1. Tree mortality submodels drive simulated long-term forest dynamics: assessing 15 models from the stand to global scale
- Author
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Bugmann, Harald, Seidl, Rupert, Hartig, Florian, Bohn, Friedrich, Brůna, Josef, Cailleret, Maxime, François, Louis, Heinke, Jens, Henrot, Alexandra-Jane, Hickler, Thomas, Hülsmann, Lisa, Huth, Andreas, Jacquemin, Ingrid, Kollas, Chris, Lasch-Born, Petra, Lexer, Manfred J., Merganic, Jan, Merganicova, Katarina, Metter, Tobias, Miranda, Brian R., Nadal‐Sala, Daniel, Rammer, Werner, Rammig, Anja, Reineking, Björn, Roedig, Edna, Sabaté, Santi, Steinkamp, Jörg, Suckow, Felicitas, Vacchiano, Giorgio, Wild, Jan, Xu, Chonggang, Reyer, Christopher P.O., ETHZ ZURICH CHE, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), University of Natural Resources and Life Sciences (BOKU), UNIVERSITY OF REGENSBURG DEU, UFZ HELMHOLTZ CENTRE FOR ENVIRONMENTAL RESEARCH LEIPZIG DEU, Czech Academy of Sciences [Prague] (CAS), UNIVERSITY OF LIEGE BEL, PIK POTSDAM INSTITUTE FOR CLIMATE IMPACT RESEARCH POTSDAM DEU, BIK SENCKENBERG BIODIVERISTY AND CLIMATE RESEARCH CENTER FRANCKFURT DEU, Technical University in Zvolen (TUZVO), LWF BAVARIAN STATE INSTITUTE OF FORESTRY FREISING DEU, USDA WINCONSIN USA, UNIVERSITAT DE BARCELONA ESP, Laboratoire des EcoSystèmes et des Sociétés en Montagne (UR LESSEM), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), UNIVERSITA DEGLI STUDI DI MILANO ITA, and LOS ALAMOS NATIONAL LABORATORY NEW MEXICO USA
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forest dynamics ,Earth sciences ,model comparison ,[SDE]Environmental Sciences ,ddc:550 ,climate change impacts ,Articles ,mortality modeling ,succession ,Article - Abstract
International audience; Models are pivotal for assessing future forest dynamics under the impacts of changing climate and management practices, incorporating representations of tree growth, mortality, and regeneration. Quantitative studies on the importance of mortality submodels are scarce. We evaluated 15 dynamic vegetation models (DVMs) regarding their sensitivity to different formulations of tree mortality under different degrees of climate change. The set of models comprised eight DVMs at the stand scale, three at the landscape scale, and four typically applied at the continental to global scale. Some incorporate empirically derived mortality models, and others are based on experimental data, whereas still others are based on theoretical reasoning. Each DVM was run with at least two alternative mortality submodels. Model behavior was evaluated against empirical time series data, and then, the models were subjected to different scenarios of climate change. Most DVMs matched empirical data quite well, irrespective of the mortality submodel that was used. However, mortality submodels that performed in a very similar manner against past data often led to sharply different trajectories of forest dynamics under future climate change. Most DVMs featured high sensitivity to the mortality submodel, with deviations of basal area and stem numbers on the order of 10-40% per century under current climate and 20-170% under climate change. The sensitivity of a given DVM to scenarios of climate change, however, was typically lower by a factor of two to three. We conclude that (1) mortality is one of the most uncertain processes when it comes to assessing forest response to climate change, and (2) more data and a better process understanding of tree mortality are needed to improve the robustness of simulated future forest dynamics. Our study highlights that comparing several alternative mortality formulations in DVMs provides valuable insights into the effects of process uncertainties on simulated future forest dynamics.
- Published
- 2019
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