Natural Regeneration of Beech Forests in the Strict Protected Area of the Plitvice Lakes National Park

Background and Purpose: The study presents the results of an investigation of regeneration processes, growth, development and survival of young growth by field measurement and three-dimensional visualization of horizontal and vertical structure. The results are based on the ten-year investigation (1998-2009) on a permanent experimental plot in a mountain beech forest with dead nettle tree (Lamio orvale - Fagetum sylvaticae Ht. 1938) in conditions of passive protection. Materials and Methods: Basic structural indicators were measured (diameter at breast height and height), structural crown elements (size and shape, ground cover crowns) and the occurrence and survival of young growth as the basic conditions of natural regeneration. Particular emphasis in the investigation was paid to the development of crown structures and the process of natural regeneration during the 10 year period. Results and Conclusions: Investigation indicates the occurrence of young growth regeneration cores arising as a result of the die-back of one dominant beech tree with horizontal crown projections of 145 m2 which initiated the possibility of natural regeneration. The greatest change occurred in the beech seedling count, whose numbers increased fourfold from 3556 plants per hectare in 1998 to 12694 plants per hectare in 2009. The share of beech seedlings increased from 8.7% to 22.6% of all species of young growth and shrubs. Thus beech became dominant among the tree species regeneration. However, the majority of the young plants of beech are of poor quality and thus their further development in conditions of passive protection is questionable. The investigations also showed the possibility of a new approach to the study of the dynamics of crown structures and the process of natural regeneration by methods of three-dimensional visualization of horizontal and vertical structures. The methods presented offer a more graphic illustration of the development of stands and high quality presentation of the obtained results. For a long-term scientifically based plan, with the aim of reaching the most favourable decisions on the future of forest stands in protected areas, particularly in today’s conditions of climatic changes, continuous improvement and expansion of monitoring methods by means of a network of permanent experimental plots in all protected forest areas is necessary