FIRE 323 Final

What fuels contribute to ground fire?

duff, peat, litter, organic soil horizon

What are the two limiting factors that result in smoldering combustion and inhibit flaming combustion?

1) Lack of sufficient oxygen

2) Lack of sufficient generation of gaseous vapors from pyrolysis.

What fire behavior model is best used to predict the rate of spread of a ground fire?

Operational models of ground fire do not exist

List and briefly explain at least three reasons it is important to understand ground fire behavior.

It occurs on all fires, it is the primary fire type in some ecosystems (boreal forests), it has distinct fire behavior and drivers, smoldering and ground fire represent a large component of fuel consumption

Briefly describe three drivers that contribute to smoldering ignition and combustion

fuel moisture, bulk density, fuelbed depth, mineral content, lignin content, and vectors

What time-lag class would you characterize duff based on its ability to gain and lose moisture?

1-hr

Briefly describe the difference between first-order and second-order fire effects, provide at least two examples of each.

First order fire effects occur within the first year following fire: fuel consumption, smoke production, carbon change, soil heating, post fire- tree mortality, vegetation change

Second order fire effects are delayed changes following fie: flooding, erosion, delayed tree mortality, vegetation recovery, seedling regeneration, wildlife and habitat change, longer term carbon storage.

Provide three reasons it is important to predict or monitor fuel consumption.

it directly informs smoke production, carbon cycling, relates to wildlife habitat, informs soil stability.

List the five different fuel characteristics and their units of measure that can influence fuel consumption.

chemistry (moisture composition), geometry (size/shape), quantity (loading), density (particle & fuelbed packing ratio), continuity (vertical and horizontal arrangement)

What are the two main factors that are used to predict fine fuel consumption using FOFEM?

Pre-fire total fuel load, moisture content

Which of the following scenarios would result in greater consumption during a fire burning under the same conditions/intensity?

1. A large diameter (20 in) sound log with low moisture content

2. A large diameter (20 in) sound log with high moisture content

3. A large diameter (20 in) rotten log with high moisture content

4. A large diameter (20 in) rotten log with low moisture content

A large diameter (20 in) rotten log with low moisture content

Briefly describe three benefits and three drawbacks of smoke to ecosystems.

Benefits: Smoke/char are known to increase germination rates of some plant species, smoke can serve as a cue to animals to seek refuge; smoke inversions can reduce fire behavior, water temperature, and evapotranspiration of vegetation; decrease fungal or insect pests; nutrient cycling, dispersal of microorganisms.

Negative effects: impacts on human health; nitrous oxides and sulfur dioxides impacts water quality; particulate matter and black carbon impact snow and glacial melt; contributes to greenhouse gases and global warming; impacts agricultural crops; smoke damage to property; decreased visibility.

Explain three long-term impacts of smoke on human health and well-being

mortality, reduced lung function, short children, morbidity, mental health issues.

Describe what modified combustion efficiency represents in reference to smoke productions.

proportion of combustion that is flaming. As MCE increases, CO2 increases and PM 2.5, CO, and SO2 decrease.

Calculate the estimated amount of CO₂ production (kg/ha) that results from a wildfire if you have predicted 10 Mg/ha of fuel consumption and the emissions factor for flaming and smoldering combined is 1500 kg/Mg

Provide the two aspects of smoke that are commonly modeled

distance and direction

Provide two examples of smoke models that can be used to predict smoke.

FOFEM, Bluesky Playground

Briefly describe an example of how fire damage to trees can result from each of the three heat transfer mechanisms.

convection- bole damage, needle death and bud kill

conduction- root damage

radiation- can cause pyrolysis of trees trunks and foliage

Provide the two main inputs/measurements that are required to predict tree mortality for a given species using a FOFEM type model.

bark thickness and dbh

what are the factors that can influence tree mortality that are not considered by existing models?

delayed mortality in the years following fire and reduced growth rates prior to fire due to competition or climate.

Describe a known example (i.e. results of a study) of an interaction between fire and drought and its impacts on post-fire tree mortality.

• Between 1984 and 2016,  a study involving over 66,00 trees across the western U.S. found that drought conditions before a fire increase post-fire tree mortality.

•  Trees that were drought stressed before the fire were more likely to die after the fire occurred than those that were not drought-stressed.

Based on a study of redwood forests, list and explain the three stand characteristics that were found to influence tree mortality following wildfire.

1) Canopy Damage Height: Fires that cause taller scorch/consumption within the tree crown are associated with higher tree death rates.

2) Basal Area (Stand Density): RW basal area has a negative relationship with stem mortality. Denser stands may experience lower levels of fire-induced mortality.

3) Sudden Oak Death (SOD) Infection Stage: RW trees in the late stage of infection showed higher predicted mortality probability than trees that were in the early stage or were not infected.

Explain at least three characteristics of a species that can influence post-fire regeneration.

mode of reproduction (serotiny and seed viability), tree size (bigger trees produce more seeds), seed mass (larger seeds survive better), seed dispersal (seeds with larger wings can disperse further)

Draw or clearly describe the commonly observed pattern of post-fire regeneration density with distance from a living edge of a forests of non-serotinous tree species.

 Post-fire seedling regeneration density rapidly decreases with increasing distance from a living edge of a forest. Tree regeneration density is highest close to the edge of burned areas where mature trees survived.

Explain some commonly observed patterns of how post-fire regeneration density in non-serotinous species changes with fire severity (low, moderate, and high).

Regen density is low at both LOW fire severity & HIGH fire severity.

Regen is higher at moderate fire severity.

Based on a model of post-fire conifer regeneration developed based on observations following numerous wildfires in California (Shive et al. 2018), provide the top three factors found to influence the probability of post-fire regeneration.

Precipitation, fire severity, aspect

Communicate at least two reasons understanding post-fire tree regeneration is needed.

1) Understanding post-fire regen is vital because it is essential for the long-term persistence of forest ecosystems.

2) Post-fire regen knowledge is important for developing strategic land management with applied understanding of how fire affects the landscape.

Which of the following statements is most correct for post-fire resprouting in redwood (but likely other species too)?

1. Increased fire damage results in decreased resprouting biomass

2. Increased fire damage results in increased resprouting biomass

3. As fire damage increases resprouting biomass increases at first and then decreases above some intermediate fire damage

Increased fire damage results in increased resprouting biomass

Describe the two main soil characteristics that influence soil heating during a fire

Soil Depth: the heating of soil declines rapidly with increased depth.

Soil Moisture: moisture content dampens heat transfer to soil, buffering temperatures

Explain how hydrophobicity changes with fire intensity and describe the potential impacts of hydrophobic soils following a fire

Hydrophobicity is influenced by soil heating during fire. Fire intensity can influence the depth and severity of hydrophobic the layer becomes post-fire.

Provide at least three soil nutrients or minerals that can increase following fire.

ammonium and nitrate, soil pH

What is the most common change in soil pH following wildfire?

Usually increases

Briefly explain two reasons why the strict use of a lethal temperature thresholds (e.g. 60 degrees C for 1 sec) is a limiting approach.

1. Lethal temps vary widely across various organisms, and the lethality also varies with the duration of heating. 

2. The ignition process is dynamic 

Describe the impact of high severity fire on snowpack dynamics following wildfire.

More snow is able to accumulate because of the lack of interception, earlier peak snowpack. Snow melts more rapidly (more direct sun exposure).

Explain two potential benefits and two potential drawbacks of fire to aquatic ecosystems.

Benefits

1) provides large complex wood structures that provide habitat

2) smoke cover can decrease temperatures in rivers and streams

Drawbacks

1) increase sedimentation

2) decrease dissolved oxygen concentration (leading to fish kills)

Provide two examples of how fire can negatively influence the physical and mental well-being of humans

Death and PTSD

Provide two examples of how fire can positively influence the physical and mental well-being of humans.

Soliphilia, connection to culture

Define what the terms solastalgia an soliphilia mean in reference to the presence or absence of fire to humans/communities.

Soliphilia- the love or responsibility a person feels for a particular place/home (perhaps while taking care of it with a prescribed or cultural burn)

Solastalgia- emotional distress due to changes in a particular place (home) while still being present in that particular location (perhaps because it burned down)

Describe the potential impacts of fire on cultural, economic, or other aspects of human communities.

Cultural - fire can have negative impacts on cultural resources, practices and places but it is also a essential way to maintain cultural practices

Economic- Fire can cause the loss of homes and structures, displacement of residents, disruption or loss of local economy and businesses, loss or reduction of resources. Good fire can be restorative to local resources and protect the local economy.

What are the three unique measures of landscape fire behavior?

1. Fire size and shape

2. minimum travel time

3. spotting distance

List and briefly describe three of the landscape fire behavior models and decision support tools commonly used by managers.

WFDSS- Wildland Fire Decision Support System. Uses landscape fire models to support decision making on emergency incidents.

IFTDSS - Interagency Fuel Treatment Decision Support System. Uses landscape fire modeling to assess fuel treatment effectiveness

FARSITE- maps of potential fire growth, perimeter and behavior

Create a chart that communicates how the different landscape fuel models are used to estimate fire behavior across the numbers of fires and weather scenarios.

1 weather scenario and 1 fire - FARSITE

1 weather scenario and all fires - FSPro

All weather and 1 fire - FlamMap

All weather and All fire - FPA

List at least five of the data layers needed from LANDFIRE to model landscape fire behavior.

1. Topography

2. Fuels data 

3. Vegetation

4. Fire History

5. Fire Departure Into

Provide the six recommendations from FBAN/Fire planner, Eamon Engber, when modeling landscape fire behavior on a wildfire incident.

1. Use the right tool for management question

2. Get the landscape right

3. calibrate and re-calibrate

4. make clear your assumptions

5. observe the fire

6. be student of fire behavior

List and briefly describe the two types of next generation fire behavior models.

FIRETEC- 3D time sensitive modeling, sub-meter resolution, computationally intensive

QUIC-FIRE- Fire simulation tool that considers fire-fuel-small scale atmospheric conditions

Select all of the following that are considered physics-based fire models

1. FIRETEC

2. FLAMEMap

3. WFDSS

4. WFDS

5. IFTDSS

FIRETEC and WFDS

Explain two advantages and two disadvantages of next generation fire behavior models compared to the Rothermel fire behavior model at this time.

Advantages- incorporates physics, fire-fire and fire-atmosphere interaction, accurate

Disadvantages- too time consuming to use in active wildfire scenario, training-intensive, not widely available

Provide two specific impacts of tree spatial patterns on fire behavior and effects based on simulations generated from computational fluid dynamics models.

Forests with aggregated fuel patterns experience increased variability in fire behavior. Forest with less cover had lower fire behavior and higher wind speeds

What is QUIC-FIRE and what is a current use of this model?

It is a fire simulation tool that considers fire-fuel-small-scale atmospheric conditions interactions. It can rapidly assess fire behavior at a landscape level. Currently being used in the Southeast for prescribed burn planning

Provide a definition for a two-way fire-atmosphere model and give the name of one that is in common current use.

Coupled models that predict both fire behavior and weather conditions. A common one is WRF-SFIRE

Based on previous research/case studies, provide a major finding that describes the potential utility of a fire-atmosphere model.

WRF-SFIRE has the potential to pyroconvective activity

Describe the two types of wildland urban interface. Which one of these tends to result in a higher loss of structures, based on existing research?

Interface- area with abrupt transition/border between structures/homes and wildland/vegetation

Intermix- area where structures/homes are intermixed with wildland vegetation

Communicate a concerning trend of wildland urban interface development in the United States and provide a couple of reasons this trend is concerning.

Human ignitions are associated with proximity to the WUI. These human ignited fires are associated with increa

Provide four known home-hardening related characteristics that are known to reduce structure loss during a wildfire.

Dual-paned windows, enclosed eaves, vent screens, defensible space, tile roof, stucco walls

What are two of the potential benefits of treating the broader landscape within and around the wildland urban interface?

Reduction in exposure and predicted loss

In some studies conducted in California, there was not a clear benefit of defensible space, provide two reasons that defensible space (clearing of vegetation around a structure) may not be sufficient to reduce the probability of structure loss during a wildfire

Many structures are ignited through embers even if there is not vegetation within 5 feet of your home it can still catch on fire. If your neighbor does not have defensible space your home is at risk

Describe three known trends in wildfires that are partially attributed to increasing temperatures associated with human-caused climate change.

increased nighttime fire intensity, increased burned area overtime since 1990, increased number of large fires in western US.

Provide three factors that are potentially contributing to climate-change related increases in wildfire activity within the western US.

fire exclusion, longer lightning residence time, poorer nighttime recovery of fuel moisture

Most area burned in California forests is attributed to what percentile fire size classes?

99^th percentile

Most of the area burned in recent large wildfires is burning at what severity level?

High severity