Scenario analysis

EFISCEN is mostly used as a tool to evaluate and compare different scenarios. Scenarios can be defined in terms of management regime and expected wood demand, changes in forest area and increment level (e.g. due to climate change).

Management with regards to harvest is controlled at two levels in the model. First, for each forest type a basic management of thinning and final felling is incorporated. This theoretical management regime defines age limits for thinning and final fellings according to handbooks or expert knowledge for forest management in the region or country to be studied. This theoretical regime must be seen as constraint of what might be felled. Second, total required harvest volumes (or wood demand) from thinning and final felling are specified for a region or country as a whole for each time period. The demand for wood is usually derived from statistical sources and/or external models. Based on the theoretical management regimes, the model searches and might find, depending on the state of the forest, the required volumes.

During thinning and final fellings, logging residues consisting of stem parts, branches, foliage and coarse roots are produced. A share can be specified defining the amount of logging residues that should extracted from the forest, e.g. for energy purposes. Logging residues that are not extracted remain in the forest to decompose.

It is possible to take afforestation and deforestation into account. The user can add or remove area per tree species in each time step of the simulations. The maximum area for deforestation in one time steps equals the area in the bare-forest-land-class, but in that case also no regeneration will occur.

The model can simulate the development of the forest for decades. For various reasons, e.g. climate change, increment rates may change during long simulation periods. The model can take into account such changes in increment rate by defining an expected relative change. The basis of the increment calculation is always the increment as calculated by the incorporated growth functions, which are based on the inventory data. The new increment rates are defined relative to the basic growth functions. The expected relative change can be defined per time step, by forest type and age class and are usually derived from external models.