This research took place in an old-growth forest reserve, Rajhenavski Rog, located in the Dinaric Mountains in southern Slovenia. It was the fourth measurement of tree regeneration in permanent plots located in six gaps with a 5 x 5m grid used to define the plot locations. The analysis confirmed a decline in regeneration density (competitive thinning) and an increasing proportion of beech. There was also a significant decline in regeneration cover, and an increase in the cover of dead wood and rock cover, which was against our expectations. There was no recruitment of fir and sycamore maple in different regeneration height layers, and their densities in the first regeneration layer heavily decreased over the length of the study. The density of the fir is now 0,01 m-2 and the density of sycamore maple 0,005 m-2. Beech exhibited normal development considering the density changes in regeneration layers. Even though regeneration has recruited to taller height classes over time, we could not confirm that browsing decreased. We also measured and evaluated different parameters on dominant beech stems in each plot, including tree architecture. The results show that the proportion of stems with single terminal shoots (optimal architecture), contrary to our expectations, slightly declined over time, while the share of stems with plagiotropic growth and two terminal shoots rose considerably. Finally, the height-diameter ratio of the dominant stems rose continuously over time.
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