1. General Model Information

Name: Individual-based mixed rain forest growth simulator

Acronym: FORMIND

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

Contact:

Peter Koehler
Alfred Wegener Institute for Polar and Marine Research,
PO Box 12 01 61,
D-27515 Bremerhaven,
Germany
Phone: +49 471 4831 1687
Fax: +49 471 4831 1149
email: pkoehler@awi-bremerhaven.de
Homepage: http://www.awi-bremerhaven.de/People/show?pkoehler

Author(s):

Peter Koehler, Andreas Huth

Abstract:

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

II.1 Executables:

Operating System(s): Linux, Unix, Windows

II.2 Source-code:

Programming Language(s): C++

II.3 Manuals:

II.4 Data:

Physiological parameters for
- photosynthesis,
- mortality,
- recruitment and
- tree geometry for different plant functional types.
Stem number per plant functional type and diameter class of initial stand.

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

Above-ground biomass of inidvidual trees

III.2.1 Input

III.2.2 Output

Biomass,
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

IV. References

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