Wildland Fire Trends Tool

Land and fire managers often ask the questions:

• Where are wildfires burning?
• Are wildfires burning more area over time?
• What are general trends in wildfire size?
• What are general trends in wildfire count?
• Are some locations experiencing more wildfire than others?

Answers to these questions can inform fire management and help people understand how fire activity is changing across the landscape and over time. Accurately answering these questions is critical for numerous federal, state, and local agencies who manage fire-prone landscapes. Information about past fires can help managers assess risk and plan for fuel management and restoration needs. In addition, a better understanding of fire occurrence can help to justify the tremendous public expense to prevent, manage, and rehabilitate ecosystems following wildfire.

The WFTT is a publicly available web application that will retrieve fire data and generate graphically compelling maps and charts of fire activity. Although wildland fire data are publicly available, these data are often unusable to those without specific expertise. Many data sets require knowledge of Geographic Information System (GIS), have significant limitations that may confound their use and interpretation, or require statistical expertise to appropriately assess and summarize. For example, wildfire trend discrepancies can confuse public perceptions of wildfire risk and confound management and policy decisions, making it less clear how, where, and when to address fire management.

The tool provides wildland fire data in two formats:

The Wildland Fire Perimeter Dashboard displays historical fire records (1830s-2020) that represent the entire area within the boundary of wildfire and/or prescribed fire (Welty and Jeffries 2021). These historical fire data are from a variety of sources, and wildland fire records prior to 1984 are less likely to be complete, especially for smaller fires. Because of the incomplete documentation, we suggest you filter out the smaller fires that are less than 1,000 acres. This suggestion follows commonly used methodology, such as that used for the Monitoring Trends in Burn Severity (MTBS) program.

Media

Sources/Usage: Public Domain. View Media Details

The Wildfire Burned Area Dashboard displays yearly trends in area burned by wildfire (over 1,000 acres in size) for a recent period of record (1984-2019) classified using Landsat imagery (MTBS; Eidenshink 2007).  The data exclude prescribed fires and any unburned area within a fire perimeter.

Media

Sources/Usage: Public Domain. View Media Details

Technical Notes

Some figures displayed on the Wildland Fire Perimeter Dashboard and Wildfire Burned Area Dashboard use log transformed data. Wildfire data typically have non-normal distributions and log transformation of the data is a commonly used assessment method, as described by Williams et al. 2019, for example.  To determine whether the area burned over time is increasing or decreasing, we calculated Sen’s slope for log-transformed fire area data, which indicates the magnitude of a trend, and then used the Mann-Kendall test to evaluate if a trend is increasing or decreasing over time and if the direction is significant. If trends are changing consistently, they are considered monotonic. The adjusted p-value indicates significance, and it accounts for autocorrelation of time series data using methods developed by Hamed and Rao (1998) and Hamed (2009).  Trends are not calculated for query areas less than 50,000 ha or in which over 50% of years had no fire.  For display purposes, the data in graphs of burned area trends are back-transformed to original units (hectares or acres). 

Data Disclaimer 

Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data do not depict real time information. Please see the listed data sources for more information on input data.

Data Sources

Wildland Fire Data Sources

Welty, J.L., and Jeffries, M.I., 2021, Combined wildland fire datasets for the United States and certain territories, 1800s-Present: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZXGFY3

MTBS Data Access: Raster Geospatial Data. (2021, September - last revised). MTBS Project (USDA Forest Service/U.S. Geological Survey). Available online: https://www.mtbs.gov/direct-download

Ancillary Data Sources

Bunzel, Ken; Ager, Alan A.; Day, Michelle A.; Dillon, Gregory K. 2021. Community zones for assessing wildfire exposure in the United States. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2021-0046

Eidenshink, J., B. Schwind, K. Brewer, Z. Zhu, B. Quayle, and S. Howard. 2007. A Project for Monitoring Trends in Burn Severity. Fire Ecology 3: 3–21. https://doi.org/10.4996/fireecology.0301003

Hamed, K. H., and A. Ramachandra Rao. 1998. A modified Mann-Kendall trend test for autocorrelated data. Journal of Hydrology 204:182–196. https://doi.org/10.1016/S0022-1694(97)00125-X

Hamed, K. H. 2009. Enhancing the effectiveness of prewhitening in trend analysis of hydrologic data. Journal of Hydrology 368:143–155. https://doi.org/10.1016/j.jhydrol.2009.01.040

LANDFIRE, LANDFIRE: Biophysical Settings, U.S. Department of Agriculture and U.S. Department of the Interior. Accessed July 2021 at https://landfire.gov/bps.php

National Interagency Fire Center, Jurisdictional Unit Tile Map Service, 2020, Accessed February 2022, https://www.arcgis.com/home/item.html?id=3b2c5daad00742cd9f9b676c09d03d13

Short, Karen C.; Grenfell, Isaac C.; Riley, Karin L.; Vogler, Kevin C. 2020. Pyromes of the conterminous United States. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2020-0020

Williams, A. P., J. T. Abatzoglou, A. Gershunov, J. Guzman-Morales, D. A. Bishop, J. K. Balch, and D. P. Lettenmaier. 2019. Observed Impacts of Anthropogenic Climate Change on Wildfire in California. Earth’s Future 7:892–910. https://doi.org/10.1029/2019EF001210

U.S. Census Bureau, 2021, TIGER/Line Files, Redistricting Census, https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html 

U.S. Environmental Protection Agency, 2013, Level III ecoregions of the continental United States: Corvallis, Oregon, U.S. EPA – National Health and Environmental Effects Research Laboratory, https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-continental-united-states