Individual seedling mortality as a function of size, growth and competition in naturally regenerated beech seedlings

Young forest stands that are naturally regenerated are characterized by a large number of seedlings and high mortality rates. Good prediction of seedling mortality is therefore necessary to model the dynamics of young stands. We used data obtained in a natural beech (Fagus sylvatica L.) regeneration in north-eastern France, to fit logistic models to predict seedling mortality and to analyse how seedling size, seedling growth and local competition relate to seedling mortality. Good relationships were obtained with recent seedling diameter growth, and with a combination of local competition and initial seedling size. However, the relationships between the probability of mortality and recent growth appeared to be unstable and to vary substantially with local competition and among measurement years, precluding the use of these relationships in regeneration models.