Forests and Grassland Dynamics

Image of a secondary tropical forest in Sabah, Malaysia, © Nikolai Knapp.

Forests cover roughly 30% of the earth’s land surface, but land-use and climatic change are modifying and threatening these ecosystems. To protect forests a better understanding of forest dynamics is crucial. Therefore, we have developed a family of process-based forest models: FORMIND and FORMIX. The models are used to simulate the spatio-temporal dynamics of mixed-species forests in combination with disturbances (e.g. logging, drought, storms). Both models calculate tree growth, tree mortality, the carbon balance of individual trees, competition for light, water and space, and recruitment processes by explicit seed dispersal. Our forest models have been applied in

Malaysia, French Guyana, Ecuador, Paraguay, Venezuela, Brasilia, Mexico, Chile, Panama, Sri Lanka, Madagascar, Tansania and Germany. New versions for forests of the Amazonian region are in work. We apply complex spatial statistics on observed and simulated tree data in order to get new insights into forest structures and dynamics.

A recently developed forest packing model FPM follows a novel static approach focussing on the structure of forests. Thereby, tree crowns are randomly packed within a forest only competing for space. The simple model has so far been applied to forests in Panama and Sri Lanka. The forest packing model predicts the tree size distribution of forests as well as the spatial heterogenity of local forest structure.

Virtual Forest
Visualization of a crown packing for a tropical forest in Panama. © Thorsten Wiegand /UFZ

Grasslands have been received increasing attention with the rise of several biodiversity experiments. In such experiments, numerous ecosystem functions like productivity, carbon storage often increased as species-richness has been raised, but some experimental sites also shows opposite effects.

In order to examine differently emerging relationships between species diversty and ecosystem functions in grasslands, we developed the process-based and individual-oriented grassland model GRASSMIND analogous to our forest model FORMIND. Therein, individual plants compete for light and space aboveground and for soil water and nitrogen belowground. For the latter, we coupled GRASSMIND with the soil model CANDY.

If you are interested in using FORMIND, FORMIX or GRASSMIND, please contact us or visit for download requests.

Selected Publications