Development of a Novel Hydrodynamic Approach for Modeling Whole-plant Transpiration DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Golnazalsadat Mirfenderesgi Graduate Program in Civil Engineering The Ohio State University 2017 Dissertation Committee: Gil Bohrer, Advisor Peter S. Curtis Ethan Kubatko Andrew A. May Copyrighted by Golnazalsadat Mirfenderesgi 2017 Abstract The Finite-difference Ecosystem-scale Tree-Crown Hydrodynamics model (FETCH2) is a novel tree-scale hydrodynamic model of transpiration. The FETCH2 model employs a finite difference numerical methodology and a simplified single-beam conduit system and simulates water flow through the tree as a continuum of porous media conduits. It explicitly resolves xylem water potential throughout the tree’s vertical extent (from root to shoot). Empirical equations relate water potential within the stem to stomatal conductance of the leaves at each height throughout the crown. While highly simplified, this approach brings additional realism to the simulation of transpiration by linking stomatal responses to stem water potential rather than directly to soil moisture, as is currently the case in the majority of land-surface models. FETCH2 accounts for plant hydraulic traits, such as the degree of anisohydric/isohydric response of stomata, maximal xylem conductivity, vertical distribution of leaf area, rooting depth, and maximal and minimal stem water content. We used FETCH2 along with sap flow and eddy covariance data sets to conduct an analysis of the inter-genera variation of hydraulic strategies and their effects on diurnal and seasonal transpiration dynamics. We define these strategies through the parameters that describe the genus-level transpiration and xylem conductivity responses to changes in stem water potential. Using a virtual experiment, we showed that the model was able to capture ii the effect of hydraulic strategies such as isohydric/anisohydric behavior on stomatal conductance under different soil-water availability conditions. Our evaluation revealed that FETCH2 considerably improved the simulation of ecosystem transpiration and latent heat flux than more conventional models. Whole-plant hydraulic performance depends on the integrated function of complexes of traits, such as embolism resistance and xylem anatomy, stomatal closure mechanisms, hydraulic architecture, and root properties. The diversity of such traits produces a wide range of response strategies to both short-term variation of environmental conditions and long-term changes to climate and hydrological cycles which affect water availability. FETCH2 resolves plant functional traits at the root, stem and leaf levels and simulates the integrated plant-level transpiration, provided hydraulic traits and environmental forcing. This framework may be helpful in studying the influence of each suits of plant hydraulic traits independently and assess how the different trait groups interact with each other to form viable hydraulic strategies for different environmental conditions. We define a multi-dimensional hydraulic “strategy space” by considering a broad continuum of hydraulic traits at each of the leaf, stem, and root levels, and test the consequences of different strategies under a range of environmental conditions in a research forest in Northern Michigan, USA. We evaluated the degree to which simulated trees suffer hydraulic failure due to cavitation resulting in loss of xylem conductivity or carbon starvation through leaf-water-potential-driven reduction of stomatal conductance. iii Finally we concluded that incorporation of the plant functional traits into FETCH2 allows us to simulate the dissimilar water use patterns of species with contrasting hydraulic strategies. This will improve predictions of transpiration, growth, and mortality, and consequently simulations of the surface energy budget and the global carbon and water balances. iv Dedication To my parents, For their love, support, and kind guidance. I owe them everything I have achieved in my life To my husband For being the best thing happened to me in this life and for supporting me during my PhD studies And to the memory of my grandfather v Acknowledgments I would like to thank my advisor, Gil Bohrer, for his mentorship, support, and encouragement; Karina Schäfer for providing data for parametrization of FETCH2, including sap flux and meteorological observations collected from Silas little experimental forest; Peter Curtis, Ethan Kubatko, Gaj Sivandran, and Andrew May for their guidance as my thesis committee; Simone Fatichi for his assistance and direction in development of the capacitance term for FETCH2; Renato Frasson for his assistance in the process of data preparation for the model and learning ED2; Tim Morin, Ashley Matheny, Camilo Rey Sanchez, and Stephano Manzoni for providing the data for model simulation and parameterizations of FETCH2; And all of my current and previous lab members. Funding for this study was provided the National Science Foundation Hydrological Science grant 1521238. Meteorological observations at the UMBS are supported in part by U.S. Department of Energy’s Office of Science, Ameriflux Management Program under Flux Core Site Agreement No. 7096915 through Lawrence Berkeley National Laboratory. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the funding agencies. vi Vita May 2005 .......................................................Isfahan University of Technology high School, Isfahan, Iran Summer 2007 .................................................Structural Design Intern, Organization for development, Renovation and Equipping Schools of I.R.Iran, Isfahan, Iran Summer 2007 .................................................Structural Engineer, Tara Tahlil Sazeh Consulting Firm, Isfahan, Iran June 2008 .......................................................B.S. Civil Engineering (Structural Engineering), Isfahan University of Technology, Isfahan, Iran Summer 2008 .................................................Structural Engineer, Saraman Isfahan Co, Isfahan, Iran 2011................................................................M.Sc Civil Engineering (Water Engineering), AmirKabir University of Technology (Tehran Polytechnic), Tehran, Iran vii 2012-2013 ......................................................Graduate Research Associate, Portland State University, Portland, OR Jan 2013 .........................................................Graduate Teaching Associate, Portland State University, Portland, OR 2013 to resent .................................................Graduate Research Associate, Civil, Environmental and Geodetic Engineering, the Ohio State University, Columbus, OH Spring 2015 ....................................................Graduate Teaching Associate, Civil, Environmental and Geodetic Engineering, the Ohio State University, Columbus, OH Spring 2017 ....................................................Instructure, Civil, Environmental and Geodetic Engineering, the Ohio State University, Columbus, OH Publications Mirfenderesgi, G., G. Bohrer, A. M. Matheny, (2017), “Hydrodynamic Trait Coordination and Cost-Benefit Tradeoffs throughout the Isohydric-Anisohydric Continuum in Trees”, Ecohydrology (under submission). Rey-Sánchez, C., Bohrer, G., Morin, T. H., Sclomo, D., Mirfenderesgi, G., Gildor, H., Genin, A, (2017), “Evaporation and CO2 flux in a coastal reef lagoon: Comparing eddy viii covariance measurements to model estimates”, Ecosystem Health and Sustainability (under review). J.C. Angle, T.H. Morin, G.J. Smith, L.M. Solden, A.B. Narrowe, M.A. Borton, R.A. Daly, D.W. Hoyt, A.C. Rey-Sanchez, G. Mirfenderesgi, W.R. Riley, C.S. Miller, G. Bohrer, K.C. Wrighton, (2017), “Methanogenesis in oxygenated soils is a substantial fraction of wetland methane emissions”, Nature Communications (under review). Matheny, A.M., Mirfenderesgi, G., Bohrer, G., (2016) “Trait-based representation of hydrological functional properties of plants in weather and ecosystem models”, Plant Diversity, doi: 10.1016/j.pld.2016.10.001. Mirfenderesgi, G., G. Bohrer, A. M. Matheny, S. Fatichi, R. P. de M. Frasson, and K. V. R. Schäfer, (2016), Tree level hydrodynamic approach for resolving aboveground water storage and stomatal conductance and modeling the effects of tree hydraulic strategy, J. Geophys. Res. Biogeosci., 121, doi:10.1002/2016JG003467. Mirfenderesgi, G., Mousavi, S.J., (2015) “Adaptive meta-modeling-based simulation optimization in basin-scale optimum water allocation: a comparative analysis of meta- models”, Journal of HydroiInformatics, 2015, DOI: 10.2166/hydro.2015.157. Matheny, M, A., Bohrer, G., Vogel, S, C., Morin, H, T., He, L., Mirfenderesgi, G., Schafer, V, K., Gough, M, C., Ivanov, V., Curtis, S, P., (2014) “Species-specific transpiration responses to intermediate disturbance in a northern hardwood forest”, Journal of Geophysical Research: Biogeosciences, 119, 2014JG002804. DOI:10.1002/2014JG002804. ix Fields of Study Major Field: Civil Engineering x Table of Contents Abstract ............................................................................................................................... ii Dedication ........................................................................................................................... v Acknowledgments.............................................................................................................