fire ecology notes ppt
TRANSCRIPT
Fire: Ecology, Behavior & Home
Agenda 11/2/16
• Wildfire Science– Definition of wildfire– Watch a couple of wildfire science videos– Fire Triangle– Fire Behavior Triangle– Learn about how fires spread
Fire is fire!
. . . Is it bad?
. . . Is it good?
. . . Who’s asking?
Fire is bad !
• Fire is good !
Ecological Effects of Fire Basic Premises
1. All ecosystems change over time2. Fire is neither innately good nor bad; it
is just an agent of change3. Human perception of whether it is good
or bad depends on resource objectives4. Do people think fire is good for wildlife?
WILDFIRE• Create a mental picture
• What does it look like?
• What does it sound like?
• What does it smell like?
• How would you define it?
Definition of Wildfire:
• An unplanned and uncontrolled fire spreading through vegetative fuels, at times involving structures.
Science of Wildfires• https://www.youtube.com/watch?v=F8OrmGAIqI4
Science of WildfireFIRE TRIANGLE
What is the source of :– Oxygen– Heat– Fuel
DEMO!
• Yep, time to examine the Fire Triangle.
Science of WildfireFIRE BEHAVIOR TRIANGLE– How does weather affect occurrence and spread of wildfire?– Which types of fuel feed a wildfire?– How can topography affect the occurrence and spread of wildfire?
Look at the factors• Weather
Look at the factors• Topography - Slope
Steep Slopes
Legend
Look at the factors• Fuel - Vegetation
Gap Data
Science of Wildfire- Types of Fuel
• Light Fuels• Heavy Fuels• Ladder Fuels• Fuel Breaks
Science of Wildfire• Fire Spread- Transference
of Heat– Conduction – Radiation => Surface fires– Convection => Crown fires
Fire Spread
Ember movement is the “wild card”
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High Intensity Crown Fire
https://www.youtube.com/watch?v=zvPa_yEEd4E
We have liftoff and ignition!
Agenda
• Update last set of notes (Fire spread)• History of fire policy in U.S. • Leading causes of fire in Oregon• Ecological Role of Fire
History of Fire in U.S.• 1800s- BIG forest fires began argument (among conservationists) that
fires threatened commercial timber supplies• 1891- U.S. Gov’t began setting aside national forest reservations• 1905- U.S. Forest Service established and given managerial control of
forest reservations• 1910- “Big Blowup”- 3 million acres burned in Montana, Idaho, and
Washington in only TWO days• “Big Blowup” greatly affected national conversation about fire policy
=> thought that total fire suppression would prevent big blowup again.
• 1920-1938- policies developed to – 1. Prevent Fires and – 2. Suppress fire as quickly as possible
• 1930s- Many fires led to even greater fire suppression urgency• 1944- Smokey Bear introduced to spread the message• 1960s- first scientific studies came out linking positive role fire played
in forest ecology• 1970s- Radical change in Forest Service policy
1970s Policy Changes
• Let fires burn when and where appropriate• Natural-caused fires allowed to burn in
designated wilderness areas• => “let-it-burn” policy • Last 25 years we’ve seen fires grown in size
and ferocity due to suppression efforts of early 1900s=> lots of money spent in effort to fight fires
History of Fire Suppression in 3 minutes
https://www.youtube.com/watch?v=NX1xnWPSjKg
Oregon Statistics
• 140,000 acres of Oregon burned in 2015• 595 people were responsible• Cost: $68,000,000• 297 fires were started at home• 55 fires started on the job
Oregon Statistics
Leading causes of fires in Oregon
• Cigarettes• Campfires build in poor locations• Campfires not properly extinguished• Fuel leakage from cars or logging equipment• Use of fireworks in any forestland area
What can YOU do to prevent wildfires?
What can you do to prevent starting a wildfire?
• Create defensible space around your home• Put out camp fires- there’s a science to this!• Build SMALL fires (not big bonfires) • If camping, use designated metal fire pits. • Don’t smoke. Anything. • No fireworks in public lands.
Ecological Role of Fire in Forest Ecosystems
1. Reduces probability of catastrophic fire
2. Nutrient input into soils3. Control of insect pests4. Control of tree pathogens5. Maintains species diversity
Fire Adaptations
1. Fire- activated seeds/cones2. Thermal insulation3. Resprouting4. Prolific Flowering5. Tall crowns and few to no
lower branches
Fire Activated Seeds• Require fire for seeds to sprout• Serotinous cones or fruit sealed with resin• Ex. Lodgepole Pine, Manzanita
Thermal Insulation
• Thick bark, dead leaves, or moist tissues prevents damage to inner layers of tree
Resprouting
• Grown new shoots after fire• Resprout from buds in plants underground• Ex. Madrone
Prolific Flowering
• Flowers pop up quickly after fires• Take advantage of ash-fertilized soil• Ex. Fire Lily
Tall Crown and Few Lower Branches
• Drop lower branches to prevent ladder fuels
• Called “self-pruning”• Ex. Ponderosa Pine
Healthy or Unhealthy?
BC
AB
Depends on Who You Ask!
Forester: “if its meeting management goals for that area and insect and disease were at” low levels.
Wildlife biologist: if it has a “mosaic of trees and openings providing a variety of habitat for a diversity of
wildlife.”
Hydrologist: “the most important component of a healthy forest is that there is ground cover…to act like a sponge, absorbing
water, filtering it and slowly releasing it.
Fire ecologist: “one that was disturbed by fire at a severity and frequency that mimicked what once
occurred naturally.”
Historically, fire would burn a stand every 40 years or less.
Wilderness specialist: “one where processes were allowed to play out without interference by humans.
Large bug kills are part of those processes…”
HEALTHY FORESTS?
UNHEALTHY FOREST??