Modeling Forest Response to Elevated CO 2

1. Modeling Forest Response to Elevated CO2 Status of FACE Short-term research opportunities Longer term research opportunities Archival material Current modeling activities NCEAS working group Data availability Opportunities Discussion of expanded modeling activities

2. ORNL FACE shutdown Objectives Year 12 NPP response Complete 15N cycling analysis and other ongoing measurements Soil pits for root and soil quantification Tree harvest for canopy structure and checking allometric relationships Archive plant and soil samples Maintain most of stand for post-CO2 monitoring Timeline April – restart CO2 June – dig soil pits 1 x 1 x 1.5 m July -- harvest trees with leaves August – short-term suspension of fumigation for 13C pulse- chase September – turn off CO2 October – soil C measurements (Argonne) November – harvest more trees

3. Research Opportunities Short-term Physiological and nutrient cycling measurements on roots in soil pits Collect samples/data from felled trees Measurements 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-term Relaxation of CO2 responses Tracking 13C signal in SOM Anything else that would benefit from a well-monitored and well-studied tree stand Sample archive Suggest samples to collect and preserve Request samples for analysis

4. Duke FACE Harvest Plans CO2 Fumigation: Thru October 2010 (tentative) CO2 Off Activities and Timeline: November 2010: branch harvesting from 5 trees per 1/2 plot (1/4 unfertilized, 1/4 fertilized w/N) leaf and canopy-level estimates of SLA, %N, leaf area distribution, etc November 2010-January 2011: spatially extensive surface soil sampling overcome spatial variation in: bulk density soil C content, soil N content, fine root mass March 2011: Tree harvest in 1/2 plot detailed allometries diameter-height relationships April-May 2011: 2.8m x 5.6m x 2m depth taproot mass soil C, N and fine root biomass @ depth Opportunity 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

5. aspen- birch aspen aspen- maple Rhinelander FACE -Elevated CO2 and O3 Above- and Belowground Harvest – June 2009 Protocol can be found at: www.aspenface.mtu.edu

6. 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)

7. NCEAS Working Group Objectives Challenging 11 ecosystem and global models with data from Duke and ORNL FACE experiments Use results to improve models Make projections of future Current working group activities Data sets assembled Model protocol agreed upon Model output format agreed upon Working group plans Initial model runs to be assembled and compared in May Once 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/

8. Benchmarking Ecosystem Response Models with Experimental Data from Long-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?

9. 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.

11. NCEAS Working Group Objectives Challenging 11 ecosystem and global models with data from Duke and ORNL FACE experiments Use results to improve models Make projections of future Current working group activities Data sets assembled Model protocol agreed upon Model output format agreed upon Working group plans Initial model runs to be assembled and compared in May Once an initial publications is produced, the protocol will be shared with all interested modelers Data publicly availability http://public.ornl.gov/face/

12. 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