South-East European Forestry (Dec 2010)
First Results of Monitoring of Stand Structure Changes in Unmanaged Beech Stands in NP Plitvice Lakes
Abstract
Background and Purpose: It is possible to monitor and study the natural growth and development of the forest ecosystems in the example of protected forest stands, which were excluded from management, and which are not under a negative influence of human activity. Therefore the aim of the research through the repeated measurements is to estimate the stand structure development on the Medveđak permanent experimental plot in the Plitvice Lakes national park area. In this paper we presented the first preliminary results of established monitoring, i.e. comparison of results of stand structure elements between two measurements (1998 and 2008). Furthermore, obtained results were compared with data from growth-yield tables for common beech stands similar characteristics as researched stand. In this case data from growth-yield tables present managed pure beech stands. Material and Methods: The permanent experimental plot was set in 1998 in the natural stand of mountain beech forest (Lamio orvale-Fagetum sylvaticae Ht. 1938). It is in rectangular shape, dimensions 100×100m, with subplot 60×60 m and 30×30 m. The plot is founded according to the experimental plot setting methodology (Dubravac & Novotny, 1992 and Novotny, 1997) extended on the ICP Forest workgroup demand. Tree crown damage assessment was repeated in 2003, and in June 2008 another measurement of basic stand structural elements was done. Results and Conclusion: The results in this paper show the development of the observed structural elements of the pure beech stand in the natural conditions without the management activities. According to the results of stand structure development (shape of diameter distribution, number of trees, stand basal area and volume) and results obtained in other research at the same plot [9] (number, vitality and quality of beech young growth) it can be concluded that our stand is developing towards the optimum phase of the secondary virgin forest. Furthermore, obtained results (N/ha, G/ha, V/ha) show discrepancies in relation to managed pure beech stand from growth-yield tables. Decrease in the number of trees, increase of the proportion of dead trees and proportion of significantly damaged trees in the monitoring period indicate the decrease of the stand vitality and health. Therefore, the question arises: Should protected forests today be absolutely left to the natural process of growth, development and dying? Since ten years is a brief period for research and conclusions about structural changes in the stand, further research efforts are necessary. They must be expanded with additional information and data from other permanent experimental plots which are also founded in other special purpose forests within project as well.
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