An Empirical and Simulation-Based Assessment of Tree Growth in Temperate Alley-Cropping Systems Von der Fakultät für Umwelt und Naturwissenschaften der Brandenburgischen Technischen Universität Cottbus-Senftenberg zur Erlangung des akademischen Grades eines Doktor der Ingenieurwissenschaften (Dr.-Ing.) genehmigte Dissertation vorgelegt von Master of Science (M. Sc.) Diana-Maria Seserman aus Iași (Jassy), Rumänien Gutachter: Apl. Prof. Dr. agr. habil. Dirk Freese Brandenburgischen Technischen Universität (BTU) Cottbus–Senftenberg Fachgebiet Bodenschutz und Rekultivierung, Cottbus, Deutschland Gutachter: Prof. Dr. Jörg Michael Greef Bundesforschungsinstitut für Kulturpflanzen Julius Kühn-Institut (JKI), Braunschweig, Deutschland Datum und Ort der mündlichen Prüfung: 13. Dezember 2019, Cottbus Preface The SIGNAL-Project (Sustainable Intensification of Agriculture through Agroforestry) was initiated and planed in relation to the proposal call “Soil as a Sustainable Resource for the Bioeconomy – BonaRes” (www.signal.uni-goettingen.de). The present dissertation was carried out under the BonaRes - SIGNAL project (FKZ 031A562E, 2015-2018) and funded by the German Federal Ministry of Education and Research (BMBF – Bundesministerium für Bildung und Forschung). In the following, a compilation of three peer-reviewed journal papers, together with several conference papers, are presented as central components of the dissertation. For an adequate readability of the printed version, some of the illustrations were realigned or altered. These studies were written and published during four years of scientific work at the Brandenburg University of Technology Cottbus–Senftenberg, Institute of Environmental Sciences, Chair of Soil Protection and Recultivation. Seserman, D.M.; Pohle, I.; Veste, M.; Freese, D. Simulating Climate Change Impacts on Hybrid-Poplar and Black Locust Short Rotation Coppices. Forests 2018, 9(7), 419. Seserman, D.M.; Freese, D.; Swieter, A.; Langhof, M.; Veste, M. Trade-Off between Energy Wood and Grain Production in Temperate Alley-Cropping Systems: An Empirical and Simulation-Based Derivation of Land Equivalent Ratio. Agriculture 2019, 9(7), 147. Seserman, D.M.; Freese, D. Handling Data Gaps in Reported Field Measurements of Short Rotation Forestry. Data 2019, 4(4), 132. Table of Contents List of Abbreviations .................................................................................................................. vii List of Figures ............................................................................................................................ viii List of Tables .............................................................................................................................. xii Summary ....................................................................................................................................xv Zusammenfassung ................................................................................................................. xviii 1. General Introduction ...............................................................................................................1 1.1. Domain Analysis ...................................................................................................................... 1 1.2. Problem Statement ................................................................................................................... 2 1.3. Research Aim and Objectives ................................................................................................. 3 1.4. Methodological Approach ....................................................................................................... 4 1.5. Dissertation Structure and Outline ......................................................................................... 8 2. Handling Data Gaps in Reported Field Measurements of Short Rotation Forestry ......11 2.1. Background and Summary .................................................................................................... 12 2.2. Data Description ..................................................................................................................... 13 2.3. Methods and Materials .......................................................................................................... 15 2.3.1. Regression Analysis ........................................................................................................... 15 2.3.2. Interpolation ......................................................................................................................... 16 2.3.3. Multiple Imputation ............................................................................................................ 17 2.3.4. Forest Growth Functions .................................................................................................... 17 2.3.5. Process-Oriented Growth Model ...................................................................................... 18 2.3.6. Statistical Analysis .............................................................................................................. 18 i 2.4. Results and Discussion ........................................................................................................... 19 2.4.1. Regression Analysis ............................................................................................................ 19 2.4.2. Interpolation ......................................................................................................................... 21 2.4.3. Multiple Imputation ............................................................................................................. 22 2.4.4. Forest Growth Functions .................................................................................................... 23 2.4.5. Process-Oriented Growth Model ....................................................................................... 25 2.5. Conclusions ............................................................................................................................. 26 Author Contributions ..................................................................................................................... 28 Funding ............................................................................................................................................ 28 Acknowledgments ........................................................................................................................... 28 Conflicts of Interest ........................................................................................................................ 28 3. Climate Change Impacts on Hybrid-Poplar and Black Locust Short Rotation Coppices by a Combined Experimental and Simulation Study ............................................................ 29 3.1. Introduction.............................................................................................................................. 30 3.2. Materials and Methods ........................................................................................................... 31 3.2.1. Site Description .................................................................................................................... 32 3.2.2. Yearly Measurements of Above-Ground Woody Biomass ........................................... 32 3.2.3. Modelling the Above-Ground Woody Biomass .............................................................. 33 3.2.3.1. Description of the Yield-SAFE model .......................................................................... 33 3.2.3.2. Sensitivity analysis of the Yield-SAFE model ............................................................. 34 3.2.3.3. Parameterization and validation of the Yield-SAFE model ....................................... 35 3.2.4. Prospective Climate Change .............................................................................................. 36 3.3. Results ...................................................................................................................................... 37 3.3.1. Observed Woody Biomass Productivity of Poplar and Black Locust Trees ............... 37 3.3.2. Sensitivity Analysis of the Yield-SAFE Model ............................................................... 38 3.3.3. Model Validation ................................................................................................................. 38 ii 3.3.4. Modelled Woody Biomass under STAR 2K Weather Realisations ............................. 40 3.3.4.1. A forty-year comparison with respect to the average precipitation sum .................. 40 3.3.4.2. A forty-year comparison with respect to the mean temperature ............................... 42 3.3.4.3. Comparison between the ten year growing periods in terms of average precipitation sum ................................................................................................................................................... 43 3.3.4.4. Comparison between the ten year growing periods in terms of mean temperature 46 3.3.4.5. Comparison between the ten year growing periods in terms of accumulated woody biomass ............................................................................................................................................ 47 3.3.4.6. Comparison between the ten year growing periods in terms of woody biomass increment ........................................................................................................................................