EGUsphere EGUsphere EGUsphere EGUsphere 1991-962X Copernicus Publications Göttingen, Germany 10.5194/egusphere-2022-49 FORCCHN V2.0: An individual tree-based model for predicting multiscale forest carbon dynamics Fang Jing https://orcid.org/0000-0002-4955-1212 1 2 Shugart Herman 3 Liu Feng https://orcid.org/0000-0003-3383-7598 1 2 Yan Xiaodong https://orcid.org/0000-0002-0774-9140 4 Song Yunkun 4 Lv Fucheng 4 CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, USA State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China National Natural Science Foundation of China 32101349 32171599 32130069 National Key Research and Development Program of China 2019YFC0606904 17 03 2022 2022 1 26 Copyright: © 2022 Jing Fang et al. 2022 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2022/egusphere-2022-49/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2022/egusphere-2022-49/egusphere-2022-49.pdf

<p>Process-based ecological models are essential tools to quantify and predict forest growth and carbon cycle under the background of climate change. The accurate description of phenology and tree growth processes enables an improved understanding and predictive modeling of forest dynamics. An individual tree-based carbon model, FORCCHN2 (FORest ecosystem Carbon budget model for CHiNa Version 2.0), used the non-structural carbohydrates (NSC) pools to couple tree growth and phenology. This model performed well in reducing uncertainty in predicting forest carbon fluxes. Here, we describe the framework in detail and provide the source code of FORCCHN2. We also present a Dynamic Link Library (DLL) package containing the latest version of the FORCCHN2 model. This package has the advantage of using Fortran as an interface to make the model runs fast on a daily step, the package also allows the users to call it with their preferred computer tools (e.g., Matlab, R, Python, <em>etc</em>.). FORCCHN2 model can be used directly to predict the yearly phenology as well as the daily carbon fluxes (including photosynthesis, above- and belowground autotrophic respiration, and soil heterotrophic respiration) and biomass on plot, regional, and global scales. As case studies, we provide an example of the FORCCHN2 running, model validations in 78 forest sites, and an example model application for the carbon dynamics of Northern Hemisphere forests. We demonstrate the FORCCHN2 model can produce a reasonable agreement with flux observations. Given the potential importance of the application of this ecological model in many studies, there is substantial scope for using the FORCCHN2 model in fields as diverse as forest ecology, climate change, and carbon estimations.</p>