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ŠUMARSKI LIST 3-4/2013 str. 38     <-- 38 -->        PDF

1996; Carus 2004; Milios et al. 2007, 2011; Ozkan et al. 2010). According to Hall (1984) timber of J. excelsa has an economic value, while Milios et al. (2009) refer that in productive sites the species may exhibit sufficient high height growth rates.
Regarding the total area of the species expansion in many studies facilitation of nurse plants is considered as a crucial process in the J. excelsa regeneration (Ahmed et al. 1989, 1990; Fisher and Gardner 1995; Milios et al. 2007). On the other hand in other cases establishment in full light seems to predominate (Hall 1984; Milios et al. 2011).
In Greece J. excelsa appears as very small groups of trees or as scattered individual trees in rocky slopes in open forests and only in few cases creates large formations of pure and mixed stands (Milios et al. 2007). One of these areas is Prespa National Park at the northwester Greece.
The analysis of the species regeneration patterns in different regions of the planet as well as under various ecological conditions will contribute to the better understanding of its ecology. This knowledge will not only lead to a better management of J. excelsa formations but it may enhance the usage of the species in order to achieve various goals.
The aims of this study were: a) the regeneration analysis of J. excelsa pure stands in Prespa National Park of Greece and b) the determination whether regeneration in gaps or under facilitation of nurse plants dominates.
Materials and methods
Materijali i metode
The study was conducted in an area of approximately 2732 ha at elevations from 840 to 1360 m where the pure and mixed J. excelsa stands appear. This area is located in the western part of Prespa National Park in Greece, which lies in northern-western part of Greece close to the Albanian and F.Y.R.O.M. borders (40°50’14.91’’ N, 21°00’59.66’’ E). Τhe soils are clay to clay silt and the substratum consists of limestones and dolomitic limestones (Pavlides 1985). The soils are rather shallow and in many cases surface appearances of parent material are observed (Pavlides 1985). In Nestorio, which is one of the closest meteorological stations (elevation of 950 m) the annual sum of precipitation averages 817 mm, and the mean annual air temperature is 10.8 °C.
In the past, the disturbances in the area were the cutting of all the trees by the army in some location of site type B, in