Assessing the Vulnerability of Tree Species in the Sub-Boreal Spruce Zone to Climate Change

Craig Nitschke, Ph.D., F.I.T.BV Research Centre,

Dept. Forest Resources Mgt, University of British ColumbiaSchool of Forest and Ecosystem Science, University of Melbourne

By:Craig Nitschke, Rasmus

Astrup, Aaron Trowbridge

OutlineIntroduction

Research Area & Objectives

Methods

Results

Summary

A History of Climatic ChangeClimate is changing, but it always has!

In the last 14,000 years we have seen the end of a:

Great Ice Age (10,000 – 14,000 yrs);Medieval Warm Period (850 – 1250); Little Ice Age (1350 - 1850)

In the last century we have warmed by 0.6 °C

Now we are in a period of rapid climate change

Global Warming

Projected Climate Change

For WorldGCMs predict a 1.4 to 5.8 ºC increase by 2085

For CanadaGCMs predict a 4.9 to 6.8 ºC increase by 2085

Northern Canada & AlaskaUp to a 10 ºC increase in temperature predicted in some locations

Impacts of Climate ChangeIncreased frequency and severity of natural disturbancesIncreased Variability in Weather AnomaliesChanges in phenological responsesShifts in Species Distributions

Change in ecosystems compositions

Extinction and Extirpation

Research Area & Objectives

Year 1 of Multi-Year FSP Project

Assessing the vulnerability to climate change from the tree- to the stand- to the landscape-level

Year 1: regeneration and site type

Link to ongoing FSP project investigating the influence of site type on competition

Year 2 : Species competition & stand succession under climate change

Study Area

Bulkley Valley

Sub-Boreal Spruce Zone

SBSdkSBSmc2

Elevation500 -1400 m

SBSdk: 500-1100 mSBSmc2: 500-1350 m

Smithers

A.P. Topley

Landing

Research Questions

Are tree species in the Sub-Boreal Spruce zone vulnerable to predicted climate change in their regeneration niche?

What climate thresholds are trigger points for species?

Methods

Vulnerability Approach

Vulnerability assessments of ecosystems to climate change are recommended by the IPCC

Assessed Vulnerability of Species in their Regeneration Niche

Species and ecosystems are most sensitive in the regeneration phase to changes in climateMature individuals and communities can withstand large changes in climate

Biological InertiaDisturbances that remove mature communities/ individuals will require regeneration for ecosystem to sustain itself

Why Species and Ecosystem Vulnerability?

Ecosystems are the basic units of nature on Earth

Determined by the interaction between biotic and abiotic components

Maintenance of ecosystems health and function are at the foundation of sustainable forest management

If ecosystems are vulnerable:Ecological services they provide are threatened sustainable management is threatened

AdaptationHow do you undertake adaptation if you do not understand what needs to be adapted?

Ecological Resilience

Adapted from Gunderson and Holling (2001)

α Κ

Γ Ω

Connectedness

Resilience

Exit

Reorganisation

Exploitation

Conservation

Release

Modelling Species and Ecosystem Response

TACA Tree and Climate Assessment

Nitschke and Innes. 2008. A tree and climate assessment tool for modelling ecosystem response to climate change. Ecological Modelling 210 (3): 263-277.

Fundamental-regeneration niche modelMechanistic model Species response to climate-driven biophysical mechanisms that hinder/ prevent regeneration

Assess the regeneration potential of species under different climate scenarios and edaphic conditions (i.e. presence/ absence)

CurrentClimate Change Projections

Model Parameterisation

Empirical-based thresholdsPeer-Reviewed Literature

Field surveys Soil DepthSoil Texture Slope PositionSMR-SNR

Climate Transects1400 m

500 m

ESSF

SBS

North South

Environmental Lapse Rates

• Temperature (0.58 C/ 100m)

• Precipitation (5.3 %/ 100m)

Northern aspects are 1-3 C warmer than Southern aspects

100 m Plot Interval

Microclimate Treatments

T1: Open Stand ConditionsNorth AspectSouth Aspect

T2: Understorey ConditionsNorth AspectSouth Aspect

A B CA B C

T1 T2

Edaphic

ConditionsA: Xeric

B: Mesic

C: Subhygric

D: hygric

+

Climate/ Weather Data

2 Weather Stations

Generated Multiple climate scenarios for each station

Average climateBelow Average Climate (x 2)Above Average Climate (x 2)

Represent observed variability in historical climate records

Daily Resolution

Multiple stations increase variability

Smithers A.P. Topley

Landing

Climate Change Predictions

Pacific Climate Impacts ConsortiumCGCM2

SRES A2X Scenario

CGCM2SRES B2X Scenario

Hadley CM3SRES A2X Scenario

Hadley CM3SRES A1F1 Scenario

Direct Adjustment ApproachMonthly resolution

Climate Change Scenarios: Ensemble

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Minimum Temperature Maximum Temperature Precipitation

Climate Variable

Cha

nge

in C

limat

e (

o C &

% )

20252055

2085

Testing for Differences

Student’s t-test

Test for difference in regeneration potential between climate scenarios

Test for difference in soil moisture between climate scenarios

Standard error and confidence intervals

Results

Regeneration Potential Weighted by Proportion of Site Types

1: NilRegeneration Probability = 0

2: Rare Regeneration Probability = < 0.10

3: InfrequentRegeneration Probability = 0.10 – 0.25

4: FrequentRegeneration Probability = 0.25 - 0.50

5: Very FrequentRegeneration Probability = > 0.50

Change in Regeneration Potential non-spatial!

By 2025:South Aspect:

3 species respond significantly (Sx, Sb, Se)North Aspect:

2 species (Fd, Lw)

By 2055South Aspect:

6 species respond significantly (Bl, Pa, Pl, Sx, Sb, Se)North Aspect:

3 species (Sx, Sb, Se)

By 2085South Aspect:

10 species respond significantly (Ac, At, Bl, Ep, Hw, Pa, Pl, Sx, Sb, Se)North Aspect:

5 species (Bl, Pl, Sx, Sb, Se)

Regeneration Potential South Aspect

1

2

3

4

5

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Reg

ener

atio

n Po

tent

ial

Current202520552085

Regeneration Potential North Aspect

1

2

3

4

5

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Reg

ener

atio

n Po

tent

ial

Current202520552085

Change in Regeneration Potential: Understorey

non-spatial!

By 2025:South Aspect:

1 species respond significantly (Pm)North Aspect:

7 species (Bg, Cw, Dm, Fd, Lw, Pm, Py)

By 2055South Aspect:

6 species respond significantly (Bl, Pa, Pl, Sx, Sb, Se)North Aspect:

2 species (Bg, Dm)

By 2085South Aspect:

11 species respond significantly (At, Ba, Bl, Ep, Hm, Hw, Pa, Pl, Sx, Sb, Se)North Aspect:

3 species (Ba, Dm, Sb)

Regeneration Potential Understorey: South Aspect

1

2

3

4

5

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Reg

ener

atio

n Po

tent

ial

Current202520552085

Regeneration Potential Understorey: North Aspect

1

2

3

4

5

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Reg

ener

atio

n Po

tent

ial

Current202520552085

Vulnerability Classes: Based on IUCN Categories

0 = NilNo change or Increase in range

1 = Low< 20 % contraction in range

2 = Medium< 40 % contraction in range

3 = High< 50 % contraction in range

4 = Very High 80 % contraction in range

Species Vulnerability South Aspect

0

1

2

3

4

5

6

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Vuln

erab

ility

Cla

ss

202520552085

Species Vulnerability North Aspect

0

1

2

3

4

5

6

7

8

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Vuln

erab

ility

Cla

ss

202520552085

Understorey Species Vulnerability South Aspect

0

1

2

3

4

5

6

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Vuln

erab

ility

Cla

ss

202520552085

Understorey Species Vulnerability North Aspect

0

1

2

3

4

5

6

Blac

k C

otto

nwoo

d

Trem

blin

g As

pen

Amab

ilis F

ir

Gra

nd F

ir

Suba

lpin

e Fi

r

Wes

tern

Red

ceda

r

Mou

ntai

n Al

der

Pape

r Birc

h

Dou

glas

-fir

Wes

tern

Lar

ch

Whi

teba

rk P

ine

Lodg

epol

e Pi

ne

Wes

tern

Whi

te P

ine

Pond

eros

a Pi

ne

Blac

k Sp

ruce

Enge

lman

n Sp

ruce

Hyb

rid W

hite

Spr

uce

Wes

tern

Hem

lock

Mou

ntai

n H

emlo

ck

Species

Vuln

erab

ility

Cla

ss

202520552085

Summary of Vulnerability: Open Sites

0

1

2

3

4

5

6

7

8

9

10

2025 2055 2085

Climate Period

Num

ber o

f Spe

cies Nil

LowMediumHighVery HighExtreme

0

2

4

6

8

10

12

2025 2055 2085

Climate Period

Num

ber o

f Spe

cies Nil

LowMediumHighVery HighExtreme

South Aspect

North Aspect

Summary of Vulnerability: Understorey

0

2

4

6

8

10

12

2025 2055 2085

Climate Period

Num

ber o

f Spe

cies Nil

LowMediumHighVery HighExtreme

0

2

4

6

8

10

12

14

16

18

2025 2055 2085

Climate Period

Num

ber o

f Spe

cies Nil

LowMediumHighVery HighExtreme

South Aspect

North Aspect

Species Diversity: South Aspects

50060070080090010001100120013001400

Curre

nt20

2520

5520

85

0

2

4

6

8

10

12

14

16

Number of Species

ElevationClimate Period

Species Diversity: North Aspects

50060070080090010001100120013001400

Curre

nt20

2520

5520

85

0

2

4

6

8

10

12

14

16

Number of Species

ElevationClimate Period

Driving Variables for Species Response

Soil Water Deficits Open Sites

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

Soil 1 Soil 2 Soil 3

Soil Type

Ann

ual A

ET/P

ET R

atio

Current202520552085

Driving Variables: Open Sites

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Growing DegreeDays

MinimumTemperature

ChillingRequirement

Soil 1-Drought Soil 2-Drought Soil 3-Drought Frost Days Frost Damage

Driving Variable

Prob

abili

ty o

f Thr

esho

ld E

xcee

ded

Current202520552085

Driving Variables: Understorey Sites

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Growing DegreeDays

MinimumTemperature

ChillingRequirement

Soil 1-Drought Soil 2-Drought Soil 3-Drought Frost Days Frost Damage

Driving Variable

Prob

abili

ty o

f Thr

esho

ld E

xcee

ded

Current202520552085

Vulnerability of dominant Sub-Boreal Spruce zone tree species

Black Cottonwood

Current 2025

Black Cottonwood

Current 2055

Black Cottonwood

Current 2085

Trembling Aspen

Current 2025

Trembling Aspen

Current 2055

Trembling Aspen

Current 2085

Lodgepole Pine

Current 2025

Lodgepole Pine

Current 2055

Lodgepole Pine

Current 2085

Hybrid White Spruce

Current 2025

Hybrid White Spruce

Current 2055

Hybrid White Spruce

Current 2085

Black Spruce

Current 2025

Black Spruce

Current 2055

Black Spruce

Current 2085

Subalpine Fir

Current 2025

Subalpine Fir

Current 2055

Subalpine Fir

Current 2085

Western Hemlock

Current 2025

Western Hemlock

Current 2055

Western Hemlock

Current 2085

The Bulkley Valley in the Future?

Douglas-Fir

Current 2025

Douglas-Fir

Current 2055

Douglas-Fir

Current 2085

Western Larch

Current 2025

Western Larch

Current 2055

Western Larch

Current 2085

Ponderosa Pine

Current 2025

Ponderosa Pine

Current 2055

Ponderosa Pine

Current 2085

Understorey?

Ponderosa Pine: Understorey

Current 2025

Ponderosa Pine: Understorey

Current 2055

Ponderosa Pine: Understorey

Current 2085

Western Red Cedar: Understorey

Current 2055

Western Red Cedar: Understorey

Current 2055

Western Red Cedar: Understorey

Current 2085

Western Hemlock: Understorey

Current 2025

Western Hemlock: Understorey

Current 2055

Western Hemlock: Understorey

Current 2085

Summary

General Pattern of ResponseContraction from lower elevations to higher elevations

Increase in drought conditionsIncrease in temperatureDecline in chilling weeks

Contraction from xeric-mesic sites with increased water deficits

Drought

Expansion to higher elevationsIncrease in temperatureIncrease in chilling weeksIncrease in frost free periodDecrease in growing season frosts

Are SBS Species Vulnerable?

All dominant SBS species exhibited a:significant contraction in regeneration potentialcontraction to higher elevation

Understorey conditions ameliorated responsesSignificant change occurs at higher degree of climate change

Aspect moderated responsesNorth aspects will benefit understorey species over shade-intolerant species

The Future BV Ecosystems?

Below 1000 m Dominants

Douglas-firWestern larchPonderosa pineTrembling aspen

(above 600 m) Understorey

Douglas-firPonderosa Pine

Western hemlockWestern red cedar

Grand firWestern white pine

Above 1100 m

All current SBS Species

But suitable, to some degree, for most lower elevation species

Are there Thresholds?

Increase in evapotranspiration offsets increase in precipitation

Increase in soil water deficits

Variable Response by Species by SiteOpen sites

South: 1.3 °C to 5.2 °C North: 2.8 °C to 5.2 °C

UnderstoreySouth: 2.8 °C to 5.2 °C North: 5.2 °C

Bl, Sx: no significant response

Take Home MessageThese are NOT predictions, it is an assessment of vulnerability

Conducted to provide and understanding of a hazardAllows for management under risk not uncertainty

Even if the assessment is 50 % wrong the dominant SBS species are still vulnerable!

The cost of doing nothing could far outweigh the costs of undertaking adaptation

Mitigation is more expensive than Adaptation

Acknowledgements

B.V. Centre

Forest Sciences Program

Ministry of ForestsDave CoatesAlex Woods

Prof. John InnesUBC

TACA (Nitschke and Innes 2008)

Daily Weather ParametersMaximum TemperatureMinimum Temperature

Precipitation

Growing Degree Day Requirements met?

Heat Sum Accumulated until Bud Burst

Drought Tolerance Exceeded?

Chilling Week Requirement Met?

YesNo

Minimum Temperature Threshold Exceeded?

Growing Season Frost Event Occurs?

NoYes NoYes

Absent Absent

Absent

YesNoNoYes

Absent Regeneration in Scenarioi

Regeneration Probability Modified

Multiple Annual Climate ScenariosMean Daily Scenario

Below Average Scenarios Above Average Scenarios

Presence/ Absence Probability:P/A = (∑Regeneration in Scenarioi

)/ Total # of Scenarios

Frost Free Period Exceeded?

Yes No

Absent

Understorey

50060070080090010001100120013001400

Curre

nt20

2520

5520

85

0

2

4

6

8

10

12

14

16

18

Number of Species

ElevationClimate Period

50060070080090010001100120013001400

Curre

nt20

2520

5520

85

0

2

4

6

8

10

12

14

16

18

Number of Species

ElevationClimate Period

Soil Water Deficits Understorey Sites

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

Soil 1 Soil 2 Soil 3

Soil Type

Ann

ual A

ET/P

ET R

atio

Current202520552085

North-Open

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

Soil 1 Soil 2 Soil 3

Soil Type

Ann

ual A

ET/P

ET R

atio

Current202520552085

Impacts of Recent Climate Change

1896

Impacts of Recent Climate Change

1996

Assessing the Vulnerability of Tree Species in the Sub-Boreal Spruce Zone to Climate ChangeOutlineA History of Climatic ChangeSlide Number 4Impacts of Climate ChangeResearch Area & ObjectivesYear 1 of Multi-Year FSP ProjectStudy AreaResearch QuestionsMethodsVulnerability ApproachWhy Species and Ecosystem Vulnerability?Ecological ResilienceModelling Species and Ecosystem ResponseModel ParameterisationClimate TransectsMicroclimate TreatmentsClimate/ Weather DataClimate Change PredictionsClimate Change Scenarios: EnsembleTesting for DifferencesResultsRegeneration Potential�Weighted by Proportion of Site TypesChange in Regeneration Potential�non-spatial!Regeneration Potential�South AspectRegeneration Potential�North AspectChange in Regeneration Potential:�Understorey� non-spatial!Regeneration Potential�Understorey: South AspectRegeneration Potential�Understorey: North AspectVulnerability Classes: �Based on IUCN CategoriesSpecies Vulnerability �South AspectSpecies Vulnerability �North AspectUnderstorey Species Vulnerability �South AspectUnderstorey Species Vulnerability �North AspectSummary of Vulnerability:�Open SitesSummary of Vulnerability:�UnderstoreySpecies Diversity: South AspectsSpecies Diversity: North AspectsDriving Variables for Species ResponseSoil Water Deficits �Open SitesDriving Variables: �Open SitesDriving Variables: �Understorey SitesVulnerability of dominant Sub-Boreal Spruce zone tree species �Black CottonwoodBlack CottonwoodBlack CottonwoodTrembling AspenTrembling AspenTrembling AspenLodgepole PineLodgepole PineLodgepole PineHybrid White SpruceHybrid White SpruceHybrid White SpruceBlack SpruceBlack SpruceBlack SpruceSubalpine FirSubalpine FirSubalpine FirWestern HemlockWestern HemlockWestern HemlockThe Bulkley Valley in the Future?Douglas-FirDouglas-FirDouglas-FirWestern LarchWestern LarchWestern LarchPonderosa PinePonderosa PinePonderosa PineUnderstorey?Ponderosa Pine:�UnderstoreyPonderosa Pine:�UnderstoreyPonderosa Pine:�UnderstoreyWestern Red Cedar:�UnderstoreyWestern Red Cedar:�UnderstoreyWestern Red Cedar:�UnderstoreyWestern Hemlock:�UnderstoreyWestern Hemlock:�UnderstoreyWestern Hemlock:�UnderstoreySummaryGeneral Pattern of ResponseAre SBS Species Vulnerable?The Future BV Ecosystems?Are there Thresholds?Take Home MessageAcknowledgementsTACA�(Nitschke and Innes 2008)Understorey Soil Water Deficits �Understorey SitesNorth-OpenImpacts of Recent Climate ChangeImpacts of Recent Climate Change