Findings from a decadeplus study of comparative carbon

Findings from a decade-plus study of comparative carbon, water and energy fluxes from an oak savanna and an annual grassland in the Mediterranean climate of California Dennis D. Baldocchi, Siyan Ma, Joe Verfaillie, Naama Raz-Yaseef, Hideki Kobayashi, Youngryel Ryu, Laurie Koteen University of California, Berkeley, CA, Baldocchi@berkeley. edu Carbon and Water Fluxes Abstract We have been collecting carbon and water fluxes of an oak savanna and annual grassland in the Mediterranean climate of California since 2000. This long, continuous and comparative data record gives us an unprecedented ability to understand quantify the interannual variations in carbon, water and energy exchange of contrasting functional types and ecosystem processes and strategies in responses to the highly variable annual or seasonal precipitation inputs. 10 NEE (g. C m-2 d-1) 5 Tonzi grass-oak savanna 0 Below canopy fluxes (grasses and soil) -5 Floor Tower -10 Canopy fluxes (trees) Our scientific approach uses the eddy covariance to measure the net and gross fluxes of trace gases between ecosystems and the atmosphere. We augment these measurements with a variety of mechanistic studies that examine the physiological and biophysical control on these fluxes. 2000/1 2001/2 2002/3 2003/4 2004/5 2005/6 2006/7 Inter-annual Variability and Trends Precipitation and Evapotranspiration Carbon Fluxes 2007/8 2008/9 2009/10 2010/11 2011/12 Below-ground Resources Electromagnetic Induction (EMI) Survey of Soil Depth Ground Penetrating Radar (GPR) Coarse Root Survey These efforts involve laboratory and field measurements on the exchange of gases from the soil, leaves and plants, such as: ► understory eddy flux measurements ► pre-dawn water potential ► soil moisture ► leaf-level photosynthetic capacity ► soil respiration ► the water table ► excavation of roots EC ~ hydraulic conductivity analyzed from EMI data following a rain event To upscale our flux measurements we rely on an assortment of remote sensing measurements. These efforts include: Full rectangles – tree bole Empty rectangles – excavated pits ► measuring light transmission through vegetation ► monitoring hyperspectral reflectance of the vegetation ► time series of canopy photos to monitor phenology ► LIDAR surveys of vegetation structure. CANOAK-3 D Modeling LIDAR Image Canopy Structure in 3 D scheme Coarse Root Density derived from GPR calibrated by root excavation BESS - Breathing Earth System Simulator Direct Canopy Picture (DCP) Groundwater Depth from three wells Flowchart of 3 D radiation and energy model 2007 0 2008 2009 2010 2011 Road Depth (m) 2 4 Floor Tower 6 8 Forest Structure 10 12 14 LAI and Phenology Spatial variations in light environments (12: 00 p. m. , DOY 194, 2008) Model comparison 0 5 10 15 20 25 hour Acknowledgments References This research has been supported by the Office of Science (BER), the U. S. Department of Energy (DE-FG 0203 ER 63638), and the Western Regional Center of the National Institute for Global Environmental Change under Cooperative Agreement (DE-FC 0203 ER 63613). We gratefully thank Mr. Ted Hehn for his technical support between 2001 -2008. We appreciate Mr. Russell Tonzi and Mr. Fran Vaira for allowing us to access their ranch for scientific research. Raz-Yaseef, N. , Baldocchi, D. D. , et al. in prep. Koteen, L. , Baldocchi, D. D. , et al. in prep. Ryu, Y. , Baldocchi, D. D. , et al. in prep. Ma, S. , Baldocchi, D. D. et al. 2012. Agricultural and Forest Meteorology 154– 155: 203 -213. Ryu, Y. , Baldocchi, D. D. , et al. 2011. Global Biogeochemical Cycles. 25 : GB 4017 Grant, R. , Baldocchi, D. D. and Ma, S. 2011. Agricultural and Forest Meteorology. 152: 189 -200 Kobayashi, H. , Baldocchi, D. D. , et al. 2011. Agricultural and Forest Meteorology. 152: 83 -100. Ma, S. , Baldocchi, D. D. , et al. 2011. Functional Ecology, 25: 258 -270. Baldocchi, D. D. , Ma, S. , et al. 2010. Ecological Applications. 20: 1583 -1597 Miller, G. , Chen, X. , Rubin, Y. , Ma, S. and Baldocchi, D. D. , 2010. Water Resources Research, 46: W 10503 Baldocchi, D. D. 2008. Australian Journal of Botany. 56, 1 -26. Baldocchi D. D. , Liukang Xu. 2007. Advances in Water Research. 30, 2113 -2122. Ma, S. , Baldocchi, DD. , Xu. L*, Hehn, T. 2007. Agricultural and Forest Meteorology. 147, 157 -171. Curiel-Yuste, J. . , Baldocchi, DD. , et al. , 2007. Global Change Biology, 13: 1 -18. Baldocchi, D. D. , Tang, J*. Xu, L. 2006. Journal of Geophysical Research, Biogeosciences. 111, G 02008 … (for more, please visit http: //nature. berkeley. edu/biometlab/publications. html)