Transcript Projecting Future Canadian Forest Fire Regimes and Impacts

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
Circumboreal Forest Fire
Activity
• Annual burned area: 5-15 million
•
•
Annual Area Burned 1980-1999
8
•
6
5
4
ALASKA
3
RUSSIA
CANADA
2
1
1998
ALASKA
1999
1996
1997
1994
1995
1992
CANADA
1993
1990
1991
1988
1989
1986
1987
1984
1985
1982
1983
1980
0
1981
Area Burned ( 10 6 ha )
7
•
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
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
Canadian Fire Statistics
•
•
•
•
•
•
•
•
Incomplete prior to 1970
< 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 >200 ha (used in Large
Fire Database)
 Remainder suppressed early
 Represent 97% of area burned
Large Fire Database (LFDB)
• Fires >200 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
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
Hum an- vs. Lightning-Caused Fires by Decade
Area Burned (x10 6 ha)

30
25
Lightning
Human
20
15
10
5
0
1959-69
1970-79
Years
1980-89
1990-99
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
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
All Ecozones
35.0
30.0
Percent
25.0
20.0
15.0
10.0
5.0
0.0
1
Area Burned
2
3
No. of Fires
4
5
6
Size Class
7
8
9
Carbon Release Through Fire
• Direct release to atmosphere averages 27 Tg C/yr (20% of
Canada’s 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)
160
Fire
140
Fossil Fuel
120
100
80
60
40
20
0
1958
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
Megatonnes Carbon
Canadian Direct Carbon Emissions
Year
10
8
6
4
2
0
1920 1940
1960 1980
ClearCut Fire Insects
Note rise in natural disturbances (fire and insects)
post 1970
2000
Total
Tg C / yr
Area (Million ha)
Disturbances and the Carbon Budget
Corresponding decrease in C sink strength
of CDN forest post-1970
400
300
200
Note change
after 1970
Sink
100
0
-100
Source
-200
1920
1940
1960
Variable Temp
1980
2000
Constant Temp
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
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 (>GHG
•
•
•
•
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
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
Questions?