Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Mathias Göckede1, Beverly Law1, Tara Hudiburg1, David Turner1, Warren Cohen1,2

1OSU Dept. Forest Ecosystems & Society; 2USFS Pacific Northwest Research Station

Synthesizing multiple approaches to obtain comprehensive

regional scale carbon budgets

The ORCA2 West Coast Project

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Three states- California- Oregon- Washington

Three approaches- Bottom-up modeling- Top-down modeling- Biometric inventories

Project focus- climate variability- disturbance history- stand age- drought stress

ORCA2 project

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

(Hudiburg et al., Ecol Appl 2009)

Biometric Inventory

Results based on

Forest Inventory and Analysis plots (~7000)~200 additional intensive study areas

Basic results

Biomass (e.g. live/dead trees, detritus)Net primary production (increment data)

Extended results

Net ecosystem production (includes e.g. wood decomposition, litterfall, Dsoil C)Net biome production (include havest, fire)

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

(Hudiburg et al., in review)

Inventory Results

Fluxes in [Tg C yr-1]

High net uptake in California forests

High productivity along CA coast

CA harvest half of OR and WA

Current NBP

[gC m-2 yr-1]

State WA OR CA forested area [ha]

NEP 11.4 15.3 18.6Harvest 5.1 6.5 2.7Fire 1.1 1.5 1.0NBP 5.2 7.3 14.9

9.0 ∙ 106 12.2 ∙ 106 12.2 ∙ 106

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Biome-BGC Bottom-Up Modeling

Veg type & disturbance history

Physiological Parameters

30-year climate

Carbon Stocks,GEP, and NEP

BGC Simulation

(Turner et al., BioGeoSciences 2007)

Main featuresFully coupled C/N/H2O cycles

Prognostic phenologyConsiders disturbances (e.g. crop/forest harvest, wildfires)

Reference datasetsBiometric inventories- biomass - foliar C/N ratios Trained at the ecoregion scale

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

(Turner et al., in prep.)

Main sinksCoastal forestsCroplands (CA, WA)

DisturbanceClearcuts and wildfireshighly important for regional carbon budget

Spatial setup

<1k grid resolution needed to capture disturbance mosaic

Bottom-Up Results

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

NBP offsets a significant portion of fossil fuel emissions in Washington and Oregon, but just a small fraction in California

State-Level Carbon Fluxes

NBP/ff: 0.50

NBP/ff: 0.96

NBP/ff: 0.12

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

ORCA2 Top-Down Modeling

SO

UR

CE

S

Biosphere CO2 flux model

Fossil fuel CO2

Simulated[CO2]

SIN

KS

Atmospheric transport modeling

SO

UR

CE

S

STILT

Bac

kgro

und

CO

2 WRF

Atmospheric[CO2]

observations

OPTIMIZE

5 sites for continuous CO2 mixing ratios- 3 provide input for inversion- 2 used for quality assessment

Background CO2: NOAA CarbonTracker

Fossil fuel source: VULCAN database (Göckede et al., JGR 2010a)

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

ORCA2 Top-Down Results

(Göckede et al., JGR 2010b)

Regional CO2 budgets highly sensitive to background CO2

0.1 ppm offset in incoming air masses shifts Oregon CO2 budget by ~10%

Correcting for biases in background CO2 mixing ratios reduced the statewide CO2 sink by ~47% (32 TgC yr-1)

Background offsets

NEP

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

145 ± 31 gC m-2 yr-1

Methods comparison over Oregon

Forest fluxes5-yr avg, 2000-05

All fluxesAnnual NEP, 2007

80 ± 24 gC m-2 yr-1

Top-Down model

Biometric inventory

Bottom-Up model125 ± 13 gC m-2 yr-1

103 ± 20 gC m-2 yr-1

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Bottom-Up vs. Inventory Approach

Good agreement for many ecoregions, but some outliers

Mathias Göckede, College of ForestryOregon State University

The ORCA2 West Coast Regional ProjectTowards a Top-Down/Bottom-Up Synthesis

Component of NACP-W

Uncertainties in Top-Down Model

Background CO2 correction

Regional flux budget highly sensitive to incoming [CO2]

Large uncertainties associated with monitoring and correction

Concentration footprints

Information focused on center and coast

Coverage gaps particularly in SW and NE corners of state

Mathias Göckede, College of ForestryOregon State University

The ORCA2 West Coast Regional ProjectTowards a Top-Down/Bottom-Up Synthesis

Component of NACP-W

Analyzing / Interpreting Differences

Concept

Fit an independent model that explains spatiotemporal flux differences based on auxiliary variables (e.g.RS, meteorol,...)

Research tool

Geostatistic inverse modeling

Important factors

Stand age influence

Drought stress

Bottom-Up NEP

Top-Down NEP

New model explaining differences

(Göckede et al., in prep., cooperation with A. Michalak, V. Yadav, K. Mueller, S. Gourdji)

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Effects of biofuel management on regional forest carbon budget

(Hudiburg et al., in review)

Fire prevention: minimum impact, only aim to reduce wildfires

Economically feasible: medium impact, offset cost by wood sale

Bioenergy production: highest impact, thin 50% everywhere

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Biofuel management impacts

(Hudiburg et al., in review)

Managing forests for biofuels may increase emissions in region

Net impacts depend on current sink and forest sector FFE

0

10

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Sce

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io s

ink

s/s

ou

rce

s [T

gC

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Added emissions

FF Substitution

Fire emissions

Biofuel emissions

Wood Decomposition

Forest Sector FFE

Regrowth

NEP

BAU Fire Prevention

Economic Feasibility

EnergyProduction

Mathias GöckedeCollege of ForestryOregon State University

The ORCA2 West Coast ProjectSynthesizing multiple approaches to constrain

regional scale carbon budgets

Summary of Analysis

Range of NEP estimates for the West Coast region, agreement between three methods improved with latest results

Each approach has individual strengths and weaknesses, combination helps to identify problems and uncertainties

NBP offsets a significant portion of fossil fuel emissions in Washington and Oregon, but just a small fraction in California

Disturbance (harvest, fire) is a significant driver of NEP and NBP in region (harvest dominates)

Thinning forests for bioenergy production increasesemissions of the region (20 year life cycle analysis)