Forest Fires in the Global Boreal Zone: Characteristics, Impacts, Trends and Future Uncertainties

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Forest Fires in the Global Boreal Zone
Characteristics, Impacts, Trends and Future
Uncertainties

• Brian J. Stocks
• B.J. Stocks Wildfire Investigations Ltd.
• Sault Ste. Marie, ON, Canada

POLARCAT Science Meeting, June 4-6, 2007, Paris,
France
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Outline

• Boreal Fire Statistics/Distribution
• Boreal Fire Characteristics
• Emerging Vulnerabilities
• IPY/Boreal Fire

Provide some context around current and future
boreal fire issues
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Circumboreal Forest Fire Activity
Canada Fires/AB 1920-2005

• Annual burned area 5-20 million hectares
• Primarily Canada, Russia and Alaska
• Russian pre-1995 statistics were underestimated
• Area burned shows great inter-annual variability
  - makes trend analysis difficult
• Driven by
• Continental climate
• Extreme weather
• Multiple ignitions

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Recent Area Burned in Russia, Canada, Alaska

• Russian statistics much more accurate post-1995
  (satellite validation)
• Longer baseline required for Russia (post-1980)
  now being developed
• Annual area burned highly episodic makes
  detecting a climate change signal very difficult

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Reconstructing Russian Fire Activity Post-1980

• Reconstruction of fire weather and area burned in
  post-1980 Russia is critical to predicting
  potential climate change and carbon budget
  impacts
• Post-1995 reasonably accurate (satellite link)
• 1980-1995 period being reconstructed using AVHRR
  GAC records
• Mapping large fire scars spatially
• Using AI to determine burn dates
• Fire danger reconstructed using CFFDRS

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July 31, 1984
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July 18, 1985
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Composite 1985
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Intensive/Extensive Protection Zones

• Fire management agencies attempt to protect
  economic interests while permitting the natural
  and essential role of fire in ecosystem
  maintenance
• Intensive protection in high value areas with
  modified suppression in more remote regions

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Canadian Actioned/Non-Actioned Fires
Percent AB by NA fires increasing?
AB
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CDN Large Fire Database (LFDB)

• Fires gt200 ha post-1950 nationally (13,000
  fires)
• Polygons with attributes (fire size, cause, start
  and end dates etc.) from fire management agencies
• Updated annually working back in time with
  satellite imagery
• Similar database for Alaska not for Russia

1980s in central Canada
1959-1999 in Canada/AK
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CDN Large Fire Database (contd)

• Relatively small database very large impact
• 3 of total fires 97 of area burned
• Lightning 72.7 of fires, 85 of AB
• Non-actioned fires 40 of fires, 48.5 of AB

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Large Fire Database Outputs

• PAAB by ecozones/ecoregions
• Large fire size class distributions
• Fewer large fires contribute most of AB

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Seasonal CDN Large Fire Distribution

• June/July in high boreal
• Lightning fires
• Generally freeburning
• Natural/essential

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Boreal Fire Characteristics

• High fuel consumption,fast spread
  rates, sustained high intensity levels, towering
  convection columns, long-range smoke transport
• Lightning dominant cause of large fires in NA
  variable in Russia in Canada lightning causes
  35 of fires, 85 of AB

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Fire Intensity/Energy Release

• Combine rate of spread/fuel consumption/heat of
  combustion to determine fire intensity (IHWR)
  resistance to control
• Savanna Fires
• 0.1-1.2 kg/m2
• 500-10,000 kW/m
• Lower convection columns
• Boreal/Temperate Forest Fires
• 2.5-5.0 kg/m2
• 100-100,000 kW/m
• gt fuel consumption intensity
• Towering convection columns reaching UTLS

A typical high-intensity boreal crown fire
convection column viewed from an altitude of 10
km (photo courtesy Mr. Todo, JAL)
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Fuel Consumption

• Highly variable within/between fuel types and
  individual fires
• Fuel available for combustion primarily a
  function of moisture content effect of current
  and antecedent weather
• Measured on experimental fires (preburn/postburn)
  and wildfires
• Measure crown, surface, and forest floor fuel
  consumption
• Use cruises, fixed plots, and depth-of-burn/bulk
  density measures
• Good accuracy

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Crown Fire Fuel Consumption

• What burns
• Foliage/small branchlets in living crowns
• Understory foliage and twigs
• Ground layer shrubs
• Woody debris on forest floor
• Forest floor (organic layer) to varying depth
• Crown and surface fuel consumption relatively
  constant, but forest floor fuel varies with MC
• Typically 1.0 kg/m2 for crowns, 0.5 kg/m2 for
  surface fuels, and 1.0-3.5 kg/m2 for forest floor
  (total 2.5-5.0 kg/m2)
• Potential for gt fuel consumption/intensity
  depends largely on forest floor consumption

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Crown Fire Development

• Propagating surface fire requires a minimum level
  of fuel consumption to survive
• When surface fuel consumption reaches a certain
  level, fire intensity levels increase enough to
  involve the crown layer
• Crown fires access the ambient wind field,
  increasing spread rates and intensity
• Crown and surface phases of fire advance as a
  linked inter-dependent unit
• Crown fires dominate in North American boreal zone

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Crown Fire Characteristics

• High spread rates fuel consumption result in
  high intensity levels sustained throughout
  afternoon burning period on boreal wildfires
• Result is well-defined convection column with
  potential for great vertical development
• Contrast with savanna fires with similar spread
  rates but much lower fuel consumption less
  defined column with little vertical energy
• Contrast with experimental fires in boreal
  similar intensity, not sustained plume only

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Boreal Fire Convection Column Dynamics

• Column is integrator of FC, RoS and intensity
• Column develops if rate at which thermal energy
  is converted to kinetic energy above the fire gt
  kinetic energy of windfield
• Reverse produces a wind-driven fire
• Buoyant, heated gases above fire rise and entrain
  surrounding cool air buoyancy the force through
  which fire thermal energy converted to kinetic
  energy of motion in column
• Height/dynamics of column function of atmospheric
  lapse rate and size/intensity of fire
• Columns attain full potential if winds
  decreasing/constant above fire, while higher
  winds aloft sheer off column
• Solid structure moving across landscape, blocking
  ambient wind, whirlwinds on lee side

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Convection Column Zones

• Fuel bed, combustion turbulence zones (up to
  100m)
• Fire convection zone up to base of convection
  column cap (from 300 to 6000m in height)
• Smoke fallout zone thin layer at base of
  convection cap
• Condensation convection zone or capping cumulus
  rising to top of column smoke still present in
  this zone

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Changing Context of Canadian Fire Management

• Sophisticated fire management systems developed
  over past century highly effective but large
  fires prevalent
• New sustainable development philosophy introduces
  conflicting social, economic and ecological
  demands that fire managers must reconcile
• Globalization of forest industry greater
  consolidation in Canada to stay competitive
  more demands for a secure wood supplyat a time
  when fire suppression effectiveness is reaching
  physical economic limits
• An expanding WUI and an increase in forest-based
  aboriginal communities
• The information explosion (internet, 24-hr news)
  increases public awareness but results in
  increased scrutiny of fire management
  practiceslarger need for outreach and education

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Emerging Issues and Challenges

• Climate Change
• Boreal zone bulls-eye for CC impacts
• More frequent and severe fire activity
• Longer fire seasons
• Increase in area burned
• Shorter fire return intervals
• Less terrestrial C storage
• More smoke transport/public health issues
• Significant impacts on forest
• industry and communities

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Emerging Issues and Challenges

• Managing Public Risk and Expectations in the
  Wildland-Urban Interface
• Lack of building codes requiring fire-resistant
  structures
• Hazard mitigation programs (communities and
  homes) just beginning no pan-Canadian technical
  standard
• Evacuations of northern aboriginal communities
  increasing major smoke/health issues

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Emerging Issues and Challenges

• Forests Under Stress
• Attempted fire exclusion shift to older forests
• Changes in fuel structure/quantity more intense
  fires
• Insect infestations in older forests (e.g.
  mountain pine beetle, spruce budworm) increased
  fire intensity
• Competition for the Forest Land Base
• Economically accessible, merchantable forest
  already allocated
• Pressure to set aside more areas for recreation,
  biodiversity conservation etc.
• Aboriginal groups seeking expanded access for
  traditional pursuits
• These factors have eliminated the buffer stocks
  once available to offset major fire losses

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Emerging Issues and Challenges

• Public Expectation
• Expect that government will protect their values
• Public and stakeholders increasingly involved
• Wildland fire management now a local, provincial
  and federal issue must together engage all
  constituents/shareholders
• Fire Management Infrastructure
• Suppression effectiveness nearing physical and
  economic limits, diminishing marginal returns on
  further investment
• Suppression capacity eroding (aging equipment,
  aircraft)
• Fire management costs rising while budgets
  constrained
• Fire management personnel demographics
  experienced staff retiring with few qualified
  personnel behind

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Canadian Wildland Fire Strategy

• Developed over the past 2-3 years
• Authorized by Canadian Council of Forest
  Ministers after 2003 fire season in western
  Canada (hundreds of homes lost, tens of thousands
  evacuated, hundreds of millions in personal
  property damage, and 1 billion in suppression
  expenditures)
• Declaration signed by all Ministers
  (provincial/territorial/federal) in late 2005
• Framework now in place and agreed-upon in
  principal by all levels of government
• Now looking for funding (estimated at 1 billion
  over next 10 years)
• Political issue now would be helped by
  continuing significant fire years that focus
  public and political awareness

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Increasing Boreal Forest Fire Future Impacts on
Arctic Environment Climate

• POLARCAT Sub-Project
• Not funded by CDN IPY Program
• Two major screening criteria Climate Change and
  Health/Wellness of Northern Communities
• Proposal met first, not second (? obtained
  licence and vetted with aboriginal communities)
• Only 25 of proposals funded (with partial
  funding)
• No real focus on Arctic atmosphere (e.g. aircraft
  emissions proposal not supported)

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POLARCAT Goals Relative to Boreal Fire

• Overall goals of POLARCAT include the following
  related to boreal forest fires
• Study the impact of boreal forest fire emissions
  on the chemical composition of the Arctic
  troposphere.
• Study the pathways of boreal forest fire plumes
  into the Arctic, with particular emphasis on
  plume altitudes.
• Quantification of the impact of the deposition of
  soot from forest fires on the surface albedo of
  snow and ice surfaces, and investigation of the
  linkage with the retreat of Arctic sea ice and
  glaciers.
• Determination of the residence times of pyroCb
  aerosols in the Arctic stratosphere and their
  contribution to stratospheric background aerosol
  concentrations.
• Investigation of the fate and effects of aerosols
  and chemical compounds injected into the
  stratosphere by pyro-convection, including their
  role for ozone formation and ozone depletion in
  the polar stratosphere.

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Boreal Fire Sub-Project of POLARCAT

• This proposed Sub Project of POLARCAT addresses
  these broad goals using a combination of ground-
  and aircraft-based remote sensing platforms to
• characterize the energy release rates and
  convection column dynamics of high-intensity
  boreal forest crown fires.
• measure plume altitude/thickness to determine
  constraints for satellite (e.g. TOMS Aerosol
  Index) and AERONET validation.
• measure water vapor concentration in the UTLS to
  characterize the background and perturbed (smoky)
  state.
• characterize triggers/thresholds for the
  transition of pyroconvection above fires to
  pyroCb development, and determine accurate
  injection heights of smoke products in the UTLS
  zone..
• characterize smoke and aerosol properties soon
  after exiting the convection column and at
  various points downwind in the source region.
• observe/assess the dynamics/effects of non-pyro
  deep convection as it occurs in the Canadian
  boreal realm, as a basis for comparison with
  pyroconvection.
• serve as prime baseline data collector for other
  downwind POLARCAT investigations.

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Methodology

• Location/timing of aircraft deployment
• June/July 2008 in NWT
• Logistical support from fire management agencies
• Forecasting fire occurrence and pyroCb
  development/smoke movement
• tested in 2006 and worked well
• Deployment activities in anticipation of pyroCb
  development
• 3 aircraft in northern Canada (CT-133 jet, Twin
  Otter, Sea Heron)
• Track smoke as far as Greenland (then other
  POLARCAT aircraft)
• PyroCb documentation at source and downstream
• Data analysis/publication/outreach

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Boreal Fire Outlook

• North America
• Increasing fire activity and severity
• Increasing vulnerabilities
• Diminishing marginal returns on more expenditures
• Russia
• Fire management program without funding
• Widespread forest exploitation of forests
  exacerbating fire problems
• No funding for forest protection despite fact
  that natural resources (mining/gas and oil) are a
  major driver of the Russian economy
• Increasing vulnerabilities
• Shift to regional fire control will it happen?
  Will it be funded?
• Major uncertainties going forward

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Final Thoughts

• Fire essential to boreal zone
• Sophisticated fire management programs in North
  America under increasing stress
• Russian fire management basically in limbo
• Increased suppression is both economically
  impossible (decreasing marginal returns) and
  ecologically undesirable
• Projected climate change impacts very significant
• Fire management is, and will be, a continuously
  evolving challenge
• Ability to mitigate impacts very limited
• Adaptation means a new paradigm that accepts
  reality of gtfire
• Addresses more fire through re-evaluation of
  protection levels
• Boreal countries must address this emerging
  change cooperatively
• Solid progress since early 1990s but this must
  expand quickly
• Public political awareness and support will be
  critical

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Thank You!

• Questions?