Climate-related drought resistance of Douglas-fir

Sheel Bansal, Connie Harrington,

Peter Gould, J. Bradley St. Clair

Pacific Northwest Research Station

USDA Forest Service

Genotypic and environmental effects on water deficit and water

loss in coastal Douglas-fir(Pseudotsuga menziesii

var. menziesii)

Genetic differentiation

 Pseudotsuga menziesii var. 

menziesii

 Pseudotsuga menziesii var. 

glauca

U.S. Geological Survey

 http://www.galuzzi.it

Barrie Andrian

 Pseudotsuga menziesii var. men

ziesii

Genetic differentiation

CaliforniaOregon

Environmental effects

Same populationTwo environments

Temperature

Copyright © 2014, PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu Map created 5 May 2014

PrecipitationSummerSummer WinterWinter

WA coast

CA inland

Climate is getting warmer and drier

Decrease in June, July and August precipitation

Mote and Salathé. 2009. Future climate in the Pacific Northwest

Key questions

Which populations are most at risk?

Which populations are least at risk?

Key questions

Is there variation in drought-resistance among populations?What are the climate factors associated with drought-resistance?How do environmental conditions interact with genotype to influence drought-resistance?

Hypothesis:Populations from warmer, drier climates will be more drought-resistant that those from cool climates.

Test: Genecology, reciprocal transplant study• Multiple populations at multiple

common gardens

0 1 2 3 4 5 6 7 80

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Aridity

Dro

ught

-res

ista

nce

Warmer, drier source-climateCooler, wetter source-climate

Hypothesis:Populations from warmer, drier climates will be more drought-resistant that those from cool climates.

Test: Genecology, reciprocal transplant study• Multiple populations at multiple common

gardens

0 1 2 3 4 5 6 7 80

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Aridity

Dro

ught

-res

ista

nce Warm conditions

Cool conditions

DF Seed-Source Movement Trial

60 populations9 test sites 5-years

Drought-resistance trial

Doorstop (WA high elevation): coldest, wettest siteMean max T = 16.1° CGrowing season precip = 671 mm

Buckhorn (WA low elevation): intermediate siteMean max T = 18.7° CGrowing season precip = 420 mmStone (OR low elevation): warmest, driest siteMean max T = 24.9° CGrowing season precip = 184 mm

35 populations3 test sites

Drought-resistance traits

8 cm of twig collectedtransport in ziplock bag

Leaf drying curve

Transpirationmin

0 1 2 3 4 5 6 7 8 9 100

0.10.20.30.40.50.60.70.80.91

Days

Wei

ght (

g)Mass loss/time

Seal end of twig with wax

Drought-resistance traits

8 cm of twig collectedtransport in ziplock bagfresh weight and leaf areaWater deficit and Specific leaf area

Place end of twig in waterturgid weightdry weightWater deficit (TW-FW)/(TW-DW)

Specific leaf area leaf area/dry leaf mass

Trait

Source-climate

3 test sites

35 populations

significance

G x E interaction• Only at

warm test site

Genetic effects• Trees from

warmer climates had

< water loss

Environmental effects(phenotypic plasticity)• Trees at warm

site had < water loss (cuticle thickening)

Genetic effectsTrees from cooler climates had lower rates of water loss (cuticle thickening)

Winter-drought• Needle

desiccation and mortality

Auto-correlated traits• Cold-hardiness =

drought-resistanceAuto-correlated

climate• cold winters +

warm summersMultiple climate variables• simple linear

relationships inadequate

Multiple regression• transpirationmin = 0.19 +

0.0067*Tmin + 0.00012*PrecipGS (R2 = 0.66)

Multiple regression• transpirationmin = 0.19 +

0.0067*Tmin

+ 0.00012*PrecipGS (R2 = 0.66)

Transpirationmin

ConclusionPopulations from regions with:

a)cool winters + dry summers >> drought-resistance.

b)dry summers + warm conditions > drought-resistance

c)cool-climate have ‘built-in’ protection against drought

Questions?

sheelmbansal@fs.fed.us