The Impact of Sanitary Felling During Large-Scale Disturbances on Regulating Ecosystem Services in Norway Spruce-Dominated Pre-Alpine Beech Forests of Slovenia

Ecosystem services (ES) are closely linked to nature-based solutions, which can mitigate the negative impacts of climate change or provide society with direct tangible and intangible benefits. In the context of a changing climate, it is essential to preserve these services despite increasing disturbances. In this study, we analysed changes in the structure and composition of the Jelovica forest complex (NW Slovenia) over the past two decades and assessed the provision of key regulating forest ES—specifically, soil erosion control, regulation of surface and groundwater flows, and regional climate regulation. The area has historically seen the artificial promotion of Norway spruce and, in recent decades, has been increasingly affected by large-scale disturbances and bark beetle outbreaks. We examined how these climate-related disturbances have influenced the availability of regulating ES. Over the past twenty years, the share of spruce in the growing stock in the Jelovica area decreased from 67% to 62%. We compared structural and compositional changes between two periods, 2001–2009 and 2015–2023, based on available forest management data. In both periods, mature stands were the dominant developmental stage. In the northwestern part of the Jelovica plateau, where extensive sanitary felling was carried out, the proportion of sapling stands increased significantly—unlike in other parts of the plateau. Areas affected by extensive sanitary felling exhibited statistically significantly lower evapotranspiration and reduced soil erosion control capacity, as well as higher levels of groundwater recharge, compared to other areas.