Lee Frelich's "Climate Change & Forests" Presentation
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Transcript of Lee Frelich's "Climate Change & Forests" Presentation
Climate change, invasive species and forests
Lee E. Frelich
Director, The University of Minnesota Center for Hardwood Ecology
Vice President, Eastern Native Tree Society
Chair, Board of Directors, Great River Greening
Dave HansenUniv. of MN
John Knuerr
Svante August Arrhenius(Nobel prize, Chemistry,1903)
Developed the hothouse theory forCO2 in 1896, and in 1905 predicted that raising CO2 content of the atmospherewould cause an increase in mean globaltemperature similar in magnitude tomodern predictions
Evidence that CO2 increase and climate change are caused by humans
1. Keeling curve corresponds to population and known emissions of CO2
2. Suess effect
3. Temperature profile of the atmosphere—warmer lower atmosphere and cooler stratosphere
4. Existing ‘Greenhouse effect’ of 56 degree F before human enhancementof heat trapping gases in the atmosphere
5. Models with human greenhouse gas enhancement match observed temperatures over the last 100 years, models with only naturalforcings on climate do not
Climate change occurs in the context of large year toyear variability—summer temperatures for 2009
Summer 2009—Example of regional temperature anomalies versus global mean in a warming climate. A cold summer in central and eastern North America, although 80% of the world had above average temperatures.
…and spatial variability
http://www.cgd.ucar.edu/ccr/ammann/millennium/CODES_MBH.html
Comparison of the original Mann ‘hockey stick’ reconstruction of temperature(red) with implementation of valid criticisms of the PC methodology (green).From Wahl and Amman 2006.
Tree ring analyses showing climate over the several hundred years
Osborne and Briffa 2006, instrumental record for northern hemisphere (red)and for records closest to proxy sites (green).
Tree ring analyses from 14 sites
Oerlemans, 2005 temperature reconstruction of global mean temperaturebased on 169 glaciers.
Borehole temperature data from Huang, Pollock and Shen, Nature, 2000
Temperature evidence from boreholes
From McCarthy, 2009, Science
Modeling of temperatureshowing how natural andhuman influences work together.
Natural versus human CO2 forcing on the climate
British Meteorological Office, December 2009
Migration maps for tree response to past climate change in 1000s years before present (M.B. Davis 1983)
Spruce White pine
Current and simulated future range of black spruce, from Lenihan and Neilson 1995.
300 mile shift is equal todistance moved in ~ 2000years in paleorecord
Forest cover of central North America (green)DeFries, R., M. Hansen, J.R.G. Townshend, A.C. Janetos, and T.R. Loveland (2000), 1 Kilometer Tree Cover Continuous Fields, 1.0, Department of Geography, University of Maryland, College Park, Maryland, 1992-1993.
It is possible that the pbf will move 500 km to the north and east, deforesting an area 2X the size of California
Native species have migrated in the past without going extinctwhat’s different now?
Rate of climate change—many species cannot migrate fast enoughFragmented environment—makes species to movement more difficultHabitat loss—less habitat now and can support fewer speciesInvasive species—can reproduce and move fast, they have opportunity
to displace native species during times of rapid change Exotic diseases and pests—can spread faster in a warmer climateDeer grazing—will increase in the north, can extirpate native plants
David Augustine
TNC
Minneapolis Star tribune
Before and after the 1999 blowdownin the Boundary Waters, northern MN
Wind plus fire = major forest transformationNick Fisichelli and Roy Rich, Cavity Lake Burn, Seagull Lake, July 2007.Photo: Dave Hansen, University of MN
Several forces are at work that may push MN foreststowards savanna:
If soils become drier for any reason sites can support fewer trees:
Warmer soilsHigher evaporation to precipitation ratioEuropean earthworms stripping the insulating duff layer
More drought = trees under stress and forest dieback
Photo: 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
Sylvania Wilderness maple and hemlock forest in 1988
Sylvania in 2006
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
Soil profile, no earthworms (left), with earthworms (right).The loss of the duff layer will affect summer soil temperature
Photos: Dave Hansen, University of MN
00.20.40.60.8
11.21.41.6
-5 0 5 10 15 20 25 30
Invasion timing (years)
Rin
g w
idth
inde
x
Worm freeworm invaded
Earthworm invasion in maple forest causes a decreasein tree ring width and loss of seedling density and herb specieson the forest floor
Recent literature shows that Earthworms also facilitate germination and establishment of European buckthorn and garlic mustard by changing the seed bed
Kathleen Knight
Photos: The Nature Conservancy
Exotic earthworms + deer =major transformation of theforest. Bare soil and lowernutrient status should favor hemlock over maple, but deer favor maple.
Both dominant species aredisfavored, combined withwarmer climate and sandysoils, probably meansSylvania will become oaksavanna in the future
Paul Jost
Summary of impacts on Lake Statestree species
Global warming and rate of migration:All species Sudden oak death: red oak, pin oakDeer: white cedar, yellow birch, white pine, oaksBalsam woolly adelgid: balsam firEmerald ash borer: green ash, black ash, white ashAsian long-horned beetle: red maple,sugar maple, aspenHemlock woolly adelgid: hemlockMountain pine beetle: jack pineNative insects: eastern larch, others Earthworms: sugar maple and others
Overall scheme for change at the prairie-forest border proposed by Frelich and Reich
We can expect a messy transitionHistory shows that development of a new ecosystem takes 100sto 1000 years to develop
Dave Hansen
Lee Frelich
Old
Transitional
New
Layne Kennedy
Lee Frelich and clones at work during Ham Lake Fire, Seagull Lake, May 6, 2007
Questions?