Effectiveness of prescribed fire as a fuel treatment in Californian coniferous forests

Effective fire suppression and land use practices over the last century have altered forest structure and increased fuel loads in many forests in the United States, increasing the occurrence of catastrophic wildland fires. The most effective methods to change potential fire behavior are to reduce surface fuels, increase the canopy base height and reduce canopy bulk density. This multi-tiered approach breaks up the continuity of surface, ladder and crown fuels. Effectiveness of fuel treatments is often shown indirectly through fire behavior modeling or directly through monitoring wildland fire effects such as tree mortality. The present study investigates how prescribed fire affected fuel loads, forest structure, potential fire behavior, and modeled tree mortality at 90th and 97.5th percentile fire weather conditions on eight National Forests in California. Prescription burning did not significantly change forest structure at most sites. Total fuel loads (litter, duff, 1, 10, 100, and 1000-h) were reduced by 23 to 78% across the sites. The reduction in fuel loads altered potential fire behavior by reducing fireline intensity and increasing torching index and crowning index at most sites. Predicted tree mortality decreased after treatment as an effect of reduced potential fire behavior and fuel loads. To use limited fuel hazard reduction resources efficiently, more effort could be placed on the evaluation of existing fire hazards because several stands in the present study had little potential for adverse fire effects before prescribed fire was applied.

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Prescribed fire science: the case for a refined research agenda

Fire Ecology ◽

10.1186/s42408-020-0070-8 ◽

2020 ◽

Vol 16 (1) ◽

Cited By ~ 4

Author(s):

J. Kevin Hiers ◽

Joseph J. O’Brien ◽

J. Morgan Varner ◽

Bret W. Butler ◽

Matthew Dickinson ◽

...

Keyword(s):

Prescribed Fire ◽

Research Agenda ◽

Wildland Fire ◽

Fire Behavior ◽

Fire Effects ◽

Prescribed Fires ◽

Wildfire Management ◽

Fire Science ◽

Useful Knowledge ◽

Global Challenge

Abstract The realm of wildland fire science encompasses both wild and prescribed fires. Most of the research in the broader field has focused on wildfires, however, despite the prevalence of prescribed fires and demonstrated need for science to guide its application. We argue that prescribed fire science requires a fundamentally different approach to connecting related disciplines of physical, natural, and social sciences. We also posit that research aimed at questions relevant to prescribed fire will improve overall wildland fire science and stimulate the development of useful knowledge about managed wildfires. Because prescribed fires are increasingly promoted and applied for wildfire management and are intentionally ignited to meet policy and land manager objectives, a broader research agenda incorporating the unique features of prescribed fire is needed. We highlight the primary differences between prescribed fire science and wildfire science in the study of fuels, fire behavior, fire weather, fire effects, and fire social science. Wildfires managed for resource benefits (“managed wildfires”) offer a bridge for linking these science frameworks. A recognition of the unique science needs related to prescribed fire will be key to addressing the global challenge of managing wildland fire for long-term sustainability of natural resources.

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Spot Weather Forecasts: Improving Utilization, Communication, and Perceptions of Accuracy in Sophisticated User Groups

Weather Climate and Society ◽

10.1175/wcas-d-15-0055.1 ◽

2017 ◽

Vol 9 (2) ◽

pp. 215-226 ◽

Cited By ~ 3

Author(s):

Tamara U. Wall ◽

Timothy J. Brown ◽

Nicholas J. Nauslar

Keyword(s):

Prescribed Fire ◽

Wildland Fire ◽

Forecast Accuracy ◽

Weather Forecast ◽

Weather Conditions ◽

The United States ◽

Weather Forecasts ◽

Improving Accuracy ◽

Sophisticated User ◽

Weather Service

Abstract Spot weather forecasts (SWFs) are issued by Weather Service offices throughout the United States and are primarily for use by wildfire and prescribed fire practitioners for monitoring local-scale weather conditions. This paper focuses on use of SWFs by prescribed fire practitioners. Based on qualitative, in-depth interviews with fire practitioners and National Weather Service forecasters, this paper examines factors that influence perceptions of accuracy and utilization of SWFs. Results indicate that, while several well-understood climatological, topographical, and data-driven factors influence forecast accuracy, social factors likely have the greater impact on perceptions of accuracy, quantitative accuracy, and utilization. These include challenges with building and maintaining relationships between forecasters and fire managers, communication issues around updating SWFs, and communicating forecast confidence and uncertainty. Operationally, improved quantitative skill in a forecast is always desirable, but key opportunities for improving accuracy and utilization of these forecasts lie in 1) enhancing the processes and mechanisms for communication between a Weather Forecast Office and fire practitioners—before, during, and after an SWFs is issued—and 2) working with the wildland fire community to experiment with forecast uncertainty and confidence information in SWFs and evaluate impacts of these approaches.

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Using the Landsat Burned Area Products to Derive Fire History Relevant for Fire Management and Conservation in the State of Florida, Southeastern USA

Fire ◽

10.3390/fire4020026 ◽

2021 ◽

Vol 4 (2) ◽

pp. 26

Author(s):

Casey Teske ◽

Melanie K. Vanderhoof ◽

Todd J. Hawbaker ◽

Joe Noble ◽

John Kevin Hiers

Keyword(s):

Prescribed Fire ◽

Spatial Data ◽

Fire History ◽

Fire Management ◽

Fire Behavior ◽

Fire Risk ◽

Behavior Modeling ◽

Burned Area ◽

Burned Areas ◽

Burn Probability

Development of comprehensive spatially explicit fire occurrence data remains one of the most critical needs for fire managers globally, and especially for conservation across the southeastern United States. Not only are many endangered species and ecosystems in that region reliant on frequent fire, but fire risk analysis, prescribed fire planning, and fire behavior modeling are sensitive to fire history due to the long growing season and high vegetation productivity. Spatial data that map burned areas over time provide critical information for evaluating management successes. However, existing fire data have undocumented shortcomings that limit their use when detailing the effectiveness of fire management at state and regional scales. Here, we assessed information in existing fire datasets for Florida and the Landsat Burned Area products based on input from the fire management community. We considered the potential of different datasets to track the spatial extents of fires and derive fire history metrics (e.g., time since last burn, fire frequency, and seasonality). We found that burned areas generated by applying a 90% threshold to the Landsat burn probability product matched patterns recorded and observed by fire managers at three pilot areas. We then created fire history metrics for the entire state from the modified Landsat Burned Area product. Finally, to show their potential application for conservation management, we compared fire history metrics across ownerships for natural pinelands, where prescribed fire is frequently applied. Implications of this effort include increased awareness around conservation and fire management planning efforts and an extension of derivative products regionally or globally.

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An Evaluation of NDFD Weather Forecasts for Wildland Fire Behavior Prediction

Weather and Forecasting ◽

10.1175/waf-d-17-0121.1 ◽

2018 ◽

Vol 33 (1) ◽

pp. 301-315 ◽

Cited By ~ 6

Author(s):

Wesley G. Page ◽

Natalie S. Wagenbrenner ◽

Bret W. Butler ◽

Jason M. Forthofer ◽

Chris Gibson

Keyword(s):

United States ◽

Wind Speed ◽

Relative Humidity ◽

Air Temperature ◽

Wildland Fire ◽

Fire Behavior ◽

The United States ◽

Mean Bias Error ◽

Bias Error ◽

Behavior Prediction

Abstract Wildland fire managers in the United States currently utilize the gridded forecasts from the National Digital Forecast Database (NDFD) to make fire behavior predictions across complex landscapes during large wildfires. However, little is known about the NDFDs performance in remote locations with complex topography for weather variables important for fire behavior prediction, including air temperature, relative humidity, and wind speed. In this study NDFD forecasts for calendar year 2015 were evaluated in fire-prone locations across the conterminous United States during periods with the potential for active fire spread using the model performance statistics of root-mean-square error (RMSE), mean fractional bias (MFB), and mean bias error (MBE). Results indicated that NDFD forecasts of air temperature and relative humidity performed well with RMSEs of about 2°C and 10%–11%, respectively. However, wind speed was increasingly underpredicted when observed wind speeds exceeded about 4 m s−1, with MFB and MBE values of approximately −15% and −0.5 m s−1, respectively. The importance of accurate wind speed forecasts in terms of fire behavior prediction was confirmed, and the forecast accuracies needed to achieve “good” surface head fire rate-of-spread predictions were estimated as ±20%–30% of the observed wind speed. Weather station location, the specific forecast office, and terrain complexity had the largest impacts on wind speed forecast error, although the relatively low variance explained by the model (~37%) suggests that other variables are likely to be important. Based on these results it is suggested that wildland fire managers should use caution when utilizing the NDFD wind speed forecasts if high wind speed events are anticipated.

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Experimental fuel treatment impacts on forest structure, potential fire behavior, and predicted tree mortality in a California mixed conifer forest

Forest Ecology and Management ◽

10.1016/j.foreco.2005.03.070 ◽

2005 ◽

Vol 215 (1-3) ◽

pp. 21-36 ◽

Cited By ~ 203

Author(s):

Scott L. Stephens ◽

Jason J. Moghaddas

Keyword(s):

Forest Structure ◽

Tree Mortality ◽

Fire Behavior ◽

Conifer Forest ◽

Mixed Conifer ◽

Fuel Treatment ◽

Mixed Conifer Forest

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A Review of Community Smoke Exposure from Wildfire Compared to Prescribed Fire in the United States

10.20944/preprints201803.0262.v1 ◽

2018 ◽

Author(s):

Kathleen M. Navarro ◽

Don Schweizer ◽

John R. Balmes ◽

Ricardo Cisneros

Keyword(s):

United States ◽

Particulate Matter ◽

Land Management ◽

Prescribed Fire ◽

Wildland Fire ◽

The United States ◽

Smoke Exposure ◽

Management Tool ◽

Wildfire Smoke ◽

Scientific Papers

Prescribed fire, intentionally ignited low-intensity fires, and managed wildfires, wildfires that are allowed to burn for land management benefit, could be used as a land management tool to create forests that are resilient to wildland fire. This could lead to fewer large catastrophic wildfires in the future. However, we must consider the public health impacts of the smoke that is emitted from wildland and prescribed fire. The objective of this synthesis is to examine the differences in ambient community-level exposures to particulate matter (PM2.5) from smoke in the United States from two smoke exposure scenarios – wildfire fire and prescribed fire. A systematic search was conducted to identify scientific papers to be included in this review. Web of Science Core Collection and PubMed for scientific papers, and Google Scholar were used to identify any grey literature or reports to be included in this review. Sixteen studies that examined particulate matter exposure from smoke were identified for this synthesis – nine wildland fire studies and seven prescribed fire studies. PM2.5 concentrations from wildfire smoke were found to be significantly lower than reported PM2.5 concentrations from prescribed fire smoke. Wildfire studies focused on assessing air quality impacts to communities that were nearby fires and urban centers that were far from wildfires. However, the prescribed fire studies used air monitoring methods that focused on characterizing exposures and emissions directly from and next to the burns. This review highlights a need for a better understanding of wildfire smoke impact over the landscape. It is essential for properly assessing population exposure to smoke from different fire types.

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Local forest structure variability increases resilience to wildfire in dry western U.S. coniferous forests

10.32942/osf.io/k72ye ◽

2019 ◽

Cited By ~ 1

Author(s):

Michael J Koontz ◽

Malcolm P. North ◽

Chhaya M. Werner ◽

Stephen E. Fick ◽

Andrew M. Latimer

Keyword(s):

Sierra Nevada ◽

Forest Structure ◽

Tree Mortality ◽

Forest Ecosystems ◽

Fire Suppression ◽

Fire Severity ◽

Fire Behavior ◽

Dry Forest ◽

Structural Variability ◽

Overstory Trees

A “resilient” forest endures disturbance and is likely to persist. Resilience to wildfire may arise from feedback between fire behavior and forest structure in dry forest systems. Frequent fire creates fine-scale variability in forest structure, which may then interrupt fuel continuity and prevent future fires from killing overstory trees. Testing the generality and scale of this phenomenon is challenging for vast, long-lived forest ecosystems. We quantify forest structural variability and fire severity across >30 years and >1,000 wildfires in California’s Sierra Nevada. We find that greater variability in forest structure increases resilience by reducing rates of fire-induced tree mortality and that the scale of this effect is local, manifesting at the smallest spatial extent of forest structure tested (90 x 90m). Resilience of these forests is likely compromised by structural homogenization from a century of fire suppression, but could be restored with management that increases forest structural variability.

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Mastication and Prescribed Fire Influences on Tree Mortality and Predicted Fire Behavior in Ponderosa Pine

Western Journal of Applied Forestry ◽

10.1093/wjaf/27.1.36 ◽

2012 ◽

Vol 27 (1) ◽

pp. 36-41 ◽

Cited By ~ 4

Author(s):

Alicia L. Reiner ◽

Nicole M. Vaillant ◽

Scott N. Dailey

Keyword(s):

Pinus Ponderosa ◽

Prescribed Fire ◽

Ponderosa Pine ◽

Tree Mortality ◽

Block Design ◽

Fire Behavior ◽

Mortality Data ◽

Before And After ◽

Random Block Design ◽

Four Blocks

Abstract The purpose of this study was to provide land managers with information on potential wildfire behavior and tree mortality associated with mastication and masticated/fire treatments in a plantation. Additionally, the effect of pulling fuels away from tree boles before applying fire treatment was studied in relation to tree mortality. Fuel characteristics and tree mortality data were gathered before and after treatments in a 25-year-old ponderosa pine (Pinus ponderosa C. Lawson) plantation. A random block design was used with three treatments plus a control at each of four blocks. Four plots were established as subsamples within each of the treatment and control sections of each block. Potential wildfire behavior for posttreatment fuel conditions was modeled for 90th and 97th percentile fire weather. Predicted rates of spread and flame lengths were higher for fuel conditions resulting from the mastication treatments than for the masticated/fire treatments or the controls. Torching and crowning indices indicated that higher windspeeds would be necessary to promote torching for areas treated with mastication/fire than for mastication or the controls. Tree mortality was 32 and 17% the first year after burning in masticated/fire and masticated/pull-back/fire plots, respectively, and 49 and 27% the second year. Our potential wildfire behavior results indicate that the risk of crown fire can be somewhat reduced by mastication and further reduced if mastication is followed up with prescribed fire to consume surface fuels. However, moderate levels of tree mortality seem inevitable when burning masticated fuels in a plantation and may only marginally be reduced by pulling fuels away from tree boles, which increases treatment costs.

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