engleski

Characteristics of gap regeneration in Dinaric beech-fir virgin forests

Research was conducted in two typical Dinaric beech-fir virgin forests: Čorkova Uvala (Croatia) and Rajhenavski Rog (Slovenia). Both virgin stands belong to the forest community Omphalodo-Fagetum Marinček et al. 1992. Their species composition is dominated by European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.). There are sporadic occurrences of spruce (Picea abies /L/ Karsten), broad-leaved lime (Tilia platyphyllos Scop.), Wych elm (Ulmus glabra Huds.) and European ash (Fraxinus excelsior L.). Both virgin forests grow in similar stand conditions. They extend at altitudes between 700 and 1, 200 m and inhabit typical karst relief with limestone geological substrate. The average annual air temperature is 7 °C and precipitation oscillates between 1, 600 – 2, 500 mm/year. The goals of research were to compare quantitative and qualitative features of natural young growth, site conditions on the basis of indicator values of ground vegetation species and light conditions in the gaps of both virgin forests. Sampling was done in the gaps created by the death of old trees. In both virgin forests 4 large (0.07 – 0.2 ha) and 7 small (~0, 02 ha) gaps were sampled. A 5 x 5 m network was established in each gap. Quantitative and qualitative features of the young growth and relative cover of ground vegetation species were measured and analysed in the network. In addition, hemispheric photographs were taken in each plot for the purpose of light analysis. Compared to the virgin forest of Čorkova Uvala, the virgin forest of Rajhenavski Rog manifested distinctly poor regeneration of silver fir and significantly better regeneration of European beech. Fluctuations in wood mass trends in the past several decades were also recorded.

forest gap; natural regeneration; direct and diffuse light; Dinaric virgin forests; Fagus sylvatica L.; Abies alba Mill.

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