1. General Model Information
Name: Individual-based mixed rain forest growth simulator
Main medium: terrestrial
Main subject: forestry, biogeochemistry
Organization level: Ecosystem
Type of model: individual based, difference equations
Main application: research, decision support/expert system
Keywords: physiological processes, tropical forest, rain forest, species composition, timber yield, habitat diversity, forest management, gap model, individual-based
Alfred Wegener Institute for Polar and Marine Research,
PO Box 12 01 61,
Phone: +49 471 4831 1687
Fax: +49 471 4831 1149
Peter Koehler, Andreas Huth
For answering questions concerning anthropogenic impacts on tropical forest
development the individual-oriented and process-based forest growth model
Formind2.0 was developed. It simulates the spatio-temporal dynamics of
uneven-aged mixed forest stands in areas of one hectare to several km2.
The model describes forest dynamics as a mosaic of interacting forest
patches of 20 m^2×20 m2 in size. Within these patches trees are not
spatial-explicitly distributed, and thus all compete for light and space
following the gap model approach. Tree species diversity is aggregated
into 5-20 plant functional types (PFT) on the basis of species maximum tree
height and successional status. The carbon balance of each individual tree
including photosynthesis and respiration is modelled explicitly.
Thus, we can match measured diameter increment for different PFT, size and
light conditions accurately. Allometric relationships connect above-ground
biomass, stem diameter, tree height and crown dimensions. Beside increasing
mortality through self-thinning in dense plots one of the main processes of
mortality is gap creation by falling of large trees. This process as well as
seed dispersal from mature trees interlinks neighbouring plots with each other.
The model was parametrised for three different sites in South-East Asia and
South-America: Sabah (Malaysia), Venezuela, and French Guiana. Model accuracy
is tested with growth data from permanent sampling plots in Sabah. Sensitivity
of various result variables on variation of most parameter values is tested and
give important insights into general model behaviour.
Two examples of anthropogeneous impacts on tropical forest dynamics are
management practise and fragmentation, both of major concern. Following
applications are performed: Growth and yield of Venezuelan rain forest under
various logging methods, intensities and cycles are analysed for their
ustainability. Effects of logging (method and cycles), fragmentation and
recruitment assumptions on forest dynamics in Sabah are discussed. Finally,
fragmentation impacts on mortality and recruitment are simulated and
their effects on forest dynamic and biomass loss are evaluated for a
forest site in French Guiana.
II. Technical Information
Operating System(s): Linux, Unix, Windows
Programming Language(s): C++
- Physiological parameters for
- recruitment and
- tree geometry for different plant functional types.
- Stem number per plant functional type and diameter class of initial stand.
III. Mathematical Information
Above-ground biomass of inidvidual trees
- basal area and stem number (total or per plant functional type),
- species distribution,
- logging yield
- Temporal resolution: 1 yr,
- Spatial resolution: 20x20m2,
- Simulated area: 1ha up to several km2, depending on computing power
Koehler, P., Chave, J., Riera, B., Huth, A. (2003). Simulating long-term response of tropical wet forests to fragmentation, Ecosystems, in press.
Kammesheidt, L., Koehler, P., Huth, A. (2001). Sustainable timber harvesting in Venezuela: a modelling approach, Journal of Applied Ecology, 38(4), 756-770.
Koehler, P., Ditzer, T., Ong, R.C., Huth, A. (2001). Comparison of measured and modelled growth on permanent plots in Sabahs rain forests, Forest Ecology and Management, 144(1-3), 101-111.
Koehler, P., Ditzer, T., Huth, A. (2000). Concepts for the aggregation of tropical tree species into functional types and the application on Sabah's lowland rain forests, Journal of Tropical Ecology, 16(4),591-602.
Koehler, P. (2000). Modelling anthropogenic impacts on the growth of tropical rain forests - using an individual oriented forest growth model for the analyses of logging and fragmentation in three case studies, Der Andere Verlag, Osnabrueck, Germany. PhD thesis at the Center for Environmental Systems Research and the Department of Physics, University of Kassel, Germany. - University of Kassel, phdthesis.
Koehler, P., Huth, A. (1998). An individual based rain forest model - concepts and simulation results, A. Kastner-Maresch, W. Kurth, M. Sonntag and B. Breckling (editors). Individual-based structural and functional models in ecology. Bayreuther Institut für terrestrische Ökosystemforschung, Bayreuth. Bayreuther Forum Ökologie,, 52, 35-51.
Koehler, P., Huth, A. (1998). The effects of tree species grouping in tropical rain forest modelling - simulations with the individual based model FORMIND, Ecological Modelling, 109(3), 301-321.
V. Further information in the World-Wide-Web
VI. Additional remarks
Last review of this document by: : Tue Sep 17 17:06:25 2002
Status of the document: Contributed by Peter Koehler
last modified by
Joachim Benz Wed Sep 18 12:37:27 CEST 2002