Transcript California Wildfires: Causes and Consequences

What Fuels Wildfires?
What fuels So Cal wildfires?
California Chaparral Ecosystem
 Coastal woodlands and
grasslands of So Cal
have precipitation of 12
to 40 inches per year
 Climate is hot and dry
in summer, rainy and
mild in winter
 Plants have adapted by
conserving water, have
small, waxy leaves
California Scrub Oak
 The name of the chaparral
ecosystem was derived from
the Spanish word for scrub
oak, chaparro
 This is a small evergreen or
semi-evergreen shrubby oak,
which may be small and
compact, or grow several
meters high, depending on
terrain and local conditions
 Its acorns were an important
Native American food source
Fire-prone plant community
 Chaparral is fire-prone
 The plants produce
volatile oils that help
them to retain moisture,
but evaporate when the
weather turns hot
 Escaping gases form a
cloud above shrubs that
explodes when touched
by flame, flying embers
Santa Ana Winds
 Winter rains bring a flush of
new growth in chaparral
 When the plants dry out in
the summer and fall,
 Lightening, arson or human
carelessness may spark fire
 Santa Ana winds can move a
wildfire at speed of 40 miles
(60 km) per day
 Dense clouds of burning
embers can blow across
firebreaks, spreading fire
Danger to Houses
 Housing developments
have been built amidst
chaparral-cloaked hills
 Fire danger has risen
with population growth
 Probability of accidental
fires grows as more
people come to live in
chaparral ecosystem
Land Use Planning Needed
 Landscape with average
of 45 humans per
square kilometer is
most prone to burn
 Lower density has less
human activity
 Higher density leaves
less wild land to burn
 As CA population grows,
planning will be needed