Modeling Forest Response to Elevated CO2

Status of FACEShort-term research opportunitiesLonger term research opportunitiesArchival material

Current modeling activitiesNCEAS working groupData availabilityOpportunities

Discussion of expanded modeling activities

ORNL FACE shutdown

ObjectivesYear 12 NPP responseComplete 15N cycling analysis and other ongoing

measurementsSoil pits for root and soil quantificationTree harvest for canopy structure and checking allometric

relationshipsArchive plant and soil samplesMaintain most of stand for post-CO2 monitoring

TimelineApril – restart CO2

June – dig soil pits 1 x 1 x 1.5 mJuly -- harvest trees with leavesAugust – short-term suspension of fumigation for 13C pulse-

chaseSeptember – turn off CO2

October – soil C measurements (Argonne)November – harvest more trees

Research Opportunities

Short-termPhysiological and nutrient cycling measurements on roots in

soil pitsCollect samples/data from felled treesMeasurements during short-term CO2 suspension (13C pulse-

chase)Last chance for any other CO2 response measurements!(3-D root architecture; root hydraulics; canopy spectral

properties)

Longer-termRelaxation of CO2 responsesTracking 13C signal in SOMAnything else that would benefit from a well-monitored and

well-studied tree stand

Sample archiveSuggest samples to collect and preserveRequest samples for analysis

COCO22 Fumigation: Fumigation: Thru October 2010 (tentative) Thru October 2010 (tentative)

COCO22 Off Activities and Timeline: Off Activities and Timeline:November 2010November 2010: branch harvesting from 5 trees per 1/2 plot (1/4 unfertilized, 1/4 : branch harvesting from 5 trees per 1/2 plot (1/4 unfertilized, 1/4

fertilized w/N)fertilized w/N)leaf and canopy-level estimates of SLA, %N, leaf area leaf and canopy-level estimates of SLA, %N, leaf area

distribution, etcdistribution, etc

November 2010-January 2011November 2010-January 2011: spatially extensive surface soil sampling: spatially extensive surface soil samplingovercome spatial variation in:overcome spatial variation in:

bulk densitybulk densitysoil C content, soil C content, soil N content,soil N content,fine root massfine root mass

March 2011March 2011: Tree harvest in 1/2 plot: Tree harvest in 1/2 plotdetailed allometriesdetailed allometries

diameter-height relationshipsdiameter-height relationships

April-May 2011:April-May 2011:2.8m x 5.6m x 2m depth2.8m x 5.6m x 2m depth

taproot masstaproot masssoil C, N and fine root biomass @ depthsoil C, N and fine root biomass @ depth

Opportunity to study change in 13C signal in formerly elevated CO2Opportunity to study change in 13C signal in formerly elevated CO2

Biomass and soil samples will be preserved at -80 oC and oven drying at 60 oC

Duke FACE Harvest Plans

Rhinelander FACE -Elevated CO2 and O3

aspen

aspen-birch

aspen-maple

Above- and Belowground Harvest – June 2009Protocol can be found at: www.aspenface.mtu.edu

Contacts

To propose short-term collaborations, long-term research at the sites, or to request archived samples, contact:

ORNL FACE – Rich Norby (rjn@ornl.gov)

Duke FACE – Ram Oren (ramoren@duke.edu) or Adrien Finzi (afinzi@bu.edu)

AspenFACE – Don Zak (drzak@umich.edu)

NCEAS Working Group

ObjectivesChallenging 11 ecosystem and global models with data from

Duke and ORNL FACE experimentsUse results to improve modelsMake projections of future

Current working group activitiesData sets assembledModel protocol agreed uponModel output format agreed upon

Working group plansInitial model runs to be assembled and compared in MayOnce an initial publications is produced, the protocol will be shared with all interested modelers

FACE data are publicly availability, and modelers are encouraged to use it -- http://public.ornl.gov/face/

Benchmarking Ecosystem Response Models with Experimental Data fromLong-term CO2 Enrichment Experiments

Model predictions of feedbacks between the terrestrial biosphere and the atmosphere are critical components coupled carbon-climate models; to have confidence in their predictions it is important that the models be benchmarked against relevant experimental data. Using 12 ecosystem process and land surface models and 10-year data sets from two free-air CO2 enrichment (FACE) experiments, we will ask a series of questions:

• Are the models good enough to replicate the experimental results describing the measured processes of the carbon, water, and nitrogen cycles at the scale for which the models are intended?

• Can the models explain the observed variation in response within, and differences between, the two experiments in forest stands?

• Can we explain reasons for differences between model and data?

• Will the comparison between model and experimental results lead to improvements in the models and give increased confidence in their predictive capacity?

1. Evaluate the ability of hourly and daily time step models to capture carbon, water and nitrogen cycle processes for loblolly pine and sweetgum stands for both intra- and inter-annual time steps.

2. Evaluate how well various models simulate the multi-year impact of elevated CO2 for loblolly and sweetgum stands:a. exercise models with actual weather data over a multi-year period covering the range of environmental conditions observed at each sites;b. focus on the plot scale and emphasize nutrient cycling limitations and feedbacks;c. evaluate the models’ ability to reproduce key responses to elevated CO2 including GPP, transpiration, leaf area index and litter production, SOM, wood increment, C allocation, andN availability and uptake.

• Demonstrate the utility of models for application to extrapolation to environmental change extrapolations

Those models that adequately reproduce the responses observed in the FACE experiments will be further evaluated for prognostic simulations to address regional or global questions. The models will be run to produce decadal predictions of forest growth and carbon sequestration under elevated CO2.

NCEAS Working Group

ObjectivesChallenging 11 ecosystem and global models with data from

Duke and ORNL FACE experimentsUse results to improve modelsMake projections of future

Current working group activitiesData sets assembledModel protocol agreed uponModel output format agreed upon

Working group plansInitial model runs to be assembled and compared in MayOnce an initial publications is produced, the protocol will be shared with all interested modelers

Data publicly availabilityhttp://public.ornl.gov/face/

Discussion

Should there be an NACP synthesis activity to model ecosystem response to elevated CO2?

This could be a follow-on to the current site-specific synthesis

Include multiple ecosystem types – forest, grassland, ag – wherever there are experiments

Include interactive factors (ozone, temperature) when possible

Focus on mechanisms of response

Produce other outputs besides NPP – e.g., fuel combustability