Stable isotope composition in tree rings of Fagus sylvatica L. saplings reflects environmental variation induced by silviculture and microsite factors

Natural regeneration of tree species is sensitive to silvicultural interventions. This study aimed investigate the effects different cutting intensities and local topographic soil conditions on composition stable carbon (δ13C) oxygen (δ18O) isotopes in wood young beech (Fagus sylvatica L.) trees. Beech saplings layer were sampled summer 2018 at three sites Dinaric fir-beech forests karst area Slovenia. Three performed 2012: i) no (control), ii) 50% stand’s growing stock creating thinned stands, iii) 100% 0.4 ha canopy gaps. We show that δ13C increased along gradient intensity. On average, values rings ∼ 2‰ trees from gaps than closed control stands. Furthermore, was higher south-facing slopes characterized by air temperatures lower relative humidity compared north-facing sinkholes. Additionally, results suggest a dependence δ18O interannual cross-site climatic variations, particularly case precipitation amount. also responded depth, with individuals exhibiting deeper soils, presumably water availability shallow soils. The are discussed context future climate change, as many beech-dominated terrain Mountains affected warming drying due prolonged reoccurring droughts, intensified large-scale disturbances, often soils low storage capacity.