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Managing forests for carbon storage
Bill Keeton
Rubenstein School of Environment and Natural Resources
University of Vermont
What is the best way to increase carbon storage in forest ecosystems?
• Intensified forest harvests, favoring fast rates of uptake and storage in wood products?
• Reduced harvesting intensity/frequency and/or passive management (reserves) favoring carbon storage in extant forests?
R2 = 0.65
0
50
100
150
200
250
300
350
400
0 100 200 300 400 500
Dominant Tree Age (yrs)
Ab
ove
gro
un
d T
ree
Bio
ma
ss (
Mg
/ha)
Carbon storage in old and structurally complex forests
Keeton et al. 2007. Ecological Applications
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100
200
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700
Northeastern USA Pacific Northwest USA Uholka, Carpathians,Ukraine
Liv
e T
ree
Bio
mas
s (M
g/h
ecta
re)
MatureOld-growth
Biomass in Mature vs. Old-growth Forests:
Old Forests Store Large Amounts of Carbon!
Ukraine: M. Tchernyavskyy and W. Keeton U.S. Pacific Northwest: J. Franklin
U.S. Northeast: W. Keeton
Data Sources:
Modified from: Schelhaas, M.J. et al. 2004. CO2FIX V 3.1 – A modelling framework for quantifying carbon sequestration in forest ecosystems.
Figure from Ingerson. 2007.
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0.9
1
0 10 20 30 40 50 60 70
Years after clearcut
Fra
ctio
n o
f ca
rbo
n r
elat
ive
to t
ime
zero
Total productsHardwood sawlogs
Carbon residence time in wood products
Northern hardwood forests in the U.S. Northeast
Data from Smith et al. (2006). USDA Forest Service GTR NE-343
Figure from Ingerson. 2007.
Modified from: Schelhaas, M.J. et al. 2004. CO2FIX V 3.1 – A modelling framework for quantifying carbon sequestration in forest ecosystems.
Forest Biomass Fuel
• Added harvest margin during regeneration harvest. e.g. whole-tree harvesting or increased removal of cull
• Stand improvement or thinning to harvest cull.
• Issues and concerns
Key: how will this be generated?
Coarse Woody Debris in Northern Hardwood Forests
Even-aged Single-tree Selection Old-Growth
• Habitat
• Nitrogen Fixation
• Soil organic matter
• Mycorrhizal fungi
• Nurse logs
• Erosion reduction
• Riparian functions Figure from McGee et al. (1999)
Modified from: Schelhaas, M.J. et al. 2004. CO2FIX V 3.1 – A modelling framework for quantifying carbon sequestration in forest ecosystems.
Key Points• Forest carbon sequestration is not a silver bullet solution
• Sustainable forest management is one of many strategies:
– 10% of U.S. CO2 emissions are offset annually by sequestration in forests
– Deforestation accounts for 20 to 30% of global greenhouse gas emissions
• Sustainable forest carbon management can provide co-varying ecological values
• There are management issues that must be resolved
Carbon Credits Through Forest Management
Kyoto Agreement:
• Reforestation or afforestation (plantations established prior to 1990) in developing countries
• In developed countries, 5% of emissions can be offset through forest management.
Developing “Cap and Trade” Markets:
• Reforestation/afforestation• Avoided deforestation• NEW! Credits for “improved forest management”
– Have to demonstrate “additionality” in carbon storage over baseline management– Permanence and leakage issues
Credits for Active Forestry
Credits for Active Forestry
VMC - Vermont Forest Ecosystem Management Demonstration Project
1. Single-Tree Selection
BDq modified to enhance post-harvest structural retention
2. Group Selection
BDq modified to enhance post-harvest structural retention
Mimic opening sizes (0.05 ha) created by fine-scale disturbances (Seymour et al. 2002)
3. Structural Complexity Enhancement:
Promotes late-successional/old-growth characteristics
Mt Mansfield State Forest
University of Vermont, Jericho Research Forest
N
100 0 100 200 Meters
Cumulative Projected Total Basal Area
How much have we accelerated growth rates?Normalized cumulative BAI: “treatment BAI” minus “no treatment BAI” at each time step
Keeton. 2006. Forest Ecology and Management
15
20
25
30
35
40
0 5 10 15 20 25 30 35 40 45 50
Structural Complexity Enhancement
Conventional Uneven-Aged
Control Units
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1
2
3
4
5
6
0 5 10 15 20 25 30 35 40 45 50
Structural Complexity Enhancement
Conventional Uneven-aged
Projected Years
Cum
ulat
ive
Bas
al A
rea
Incr
emen
t (m
2ha
-1)
Silvicultural Options:
• Even-Aged/Multi-aged systems
Extended Rotations
Periodic annual increment
Mean annual increment
Stand age (Years)20 120
Cub
ic f
t./ac
re/y
ear
0
300
From Curtis (1997)
Silvicultural Options:
• Disturbance-based/retention forestry
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50
100
150
200
250
0 20 40 60 80 100 120 140 160 180 200 220 240 260
Stand Age (Years)
Ab
ov
eg
rou
nd
Bio
ma
ss
(M
g/h
a)
Normal Rotation
75 Mg/Ha
0
50
100
150
200
250
0 20 40 60 80 100 120 140 160 180 200 220 240 260
Stand Age (Years)
Ab
ov
eg
rou
nd
Bio
ma
ss
(M
g/h
a) Normal Rotation
Extended Rotation
75 Mg/Ha
90 Mg/Ha
0
50
100
150
200
250
0 20 40 60 80 100 120 140 160 180 200 220 240 260
Stand Age (Years)
Ab
ov
eg
rou
nd
Bio
ma
ss
(M
g/h
a) Normal Rotation
Extended Rotation
Normal with Retention
20 Mg/ha
0
50
100
150
200
250
0 20 40 60 80 100 120 140 160 180 200 220 240 260
Stand Age (Years)
Ab
ov
eg
rou
nd
Bio
ma
ss
(M
g/h
a)
Normal Rotation
Extended Rotation
Normal with Retention
Extended with Retention
20 Mg/ha
Silvicultural Options:
• Uneven-Aged
40 cm max. 50 cm max. 80-100 cm max.
Maximized volume production
Lower vol. production but large dimension sawtimber
Maximized large sawtimber volume and value growth
Low Carbon Medium Carbon High Carbon
Low Intermediate High
Stand Structural Complexity
# st
ems
Diameter
# st
ems
Diameter Diameter
# st
ems
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55
Years
Ab
ov
eg
rou
nd
Tre
e B
iom
as
s (
Mg
/ha
)
Uneven-Aged (Multiple Entries)
178.9 Mg/ha
NE-FVS projections run in NED-2:
• “planting” to simulate regeneration
• Regeneration based on plot data
• Mixed species, proportions as sampled
0
50
100
150
200
250
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350
400
0 5 10 15 20 25 30 35 40 45 50 55
Years
Ab
ov
eg
rou
nd
Tre
e B
iom
as
s (
Mg
/ha
)
Uneven-Aged (With Treatment)
Uneven-Aged (Multiple Entries)
216.6 Mg/ha
178.9 Mg/ha
37.7
Mg/ha
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55
Years
Ab
ov
eg
rou
nd
Tre
e B
iom
as
s (
Mg
/ha
)
Uneven-Aged Units (No Treatment)
Uneven-Aged (With Treatment)
Uneven-Aged (Multiple Entries)
216.6 Mg/ha
178.9 Mg/ha
292.3 Mg/ha
75.7 Mg/ha114.4 Mg/ha
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55
Years
Ab
ov
eg
rou
nd
Tre
e B
iom
as
s (
Mg
/ha
)
Uneven-Aged Units (No Treatment)
Uneven-Aged (With Treatment)
SCE (Multiple Entries)
Uneven-Aged (Multiple Entries)
223.8 Mg/ha
178.9 Mg/ha
216.6 Mg/ha 59.9 Mg/ha
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55
Years
Ab
ov
eg
rou
nd
Tre
e B
iom
as
s (
Mg
/ha
)
Uneven-Aged Units (No Treatment)
SCE (With Treatment)
Uneven-Aged (With Treatment)
SCE (Multiple Entries)
Uneven-Aged (Multiple Entries)
223.8 Mg/ha
251.6 Mg/ha27.8 Mg/ha
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55
Years
Ab
ov
eg
rou
nd
Tre
e B
iom
as
s (
Mg
/ha
)
SCE Units (No Treatment)
Uneven-Aged Units (No Treatment)
SCE (With Treatment)
Uneven-Aged (With Treatment)
SCE (Multiple Entries)
Uneven-Aged (Multiple Entries)
304.5 Mg/ha
216.6 Mg/ha
292.3 Mg/ha
178.9 Mg/ha
251.6 Mg/ha
223.8 Mg/ha
55.9 Mg/ha
80.7 Mg/ha
1000 200 300 400 500 600
25
50
75
100
125
Car
bon
(Mg/
ha)
Years
Total carbon sequestration + emissions offset
Biofuel offset of fossil fuel emissions
Soil carbon
Carbon in aboveground
biomass
Carbon in wood fuel
CO2fix Model Simulation:Scenario = harvest for biomass only, northern hardwood stand,
UVM Jericho Research Forest
Data courtesy of Andy Book, Mike Thomas, and John Shane
Car
bon
(Mg/
ha)
Total carbon sequestration + emissions offset
Soil carbon
Years
125
100
75
50
25
0 100 200 300 400 500
Carbon in wood
products
Biofuel offset
CO2fix Model SimulationScenario = low intensity selection harvest for durable
wood products and biomass, northern hardwood stand, UVM Jericho Research Forest
Carbon in aboveground biomass
Data courtesy of Andy Book, Mike Thomas, and John Shane
Conclusions
• Even, multi-aged, and uneven-aged silvicultural options are available for increasing net carbon storage in managed stands.
• Options include:– Longer rotations or entry cycles– Post-harvest retention– Modified uneven-aged approaches that promote structural
complexity and high biomass conditions– Passive management: reserves that will develop high levels
of biomass