engleski

EFFECTS OF STAND STRUCTURE ON REGENERATION DYNAMICS OF FIR AND BEECH FORESTS IN RISNJAK NATIONAL PARK

The article deals with the results of research involving the structure of a stand, regeneration processes, the structure of young growth, the conditions of its development and survival, crown damage of beech and fir, as well as the possibility of applying new methods of monitoring stand development, such as three-dimensional visualization of the horizontal and vertical stand structure in the forests of protected areas. The results are based on almost decade-long (1998-2007) monitoring undertaken in a permanent experimental plot in the forest of beech and fir (Omphalodo-Fagetum Marinček et al. 1992) in Risnjak National Park. The results of stand structure measurements suggest a disturbed uneven-aged structure. Fir is practically absent from the lower classes of diameter distribution and scarcely represented in the middle classes, thus indicating insufficient fir recruitment over the last few decades. Fir in the lower part of diameter distribution is replaced with beech of low quality, which indicates species alternation. An over-excessive canopy cover, the absence of canopy layering, and the growing stock accumulated on old, physiologically weak trees imply an inadequate uneven-aged stand structure. A combination of the above has had an unfavorable effect on the abundance, quality and survival of young plants. The results also make the expected normal process of natural regeneration uncertain. Owing to their role, stability and sustainability, protected forest ecosystems require a more active approach to protection by enhancing positive natural processes. The results of this research, combined with past insights reached by a number of forestry scientists, allow us to conclude that Croatian foresters, armed with their rich forestry tradition, have sufficient knowledge and possibilities, but also the obligation to help forest ecosystems to permanently fulfill their role in stable and sustainable manner.

National park; uneven-aged stand structure; natural regeneration; fir; beech

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