Comparison of the two main types of selection forests in Slovenia: distribution, site conditions, stand structure, regeneration and management

Selection forests cover 4 per cent of the total forest area in Slovenia. There are two main types - European silver fir-beech forests on calcareous substrates (FB type), and Norway spruce-silver fir forests on acidic substrates (SF type). Using data from forest inventory and research plots, the history, distribution, stand structure, tree species composition and regeneration of these two types is analysed and compared. The FB type is characterized by a relatively stable stand structure, with the diameter distribution having changed only slightly during the last century. The proportion of large diameter trees is much greater, growing stock volume is higher, and beech is more abundant. The SF selection forests have been subject to greater human influence. Nevertheless, during the last century, growing stock volume has increased, leading to a significant surplus of medium- and large-diameter trees. The proportion of conifers is typically high in both types, exceeding 50 per cent of the growing stock volume. In both types, the proportion of Norway spruce has significantly increased during the last century. Simultaneously, the proportion of silver fir has decreased due to the decline of fir, silvicultural measures and deer browsing. Natural regeneration is successful in both types, though the composition differs and silver fir regeneration is scarce in the FB type. Selection forests are dynamic, so their management needs to be adaptive.