Effects of Fire Suppression on Chaparral in Southern California

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Effects of Fire Suppression on Chaparral in
Southern California

• Kathleen Patarak

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Look Familiar?
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Chaparral Biome

• A biome is a large, distinctive complex of plant
  communities created and maintained by climate
• Chaparral is a major biome on Earth

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Chaparral

• Shrub dominated community
• Chaparral derived from Spanish word meaning
  dense, shrub thicket
• Mediterranean climate
• Dry, hot summers and wet mild winters
• Found in Southern Europe, northern Africa,
  California, southern Australia, and Chile

Green depicts chaparral
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Plants found in California Chaparral

• World wide Chaparral Biomes contain approximately
  2,036 species of plants other than trees.
• Madrone - Arbutus menziesii
• Manzanita - Arctostaphylos patula
• Chamise - Adenostema fasciculatum

Madrone
Manzanita
Chamise
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Adaptations

• Drought tolerant
• Sclerophyllous foliage - small, hard leaves which
  hold moisture i.e. poison oak, scrub oak, chamise
• Semidormant during summer
• Combination deep tap root and extensive lateral
  roots near surface
• Evergreen photosynthesis during winter

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Fire Community

• Chaparral sp. have adapted to recurrent fire
  conditions
• Many plants depend on the fires for regeneration
• Scarification by fire i.e. Laurel Sumac seed
  coats need to be scorched to germinate

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Fire Community

• Space at premium
• Some chaparral sp. release allelopathic chemicals
• Fire
• Opens space for reproduction and growth
• Volatilizes growth inhibiting compounds

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Fire Community

• Many Chaparral sp. contain highly flammable
  chemicals
• Combustion of these chemicals may create
  temperatures above 500C
• Only sp. highly adapted to fire survive
• Mature plants sprout
• Seeds germinate
• Fire temp
• Physical scaring
• Chemical exposure i.e. charcoal smoke
• No allelochemicals
• Massive nutrients released from dead plant
  material

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After the Fire

• 1-2 years herbaceous plants
• 5 years herbaceous plants become 2 to shrubs
  that were not killed and are resprouting
• Advantage of these shrubs large intact root
  system to obtain water nutrients

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Baja California vs. SoCal

• Frequency of fire is much higher in B.C.
• Acreage burned in southern California is much
  higher than B.C.
• Reason heavy fuel load and Santa Ana winds in
  California

Satalite imagery taken from Lan Sat shows fires
in San Diego Co., San Bernadino Co., and Ventura
Co, as well as fires near Rosarita and Encinada
B.C.
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Paradise, Cedar, and Otay Fires

• Largest fire in California history
• Burned over 383,000 acres.
• Otay fire burned out shortly after crossing the
  border into Mexico because of scarcity of fuel
• Because of frequent fires used to clear grazing
  land, the chaparral stands in B.C. have a much
  lower fuel load than the stands in the U.S.
• B.C. shrublands are a mosaic of older stands and
  younger stands

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Factors Influencing Fire

• Wind Speed Direction
• Santa Anas
• Temperature
• Humidity
• Previous exposure to fire
• Fuel load
• Stand age

Santa Ana driven dust storm after the Firestorm
of 2003
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Fire Suppression

• Suppression leads to buildup of fuel load
  resulting in large wilidfires in California
  chaparral
• USGS study Dr. Jon E. KeeleyUSGS Sequoia and
  Kings Canyon Field Stationfire suppression does
  not cause large shrubland wildfires
• fire suppression is not effective in halting
  shrubland wildfires
• Study focused on records for counties with high
  intensity wildfires from Monterey to San Diego
• Suppression failed due to Santa Ana wind
  conditions during wildfires
• Fires moved through all chaparral regardless of
  age class
• Conclusion Prescribed burning to maintain young
  growth to act as firebreaks are ineffective

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Impacts of Shrubland Wildfires

• Increase in fire frequency caused by humans
  detrimentally impacts shrublands
• Native shrubland is being replaced by non-native
  grasslands
• Unnaturally high fire frequency has been a
  leading cause of degradation of chaparral and
  coastal sage scrub ecosystems
• loss of biodiversity
• and increase in invasive species
• Shrubland ecosystems have a high number of rare
  and endangered plants
• Fire suppression does have a role in limiting the
  impacts of shrubland wildfires

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Fire Issues

• What kind of management of the wildland-urban
  interface will reduce fire movement into and out
  of the urban environment without converting
  native shrubland to nonnative grassland?
• What should be the role of prescription burning
  in shrublands?
• How can managers offset impacts of prescribed
  burning of chaparral stands (i.e., weed invasion,
  loss of native species, and conversion to
  nonnative grassland) at frequencies sufficient to
  stop Santa Ana driven fires?
• What are the benefits of fuel breaks relative to
  their visual impact and role in providing
  invasive weeds access to remote sites?
  Keeley USGS Report

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The End
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References

• http//www.signonsandiego.com/news/fires/images/03
  1028fire_satellite.html
• http//www.theshugars.com/blog/archives/000125.htm
  l
• www.werc.usgs.gov/fire/
• Keeley, J. E., C. J. Fotheringham, and M. Morais.
  (2000) Reexamining fire suppression impacts on
  brushland fire regimes. Science 284 1829-1831.
• Minnich, R. A. (1983) Fire mosaicx in Southern
  California and northern Baja California. Science
  2191287-1294.
• Moreno, J.M. and W.C. Oechel (1992) Factors
  controlling postfire seedling establishment in
  Southern California chaparral. Oecologia
  9050-60.