Algorithms for simulating thinning and harvesting in five European individual-tree growth simulators: a review

Within the last 10 years, computer simulation software for several individual-tree growth simulators has been developed. Using these simulators, long-term prognoses and scenario analyses for the development of forest stands can be conducted. However, during the growth of forest stands trees have to be removed from the stands for reasons like thinning or harvesting. In order to simulate the various types of thinning and harvesting, and for reasons of automatization of these interventions in the simulation process, algorithms are needed to clearly describe which individual trees have to be removed from the forest stand. This paper provides a description of existing thinning and harvesting algorithms of five European individual-tree growth simulators-SILVA, MOSES, PROGNAUS, STAND and BWINPro-which are involved in the EU-project ITM (Implementing Tree Growth Models as Forest Management Tools, QLRT 1999-31349). How these algorithms can be classified is proposed as well. Finally, it provides an overview of several possibilities of application and software implementation of these algorithms. This paper enables developers of individual-tree growth simulators to decide which existing thinning or harvesting algorithm could be implemented in their simulation software.