As part of efforts for protection and restoration of variability of Juglans regia in Djerdap gorge, Serbia, where it grows as autochthonous relict species, the variability of ten measured and nine derived leaf morphometric parameters of half-sib progenies Persian walnut originating from Djerdap gorge was studied in this work. According to the contribution to total expected variance, parameters that were most effected by differences between half-sib progenies are leaf width (LW), side leaflet length (lL) and top leaflet length (20-30%). Using loadings with the first four rotated principal components, describing 90.1% of total variance, all parameters were grouped in four groups, where parameters LW, lL and lt were in the first group, suggesting multicollinearity between them. These parameters had also relatively high loadings with the first canonical variable from canonical discriminant analysis. Only one of them (lt) was selected by forward stepwise discriminant analysis, where model with four selected leaf parameters achieved 26.5% of correct allocation, while model with all studied parameters achieved 62.4% of correct allocation. Half-sib progenies agglomerated in three clusters, where two small clusters originate from trees that were close to sheltered valleys of small tributaries to river Danube, opposite to mother trees of the first cluster progenies, that were exposed to dominant winds.

Soils act as sources or sinks for three major greenhouse gases (CO₂, CH₄, and N₂O). Approximately 20% of global CO₂ emissions are released from soils through the soil respiration process. Soil respiration (soil CO₂ emission) can account for over 85% of ecosystem respiration. The aim of this study was to compare managed and unmanaged stands of pedunculate oak (Quercus robur L.) in order to investigate the impact of forest management on soil CO₂ emissions. We selected one managed and two unmanaged stands. The first stand (S1) represents a managed middle-aged stand, which is the optimal stage of development. The second stand (S2) belongs to the over-mature stage of development in an old-growth oak forest, while the third stand (S3) belongs to the decay stage of development in an old-growth oak forest. The closed chambers method was used for air sampling and the air samples were analyzed using gas chromatography (GC). Multiple regression models that include soil temperature (ST), soil moisture (SM), and their interaction provide a better explanation for variation in soil CO₂ emission (SCDE) (higher R² values) compared to regression models that only involve two variables (ST and SM). The study showed that SCDE in the decay stage of old-growth forest (S3) was significantly lower (p < 0.001) compared to the other two stands (S1 and S2). S3 is characterized by very low canopy cover and intensive natural regeneration, unlike S1 and S2. However, there were no significant differences in SCDE between the managed middle-aged stand (S1) and the over-mature (old-growth) stand (S2). Over a long-term rotation period in pedunculate oak forests, forest management practices that involve the periodic implementation of moderate silvicultural interventions can be deemed acceptable in terms of maintaining the carbon balance in the soil.

Soil salinization is a major abiotic stressor limiting global agricultural and forestry productivity. This study aimed to assess the tolerance of four wild cherry (Prunus avium L.) genotypes (8-A, F-12, F-19, F-15) to salinity stress using the in vitro culture technique. Shoots were exposed to three NaCl concentrations (0—control treatment, 33, and 100 mM) in micropropagation medium under controlled laboratory conditions for 35 days. Morphological parameters, including shoot length, shoot number, survival and multiplication rate, shoot fresh and dry biomass, and shoot water content, were evaluated alongside biochemical markers such as total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities assessed through ferric reducing–antioxidant power (FRAP), ABTS radical scavenging, DPPH radical scavenging and nitric oxide (NO•) scavenging. Consistent with the experimental design, exposure to 100 mM NaCl significantly inhibited shoot growth and biomass accumulation, while survival was comparatively less affected. Genotypic variation was evident, with genotypes F-19 and F-12 demonstrating higher tolerance, maintaining greater growth and antioxidant capacity (FRAP and ABTS) under salt stress compared to more sensitive genotypes like 8-A and F-15. Phenolic and flavonoid contents were also reduced at 100 mM NaCl, suggesting that intense salinity stress limited the biosynthesis and accumulation of these antioxidant compounds. Nitric oxide scavenging activity remained largely unaffected by salinity in all genotypes, which may indicate that the applied stress levels were insufficient to markedly alter this component of the antioxidant response. The genotype F-19 emerged as the strongest salinity-tolerant genotype, retaining superior shoot number, multiplication rate, fresh/dry biomass and stable/increased total phenolic content (TPC) under 100 mM NaCl compared to other genotypes. This integrative in vitro approach effectively distinguished salt-tolerant wild cherry genotypes and offers a valuable screening tool for breeding and selection programmes targeting improved resilience to salinity stress. The findings have practical relevance for forestry, horticulture, landscape architecture and the restoration of salt-affected sites, particularly in the context of climate change. They also align with current European and global priorities focused on identifying genetically suitable reproductive material for resilient afforestation and ecosystem restoration under increased environmental stress.