risk across multiple spatial scales and its application in fire management. Ecological Modelling 221:2-18

Hessburg, Paul F., Keith M. Reynolds, Robert E. Keane, Kevin M. James, and R. Brion Salter. 2008. Evaluating wildland fire danger and prioritizing vegetation and fuels treatments. Forest Ecology and Management 247(1-3):1-17. (Refereed).

Hessburg, P.F., Reynolds, K.M., Keane, R.E., James, K.M., and Salter, R.B. 2009. Evaluating wildland fire danger and prioritizing vegetation and fuels treatments. Forest Ecology and Management 24(1-3):1-17 or Online publication: Forest Encyclopedia Network: Environmental Threats: Case Studies.

Reynolds, Keith M., Paul Hessburg, Robert E. Keane, James P. Menakis. 2009. National fuel treatment budgeting in US federal agencies: Capturing opportunities for transparent decision-making. Forest Ecology and Management 258:2373-2381 (Refereed).

Hessburg, Paul F., K. Reynolds, R. Keane, K. James, R. B. Salter. 2010. Evaluating wildland fire danger and prioritizing vegetation and fuels treatments. Pages 329-353 In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest and Southern Research Stations. 708 p. 2 vol.

Keane, R.E. and J. Menakis. March 2014. Evaluating wildfire hazard and risk for fire management applications. Book Chapter. Pages 111-135 In: Reynolds, Keith, Paul

Hessburg, and P. Bourgeron (Editors), Making transparent environmental management decisions. Springer, New York, USA [Peer Reviewed]