Lee Frelich

Effects of climate change, deer and invasive species on forests

Lee E. Frelich, Director, The University of Minnesota Center for Forest Ecology

Change in summer (JJA) temperatureChange in summer (JJA) temperature

Higher Emissions

Lower Emissions

Slide: Don Wuebbles

2010-2039 2040-2069 2070-2099

Projected Change in Precipitation: 2081-2099

Relative to 1960-1990

NOTE: Scale Reversed

Midwest: Increasing winter and spring precipitation, with drier summers

More frequent and intense periods of heavy rainfall

Slide: Don Wuebbles

White pine on its way to better climatic zone, Ontario (upper) and a cold tree wearing a sweater (lower).

Peter Aplin

How do trees respond to climate change?

Fossil pollen evidence suggests that trees respond to gradual climate change by migration and to sudden and large climate shifts by dying

Calendar years before present10,000 8,000 6,000 4,000 2,000 0

Hemlock and oak decline 5,000 ybp due to drought and insects. From Foster et al. 2006. Ecology 87: 2959-2966

John Kneurr

Fossil needles (upper row), modern needles (second row), and hemlock looper parts (fossil and modern). From Bhiry and Filion (1996) Quat Res 45: 312-320.

Pagami creek fire-NASA

Pagami Creek Fire, Sept 12, 2011Lake Kawishiwi, Photos: PJ Sikorski

Brian Sturtevant-USDA Forest Service

July 1995 derecho series

From: R.H. Johns and J.S. Evans: www.spc.noaa.gov/misc/AbtDerechos

More disturbance from wind and fire in a warmer climate

Minneapolis Star tribune

Before and after the 1999 blowdownin the Boundary Waters, northern MN

Wind does selective weeding of the forest

Divergence of forest composition after wind versus wind/fire combination BWCAW case study

Tornado reports per decade. Paul Huttner, MPR.

Wind + Fire = majortransformation of the forestPhotos: Dave Hansen

Native insects play a major role in forest changeBenign native insects can have outbreaks in a warmer climate.For example, mountain pine beetle in British Columbia—a native insect that caused massive tree mortality over 30 million acres of lodgepole pine forest, and could threaten jack pinein MN

Dai, 2010, Drought under global warming, Climate Change DOI: 10.1002/wcc.81

Comparing the 2060s with current

More drought = trees under stress and forest dieback

Photo: Dave Hansen

Impacts of deer grazing reinforcing climate changeSylvania Wilderness maple and hemlock forest in 1990

Sylvania in 2006, after the deer have eatenPictures from Salk, Frelich, Montgomery, Calcote, and Ferrari, preliminary acceptance in Forest Ecology and Management

Global warming orGlobal worming?

Earthworms are ecosystem engineers that can alter the structure of soil, and change the H2O, N and P cycles, Cdynamics and seedbed characteristics on a regional scale

Earthworm-free site. Photo: Paul Ojanen

Heavily earthworm infested sites without lawn. Photo: Paul Ojanen (left), Dave Hansen (right)

Earthworms warm the soil by removing insulating O horizon,compact the soil, cause more runoff, create lower avail-ability of N and P, lower the species richness of native plantsand facilitate invasive plants

Seed emergence experimentwith endogeic and anecicearthworms both present: Graminoids are favored

Lawn of sedge created by earthworm and deerPhoto: Paul Ojanen

Stage 2, Dendrobaena only

Stage 3, + Aporrectodea ssp.and L. rubellus

Stage 4, + L. terrestris

Photos: J. Schlaghamersky

Invasive plants that may be facilitated by earthworm invasion:Buckthorn (common and glossy)Garlic mustardTatarian honeysuckleBlack swallowwort (Cynanchum)Japanese barberryHemp nettle (Galeopsis tetrahit)Veronica ssp.Stiltgrass (Microstegium)

14 Sapling growth study sites

Fisichelli study of sapling success and growth over a 4 degree F temperature gradient in mixed boreal-northern hardwood forests

Temperate Mixed Boreal

Overstory Type

Local Scale: 3 overstory neighborhood types

>67% Temperate overstory tree rel. abundance

33-67% Temperate overstory tree rel. abundance

<33% Temperate overstory tree rel. abundance

Sugar maple

Red maple

Fir/Spruce

Species Regeneration Response to: Temp Precip pH Deer Litter Conspecific Depth Overstory

0

0/-0

0/-

Methods: Sizing Up the Competition; Growth Measurements

Radial Growth Height Growth

Distance between terminal bud scars

‘09‘08‘07

5 species

Balsam fir(Abies balsamea)

White spruce(Picea glauca)

Red maple(Acer rubrum)

Sugar maple(Acer saccharum)

Red oak(Quercus rubra)

4

5

7

10

15

17.0 17.5 18.0 18.5 19.0

Summer Temperature (°C)

He

igh

t gro

wth

(cm

yr1

)

4

5

7

10

15

17.0 17.5 18.0 18.5 19.0

Summer Temperature (°C)

He

igh

t gro

wth

(cm

yr1

)

(a) low browse pressure

(b) high browse pressure

Results: Temperate sapling relative performance ‘cooled’ by deer

A. balsameaP. glaucaA. rubrumA. saccharumQ. rubra





Abies balsamea

Picea glauca

Acer rubrum

Acer saccharum

Quercus rubra

Mean summer temperature oC

Sugar maple versus spruce in the temperate-boreal ecotone

Temp change

Deer, moose, earthworms

Temperature pushing harder than opposing forces

BorealTemperate

Temperate forest tree species are now invading boreal stands,but this process is slowed by deer in some areas. For now, themixed forest zone is becoming broader.

Serial correlation prevented maple from replacing spruce forest on sand,but not silty clay loam, for a 2xCO2 scenario. Cohen and pastor 1991.

With serialcorrelation

Silty clay loam

Sand

Sugar maple versus oak in in the temperate zone

Temperature change, earthworms

Deer

No net direction???

Expect mesic forest types such as northern hardwoods to contract their niche

Loamy sandLoam Silt loam

Ecological blueprints for a warmer climateA forest of American basswood, elms, Kentucky coffeetree, hackberry, and bur oak could be the future for central and northern Minnesota, northern Wisconsin and Upper Michigan

Mark Stennes

If the climate trends towards a Savanna climate on shallow soils:•Try for the best savanna possible (i.e. native species, not buckthorn).

•Resources for assisted migration and seed amplificationwould be necessary

The Prairie Enthusiasts

Molly McGovern

Buckthorn on rocks in northern MNPhotos: Paul Ojanen

Warmer climate, Longer growing season

More frequent and longer

droughts

Warmer and drier soil

Lower soil nutrient status

Exotic earthworms

spread faster

More deer

More fires

More wind

storms

Pests and diseases spread faster

N deposition

CO2 fertilization

Kill seedlingsand preventreproduction

Kill adult treesand lack of replacement

Savannification

Multiple impacts of climate change at the prairie-forest border. Frelich and Reich, 2010 Frontiers in Ecology and the Environment

Disturbance severityHighLow

Late successionaldominance

Low

High

Clearcut or stand leveling wind

Ecosystemunder stressfrom climate

Ecosystem well adapted to climate

Thresholds for disturbance severity necessary to change forest composition are lower when a forest is under stress

What does this all mean?

Global warming is about the effects of droughts, storms, fires, bugs, worms and deer on the forest

These factors will reinforce the impacts of changing temperature and lead to more divergence among soil types

These factors will make abrupt change after disturbance more likely

Future forests and savannas that replace the current forests will have novel plant composition due to different filters on which species are successful

Layne Kennedy

Lee Frelich and clones at work during Ham Lake Fire, Seagull Lake, May 6, 2007

Questions?

Education

Lee Frelich