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Introduction to Fire Ecology. 5/25/07. What is Fire?. Rapid oxidation reaction in which heat and light are produced. Exothermic Three ingredients Fuel Oxygen Heat. Fire Factoids. - PowerPoint PPT Presentation
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Introduction to Fire Ecology
5/25/07
What is Fire?
Rapid oxidation reaction in which heat and light are produced.
Exothermic Three ingredients
– Fuel– Oxygen– Heat
Fire Factoids 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 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– 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 Patterns and cycles of
fire/ time Includes
– Severity: ecological impact
– Intensity: fire behavior
Ex. High intensity- high burn scars, crown fire, but low severity- no soil damage, undergrowth
Fire Dependence/ Adaptation Concept applies to plants
and animals that rely on fire or are adapted to survive in fire prone environments
Plant adaptations– Serotinous cones, fire
resistant bark, heat resistant foliage, rapid growth
Animal adaptations– Generally fleeing or
burrowing
Communities Adapted to Fire Six different vegetative
communities – 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 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 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 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 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 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 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