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Pg. 57 The discovery of controlling fire made it an early technology. Examples of Fire use today PowerPoint PPT Presentation


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Pg. 57 The discovery of controlling fire made it an early technology. Examples of Fire use today constructive -used for our benefic destructive -causing us grief ADD Fire triangle Fire is oxidation in action ..... combustion is the rapid reaction of oxygen and organic material

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Pg. 57 The discovery of controlling fire made it an early technology. Examples of Fire use today

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Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

Pg. 57

The discovery of controlling fire made it an early

technology.

Examples of Fire use today

constructive -used for our benefic

destructive -causing us grief

ADDFire triangle

Fire is oxidation in action ..... combustion is the rapid

reaction of oxygen and organic material

burning wood: produces carbon dioxide, water and heat


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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  • STAGES OF FIRE

  • 1. Preheating (starting the fire):

  • a) water removed from plant/organic material

  • b) temperature of material increases – pyrolysis

  • (chemical structure of wood breaks down yields

  • flammable components)

    • 2.)Flaming combustion stand back!!!

    • burning=lots of energy released

  • 3.)Glowing combustion –

  • no flames but those embers are hot!

  • FIGURE LINK


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

Pg. 57

HOW DOES FIRE SPREAD?

1) slowly along the ground

glowing combustion dominates

2) wall of fire - flaming combustion dominates

3) crown fire-fire in tree tops similar to wall of fire just

in the tree trops

ADDLadder Fuels -stepping up from one fuel level to

the next.

ND pg. 407 Fig. 14.2


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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WHAT HELPS THE SPREAD OF FIRE?

1) Wind - pushes fire, feeds with oxygen

2) Fuel: Type of vegetation burning & how much

Oils in wood (eucalyptus)

highly flammable (chaparral) vs. flame resistant

a.) Branches close to ground or not

b.) Lots of shrubby under story

Remember ladder fuels.

c.) Slash- brush piles left from clearing vegitation

3) Moisture - wet or dry and for how long


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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WHAT HELPS THE SPREAD OF FIRE?

4) Topography of land - hills - fire burns faster up slope - (convection=heat rises so preheats)-

topography effects vegetation types

5) Positive feedback - fire creates unstable air and may create fire tornado-carry burning debris and start new fires.

Heat rises, sucks in oxygen from sides=more combustion-compare to in space to the make point

Positive Feedback is a “Vicious Cycle” but it is “positive”?


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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HOW DO HOMES CATCH ON FIRE?

1.) Physical contact -Flames travels right to home

2.) Radiant heat causes home materials to ignite.

warming your hands but be careful

*Flames do not have to touch the house.

3.) Firebrands- glowing embers blown by the wind to

new areas.


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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WHAT TO DO….

1.) HOME DESIGN

A.) set back from top of slope- 100 ft minimum.

ND pg. 420 fig. 14.25

B.) building materials -flammable vs. nonflammable

C.) design- no overhanging decks/eaves

D.) wide, easily accessible driveways

E.)Roof-fire proof because of firebrands

ND pg. 419 fig. 14.23

WHY?? on all


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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WHAT TO DO….

1.) LANDSCAPING

A.) keep a 30’ barrier around home

B.) Keep trees trimmed (side and over roof)

C.) use fire resistant plants -succulent ice plant

ND pg. 421 fig. 14.26

D.) Keep surrounding forest thin-ladder fuels-remove ground level that could spread to crown

E.) keep slash -dead stuff cleared out.

Results: ND pg. 418 fig. 14.22


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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WHERE DO FIRES OCCUR?

General Trend:

Regions that experience wet and dry seasons

(wet=plant growth dry=fire) Drought areas

Examples:

1.) Great Lakes 1871

clearing fields for ag. use = lots of wood debris left.

Long dry spell.

Strong winds.

Result - huge area burned farms and towns:

Peshtigo, WI wall of flames moved fast 1100+ casualties


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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2.) Chicago, IL-Oct. 8, 1871

Legend: Mrs. O’Leary’s cow kicked a lantern

over = wind whipped flames - heart of the city

burned, 300 casualties.

ADD

1.) Unusually dry summer

2.) City had just finished building sidewalks out of wood


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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  • 3.) CALIFORNIA ( S.F. and S. Calif.) is a location

  • where fire is always a hazard certain times of year.

  • WHY?

    • vegetation type (chaparral - very flammable

    • fire species - need fire to reseed)

  • b) hilly - fire races uphill- CONVECTION

  • c) homes built close to vegetation and on steep hills

  • d) drought not uncommon

  • e) warm winds common

  • f) people/wacko in the woods - can start fires - arsonist


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Baja vs. Southern California

Southern California

1.) Fires in the early, cooler, wetter season are put

out quickly-allows maximal plant growth.

2.) This leaves (not intended) lots of highly flammable chaparral to burn in the drier autumn.

3.) Fires are fought energetically and with lots of $

a.) leaves behind dense overgrowths of chaparral.

b.) as chaparral grows it becomes more flammable.

4.) Warm, dry winds occur in autumn when we

have lots of fuel

RESULTS: leaves lots of flammable fuel for the hot dry season


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Baja vs. Southern California

Baja

1.) Fires are NOT fought energetically and with little $

a.) leaves little overgrowth of chaparral.

b.) as chaparral grows it becomes more flammable.

SO…. We have less chaparral AND it is less flammable.

2.) Warm, dry winds occur in autumn BUT don’t have much fuel to feed fires.

RESULT: less fuel during the hot dry autumn.


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Baja vs. Southern California

* 1000’s hectares


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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Baja vs. Southern California

Distribution:

1.) S.C. a few biggies-and burns higher %

2.) Baja a bunch of little ones

ND pg. 424 fig.14.28

*BIG QUESTION: Should we continue to fight big fires or let the early season fires go more?


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

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IF YOU LIVE IN A FIRE PRONE AREA

WHAT CAN YOU DO?

1.) Build for fire

NO: Wood roof, wood house, wood deck,

no. veg. near house


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

QUIZ

1.) Which of the following best describes the southern

California case history (compared to Baja)

a.) let little fires burn

b.) fight little fires

c.) spend little money fighting fire

d.) results in a small amount of flammable material for

the hot dry season

2.) Why are fires a continual hazard in southern California?

A) older vegetation resists burning

B) moist conditions are common

C) homes on hillsides

D) cool moist winds are common


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

  • QUIZ

  • 3.) Which of the following best represents the safest

  • course of action when designing landscaping

  • a.) 50’ setback from top of slope and dense underbrush

  • b.) fire wood stored near the house and a 30’ barrier

  • surrounding the house

  • c.) trimming overhanging trees and removing slash(debris)

  • d.) building on top of a hill and planning up to the house

  • 4.) Which of the following is significant in aiding the spread of fires:

  • A) types of vegetation and topography

  • B) size of house and building material

  • C) number of rivers in area and moisture

  • how many lakes there are in an area and fuel


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

  • QUIZ

  • 5.) What best describes how convection causes burning

  • A) Heat rises and fire burns up hill

  • B) Heat rises and fire burns down hill

  • C) Heat sinks and fire burns up hill

  • D) Heat sinks and fire burns down hill

  • 6.) What best describes how radiation causes burning?

  • The fire has to physically touch the side of the house

  • B) The heat of the fire has to rise uphill to the house

  • C) Firebrands drift onto new areas causing new small fires

  • D) The flames give off energy that begins to warm things

  • around it without touching them


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

QUIZ

7.) What best describes the conditions in the

Great Lakes region in 1871

A) Dry, high winds, high topography

B) Dry, low winds, high topography

C) Dry, high winds, low topography

D) Dry, low winds, low topography

8.) Which of the following best describes a fires positive

feedback behavior?

A) a fire burning down hill causing less burning

B) A fire sends out firebrands causing the fire to get

bigger and bigger

C) moist air causing less burning

D) a fire running out of fuel


Pg 57 the discovery of controlling fire made it an early technology examples of fire use today

QUIZ

9) What contributed to the Chicago fires of 1871?

A) wooden sidewalks, dry conditions, and a cow

B) wooden sidewalks, moist conditions, and a cow

C) stone sidewalks, dry conditions, and an ostrich

D) wooden sidewalks, dry conditions, and an ostrich


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