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TREE SELECTION IN ACHANGING CLIMATE

Bert Cregg, Ph.D.Michigan State UniversityDepartment of HorticultureDepartment of Forestry

Program Outline

Midwest climate: Trends and Predictions Urban trees: The canary in the coalmine? Potential impacts of climate change on urban

trees Tree selection strategies for dealing with

climate change Tying it all together

Midwest climate:Trends and Predictions

Industrial revolution

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Since the mid-1800’s CO2 concentration hasincreased from 280 ppm to ~395 ppm Predicted to reach 700 ppm by 2050

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Recent changes in MinnesotaClimate warm winters, during which higher

temperatures have been both persistent andsubstantial; higher minimum temperatures; increased episodes of high summer dew

points; greater annual precipitation, most profoundly

in seasonal snowfall and thunderstormrainfall.

Seeley, Mark W. Minnesota Weather Almanac

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2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Annual minimum Temp MSP

Zone 4b

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Minimum temperatures are warming faster thanaverage temperatures

Krakauer, 2012

Urban trees: The canary in the coalmine?

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Atmospheric water Vapor pressure deficit:at 30% RH VPD doubles for each 20oF(11oC) increase in temperature

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55/13 75/24 95/35 115/46

temperature (F/C)

vapo

r pr

essu

re (

kPa)

VP deficitActual VP

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tem

pera

ture

(o C)

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12am 4am 8am 12pm 4pm 8pm 12am0

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vapo

r pre

ssur

e de

ficit

(kPa

)downtownEast campusLincoln WSO

Cregg and DixFig. 3

Cregg and Dix 2001. J. Arbor. 27:8-17

108oF

117oF

126oF

Cregg and Dix 2001. J. Arbor. 27:8-17

Respirationincreasesexponentially withtemperature

Source: Bolstad et al. 1999.Tree Phys. 19:871-878.

The great March warm-up of 2012

2012 Daily high temperatures vs. 25-year average high

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1-Jan 15-Jan 29-Jan 12-Feb 26-Feb 11-Mar 25-Mar 8-Apr 22-Apr

2012

25 yr avg

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March 19, 2012

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What goes up…

April 2012 Daily low temperatures

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1-Apr 8-Apr 15-Apr 22-Apr 29-Apr

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Was 2012 an aberration or sign ofthings to come?

Impacts of climate change on phenology

Source: Badeck et al. 2004. New Phyologist. 162:295-309 Source: Gunderson et al. 2012 Global Change Biology 18:2008-2025.

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Source: Gunderson et al. 2012 Global Change Biology 18:2008-2025.

Strategies for dealing with climatechange

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Organisms have three principlemeans to respond to a change intheir environment Migration Adaptation Acclimation

Assisted colonization

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BC Forest Service AssistedMigration Adaptation Trial

Provenance tests as surrogatesfor climate change

Schmidtling 1994: Tree Phys. 14:805-817

Moving seed sources northwardoften results in increased growth

Schmidtling 1994: Tree Phys. 14:805-817

Northern seed sources break bud early andmay be subject to late frosts

Johnsen et al. 1996. Tree Phys. 16:375-380

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Physiological acclimation MSU Shade Tree Acclimation Study

MSU Shade Tree Acclimation Study

Species varyin theirability toacclimate toincreasedgrowthtemperature

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Out-planting this spring with Greening ofDetroit

Tying it all together

Midwest climate is getting warmer –especially winter temperatures Trees in urban and community forests are

already ‘living on the edge’ Changes in phenological patterns and

drought stress are likely to be first impacts

Tying it all together(cont.) Moving species and seed sources northward Diversity remains the most viable risk

management tool

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Selecting a diversified portfolio Abundance of major tree genera in six Midwest cities:1980 vs. 2005

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Acer

Picea

Thuja

Fraxinus

Quercu

sPinu

s

Prunus

Jugla

ns

Cercis

Morus

abun

danc

e (%

) 1980 2005

Source: Wade 2010

Are we making progress?

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Pacific sunset mapleAcer truncatum x A. platanoides‘Warrenred’

Photo: ‘Great trees for Kansas City’ FaceBook Page

Espresso Kentucky coffeetreeGymnocladus dioicus “Espresso-JFS”

Photo: ‘Great trees for Kansas City’ FaceBook Page

State street mapleAcer miyabei ‘Morton’

Photo: ‘Great trees for Kansas City’ FaceBook Page

Scarlet oakQuercus coccinea

Photo: ‘Great trees for Kansas City’ FaceBook Page

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Crimson spire oakQuercus robur x Q. alba ‘Crimschmidt’

Photo: ‘Great trees for Kansas City’ FaceBook Page

Bur oakQuercus macrocarpa

Photo: ‘Great trees for Kansas City’ FaceBook Page

Red oakQuercus rubra

Photo: ‘Great trees for Kansas City’ FaceBook Page

GinkgoGinkgo biloba

Photo: ‘Great trees for Kansas City’ FaceBook Page

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Thanks for your attention!