FORMIX3: forest model for the simulation of tropical forests
Mounting evidence suggests that current logging practices in tropical rain forest exceed forest regeneration capacity and are not sustainable. The need for reliable assessment of rainforest growth over the long terms and under changing conditions has led to the development of a dynamic simulation model for the growth of tropical rain forest: FORMIX. The model supports the assessment of the impacts of different logging methods on forest structure.
In FORMIX3 tree species are aggregated in few functional groups. The model describes individual tree growth, neighbouring tree competition, and the whole forest's dynamics on the basis of a carbon balance: the growth of the forest is constrained by the photoproduction of its leaves due to the light climate in the different canopy layers and locations in the forest, and by biomass consumption and losses. In the model, trees compete for light and space. The shifting stand mosaic, typical of natural forests, is explicitly represented: dying large trees may fall down and form gaps in the surrounding forest.
The model was applied to investigate the long-term impact of different logging strategies in different formations of tropical rainforest, e.g. in Paraguay and Malaysia (dipterocarp forest of the lowlands in Sabah, hill dipterocarp forest in Sarawak and peat swamp forest in Malaysia Peninsula). Complete model documentation, results of comprehensive model testing and an exemplary model application the discussion of simulation results are available (Huth et al. 2000, 2001, 1998).
References with applications of the FORMIX3 rain forest model
Huth, A., Ditzer, T., Bossel, H. (1998) The rain forest growth model FORMIX3 - Model description and analysis of forest growth and logging scenarios for the Deramakot forest reserve (Malaysia). Book (ISBN 3-88452-385-6), Erich Goltze, Göttingen, p. 182
Ditzer, T. (1999). Struktur und Dynamik natürlicher und bewirtschafteter Dipterocarpaceenwälder: Eine Fallstudie der Modellbildung und Simulation für die Bewirtschaftung natürlicher Ressourcen unter Unsicherheit. Erich Goltze, Göttingen, pp. 359
Huth, A.; Ditzer, T. (2000) Simulation of the growth of a Dipterocarp lowland rain forest with FORMIX3. Ecological Modelling 134: 1-25.
Ditzer, T., Glauner, R., Förster, M., Köhler, P. and Huth, A. (2000). The process-based stand growth model FORMIX3-Q applied in a GIS-environment for growth and yield analysis in a tropical rain forest. Tree Physiology 20:367-381.
Huth, A., Ditzer, T. (2001) Long-term impacts of logging in a tropical rain forest - a simulation study. Forest Ecology and Management 142: 35-51.
Kammesheidt, L., Köhler, L., A. Huth (2002) Simulating logging scenarios in secondary forest embedded in a fragmented neotropical landscape. Forest Ecology and Management 170, 89-105.
Glauner, R., Ditzer, T., Huth, A. (2003). A new approach for AAC calculation in tropical moist forest. An example from Sabah, Malaysia, Canadian Journal of Forest Research 33, 1-15.
Tietjen, B., Huth, A. (2006) Modelling dynamics of managed species-rich forests - an aggregated approach. Ecological Modelling 199:4, 421-432.