1. General Model Information

Name: TREEDYN3 - Forest Simulation Model

Acronym: TREEDYN3

Main medium: terrestrial
Main subject: forestry,biogeochemistry
Organization level: forest stand,average tree
Type of model: ordinary differential equations
Main application:
Keywords: tree growth, carbon , nitrogen, forest ecosystems, climate change,soil


Michael Sonntag
Center for Environmental Systems Research
University of Kassel
Kurt-Wolters-Str. 3
34109 Kassel, Germany
Phone: +49-561-804-3178
Fax: +49-561-804-3176



TREEDYN3 is a process model for tree growth, carbon and nitrogen dynamics in a single-species, even-aged forest stand.

The tree/soil system is described by a set on nonlinear ordinary differential equations for the state variables: tree number, base diameter, tree height, leaf mass, fine root mass, fruit biomass, assimilate, carbon and nitrogen in litter, soil and organic matter, and plant available nitrogen. It includes explicit formulations of all relevant ecophysiological processes such as computation of radiation as a function of seasonal time and daytime, light attenuation in the canopy, and canopy photoproduction as a function of latitude, seasonal time and daytime, respiration of all parts, assimilate allocation, increment formation, nitrogen fixation, mineralization, humification and leaching, forest management, temperature effects on respiration.

TREEDYN3 was parametrized for European tree species (Picea abies, Pinus sylvestris, Pinus pinaster, Quercus ilex, Fagus sylvatica) and applied on a number of sites throughout Europe to questions of long-term impacts of climate change on carbon dynamics and forest stand growth (EU-project LTEEF). The nitrogen fertilization effect on stand growth caused by increased nitrogen deposition was evaluated for the Solling F1-site.

Author of the abstract:GSF : UFIS - Environmental research information system & M. Sonntag .

II. Technical Information

II.1 Executables:

Operating System(s): MS/DOS and UNIX

II.2 Source-code:

Programming Language(s): TURBO Pascal for SIMPAS simulator and C++ Both are available upon request.

II.3 Manuals:

Bossel (1996) and Bossel (1994) describe mathematical formulations and computer code in detail. A user guide for the C++ version is in draft form available upon request.

II.4 Data:

TREEDYN3 requires the following input data:
  • physiological (photosynthesis, respiration rates etc.) and structural (max. hd, min. hd etc.) data
  • site description (decomposition rates etc.)
  • initial data for carbon and nitrogen compartments
  • climatic data (air temperature, radiation)
  • thinning regime
  • TREEDYN3 gives the following information with a daily, weekly or annual time step:
  • upper height, dbh, standing biomass, fine root biomass, leaf biomass, number of trees, soil litter and humus nitrogen
  • gross photosynthesis, net photosynthesis,respiration of stem, fine roots, soil heterotrophic respiration, etc.

  • III. Mathematical Information

    III.1 Mathematics

    This is a list of model equations sorted by their characteristics with hypertext links for more details.

    III.2 Quantities

    This is a list of model quantities sorted by their characteristics with hypertext links for more details.

    III.2.1 Input

    III.2.2 Output

    IV. References

    Bossel, H. 1996
    TREEDYN3 Forest Simulation Model. Ecol. Model. 90, 187-227.

    Jansen, M.; Martin, P.-G.; Sonntag, M.; Ditzer, T.; Bossel, H. 1995
    Modellierung von Bestandeswachstum, Stoff- und Energieumsätzen mit TREEDYN am Beispiel Solling F1. Forschungszentrum Waldökosysteme der Univ. Goettingen, Goettingen, B45.

    Bossel, H. 1994
    TREEDYN3 Forest Simulation Model - mathematical model, program documentation, and simulation results. Forschungszentrum Waldökosysteme der Univ. Goettingen, Goettingen, B35.

    Bossel, H. Schaefer, H. 1989
    Generic simulation model of forest growth, carbon and nitrogen dynamics, and application to tropical acacia and European spruce. Ecol. Model. 48, 221-265.

    V. Further information in the World-Wide-Web

  • UFIS model documentation

  • VI. Additional remarks

    Last review of this document by: M. Sonntag, October 19th 1997
    Status of the document:
    last modified by Tobias Gabele Wed Aug 21 21:44:51 CEST 2002

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