Fire Ecology

Disturbance Defn: Force that shapes natural communities by altering resource allocation and changing structure of environment

Describing a Disturbance Natural vs. anthropogenic Scale Intensity Return time Duration

Fire Prevalent in some communities –Conifer forests –Chaparral –Grasslands Affects species composition Relationship between fire and plant communities

Fire in the Wild

Mediterranean Climates Hot dry summers Cool wet winters Mild temperatures Santa Anna winds

Changes in the Fire Cycle Fire suppression –Fire as an enemy

Changes in the Fire Cycle Controlled burns Accidental ignition Long-term alterations –Sediment analysis

Fire Spread Flying embers –Leaves –Ash Animals Heat

The Role of Fire Landscape heterogeneity –Fields –Forests Increase diversity Required for reproduction Prevent catastrophic fires

Catastrophic Fires Intense Fast return time Massive casualty –Wildlife –Trees Destroy seeds Sterilize soil

High Intensity

Low Intensity

Fire Recovery Succession: Changes in species composition over time Primary succession Secondary succession

Models of Succession Stable endpoint – climax

Chaparral Succession Burns Survivors Crown sprouts Seed banks Bulbs Colonizers Senescence

Chamise - Adenostoma Crown Sprout

California Lilac – Ceanothus Seed bank Crown sprout

Wildflowers Seed banks Bulbs Immigration

Grasses

Immigration Animals return Grazers

Post-Fire Human Impacts Slope stabilization –Hydroseed –Replants Rebuilding

Hydroseed

Forest Plantations

Living with Fire Should we live in chaparral? How can we protect lives? How can fire be re- introduced?