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NRM 415 Exam One
| Question | Answer |
|---|---|
| wildfire | a type of fire that is wildland, unplanned, may be unwanted |
| prescribed fire | a type of fire that is intentional and planned |
| mineralization | a process where nutrients are converted from organic to inorganic (plant available) forms |
| fire | chemical combustion reaction producing heat and light |
| what is the fire triangle composed of | oxygen, heat, fuel |
| endothermic | absorption of heat into biomass |
| exothermic | release energy from burning biomass into surroundings |
| pyrolysis | breakdown by fire |
| driver | amount of gases and volatile compounds produced by pyrolysis |
| what are the two types of combustion | flaming and glowing/smoldering |
| what does white smoke indicate | products of mainly dehydration; water vapor and volatile compounds |
| what does dark smoke indicate | products of mainly complete combustion; burned carbon particulates and soot |
| heat transfer | when heat energy moves to and through unburned fuel, preheating it prior to ignition and facilitating fire |
| convection | movement/transfer of (heat) energy through molecules and gases |
| advection | movement of fire horizontally, often lateral due to wind or slope |
| indraft | vacuum created for a short time in a fire |
| radiation | the movement of energy (heat) in space |
| conduction | movement of energy via contact (objects or elements in an object) |
| fire perimeter | entire outer edge/extent of fire |
| head | front, main direction of the fire |
| flank | side roughly parallel to the main direction of spread |
| rear (heel) | tail, opposite of main direction of spread/wind |
| finger | narrow (often long) extensions from the main fire body |
| flaming front | the highly intensive continuous combustion |
| flame length | length of the propagating fire front; from middle of fire base to the tallest tip of flame measured on a diagonal |
| fire break | any activity that disrupts the fuel (mineral soil) |
| fireline | burn everything to blackness |
| flame height | average vertical height of flame (base to tallest tip) |
| canopy/crown base height (CBH) | lowest height above ground at which there is a sufficient aerial fuel to propagate fire vertically into the canopy |
| rate of spread (ROS) | relative activity of fire extending its horizontal dimensions (perimeter) |
| heading fire | fire that moves along with the wind direction |
| backing fire | fire that moves against the wind direction |
| flanking fire | a fire that moves perpendicular (-ish) to the wind direction or slightly parallel |
| smoldering fire | a fire that typically burns without flame and with a very slow spread |
| creeping fire | burns with low flame and slow spread, jumps due to disconnected fuel |
| spotting | fire produces embers moved by wind that facilitate ignition beyond the main fire |
| torching | flames climb up through foliage of single/group of trees |
| residence time | time it takes the flaming front to pass over fuel at a specific location |
| fire duration | the total length of time that combustion occurs in an area |
| fire frequency | number of times fire occurs within the same area in a given time period |
| fire return interval (FRI) | duration between successive fires within the same area |
| fire intensity | energy released per unit length of the fire front per unit of time |
| fire severity | impact of fire on the components of the area burned |
| low fire severity | ground fire. herbaceous plants and some shrubs killed. some charring of tree stems to about 20% of tree height. less than 25% of trees killed |
| moderate severity | ground fire and burning lower tree limbs, herbaceous plants, and some shrubs killed. stem charring to about 70% of tree height. between 25-75% of trees killed |
| high severity | ground and canopy fire. all shrubs and herbaceous plants killed. more than 75% of stem height charred. more than 75% of trees killed |
| mixed severity | caused by spatial variations in landscape structure, vegetation patterns, fuel condition, and weather |
| "fire seasonality" | period of time that fire typically occurs in a given ecosystem type |
| ground fire | burns organic matter below the litter layer (peat, duff, dead moss, lichen) |
| surface fire | burns at or just above ground surface |
| crown fire | fire advances independently between crowns |
| stand replacement fire | (description of what a fire did, could be any of the three) significant changes in regular structure and physical environment. this fire type is lethal to all vegetation |
| what are the two types of regime classification | fire regime groups and regime condition class |
| fire regime groups | discrete categories that characterize the historical fire characteristics of a given ecosystem/landscape. based on natural, unaltered conditions |
| regime condition class | categories that describe the degree of departure from historical fire characteristics. based on the effect of departure on ecosystem characteristics |
| wildland | non-human-developed areas |
| what can wildland fires be | wildfire or prescribed fires |
| causes of wildfires | lightning, humans, escaped prescribed fires |
| benefits of fire | enhance natural regeneration of plants, nutrient release, reduce fuel buildup/accumulation, thin overcrowded/dense forests, increase floral and faunal diversity, help wildlife, and control invasives |
| characteristics of fire | rapid, oxidative, endothermic, and exothermic |
| combustion process reactions and phases | reactions: endothermic, exothermic. phases: preignition, ignition, and combustion |
| preignition phase | biomass is heated to ignition temperature. the goal is to dehydrate the fuel and raise the temperature to ignition. it is endothermic (making things "mushy mushy") |
| products of preignition | combustible gases (like methane, toluene, and xylene), volatile organic compounds (like oils and wax extractives), and char or tar |
| ignition phase | the temperature threshold for fire, indicates self-sustained heat production and external heat input ends with pyrolysis sustains |
| why might fuel not ignite? | due to inadequate heat supply and/or inadequate duration of heat supply |
| combustion phase | rapid high temperature oxidation of chemical energy in biomass (now actually breaking bonds) |
| what is the driver of combustion? | the amount of gases and volatile compounds produced by pyrolysis |
| what are the two types of combustion | flaming and glowing/smoldering |
| flaming combusiton | reactions of released vegetation compounds, oxygen, and heat. on and above the vegetation surface. results in sustained flames. continues until one side of the fire triangle breaks |
| glowing/smoldering combustion | surface oxidation, resulting in incomplete combustion of solid biomass. little to no visible flame, charring |
| why can incomplete combustion happen? | due to water vapor, gases/volatile organic compounds, and carbon particles releasing to form smoke (aka this is what smoke indicates) |
| methods of heat transfer | convection, radiation, and conduction |
| convection column | results from fast moving hot air moving upwards, carrying smoke and particles influenced by wind. |
| whirlwind fires | fires that are all over the place and crazily "organized" due to indraft. they are hard to control and can have convection columns in them |
| what units are used with rate of spread | chains per hour |
| what are factors that influence rate of spread? | fuel type, wind speed, steepness of slow, and changes in fire intensity |
| what are some potential negative impacts to soil based on smoldering fires? | longer heat exposure can cause soil organism death, change in soil properties (like aggregate structure, moisture content, and increase in Fe and Al oxides), nutrient loss and unavailable complexes of Ca and Mg, and organic matter decomposition |
| why is fire regime important? | shows the degree of departure from historical conditions and the application of fire as a management tool |
| what are characteristics used to describe a fire regime for a given ecosystem type | frequency, return interval, intensity, severity, size/extent, and seasonality |
Created by:
ethompson238
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