Research Database
Displaying 1 - 7 of 7
Fire and non-native grass invasion interact to suppress tree regeneration in temperate deciduous forests
Year: 2015
While many ecosystems depend on fire to maintain biodiversity, non-native plant invasions can enhance fire intensity, suppressing native species and generating a fire–invasion feedback. These dynamics have been observed in arid and semi-arid ecosystems, but fire–invasion interactions in temperate deciduous forests, where prescribed fires are often used as management tools to enhance native diversity, have rarely been investigated. Here we evaluated the effects of a widespread invasive grass on fire behaviour in eastern deciduous forests in the USA and the potential effects of fire and…
Publication Type: Journal Article
A Wildfire-relevant climatology of the convective environment of the United States
Year: 2015
Convective instability can influence the behaviour of large wildfires. Because wildfires modify the temperature and moisture of air in their plumes, instability calculations using ambient conditions may not accurately represent convective potential for some fire plumes. This study used the North American Regional Reanalysis to develop a climatology of the convective environment specifically tied to large fire events. The climatology is based on the period 1979–2009 and includes ambient convective available potential energy (CAPE) as well as values when surface air is warmed by 0.5, 1.0 or 2.0…
Publication Type: Journal Article
Experimental analysis of fire spread across a two-dimensional ridge under wind conditions
Year: 2015
Results from a laboratory-scale investigation of a fire spreading on the windward face of a triangular-section hill of variable shape with wind perpendicular to the ridgeline are reported. They confirm previous observations that the fire enlarges its lateral spread after reaching the ridgeline, entering the leeward face with a much wider front. Reference fire spread velocities were measured and analysed, putting in evidence the importance of the dynamic effect due to flow velocity and its associated horizontal-axis separation vortex strength without dependence on hill geometry. Similar…
Publication Type: Journal Article
Winter grazing can reduce wildfire size, intensity and behaviour in a shrub-grassland
Year: 2015
An increase in mega-fires and wildfires is a global issue that is expected to become worse with climate change. Fuel treatments are often recommended to moderate behaviour and decrease severity of wildfires; however, the extensive nature of rangelands limits the use of many treatments. Dormant-season grazing has been suggested as a rangeland fuel treatment, but its effects on fire characteristics are generally unknown. We investigated the influence of dormant-season (winter) grazing by cattle (Bos taurus) on fuel characteristics, fire behaviour and area burned in Wyoming big sagebrush (…
Publication Type: Journal Article
Evaluating crown fire rate of spread predictions from physics-based models
Year: 2015
Modeling the behavior of crown fires is challenging due to the complex set of coupled processes that drive the characteristics of a spreading wildfire and the large range of spatial and temporal scales over which these processes occur. Detailed physics-based modeling approaches such as FIRETEC and the Wildland Urban Interface Fire Dynamics Simulator (WFDS) simulate fire behavior using computational fluid dynamics based methods to numerically solve the three-dimensional, time dependent, model equations that govern, to some approximation, the component physical processes and their interactions…
Publication Type: Journal Article
The Fire Weather Accuracy and Lightning Ignition Probability System
Year: 2015
Weather forecasts can help identify environmental conditions conducive to prescribed burning or to increased fire danger. These conditions are important components of fire management tools such as fire ignition potential maps, fire danger rating systems, fire behavior predictions, and smoke dispersion modeling. Fire managers use these tools to make decisions on when to conduct prescribed burns, how to manage wildfires, and how to pre-position fire suppression forces. Forecast weather conditions provide variables such as temperature, relative humidity, solar radiation, precipitation (or lack…
Publication Type: Report
The Potential Impact of Regional Climate Change on Fire Weather in the United States
Year: 2015
Climate change is expected to alter the frequency and severity of atmospheric conditions conducive for wildfires. In this study, we assess potential changes in fire weather conditions for the contiguous United States using the Haines Index (HI), a fire weather index that has been employed operationally to detect atmospheric conditions favorable for large and erratic fire behavior. The index summarizes lower atmosphere stability and dryness into an integer value with higher values indicting more fire-prone conditions. We use simulations produced by the North American Regional Climate Change…
Publication Type: Journal Article