Fire ecology background and plant strategies

1. Fire:
Science of the Flame

2. Fire Ecology
• Essential Question of the Day:
– “What is the science behind how fires start and
how they spread?”
• Learning Objectives:
– “I can describe the positive and negative effects
fire has on forest ecosystems.”
– “I can explain how ecosystems change over time.”

3. Agenda 1/30/18
• Wildfire Science
– Definition of wildfire
– Watch a couple of wildfire science videos
– Fire Triangle
– Fire Behavior Triangle
– Learn about how fires spread

4. Fire is fire!
. . . Is it bad?
. . . Is it good?
. . . Who’s asking?

5. Fire is bad !

6. • Fire is good !

8. Ecological Effects of Fire
Basic Premises
1. All ecosystems change over time
2. Fire is neither innately good nor bad; it
is just an agent of change
3. Human perception of whether it is good
or bad depends on resource objectives
4. Do people think fire is good for wildlife?

9. WILDFIRE
• Create a mental picture
• What does it look like?
• What does it sound like?
• What does it smell like?
• How would you define it?

10. Definition of Wildfire:
• An unplanned and uncontrolled fire spreading
through vegetative fuels, at times involving
structures.

11. Science of Wildfires
• https://www.youtube.com/watch?v=F8OrmGAIqI4

12. Science of Wildfire
FIRE TRIANGLE
What is the source of :
– Oxygen
– Heat
– Fuel

13. DEMO!
• Yep, time to examine the Fire Triangle.

14. Science of Wildfire
FIRE BEHAVIOR TRIANGLE
– How does weather affect
occurrence and spread of
wildfire?
– Which types of fuel feed a
wildfire?
– How can topography affect
the occurrence and spread of
wildfire?

15. Look at the factors
• Weather

16. Look at the factors
• Topography - Slope
Steep Slopes
Legend

18. Look at the factors
• Fuel – Vegetation available

19. Science of Wildfire- Types of Surface Fuel
• Light Fuels
• Heavy Fuels
• Ladder Fuels
Fuel Breaks
help prevent the
fire from
spreading
Grasses, weeds, leaves, small twigs
Branches, logs, stumps
Small trees, bushes, low branches
Roads, rivers, human-created breaks

20. Science of Wildfire
• Fire Spread-
Transference
of Heat
– Conduction
– Radiation =>
Surface fires
– Convection
=> Crown
fires

21. Fire Spread

22. Ember movement is the “wild
card”

23. PhotoCredit:DaleWade,USDAForestService
PhotoCredit:DaleWade,USDAForestService

24. High Intensity Crown Fire
https://www.youtube.com/watch?v=zvPa_yEEd4E

25. We have liftoff and ignition!

26. Learning Target
“I can describe the positive and negative effects
fire has on forest ecosystems.”
Essential Question:
What adaptations increase the likelihood of
plants surviving wildfire?
HOM: Curiosity

27. Positive Ecological Role of Fire in
Forest Ecosystems
1. Reduces probability of
catastrophic fire
2. Nutrient input into soils, like
calcium, magnesium, carbon and
nitrogen
3. Control of insect pests
4. Control of tree pathogens
(diseases)
5. Maintains species diversity

28. Negative Effects of Fire
• Polluting air with emissions 
harmful to human health
• Releases Carbon Dioxide 
Climate change!
• Burns out root systems =>
destabilization of soil
 Erosion and landslides
 Intense flooding
 Deposition of soil and minerals
in waterways

29. Mudslides after California Fires
• https://www.youtube.com/watch?v=Y9OpMHffYR

30. Case Study- 452,000 acres
• Biscuit Fire-
– Fire burned over 1,300 o
F (more
than 2x hot typical prescribed
fires)
– Loss of topsoil and organic
material (10 tons per acre of
carbon, and 450-620 lbs/ acre of
nitrogen)
–  Loss of productivity of
ecosystem
–  Forest grows back slower,
reduced rates of carbon
sequestration
 Will take decades of nitrogen-
fixing plants to replace
necessary nitrogen back into soil

31. Pyrophytes:
Plant Strategies for Surviving Fire
• Resisters- Thermal insulation (thick bark), self
pruners
• Sprouters- Re-sprout from root crowns, burls or
underground rhizomes
• Seeders- Fire activated seeds; seeds stored in the soil
• Invaders- pioneering species; prolific flowering
• Not adapted- wait for seeds to re-enter a site; shade
tolerant, understory plants that wait to be brought in
by animals (ex. White fir)

32. Resisters: Thermal Insulation
• Thick bark, dead leaves, or moist tissues
prevents damage to inner layers of tree
• Ex. Douglas fir, Ponderosa Pine

33. Resisters: Tall Crown and Few
Lower Branches
• Drop lower branches to
prevent ladder fuels
• Called “self-pruning”
• Ex. Ponderosa Pine, Sugar
Pine

34. Sprouters: Regrow Quickly After
Fire
• Grown new shoots after fire
• Resprout from buds in plants underground
• Ex. Madrone, manzanita

35. Seeders: Fire Activated Seeds
• Require fire for seeds to sprout
• Serotinous cones or fruit sealed with resin
• Ex. Lodgepole Pine, Knobcone Pine Manzanita

36. Invaders: Prolific Flowering
• Flowers pop up quickly after fires
• Take advantage of ash-fertilized soil
• Ex. Fire Lily

37. Fight Fire with Fire??
• https://www.youtube.com/watch?v=TUTw5xegyG

38. History of Fire in U.S.
• 1800s- BIG forest fires began argument (among conservationists) that
fires threatened commercial timber supplies
• 1891- U.S. Gov’t began setting aside national forest reservations
• 1905- U.S. Forest Service established and given managerial control of
forest reservations
• 1910- “Big Blowup”- 3 million acres burned in Montana, Idaho, and
Washington in only TWO days
• “Big Blowup” greatly affected national conversation about fire policy
=> thought that total fire suppression would prevent big blowup
again.
• 1920-1938- policies developed to
– 1. Prevent Fires and
– 2. Suppress fire as quickly as possible
• 1930s- Many fires led to even greater fire suppression urgency
• 1944- Smokey Bear introduced to spread the message
• 1960s- first scientific studies came out linking positive role fire played
in forest ecology
• 1970s- Radical change in Forest Service policy

39. 1970s Policy Changes
• Let fires burn when and where appropriate
• Natural-caused fires allowed to burn in
designated wilderness areas
• => “let-it-burn” policy
• Last 25 years we’ve seen fires grown in size
and ferocity due to suppression efforts of
early 1900s=> lots of money spent in effort to
fight fires

40. History of Fire Suppression in 3 minutes
https://www.youtube.com/watch?v=NX1xnWPSjKg

41. Oregon Statistics
• 140,000 acres of Oregon burned in 2015
• 595 people were responsible
• Cost: $68,000,000
• 297 fires were started at home
• 55 fires started on the job

42. Oregon Statistics

43. Leading causes of fires in Oregon
• Cigarettes
• Campfires build in poor locations
• Campfires not properly extinguished
• Fuel leakage from cars or logging equipment
• Use of fireworks in any forestland area

44. What can YOU do to prevent
wildfires?

45. What can you do to prevent
starting a wildfire?
• Create defensible space around your home
• Put out camp fires- there’s a science to this!
• Build SMALL fires (not big bonfires)
• If camping, use designated metal fire pits.
• Don’t smoke. Anything.
• No fireworks in public lands.

46. Healthy or Unhealthy?
BC
A
B

47. HEALTHY FORESTS?

48. UNHEALTHY
FOREST??

49. Depends on Who You Ask!

50. Forester: “if its meeting management goals for that
area and insect and disease were at” low levels.

51. Wildlife biologist: if it has a “mosaic of trees and
openings providing a variety of habitat for a diversity of
wildlife.”

52. Hydrologist: “the most important component of a healthy forest
is that there is ground cover…to act like a sponge, absorbing
water, filtering it and slowly releasing it.

53. Fire ecologist: “one that was disturbed by fire at a
severity and frequency that mimicked what once
occurred naturally.”

54. Historically, fire would burn a stand every 40
years or less.

55. Wilderness specialist: “one where processes were
allowed to play out without interference by humans.
Large bug kills are part of those processes…”