Research Database
Displaying 121 - 140 of 163
Mathematical model and sensor development for measuring energy transfer from wildland fires
Year: 2014
Current practices for measuring high heat flux in scenarios such as wildland forest fires use expensive, thermopile-based sensors, coupled with mathematical models based on a semi-infinite-length scale. Although these sensors are acceptable for experimental testing in laboratories, high error rates or the need for water cooling limits their applications in field experiments. Therefore, a one-dimensional, finite-length scale, transient-heat conduction model was developed and combined with an inexpensive, thermocouple-based rectangular sensor, to create a rapidly deployable, non-cooled sensor…
Publication Type: Journal Article
Simulated western spruce budworm defoliation reduces torching and crowning potential: a sensitivity analysis using a physics-based fire model
Year: 2014
The widespread, native defoliator western spruce budworm (Choristoneura occidentalis Freeman) reduces canopy fuels, which might affect the potential for surface fires to torch (ignite the crowns of individual trees) or crown (spread between tree crowns). However, the effects of defoliation on fire behaviour are poorly understood. We used a physics-based fire model to examine the effects of defoliation and three aspects of how the phenomenon is represented in the model (the spatial distribution of defoliation within tree crowns, potential branchwood drying and model resolution). Our…
Publication Type: Journal Article
Modeling Regional-Scale Wildland Fire Emissions with the Wildland Fire Emissions Information System
Year: 2014
As carbon modeling tools become more comprehensive, spatialdata are needed to improve quantitative maps of carbon emissions from fire.The Wildland Fire Emissions Information System (WFEIS) provides mappedestimates of carbon emissions from historical forest fires in the United Statesthrough a web browser. WFEIS improves access to data and provides a consistentapproach to estimating emissions at landscape, regional, and continentalscales. The system taps into data and tools developed by the U.S. Forest Serviceto describe fuels, fuel loadings, and fuel consumption and merges informationfrom the…
Publication Type: Journal Article
Climate and very large wildland fires in the contiguous western USA
Year: 2014
Very large wildfires can cause significant economic and environmental damage, including destruction of homes, adverse air quality, firefighting costs and even loss of life. We examine how climate is associated with very large wildland fires (VLWFs ≥50 000 acres, or ~20 234 ha) in the western contiguous USA. We used composite records of climate and fire to investigate the spatial and temporal variability of VLWF–climatic relationships. Results showed quantifiable fire weather leading up and up to 3 weeks post VLWF discovery, thus providing predictors of the probability that VLWF occurrence in…
Publication Type: Journal Article
State of Fire
Year: 2014
Describing the 2013 summer fire season, the Oregon Department of Forestry called it “epic.” On those lands protected by the state, it was the costliest ever, and the first time in over 60 years that more than 100,000 acres burned. Oregon’s forests are changing. The management objectives and priorities of federal and private landowners are evolving. Drought has afflicted parts of the state, and climate trends are making fire seasons longer and more intense. And in the wildland-urban interface, more homes have been built in the path of wildfire. The ways Oregonians prevent, fight, manage and,…
Publication Type: Report
Examining fire-prone forest landscapes as coupled human and natural systems
Year: 2014
Fire-prone landscapes are not well studied as coupled human and natural systems (CHANS) and present many challengesfor understanding and promoting adaptive behaviors and institutions. Here, we explore how heterogeneity, feedbacks, and externaldrivers in this type of natural hazard system can lead to complexity and can limit the development of more adaptive approaches topolicy and management. Institutions and social networks can counter these limitations and promote adaptation. We also develop aconceptual model that includes a robust characterization of social subsystems for a fire-prone…
Publication Type: Journal Article
Mapping the daily progression of large wildland fires using MODIS active fire data
Year: 2014
High temporal resolution information on burnt area is needed to improve fire behaviour and emissions models. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly and active fire product (MO(Y)D14) as input to a kriging interpolation to derive continuous maps of the timing of burnt area for 16 large wildland fires. For each fire, parameters for the kriging model were defined using variogram analysis. The optimal number of observations used to estimate a pixel’s time of burning varied between four and six among the fires studied. The median standard error from…
Publication Type: Journal Article
The Ecology and Management of Moist Mixed-Conifer Forests in Eastern Oregon and Washington: a Synthesis of the Relevant Biophysical Science and Implications for Future Land Management
Year: 2014
Land managers in the Pacific Northwest have reported a need for updated scientific information on the ecology and management of mixed-conifer forests east of the Cascade Range in Oregon and Washington. Of particular concern are the moist mixed-conifer forests, which have become drought-stressed and vulnerable to high-severity fire after decades of human disturbances and climate warming. This synthesis responds to this need. We present a compilation of existing research across multiple natural resource issues, including disturbance regimes, the legacy effects of past management actions,…
Publication Type: Report
The Effectiveness and Limitations of Fuel Modeling Using the Fire and Fuels Extension to the Forest Vegetation Simulator
Year: 2014
Fuel treatment effectiveness is often evaluated with fire behavior modeling systems that use fuel models to generate fire behavior outputs. How surface fuels are assigned,either using one of the 53 stylized fuel models or developing custom fuel models, can affect predicted fire behavior. We collected surface and canopy fuels data beforeand 1, 2, 5, and 8 years after prescribed fire treatments across 10 national forests in California. Two new methods of assigning fuel models within the Fire and FuelsExtension to the Forest Vegetation Simulator were evaluated. Field-based values for dead and…
Publication Type: Journal Article
Challenges of assessing fire and burn severity using field measures, remote sensing and modelling
Year: 2014
Comprehensive assessment of ecological change after fires have burned forests and rangelands is important if we are to understand, predict and measure fire effects. We highlight the challenges in effective assessment of fire and burn severity in the field and using both remote sensing and simulation models. We draw on diverse recent research for guidance on assessing fire effects on vegetation and soil using field methods, remote sensing and models. We suggest that instead of collapsing many diverse, complex and interacting fire effects into a single severity index, the effects of fire should…
Publication Type: Journal Article
Wildland fire emissions, carbon, and climate: Modeling fuel consumption
Year: 2014
Fuel consumption specifies the amount of vegetative biomass consumed during wildland fire. It is a two-stage process of pyrolysis and combustion that occurs simultaneously and at different rates depending on the characteristics and condition of the fuel, weather, topography, and in the case of prescribed fire, ignition rate and pattern. Fuel consumption is the basic process that leads to heat absorbing emissions called greenhouse gas and other aerosol emissions that can impact atmospheric and ecosystem processes, carbon stocks, and land surface reflectance. It is a critical requirement for…
Publication Type: Journal Article
Examination of the wind speed limit function in the Rothermel surface fire spread model
Year: 2013
The Rothermel surface fire spread model includes a wind speed limit, above which predicted rate of spread is constant. Complete derivation of the wind limit as a function of reaction intensity is given, along with an alternate result based on a changed assumption. Evidence indicates that both the original and the revised wind limits are too restrictive. Wind limit is based in part on data collected on the 7 February 1967 Tasmanian grassland fires. A reanalysis of the data indicates that these fires might not have been spreading in fully cured continuous grasslands, as assumed. In addition,…
Publication Type: Journal Article
Modelling conditional burn probability patterns for large wildland fires
Year: 2013
We present a technique for modelling conditional burn probability patterns in two dimensions for large wildland fires. The intended use for the model is strategic program planning when information about future fire weather and event durations is unavailable and estimates of the average probabilistic shape and extent of large fires on a landscape are needed. To model average conditional burn probability patterns, we organised historical fire data from Yellowstone National Park, USA, into a set of grids; one grid per fire. We captured various spatial relationships inherent in the gridded data…
Publication Type: Journal Article
Assessing forest vegetation and fire simulation model performance after the Cold Springs wildfire, Washington, USA
Year: 2013
Given that resource managers rely on computer simulation models when it is difficult or expensive to obtain vital information directly, it is important to evaluate how well a particular model satisfies applications for which it is designed. The Forest Vegetation Simulator (FVS) is used widely for forest management in the US, and its scope and complexity continue to increase. This paper focuses on the accuracy of estimates made by the Fire and Fuels Extension (FFE-FVS) predictions through comparisons between model outputs and measured post-fire conditions for the Cold Springs wildfire and on…
Publication Type: Journal Article
Crown fire behavior characteristics and prediction in conifer forests: a state-of-knowledge synthesis
Year: 2013
Joint Fire Science Program (JFSP) project 09-S-03-1 was undertaken in response to JFSP Project Announcement No. FA-RFA09-0002 with respect to a synthesis on extreme fire behavior or more specifically a review and analysis of the literature dealing with certain features of crown fire behavior in conifer forests in the United States and adjacent regions of Canada. The key findings presented are organized along nine topical areas: types of crown fires; crown fire initiation; crown fire propagation; crown fire rate of spread; crown fire intensity and flame zone characteristics; crown fire area…
Publication Type: Report
ArcFuels10 System Overview
Year: 2013
Fire behavior modeling and geospatial analyses can provide tremendous insight for land managers as they grapple with the complex problems frequently encountered in wildfire risk assessments and fire and fuels management planning. Fuel management often is a particularly complicated process in which the benefits and potential impacts of fuel treatments need to be demonstrated in the context of land management goals and public expectations. The fuel treatment planning process is complicated by the lack of data assimilation among fire behavior models and weak linkages to geographic information…
Publication Type: Report
Social Science at the WUI: A Compendium of Research Results to Create Fire-Adapted Communities
Year: 2013
Over the past decade, a growing body of research has been conducted on the human dimensions of wildland fire. Building on a relatively small number of foundational studies, this research now addresses a wide range of topics including mitigation activities on private lands, fuels reduction treatments on public land, community impacts and resident behaviors during fire, acceptance of approaches to postfire restoration and recovery, and fire management policy and decisionmaking. As this research has matured, there has been a recognition of the need to examine the full body of resulting…
Publication Type: Report
Assessing potential climate change effects on vegetation using a linked model approach
Year: 2013
We developed a process that links the mechanistic power of dynamic global vegetation models with the detailed vegetation dynamics of state-and-transition models to project local vegetation shifts driven by projected climate change. We applied our approach to central Oregon (USA) ecosystems using three climate change scenarios to assess potential future changes in species composition and community structure. Our results suggest that: (1) legacy effects incorporated in state-and-transition models realistically dampen climate change effects on vegetation; (2) species-specific response to fire…
Publication Type: Journal Article
Current status and future needs of the BehavePlus fire modeling system
Year: 2013
The BehavePlus Fire Modeling System is among the most widely used systems for wildland fire prediction. It is designed for use in a range of tasks including wildfire behaviour prediction, prescribed fire planning, fire investigation, fuel hazard assessment, fire model understanding, communication and research. BehavePlus is based on mathematical models for fire behaviour, fire effects and fire environment. It is a point system for which conditions are constant for each calculation, but is designed to encourage examination of the effect of a range of conditions through tables and graphs.…
Publication Type: Journal Article