Climate Change and Forest Fire Activity in Canada

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Climate Change and Forest Fire Activity in Canada

• B.J. Stocks, M.D. Flannigan, B.M. Wotton, B.D.
  Amiro, and J.B. Todd
• Natural Resources Canada Canadian Forest Service

Presentation to Senate Standing Committee on
Agriculture and Forestry April 10, 2003 Ottawa,
Ontario
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Circumboreal Forest Fire Activity

• Annual burned area 5-15 million hectares
• Primarily Canada, Russia and Alaska
• Russian stats underestimated should be 5 to 10
  times higher
• Area burned shows great inter-annual variability
• Continental climate, extreme weather/fire danger
  conditions, multiple ignitions, and closed canopy
  forests are main drivers of boreal fire activity

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Boreal Fire Importance/Characteristics

• Dominant disturbance regime, natural essential
  to ecosystem maintenance, C cycling, biodiversity
• Sensitive to climate change major carbon budget
  implications - 40 of terrestrial C in boreal
  zone
• High fuel consumption, fast spread rates,
  sustained high intensity levels, towering
  convection columns (upper troposphere) with
  long-range smoke transport potential

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Canadian Fire Statistics

• Incomplete prior to 1970
• lt certainty further back in time
• Now 8000 fires, 2.8 million ha/yr
• 500 million annually
• Area burned is highly episodic
• 0.7 to 7.6 million ha
• Level of protection issue
• Protect resources vs natural fire
• Lightning fires
• 35 of total fires /85 AB
• Fire size
• 3 of fires are gt200 ha (used in Large Fire
  Database)
• Remainder suppressed early
• Represent 97 of area burned

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Large Fire Database (LFDB)

• Fires gt200 ha post-1950 nationally
• Polygons with attributes (fire size, cause, start
  and end dates etc.) from fire management agencies
• 1980s fires in central Canada illustrated
• Updated annually working back in time with
  satellite imagery

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Lightning/Human-Caused Fires

• Most lightning fires in north, H-C along travel
  corridors
• Generally lightning fires grow larger
  detection/access issue
• Lightning fire contribution to area burned
  increasing in recent decades

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Actioned/Non-Actioned Fires

• Many fires allowed to burn naturally, mainly in
  north
• Management decision based on values-at-risk
• Constitutes 50 of area burned in Canada
  post-1959

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LFDB Fire Size Distribution by Ecozone
Greatest area burned in boreal and taiga zones
of west-central Canada where unsuppressed fire
is common and fire climate most severe
Larger size-class fires, although less frequent,
account for most of area burned
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Carbon Release Through Fire

• Direct release to atmosphere averages 27 Tg C/yr
  (20 of Canadas fossil fuel emissions) -
  preliminary estimate - need further
  severity/decomposition work
• Younger forests weaker C sinks than mature
  forests
• Takes 20-30 years to fully recover after fire
  (confirmed from flux tower, aircraft and
  satellite measurements)

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Disturbances and the Carbon Budget
Note rise in natural disturbances (fire and
insects) post 1970
Corresponding decrease in C sink strength of CDN
forest post-1970
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Anticipated Changes in Seasonal Fire Danger and
Fire Season Length
Fire season length increases by 10 to 50 days by
2090
Seasonal fire danger increases by 50-100 by 2090
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Anticipated Fire Impacts

• Increase in weather conditions conducive to fires
  
• More frequent and severe fire activity
• Projected impacts
• More area burned, shorter fire return intervals
• Younger age class structure
• Ecosystem boundary/vegetation shifting
• Less terrestrial C storage
• Impacts on forest industry/communities
• Health/pollution issues
• Positive feedback to climate change (gtGHG
  emissions)
• Need to quantify impacts in order to assess
  options
• Adaptation will be required
• Ongoing CFS climate change/fire research
  addressing impacts and adaptation in
  collaboration with provinces/territories
• Funding through Green Plan, Climate Change Action
  Fund, Action Plan 2000 and CRAs with provinces

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Adapting to Increasing Fire Activity

• Local scale
• Community protection (FIRESMART)
• Regional scale
• Pilot fuelbreaks project break up fuel
  continuity to limit fire effects on fiber
  production
• Level of protection effectiveness studies cost
  of maintaining status quo with increasing risk,
  protect less and permit more natural fire
• National scale
• Cannot mitigate fire impacts across whole boreal
  forest
• Adapt based on values-at-risk
• Evaluate the impacts of an increased fire regime
  for policy-makers

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Questions?