fire history of the southern rocky mountain trench€¦ · ndt3 – stand-replacing fire, 150 yrs...

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

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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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4

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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6

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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4

6

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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4

6

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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subalpine forest

interior rainforestfire

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woodlands

montane forest

fireseverity

woodlands

montane forest

Effect of Climate Change

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fire riskfire

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montane forest

fire severity

woodlands

montane forest

Effects of Climate and Fuels

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montane forest

fire severity

woodlands

montane forest

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subalpine forest

interior rainforestfire

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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