Understanding the stand mosaic of primeval forests as a basis for close-tonature forest management: lessons from the Rajhenav virgin forest in the Dinaric mountains

Abstract

In primeval forests, it is possible to recognise patches that differ in structure and composition. These can be delineated and classified to describe the typical stages of forest stand dynamics. The stand mosaic of Rajhenav virgin forests (Dinaric Mountains, Slovenia) was analysed and the patches were classified into seven developmental stages (young growth, pole, mature, with understorey regeneration, multi-layer, two-layer and gap). The mean patch size amounted to 0.35 ha. The size of “older” stands was significantly larger. Mature stands prevail (> 50 % of the total area), approximately half of the area was covered by stands with understorey regeneration and uneven-sized stands. The proportion of gaps and young growth stage in total was quite low. No patches of pole stage were registered. Proportion of developmental stages suggests that the typical dynamics of this forest type is primarily driven by death of individual trees or small groups of trees. This is reflected in the high proportion of stages characterized by dispersed mortality of trees (two- and multi-layered stands, stands with understorey regeneration). The results indicate various possible pathways of stand development; some are just more common than others. By mimicking the dynamics of primeval forests in managed forests, it is possible to manage forest stands in a variety of pathways. Rather than rigidly applying one silvicultural system across the area, it is suggested that elements of various systems are combined. This is at the core of the free-style silviculture concept.