title: Aggregation of individual trees and patches in forest succession models: capturing variability with height structured, random, spatial distributions.
abstract: Individual based, stochastic forest patch models have the potential to realistically describe forest dynamics. However, they are mathematically intransparent and need long computing times. We simplified such a forest patch model by aggregating the individual trees on many patches to height-structured tree populations with theoretical random dispersions over the whole simulated forest area. The resulting distribution-based model produced results similar to those of the patch model under a wide range of conditions. We concluded that the height- structured tree dispersion is an adequate population descriptor to capture the stochastic variability in a forest and that the new approach is generally applicable to any patch model. The simplified model required only 4.1% of the computing time needed by the patch model. Hence, this new model type is well-suited for applications where a large number of dynamic forest simulations is required.
authors.affiliation: Systems Ecology, Institute of Terrestrial Ecology, Department of Environmental Sciences, Swiss Federal Institute of Technology Z urich (ETHZ), Grabenstrasse 3, Schlieren, CH-8952, Switzerland. lischke@wsl.ch
authors.forename: H
authors.initials: H
authors.lastname: Lischke
authors.forename: T J
authors.initials: TJ
authors.lastname: Löffler
authors.forename: A
authors.initials: A
authors.lastname: Fischlin
mesh_terms: D015982:Bias; D002980:Climate; D017753:Ecosystem; D008954:Models, Biological; D009010:Monte Carlo Method; D009716:Numerical Analysis, Computer-Assisted; D011156:Population Density; D011157:Population Dynamics; D015203:Reproducibility of Results; D013269:Stochastic Processes; D013997:Time Factors; D014197:Trees / Q000033:anatomy & histology / Q000254:growth & development*