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. 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 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