Managing Great Lakes Forests for
Climate Change Mitigation
Peter S. Curtis
Department of Evolution,
Ecology, and Organismal Biology
The Ohio State University
UMBS Forest
Carbon Cycle
Research Program
Two Definitions for this Webinar
 Forest Management
 If and when to harvest trees.
 Climate Change Mitigation
 Reducing the rate of increase of atmospheric
carbon dioxide.
 Reducing the rate of species loss due to
climate change.
UMBS Forest
Carbon Cycle
Research Program
Webinar Roadmap
 A brief overview of the Great Lakes forests.
 Forests and climate change: what is the
connection?
 Managing for carbon storage: to cut or not to cut.
 Biodiversity and ecosystem resiliency: are they
important for climate change mitigation?
 Conclusions.
UMBS Forest
Carbon Cycle
Research Program
 A Brief Overview of the Great Lakes Forests
 This is an ideal
environment for
growing diverse
and productive
forests.
 Presettlement
forest area was
about 89 million
acres (140,000
sq miles).
www.nrs.fs.fed.us
UMBS Forest
Carbon Cycle
Research Program
These Forests Were Virtually Entirely Cut
Between ~1860 and 1920
Michigan Archives
The Extent of Primary Forest
Remaining in the Lakes States
Minnesota: 264,000 ha
(2.4% original forest)
Wisconsin: 23,000 ha
(0.2% original forest)
Michigan: 82,000 ha
(0.6% original forest)
(after Frelich 1995,
Davis 2006)
Current Status of the Great Lakes Forests
 They cover
about half of their
original area.
 They bear little
structural or
compositional
resemblance to
the original
forest.
www.nrs.fs.fed.us
UMBS Forest
Carbon Cycle
Research Program
 They are mostly
young and
homogeneous.
Many Stands Are Now at an Ecological Transition,
Between Young and Potentially Old Community Types
UNEVEN-AGED
(maple, oak, pine)
Succession
ASPEN MORTALITY
natural senescence,
pathogens, insects
EVEN-AGED
(mostly aspen)
Forest age (years)
WE ARE HERE
Potentially Old Timberland (80-120 yrs)
in the Lakes States
Northern Minnesota: 369,000 ha
(10% all timberland)
Southern Superior Uplands: 830,000 ha
(16% all timberland)
Northern Superior Uplands: 104,000 ha
(9% all timberland)
Northern Great
Lakes: 643,000 ha
(13% all timberland)
Eastern Broadleaf
Forest: 672,000 ha
(19% all timberland)
All timberland: 19,494,000 ha
Potentially old: 2,747,000 ha (14%)
Old: 464,000 ha (2%)
(after Schmidt et al., 1996)
 Forests and Climate Change: What is the Connection?
UMBS Forest
Carbon Cycle
Research Program
What You Need To Know About The Forest Carbon Cycle
ECOSYSTEM
RESPIRATION
(Carbon Out)
NET
PHOTOSYNTHESIS
(Carbon In)
ECOSYSTEM
RESPIRATION
(Carbon Out)
CARBON STORAGE
(OR LOSS) =
Carbon In – Carbon Out
www.oup.co.uk/images/oxed/children/yoes/atoms/carboncycle.jpg
The UMBS Forest Carbon Cycle
Research Program
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Peter Curtis, Ohio State Univ.
Gil Bohrer, Ohio State Univ.
Chris Gough, Virginia Commonwealth Univ.
Chris Vogel, Univ. Michigan
Knute Nadelhoffer, Univ. Michigan
Danilo Dragoni, Indiana Univ.
This research is supported by the Office of
Science, U.S. Department of Energy, through the
Midwestern Regional Center of the National
Institute for Global Environmental Change, and
the National Institute for Climate Change
Research.
Ecological Studies of Forest Carbon Storage
Permanent Study Plots at UMBS
Meteorological Studies of Forest
Carbon Storage
 Managing for Carbon Storage: To Cut or
Not to Cut
 Conventional Theory: Young
Forests Sequester More Carbon
Than Older Forests.
 Some Problems With
Conventional Theory.
 Counter-theory: Carbon
Storage Increases Following
Ecological Transition in Great
Lakes Forests.
UMBS Forest
Carbon Cycle
Research Program
Conventional Theory of Carbon
Storage as Forests Age
 Wood production
(slope of line B) and
carbon storage (area
of shaded PN) are
maximized in young
forests.
 In forests > 100
yrs, both slow to
near zero.
PG = Gross Production (photosynthesis), R = Respiration,
B = Biomass, PN = Net Production (Carbon Storage)
UMBS Forest
Carbon Cycle
Research Program
E.P. Odum. 1969. The Strategy of
Ecosystem Development. Science 164.
-1 -1
NEP
(Mg C
haC-1hayr
(Mg
storage
Annual C
yr)-1)
Results From the UMBS Forest Provide
Support For This Theory
2.5
Source of variation
harvest/fire
harvest/fire
2.0
climate
1.5
disturbance
1.0
0.5
succession
0.0
-0.5
1900
1920
1940
1960
1980
2000
Year
Gough et al. (2008)
UMBS Forest
Carbon Cycle
Research Program
Annual carbon
storage is
variable, but
lower than it
was 40 years
ago.
However, Meteorological Data From Around the
World Shows Substantial Carbon Sequestration in
Forests > 200 Years Old.
Luyssaert et al. (2008)
UMBS Forest
Carbon Cycle
Research Program
Gough et al. (2008)
Forest Harvest, Even
Selective Cutting, Can Result
in Substantial Soil Carbon
Losses
Nave et al. (2010)
UMBS Forest
Carbon Cycle
Research Program
1.5
climate
A
rb
climate
y
2.0
C
+
Girdling
2.5
re
co
ve
r
3.0
Hypothetical NEP
Hypothetical N availability
stu
di
an
1.0
ce
NEP (Mg C ha-1 yr-1)
3.5
B
0.5
succession
0.0
-0.5
98 000 002 004 006 008 010 012 014 016 018
19
2
2
2
2
2
2
2
2
2
2
Year
UMBS Forest
Carbon Cycle
Research Program
-
N available for plant growth
Counter-theory: Carbon Storage Can Increase
With Forest Age Due to Increasing Ecosystem
Structural and Biotic Complexity
 We are testing this
theory at the Forest
Accelerated Succession
ExperimenT (FASET)
 A key variable is the
amount of nitrogen
available for plant
growth.
 Biodiversity and ecosystem
resiliency: are they important
for climate change mitigation?
More species that are
ecologically similar means
greater resistance to change
Higher biodiversity = greater
ecological resilience
At UMBS, More Diverse Forest Plots Are More
Resilient to Carbon Storage Declines With Age
Gough et al. (2010)
UMBS Forest
Carbon Cycle
Research Program
At UMBS, Older Plots That Are More Structurally
Complex Have Higher Wood Production
We measure
canopy complexity
(rugosity) with a
laser rangefinder.
UMBS Forest
Carbon Cycle
Research Program
Hardiman et al. (in review)
Moving Forward …
 As Great Lakes forests age they generally become more
structurally and biotically complex.
 This increasing complexity facilitates sustained carbon
storage, greater ecological resilience, and enhanced species
conservation.
 Forest management that mimics natural ecological
succession may be possible at relatively small scales.
 The 7 million acres of 80-120 year old forest in the Lakes
States should be allowed to naturally transition for maximal
climate change mitigation impact.
UMBS Forest
Carbon Cycle
Research Program
Conclusions
 Many Great Lakes forests will experience a major
ecological transition over the next 25-50 years, with
important implications for carbon cycle dynamics and
climate change resilience.
 Great Lakes forests have been, and will continue to be,
important sources of wood products, and many stands
can be sustainably managed to meet these needs.
 Managing for climate change mitigation, however,
argues for allowing natural ecological succession to
proceed within many Great Lakes forests.