1. General Model Information

Name: FORests in a changing CLIMate

Acronym: FORCLIM

Main medium: terrestrial
Main subject: forestry
Organization level: Population, Biocoenosis
Type of model: individual based, Markov chain, difference equations
Main application: research, decision support/expert system,
Keywords: forest, tree species dynamics, succession, gap model, individual-based, biodiversity


Harald Bugmann
Forest Ecology, Swiss Federal Institute of Technology Zurich,
CH-8092 Zurich,
Phone: +41 44 632 32 39
Fax: +41 44 632 13 58
email: harald.bugmann@env.ethz.ch
Homepage: http://www.fe.ethz.ch/people/harald/


Bugmann, H.K.M., 1994.
On the ecology of mountainous forests in a changing climate: a simulation study.
PhD Thesis Swiss Federal Institute of Technology Zurich, 258 pp.
(available online at http://e-collection.ethbib.ethz.ch/cgi-bin/show.pl?type=diss&nr=10638)


The model ForClim (FORests in a changing CLIMate) was developed through a detailed analysis of the classical gap model FORECE and re-designed for generality. The model is based on a minimum number of ecological assumptions. Rather than tracking each individual tree, ForClim uses cohorts to simulate growth of trees of the same species established in the same year. Trees are established as saplings with a dbh of 1.27 cm as a function of species-specific parameters to winter temperature, light availability, growing degree days and browsing pressure. Trees of a given species cannot establish if one of the establishment conditions is not met. Weather data as well as light availability are derived through explicit modeling. Similar to FORECE, the effect of browsing is highly simplified; an assumed stand browsing intensity is compared against the species-specific browsing susceptibility, whereby the effect on seedlings and saplings with a dbh smaller than 1.27 cm is not explicitly accounted for. Light availability, growing season temperature, soil moisture and soil nitrogen availability are used as modifiers to tree growth, which is modeled based on a carbon budget approach. Species age and stress, i.e. sub-optimal growth, determine tree mortality.
Rather than being calibrated against large-scale measured data, ForClim uses parameters estimated from the autecological literature. The model can thus be used for simulations in ecologically and climatically different regions without any structural adjustments. ForClim performed well in several studies simulating forest dynamics in the European Alps under a range of environmental conditions e.g. large elevation and precipitation gradients. Model applications in Central-Europe, North-America, and North-eastern China have shown good overall agreement of the simulated tree species composition with descriptions of potential natural vegetation.

II. Technical Information

II.1 Executables:

Operating System(s): PC, Apple Macintosh

II.2 Source-code:

Programming Language(s): Modula, C#

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

DBH, Temperature, Precipitation, Soil Moisture

III.2.1 Input

monthly means and standard deviation of temperature and precipitation; species specific data, e.g. max. dbh, max. height, max. age, drought and shade tolerance, min. winter temperature threshold

III.2.2 Output

output of mean species biomass, basal area and number of trees per hectare, species dbh, LAI

IV. References

Risch, A.C., Heiri, C. & Bugmann, H., 2005. Simulating structural forest patterns with a forest gap model: a model evaluation. Ecological Modelling 181: 161-172.

Wehrli, A., Zingg, A., Bugmann, H. & Huth, A., 2005. Using a forest patch model to predict the dynamics of stand structure in Swiss mountain forests. Forest Ecology and Management 205: 149-167.

Badeck, F.-W., Lischke, H., Bugmann, H., Hickler, T., Hönninger, K., Lasch, P., Lexer, M.J., Mouillot, F., Schaber, J. & Smith, B., 2001. Tree species composition in European pristine forests. Comparison of stand data to model predictions. Climate Change 51: 307-347.

Bugmann, H., 2001. A comparative analysis of forest dynamics in the Swiss Alps and the Colorado Front Range. Forest Ecology and Management 145: 43-55.

Shao, G., Bugmann, H. and Yan, X., 2001. A comparative analysis of the structure and behavior of three forest gap models at sites in northeastern China. Clim. Change, 51: 389-413.

Bugmann, H.K.M. and Solomon, A.M., 2000. Explaining forest composition and biomass across multiple biogeographical regions. Ecol. Appl., 10: 95-114.

Bugmann, H. and Cramer, W., 1998. Improving the behaviour of forest gap models along drought gradients. For. Ecol. Manage., 103: 247-263.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: : Tue Feb 14 17:03:53 2006
Status of the document: Contributed by Harald Bugmann
last modified by Joachim Benz Tue May 9 14:48:37 CEST 2006

Go back to Register of Ecological Models (R E M)