1. General Model Information

Name: ZELIG Tree Simulator Model

Acronym: ZELIG

Main medium: terrestrial
Main subject: forestry,biogeochemistry
Organization level: individual, ecosystem
Type of model: not specified
Main application: research
Keywords: forest, tree species dynamics, succession, forest growth, canopy characteristics, spatially explicit, gap model


Dean L. Urban
Box 90328
Duke University
Durham, NC 27708
Phone: 919-613-8076
Fax: 919-684-8741
email: deanu@duke.edu
Homepage: http://www.env.duke.edu/people/faculty/urban.html


Dean L. Urban


ZELIG (Urban, 1990) is an individual tree simulator that simulates the establishment, annual diameter growth, and mortality of each tree on an array of model plots. Model states are recorded in a tally of all trees on a plot, with each tree labeled by species, size (diameter), height to base of live crowns, and vigor (based on recent growth history). The competitive environment of the plot is defined by the height, leaf area, and woody biomass of each individual tree determined by allometric relationships with diameter. Plot size is defined by the primary zone of influence of a single canopy-dominant tree. The plot is considered homogeneous horizontally, but vertical heterogeneity (canopy height and height to base of crown) is simulated in some detail. Adjacent cells interact through light interception at low sun angles. Establishment and annual diameter growth is first computed under optimal (nonlimiting) conditions, and then reduced based on the constraints of available light, soil moisture, soil fertility, and temperature. Climate effects are summed across simulated months. Seedling establishment, mortality, and regeneration are computed stochastically, while the growth stage is largely deterministic. Simulations can start or stop at any point within the life cycle of a forest.

The objective of the ZELIG model is to understand the dynamics of forest growth and canopy characteristics through a simulation model of the dynamics of tree species. The initial elements of this model were developed by Dan Botkin and colleagues about 20 years ago (JABOWA) developed further on by Shugart and co-workers (e.g. FORET) resulting on one developmental line in ZELIG and successors.

Author of the abstract:
The BOREAS Information System

II. Technical Information

II.1 Executables:

Operating System(s): PC, UNIX Sun SPARC 10

II.2 Source-code:

Programming Language(s): FORTRAN, C++

Download(not maintained anymore !!!):
Zelig++ Enhanced GenericForest Gap Model (not maintained anymore)

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Urban, D.L., 1990.
A versatile model to simulate forest pattern: a user's guide to ZELIGversion 1.0.
Department of environmental sciences, University of Viginia, Charlottesville,VA, 108 pp.

Urban, D.L., G.B. Bonan, T.M. Smith, H.H. Shugart, 1991.
Spatial applications of gap models. For. Ecol. Manage., 42, 95-110.

Urban, D.L., H.H. Shugart, 1992.
Individual based models of forest succession. In D.C. Glenn-Lewin,R.K. Peet, T.T. Veblen (eds.): Plant Succession: Theory and Prediction.Chapman and Hall, London, pp. 249-286.

Weishampel, J.F., D.L. Urban 1996.
Coupling a spatially-explicit forest gap model with a 3-D solar routineto simulate latitudinal effects. Ecological Modelling, 86, 101-111.
Miller, C., and D. Urban. 1999a. A model of surface fire, climate, and forest pattern in Sierra Nevada, California. Ecol. Modelling 114:113-135.
Miller, C., and D. Urban. 1999b. Forest pattern, fire, and climatic change in the Sierra Nevada. Ecosystems 2:76-87.
Miller, C., and D. Urban. 2000. Modeling the effects of fire management alternatives on Sierra Nevada mixed-conifer forests. Ecol. Applic. 10:85-94.
Urban, D.L. 2000. Using model analysis to design monitoring programs for landscape management and impact assessment. Ecol. Applic. (in press)
Urban, D.L., M.F. Acevedo, and S.L. Garman. 1999. Scaling fine-scale processes to large-scale patterns using models derived from models: meta-models. Pagers 70-98 in D. Mladenoff and W.L. Baker (eds.), Spatial modeling of forest landscape change: approaches and applications. Cambridge University Press, Cambridge.
Urban, D.L., C. Miller, P.N. Halpin, and N.L. Stephenson. 2000. Forest gradient response in Sierran landscapes: the physical template. Landscape Ecol. (in press)

V. Further information in the World-Wide-Web

VI. Additional remarks

ZELIG can be used to assess global change associated with forests. Thematurity of this model and its ability to run at varying temporal and spatialscales is valuable for characterizing how varying climate scenarios caninfluence dynamics of multiple forest species.
Last review of this document by: J. Benz, 05/26/2004
Status of the document:
last modified by Joachim Benz Mon Dec 12 16:00:55 CET 2005

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