Introduction to Fire Ecology

1. Introduction to Fire Ecology 5/25/07

2. What is Fire? • Rapid oxidation reaction in which heat and light are produced. • Exothermic • Three ingredients • Fuel • Oxygen • Heat

3. 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

4. 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.

5. Fire Ecology Concepts • Three main concepts that provide basis for fire ecology • Fire history • Fire regime • Fire dependence/ Adaptation

6. 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

7. 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

8. 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

9. 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)

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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