fire history of the southern rocky mountain trench€¦ · ndt3 – stand-replacing fire, 150 yrs...
TRANSCRIPT
Lori Daniels & Jed Cochrane, University of British Columbia
Bob Gray, University of Victoria
Presented at Timber Growth and Value Conference: Smithers, BC 2008
Fire History of the Southern Rocky Mountain Trench
Severe drought contributed to
“unprecedented”fires
August 2003
The Fire Suppression Paradox
fire exclusion fuels buildupunusually
severe fires
human costseconomic losses
mitigation:prescribed burns
thinning
stand-maintaining
fires
+
Does this apply in British Columbia?
fire exclusion fuels buildupunusually
severe fires
human costseconomic losses
mitigation:prescribed burns
thinning
mixed fireregime
+ ??
Fire Regimes in BC
• How do fire regimes vary in mountain ecosystems?
• Have humans altered fire regimes?
• How does climate affect fire regimes?
Interpreting Fire Regimes
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dry wet
fuel
ava
ilabi
lity
fuel
com
bust
ibili
ty
fire frequency
grasslandsw
oodlands
subalpine forest
interior rainforest
montane forest
fireseverity
Historical Fire Regimes in Mountain Ecosystems
Grassland-woodland
Alpine tundra
Montaneforests
Subalpineforest
Interiorrainforest
Montane Spruce Forests:NDT3 – stand-replacing fire, 150 yrs
– even-aged, pine-dominated- Wildfires in late 1800s- Mining era 1858-1920- Industrial logging 1950-present
Jed
Montane Forests
Montane Spruce Forests in the East Kootenays
Structurally complexstands = 25% ofmontane forests
Crossdated Fire Records
• Fire records30 sites
>250 trees>400 scars
• Return Intervallocal scaleregional scale
1809
1837
1858
Site-Level Fire Chronologies
S
Start dates: 1449 to 1828Median fire intervals: 10 to 26 yrs Interval range: 2 to 123 yrs
Fire Record 1: 100 disks 295 scars 1540-1944
10 Old Growth Sites
Daniels et al. 2007
Fire Record 1: 100 disks 295 scars 1540-1944
10 Old Growth Sites
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6
20 Representative Sites
Daniels et al. 2007
Fire Record 2: 149 disks 272 scars1509-2003
, Cochrane 2007
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Daniels et al. 2007, Cochrane 2007
10 Old Growth Sites1858-1944: settlement
20 Representative Sites
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Daniels et al. 2007, Cochrane 2007
10 Old Growth Sites 1770-1857: pre-settlement1858-1944: settlement
20 Representative Sites
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Daniels et al. 2007, Cochrane 2007
10 Old Growth Sites 1770-1857: pre-settlement1858-1944: settlement1945-2006: modern era
20 Representative Sites
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Daniels et al. 2007, Cochrane 2007
10 Old Growth Sites 1770-1857: pre-settlement1858-1944: settlement1945-2006: modern era
1509-19441 fire every 3 years
20 Representative Sites
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Daniels et al. 2007, Cochrane 2007
10 Old Growth Sites 1770-1857: pre-settlement1858-1944: settlement1945-2006: modern era
1509-19441 fire every 3 years
1945-2006Expected c. 20 scarsObserved 6 scars20 Representative Sites
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Daniels et al. 2007, Cochrane 2007
10 Old Growth Sites 1770-1857: pre-settlement1858-1944: settlement1945-2006: modern era
1509-19441 fire every 3 years
1945-2006Expected c. 20 scarsObserved 6 scars
Contributing factors:- fire exclusion/suppression- cessation of burning
by First Nations- climate variation
20 Representative Sites
Global Climate and the Kootenays
El Niño – La Niña
Pacific Decadal Oscillation
“teleconnections”
AtlanticMultidecadalOscillation
Global Climate and Fire
• 1900-22 – highly susceptible to fire• 1923-43 – more fires during El Niños• 1944-66 – less conducive to fire• Since 1981 – more fires during El Niños (e.g. 2003)
+AMO - AMO
+ PDO El Niño El Niño La Niña
- PDO Few fires La Niña
PDO AMOEl Niño-La Niña
Lessons learned …
• Historical fires in mountains – low to high frequency + severity
• Climate influences on fire– global climate influences drought and fires
• Human influences on fire– fire free period = natural variation
+ fire suppression
Implications for Ecological Restoration
• Historical fires ranged from low to high severity• Suppressed many stand-maintaining fires• Current forest structures =
natural processes + fire suppression effects
Should we thin the forest and prescribe fire…to mitigate to reduce fire hazard?
to restore the ecosystem?
Prescribed FiresKootenay National Park
September 2007
Effect of Climate Change
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dry wet
fuel
ava
ilabi
lity
fuel
com
bust
ibili
ty
grasslands
subalpine forest
interior rainforestfire
frequency
woodlands
montane forest
fireseverity
woodlands
montane forest
Effect of Climate Change
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dry wet
fuel
ava
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lity
fuel
com
bust
ibili
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grasslands
subalpine forest
interior rainforest
fire riskfire
frequency
woodlands
montane forest
fire severity
woodlands
montane forest
Effects of Climate and Fuels
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dry wet
fuel
ava
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lity
fuel
com
bust
ibili
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grasslands
subalpine forest
interior rainforestfire
frequency
woodlands
montane forest
fire severity
woodlands
montane forest
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dry wet
fuel
ava
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lity
fuel
com
bust
ibili
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grasslands
subalpine forest
interior rainforestfire
frequency
woodlands
montane forest
fire severity
Effects of Climate and Fuels
Conclusions• Fire is natural and important for forests
• Increased risk of severe fires– humans impacts, droughts + global warming
• Solutions: mitigation and restoration
• BUT, fires will burn in future – with positive and negative effects
Acknowledgements• Thanks to Brad Gooderham, Janneke Lade,
Trevor Jones, Jillian Cochrane, and Brent Watson for assistance in the field and lab.
• Funding was provided by Tembec and Canfor, Forest Investment Account and Forest Science Programs of British Columbia and Parks Canada