Introduction to Fire Ecology

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Transcript Introduction to Fire Ecology

Introduction to Fire Ecology
5/25/07
What is Fire?

Rapid oxidation
reaction in which
heat and light are
produced.
 Exothermic
 Three ingredients
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Fuel
Oxygen
Heat
Fire Factoids
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Of known planets, only Earth has ingredients
essential for fire, oxygen, plant (for fuel), and
lightening to ignite the two into flames
90% of wildland fires started by humans,
most accidental.
10% by lightning, lava, heat of
decomposition
~ 4.7 million acres burn annually United
States
Estimates suggest 100 million acres burned
annually before Europeans arrived
Fire Ecology
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Branch of ecology
Focus on origins,
cycles, and effects of
wildland fire on
ecosystems
Wildland fire: any fire
burning in a natural
environment
Fire ecologist tires to
understand
relationships between
fire, living organisms
and their habitat.
Fire Ecology Concepts

Three main
concepts that
provide basis for
fire ecology
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Fire history
Fire regime
Fire dependence/
Adaptation
Fire History

How often fire occurs in
a geographic area
 Trees and soil provide
evidence of past fires
 Fire scars seen in core
samples from trees
provide evidence of
past fires
 Ash layers in soil can
show fire patterns
 Intense fires can also
leave soil hydrophobic
Fire Regime
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Patterns and cycles of
fire/ time
Includes
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Severity: ecological
impact
Intensity: fire behavior
Ex. High intensity- high
burn scars, crown fire,
but low severity- no soil
damage, undergrowth
Fire Dependence/ Adaptation
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Concept applies to plants
and animals that rely on
fire or are adapted to
survive in fire prone
environments
Plant adaptations
–
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Serotinous cones, fire
resistant bark, heat resistant
foliage, rapid growth
Animal adaptations
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Generally fleeing or
burrowing
Communities Adapted to Fire

Six different vegetative
communities
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Tall Prarie (Midwest)
Ponderosa Pine (Interior
west)
Douglas-Fir (Pacific
Northwest)
Loblolly and Shortleaf
Pine (The Southeast)
Jack Pine (Great Lake
States)
Chaparral (California
and Southwest)
Tallgrass Prarie
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Cover parts of Nebraska, Illinois, Iowa, and Kansas
Primarily grasses, forbs, shrubs, and trees
Fire helps maintain ecosystem stability and diversity
Benefits include elimination of invasive species
Ponderosa Pine
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Location Eastern Oregon and Washington, West
Idaho, Extends into Interior West
Residing among Ponderosa pines include grasses
forbs, and shrubs
Generally receives less than 25 inches of rain a year
Fire serves to replace older plants with younger ones
of same species
Fire cycle of 5 to 25 years
Douglas-Fir
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Pacific Northwest,
Oregon, Washington,
B.C.
Mixed forest with
climates that provide
over 50 inches of rain
Douglas-Fir regenerate
rapidly on site prepared
by fire
Benefits of fire include
removal of fuel and
consequent reduction
of severe crown fires
Loblolly and Shortleaf Pine
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Southeast, Maryland,
Virginia
Not highly adapted to
fire as in other species
Benefits of fire include
creation of favorable
environment for
seedlings and
hindrance of invasive
competing species
Jack Pine
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Great Lakes States,
Michigan, Minnesota, etc.
 Found among a variety of
trees, brush, forbs, and grass
 Jack Pine do not drop all
their seeds
 Thick cone protects seeds on
trees during fire
 Seeds released where fire
removed existing vegetation
 Reduce competition
Chaparral
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California and
Southwest
 General term that
applies to various types
of brushland
 Many species are
adapted to and even
promote fire
 Fire releases nutrients
locked up in plants
 Reduces competition
by eliminating invasive
species