The Fire Behavior Triangle legs include fuel, weather, topography. The interaction of these three legs and their changes in space and time along with fire determine fire behavior and characteristics.
Fuel is extremely important to fire behavior. The fuel complex includes ground, surface, and crown fuels which all interact with environmental variables such as temperature and solar radiation. Relationships between fuel complexes on the terrain, size, and location are apart of the landscape level. Dead or live fuel, fuel moisture, size, composition, and location are aspects of fuel that interact with weather and topography.
Weather is one of the primary influences on fuel moisture depending on elevation and location. Weather differs with topography …show more content…
(2009). Introduction To Wildland Fire. New York.
2. Describe and discuss the horizontal and vertical propagation of fire in grassland, shrub land, and forest as influenced by environmental variables of soil moisture, temperature, wind, and relative humidity. Include rate of spread and fire intensity in your discussion. (This is a very involved question.) (50 points)
Horizontal and vertical arrangement is the orientation of fuel particles and the spaces between them. Grassland and shrub lands are vertically arranged fuel types, while timber litter and logging debris are horizontally oriented. Low soil moisture and relative humidity and high temperatures and wind will increase the probability of a fire in all of these ecosystems. High soil moisture and relative humidity and low temperatures and wind will decrease the probability of a fire in all these ecosystems.
Vertical arrangements can influence the components of the fuel complex; ground, surface, and crown fuel that are included in the fire. A change in fire behavior and a fuel ladder can help increase fire intensity and spread the fire from the surface fuel to the crown fuel. The horizontal arrangement of fuels can affect fire behavior and fire spread. Open areas with low fuels amounts need high winds to spread, while thick forests will generate high fire intensity and can allow crown fires and ground fires to continue …show more content…
Describe and discuss different ignition techniques for prescribed fires and explain how they function relative to head fires, backfires, and flank fires. Relate the preferred use of each type to the burn objectives and the environmental conditions. (25 points)
Ignition if manageable can bring more control over a fire in the presence of light fuels, wind, and slope. Depending on the pattern and timing of ignition the spread rate, fire intensity, and fire direction can be lessened, regulated, and reversed. Strip fires and spot fires are the most common ignition techniques.
Strip firing creates an ignition line that acts as a flaming front and may be a head or back fire. Igniting strip fires has the same effects of a line fire but has a faster rate of spread. The preferred fire is a back fire that has lower fireline intensities, slower rate of spread, and more complete combustion. Strips are often arranged in various patterns to create certain effect and for ease of control. There are many ways to arrange a strip fire for certain results. A flanking fire occurs when a strip fire is laid along the sides of a burning block or an advancing head. A chevron fire occurs when a flanking fire is parallel to the spread direction, or perpendicular to the fireline and is used when a lot of fire must be started against wind or down slopes. Multiple-strip firing is a practice of laying down a series of parallel strips and can increase the spread
Fuel is extremely important to fire behavior. The fuel complex includes ground, surface, and crown fuels which all interact with environmental variables such as temperature and solar radiation. Relationships between fuel complexes on the terrain, size, and location are apart of the landscape level. Dead or live fuel, fuel moisture, size, composition, and location are aspects of fuel that interact with weather and topography.
Weather is one of the primary influences on fuel moisture depending on elevation and location. Weather differs with topography …show more content…
(2009). Introduction To Wildland Fire. New York.
2. Describe and discuss the horizontal and vertical propagation of fire in grassland, shrub land, and forest as influenced by environmental variables of soil moisture, temperature, wind, and relative humidity. Include rate of spread and fire intensity in your discussion. (This is a very involved question.) (50 points)
Horizontal and vertical arrangement is the orientation of fuel particles and the spaces between them. Grassland and shrub lands are vertically arranged fuel types, while timber litter and logging debris are horizontally oriented. Low soil moisture and relative humidity and high temperatures and wind will increase the probability of a fire in all of these ecosystems. High soil moisture and relative humidity and low temperatures and wind will decrease the probability of a fire in all these ecosystems.
Vertical arrangements can influence the components of the fuel complex; ground, surface, and crown fuel that are included in the fire. A change in fire behavior and a fuel ladder can help increase fire intensity and spread the fire from the surface fuel to the crown fuel. The horizontal arrangement of fuels can affect fire behavior and fire spread. Open areas with low fuels amounts need high winds to spread, while thick forests will generate high fire intensity and can allow crown fires and ground fires to continue …show more content…
Describe and discuss different ignition techniques for prescribed fires and explain how they function relative to head fires, backfires, and flank fires. Relate the preferred use of each type to the burn objectives and the environmental conditions. (25 points)
Ignition if manageable can bring more control over a fire in the presence of light fuels, wind, and slope. Depending on the pattern and timing of ignition the spread rate, fire intensity, and fire direction can be lessened, regulated, and reversed. Strip fires and spot fires are the most common ignition techniques.
Strip firing creates an ignition line that acts as a flaming front and may be a head or back fire. Igniting strip fires has the same effects of a line fire but has a faster rate of spread. The preferred fire is a back fire that has lower fireline intensities, slower rate of spread, and more complete combustion. Strips are often arranged in various patterns to create certain effect and for ease of control. There are many ways to arrange a strip fire for certain results. A flanking fire occurs when a strip fire is laid along the sides of a burning block or an advancing head. A chevron fire occurs when a flanking fire is parallel to the spread direction, or perpendicular to the fireline and is used when a lot of fire must be started against wind or down slopes. Multiple-strip firing is a practice of laying down a series of parallel strips and can increase the spread