The influence of stand development process on the height and volume growth of dominant Fagus sylvatica L. s.l. trees in the central Rhodope Mountains of north-eastern Greece

This study was conducted in pure and mixed Fagus sylvatica L. s.l. stands in the central Rhodope Mountains of north-eastern Greece. Forty dominant beech trees were cut and analysed using a stem analysis technique. The trees came from two different groups (structural types) of stands. The first structural type consists of pure Fagus sylvatica L. s.l. stands and the second consists of Fagus sylvatica–Pinus sylvestris L. stands. In each structural type some stands are located in good productivity sites and others in medium-productivity sites. Within each structural type the structure of the stands was the result of the same development process. The development process of pure beech stands was entirely different from the development process of beech–pine stands. The main results of this research indicate that the stand development process, without any interaction with site, influences the height and volume growth of dominant beech trees, at least up to the age of 50 years. The growth environment of Fagus sylvatica–Pinus sylvestris stands, as a result of their development process, gives a strong competitive advantage to dominant beech trees, to such a degree that the dominant beech trees of Fagus sylvatica–Pinus sylvestris stands, in sites of intermediate productivity, exhibit practically the same height and at least the same volume, on average, as those of pure Fagus sylvatica stands of good productivity sites, at least up to the age of 50 years.