Validation of an individual-based model of forest dynamics using self-thinning relationships

Self-thinning relationships link mean plant size and plant density for even -aged populations subjected to density-dependent mortality. Because the rel ationships are expressed at the population or the community level, they con stitute a validation test for individual-based models of plant population d ynamics. The model proposed here stems from forest gap models of the JABOWA /FORET-type and succeeds the validation test. Th is validates the growth an d mortality individual-based local rules used in most gap models. The resul t arises in the model because some basic assumptions make density a negativ e exponential function of time and mean individual size a sigmoid function of time. (C) 1999 Academie des sciences / Editions scientifiques et medical es Elsevier SAS.