title: The structure of tropical forests and sphere packings.
abstract: The search for simple principles underlying the complex architecture of ecological communities such as forests still challenges ecological theorists. We use tree diameter distributions--fundamental for deriving other forest attributes--to describe the structure of tropical forests. Here we argue that tree diameter distributions of natural tropical forests can be explained by stochastic packing of tree crowns representing a forest crown packing system: a method usually used in physics or chemistry. We demonstrate that tree diameter distributions emerge accurately from a surprisingly simple set of principles that include site-specific tree allometries, random placement of trees, competition for space, and mortality. The simple static model also successfully predicted the canopy structure, revealing that most trees in our two studied forests grow up to 30-50 m in height and that the highest packing density of about 60% is reached between the 25- and 40-m height layer. Our approach is an important step toward identifying a minimal set of processes responsible for generating the spatial structure of tropical forests.
authors.affiliation: Department of Ecological Modelling, Helmholtz Centre for Environmental Research - UFZ, 04318 Leipzig, Germany; franziska.taubert@ufz.de.
authors.forename: Franziska
authors.identifier: http://orcid.org/0000-0001-7594-8152
authors.initials: F
authors.lastname: Taubert
authors.affiliation: Geodetic Institute, Department of Civil Engineering, Geo- and Environmental Sciences, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany;
authors.forename: Markus Wilhelm
authors.initials: MW
authors.lastname: Jahn
authors.affiliation: Faculty of Computer Science, Mathematics and Natural Sciences, University of Applied Science-Hochschule für Technik, Wirtschaft und Kultur (HTWK), 04277 Leipzig, Germany;
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Dobner
authors.affiliation: Department of Ecological Modelling, Helmholtz Centre for Environmental Research - UFZ, 04318 Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany;
authors.forename: Thorsten
authors.initials: T
authors.lastname: Wiegand
authors.affiliation: Department of Ecological Modelling, Helmholtz Centre for Environmental Research - UFZ, 04318 Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany; Institute for Environmental Systems Research, Department of Mathematics/Computer Science, University of Osnabrück, 49076 Osnabrück, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Huth
mesh_terms: D065928:Forests; D014329:Tropical Climate
keywords: forest size structure; leaf area; stochastic geometry; tree crown packing; tropical forest