Treedyn3 forest simulation model : Wirkungskomplex Stickstoff und Wald

1995

S. 162-171

3 Lit. Ang.

Unselbständiges Werk

200063200

The TREEDYN3 forest simulation model is a generic process model of tree growth, carbon and nitrogen dynamics in a singel species, even-aged forest stand. It can be parametrized for any tree species, site, geographic and climatic conditions. It is based on energy and mass balances (carbon and nitrogen). Its purpose is to provide dynamic assessments of physically possible forest development paths for a wide range of environmental conditions (including nitrogen deposition, pollution effects, and temperature) and ecophysiological parameters. The tree/soil system is described by a set of 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, carbon and nitrogen in soil organic matter, and plantavailable nitrogen. The model 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, deasonal time, and daytime, respiration of all parts, assimilate allocation, increment formation, self-thinning, nitrogen fixation, mineralization, humification and leaching, forest management (thinning, felling, litter removal, fertilization etc.), temperature effects on respiration and decomposition, and environmental effects (pollution damage to photosynthesis, leaves, roots). Applications to spruce and pine in Central Europe, and eucalyptus and acacia in South China have produced results in good agreement with observations. Simulations of a Solling spruce stand under the historical nitrogen deposition scenario have produced very good agreement with empirical results. The simulations indicate that compared to pre-industrial nitrogen deposition, increment was significantly enhanced.