Modeling the effects of

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Modeling the effects of forest succession on
fire behavior potential in southeastern British
Columbia
S.W. Taylor, G.J. Baxter and B.C. Hawkes
Natural Resources Canada Canadian Forest Service
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Historical Background

• dry forests in western North America were
  historically exposed to high-frequency,
  low- intensity fire regimes
• favoring the development of grasslands and open
  stands of fire-tolerant tree species ponderosa
  pine, Douglas-fir, western larch
• fire suppression, logging and forest grazing
  have resulted in forest in-growth and expansion
  

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Rocky Mountain Trench
1900s
1990s
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1992
1952
B.C. Government photos
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Issues

• loss of habitat for some wildlife species
• reduction in forest grazing
• decline in forest health
• increased potential for catastrophic crown fires

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Heat Transfer
Temperatures above flame front by fire
intensity class
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Crown Fire Initiation
Surface fire
Crown fire threshold by fire intensity class
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Crown fire
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2
Foliar moisture content 100
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Rationale

• few planning tools to guide ecosystem
  restoration and fuels management programs
• need to develop techniques to project future
  change and effects of management practises

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Objectives

• Develop methods to assess historical change and
  project future change in
• forest cover
• fuel conditions
• fire behavior potential

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Study areas
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Methods

• crown closure, fuel type, terrain
  classification
• map historic and contemporary air photos
• sample stand characteristics
• stand projection using PROGNOSIS growth model
• fire weather climatology and fire behavior
  normals
• determine fire behavior potential over time

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Forest and fuel type classification
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Stand description
Douglas-fir Ponderosa pine Lodgepole pine Western
larch Trembling aspen
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Stand projection
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Inventory projection
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Climatology
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Fire behavior normals
level ground
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Fire behavior projection
Normal fire season crown fraction burned class
frequencies
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Fire behavior projection
Normal fire season fire intensity class
frequencies
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Results

• Grassland and open forest
• decreased by 50 during 1952-92
• will be eliminated by 2036 without management
• Area of closed forest doubled during 1952-92
• Area susceptible to crown fire with gt50 CFB
• increased from 7 to 14 during 1956-96
• projected to increase to 29 by 2032
• Results are preliminary - regeneration model
  needs calibration

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Research Needs

• dynamic fuel and fire behavior models
• integrate fire behavior and ignition potential in
  more sophisticated risk measures
• quantify preparedness and control costs
  associated with fire risk
• further develop fuel management planning tools

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Fuels Management Planning Tools
Tactical models

• fire behavior and effects
• stand projection and simulation

Strategic models

• inventory projection
• forest estate
• landscape level

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Tactical Models Fire Behavior Prediction
System SCORCH Tree Mortality Model
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Tactical Models Forest Vegetation Simulator
(PROGNOSIS) Fuel Dynamics and Fire Effects Model
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FVS Fuel Dynamics and Fire Effects Model Sample
Output
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Strategic Models
fssim Woodstock
Simulate forest dynamics and management
activities on vegetation growing stock and
related attributes
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Acknowledgements
Funding for this project was provided in part by
Forest Renewal British Columbia We would like to
acknowledge the cooperation of
BC Ministry of Forests
Cranbrook Forest District, Nelson Forest
Region BC Parks
Okanagan District, Thompson River
Dist.
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Thank you !
Time for questions ?
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