Improving the representation of large carbon pools in ecosystem models

1. Improving the representation of large carbon pools in ecosystem models Mat Williams (Edinburgh University) John Grace (Edinburgh University) Andreas Heinemeyer (York University) Phil Ineson (York University) Getty Images Theresa Meacham

2. Introduction: • Forests buffer the rate of atmospheric CO2 increase. • Woody biomass carbon ~ 580 Mt. • Soil carbon stock (to 0.8M) ~1200 Mt. • UK emissions 654Mt CO2 (2006). • PhD scope: • Link soil scientists and plant biologists. • Link long time series measurements of soil, canopy and forest growth. www.noaa.gov LULUCF (2006)

3. Talk outline: • Features of forest large carbon pools • The uncertainties surrounding large carbon pools • The direction of my research. Oak Woodland: Getty Images

4. Atmosphere Photosynthesis Foliage Plant respiration Wood Fungal respiration Fungi Root Soil Microbial respiration Forest carbon sequestration:

5. Fast carbon fluxes: • Atmosphere-canopy interactions View from flux tower: Harwood forest

6. Fast carbon fluxes: • Current photosynthesis drives soil respiration. Hogberg et al (2001) Calculated fungal respiration Calculated root respiration Hogberg, P., A. Nordgren, et al. (2001). "Large-scale forest girdling shows that current photosynthesis drives soil respiration." Nature411(6839): 789-792.

7. Slow carbon fluxes: Getty Images Arctopussy at Alice Holt • Soil carbon fluxes • Woody Biomass

8. Uncertainties surrounding large carbon pools: • Below ground carbon fluxes are poorly understood. Heinemeyer et al (2007) Heinemeyer, A., I. P. Hartley, et al. (2007). "Forest soil CO2 flux: uncovering the contribution and environmental responses of ectomycorrhizas." Global Change Biology13(8): 1786-1797.

9. Uncertainties surrounding large carbon pools: • CO2 fluxes change as a forest ages. Magnani et al (2007) Magnani, F., M. Mencuccini, et al. (2007). "The human footprint in the carbon cycle of temperate and boreal forests." Nature

10. 5 Bud burst Bud burst Leaf fall 4 Soil CO2 efflux (CO2 m-1 s-1) 3 2 1 March June Sep Dec March June Adapted from Heinemeyer (2008) The Direction of my research: 1. Above ground processes influence below ground carbon pools.

11. The Direction of my research: 1.Above ground processes influence below ground carbon pools. Phenology measurements Hemispherical photographs: MODIS Images: Courtesy of Mat Disney, NERC, CTCD Monks Wood, Cambridge. Courtesy of University of Southampton

12. NEP (t C ha-1 y-1) Age (Years) The Direction of my research: 2. Error within ecosystem models is lowest at mid-rotation • Disturbance recovery in young stands. • Patchy carbon allocation in old stands. • Root :Leaf Area change with age. 0

13. The Direction of my research: 3. Root optimality theory should be incorporated within ecosystem models CO2 Factors affecting the economics of carbon allocation: • Stand age • Competitive interactions • Environmental factors • Stand genetics Leaves Stems Roots Water Nutrients

14. The Direction of my research: 4. Use models to inform UK forest policy Woodland policy aims in England: • Ensure woodlands are resilient to impact of climate change. • Protect and enhance environmental resources of soil, water and biodiversity. • Improve competitiveness of woodland businesses, such as woodland products and reduction of carbon emissions. Getty Images ‘A Strategy for England’s Trees, Woods and Forests’, Defra (2007)

15. The Direction of my research:

16. Summary: • Large carbon pools sequester atmospheric carbon. • Long time series data, modelling and earth observation techniques may aid our understanding of processes. • Model outputs can help make future predictions and inform policy.

17. Thank You Any Questions? Harwood Forest; Courtesy of Mat Disney, CTCD

18. The Direction of my research: • UK Field sites • CarboAge project • Michigan biological station Griffin Forest Harwood Forest Wheldrake Forest Alice Holt