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

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Dominant Tree Age (yrs)

Ab

ove

gro

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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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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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Years after clearcut

Fra

ctio

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f ca

rbo

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elat

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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

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Structural Complexity Enhancement

Conventional Uneven-Aged

Control Units

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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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Stand Age (Years)

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Bio

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(M

g/h

a)

Normal Rotation

75 Mg/Ha

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Stand Age (Years)

Ab

ov

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Bio

ma

ss

(M

g/h

a) Normal Rotation

Extended Rotation

75 Mg/Ha

90 Mg/Ha

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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

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Stand Age (Years)

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Bio

ma

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g/h

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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

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Years

Ab

ov

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rou

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Tre

e B

iom

as

s (

Mg

/ha

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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

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/ha

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Uneven-Aged (With Treatment)

Uneven-Aged (Multiple Entries)

216.6 Mg/ha

178.9 Mg/ha

37.7

Mg/ha

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Years

Ab

ov

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rou

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Tre

e B

iom

as

s (

Mg

/ha

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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

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Years

Ab

ov

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rou

nd

Tre

e B

iom

as

s (

Mg

/ha

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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

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Years

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ov

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e B

iom

as

s (

Mg

/ha

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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

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0 5 10 15 20 25 30 35 40 45 50 55

Years

Ab

ov

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Tre

e B

iom

as

s (

Mg

/ha

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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

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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

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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