Exam #4

What are the three things needed to produce fire (Fire triangle)

Fuel,Heat, Oxygen

What can create a catastrophic fire?

fuel buildup

high temperatures

low humidity

high winds

True or false: There are no ecological ecosystems adapted for fire?

FALSE

In-fire adapted forests, what kind of trees grow?

shade-intolerant

What kind of fire can keep an ecosystem in its current state of succession (not set it back to beginning, nor allow it to succeed to the next stage)?

Surface Fire

What is the difference between surface fires and ground fires?

Surface fires- burn litter layer/understory

Ground fires- burns down IN the soil

What is the 10 AM rule the forest service used to go by?

Put out any fire by 10 AM so it does’nt spread

Fire is the rapid reversal of ________

Equation is ______

Similar to what?

Photosynthesis

Organic matter + O2 » CO2 + Ash + heat

microbial and insect decomposition

True or False: Fire is not natural

FALSE

Fire is natural (or at least was)

Embrace Fire

• Serotinous cones (lodgepole and jack pines that cones burst open with fire)

• Shade intolerant trees/forests

• Tall Grass Prairie (IA)

• Animals, insects etc. also evolved/adapted

Accommodate Fire

• White/red pine in midwest

  • lodepole,ponderosa,larch forests in rockies

• Savannahs

  • oak, african,chaparral

• FREQUENCY IS KEY

• Clear understory

• No low hanging branches on trees

Why is frequency key in accommadating forest systems for fires?

Too little time between fires > invasive species

Too much time between fires > succession (short trees which then can burn and fire can climb and burn canopy)

Resist Fire

• moist, shady forests

• deciduous forests (fire is rare)

-Porcupine Mountains

-big woods

-rain forests

What can happen if a resistant fire forest dries out?

Fire can happen!

Surface fire

• burns surface litter layers

• trees with thick bark survive

• Maintains open forests/savannahs (keeps current state of succession)

• recycles nutrients

• soil little damage

• easy-ish to control

Crown fire

• usually starts as a surface fire

• jumps to crown if hot enough or “fire ladder”

• EXTREMELY DANGEROUS

• hard to control

• can create its own weather (hurricane winds)

• can be patchy

What happened in the Big Burn?

3 million acres burned in 2 days

Ground Fire

• In organic soils - peat bogs

• Hard to fight, very destructive

Causes of fires

• lightning

• carelessness with smoking and campfires

• arson

• prescribed burns

Fire Ecology in Iowa

Fire once “managed” our prairies.

Now we mostly manage annual decomposition on our farms.

—Fire making a comeback in managing grassland, pastures, oak savannahs, closed canopy forests.

Quickly fighting and suppressing periodic surface fires is the best way to prevent destructive crown fires in the future.

True

False

FALSE

Humans start more fires (a greater # of fires) in a normal year than lightening does. Which type of fire, natural-caused or human-caused, burns more acres in an average year?

Natural-caused

Who starts more fires? natural or humans?

Humans

What part of the fire triangle is broken with water drops?

Heat

What part of the fire triangle is broken by digging fire lines?

Fuel

What part of the fire triangle is broken with slurry drops?

Oxygen

Our management has __________ fire. How?

INCREASED

• fire suppression (built up fuel)

• forest management

• Urban-wildlife infrastructure (scattered cabins, harder to protect)

• Global climate change (earlier springs, later fall, changes in moisture and temperature)

Former forest service focuses with fire v.s more now?

Then- prevent fires, put them out (smokey bear)

Now- let it burn and prescribed fires

Forest service budget on fires?

½ of budget

BILLIONS (increasing as fires increase too)

Most fires are started on what type of land? How much of this land actually burned?

state, county or private (~83%)

»42% actually burned

LA fires facts

• drought and high winds (cause)

• 14 wildfires

• 31 died directly, excess deaths (~400)

• 57,000 acres

• 200,000 people evacuated

• 16,324 structures destroyed

In Iowa all fires were caused by ?

Humans!

Where did we see most of fires take place this year?

ALASKA