The genetic variability of five populations of Quercus petraea originating from the Transylvania and Maramureș regions of Romania was investigated in this study to provide insights into the species’ adaptability, population dynamics, and potential for preservation in the face of environmental challenges. To achieve this, sequence-related amplified polymorphism (SRAP) markers, in conjunction with a set of 18 primer combinations, were employed. The outcomes of the analysis revealed a range of polymorphisms spanning from 69.78% to 85.75%. Additionally, the assessment of genetic diversity using Shannon’s information index (I) yielded values ranging between 0.2887 and 0.3955, while Nei’s gene diversity (He) exhibited a spectrum from 0.1833 to 0.2582. The analysis of genetic variability, conducted via molecular variance (AMOVA), unveiled that 9% of the genetic variation was attributable to differences among the populations, while a substantial 91% resided within the populations. A further investigation of the population structure revealed that the construction of a UPGMA dendrogram based on Nei’s genetic distances elucidated the presence of two principal genetic clusters, a finding that was reinforced by a Principal Coordinate Analysis (PCoA). The genetic diversity revealed by Quercus petraea using SRAP molecular markers offers promising potential for upcoming breeding programs to identify optimal genitors, facilitating the development of well-adapted oak populations in the Transylvania and Maramureș regions.

The production of oak seedlings in intensive crops involves the modification of natural conditions, namely the degree of humidity, through artificial irrigation, which favors the appearance of the pathogen Erysiphe alphitoides, responsible for the Oak Powdery Mildew (OPM) disease. Thus, it is necessary to identify new substances and technologies to control OPM. In this sense, new products approved by the European Union (EU) and Forest Stewardship Council (FSC) were identified, both synthetic and, a great novelty, biological (based on chito-oligosaccharides-oligogalacturonans: COS-OGA). In order to quantify the results, a correlation was made with climatic factors, by sampling data related to temperature and relative humidity with Data Logger devices. The obtained results suggest that OPM has a high virulence in the temperature range of 20 to 30 °C; at a relative humidity above 75%. The data obtained from the field experiments show that the synthetic products controlled OPM with an effectiveness between 70% and 95%, and the biological product behaved almost similarly, between 60% and 90%, which creates high opportunities for environmentally friendly control of forest pathogens.

Oak forests provide critical ecosystem services, but are being increasingly exposed to climate variability, drought, and insect outbreaks that threaten their long-term resilience. This study aims to integrate structural canopy indicators with climate-derived indices to detect early-warning signals of decline in temperate oak stands. We monitored eight Forest Management Units in western Romania between 2017 and 2021, combining field-based assessments of crown morphology, vitality traits, defoliation, and epicormic shoot frequency with hydroclimatic indices such as the Forest Aridity Index. Results revealed strong spatial and temporal variability: several stands showed advanced canopy deterioration characterized by increased defoliation, dead branches, and epicormic resprouting, while others maintained stable conditions, suggesting resilience and suitability as reference sites. Insect defoliators, particularly Geometridae, contributed additional stress, but generally at subcritical levels. By synthesizing these metrics into conceptual models and a risk scorecard, we identified the causal pathways linking climatic anomalies and biotic stressors to structural decline. The findings demonstrate that combining structural and climatic indicators offers a transferable framework for forest health monitoring, providing robust early-warning tools to guide adaptive silviculture and resilience-based management. Beyond the Romanian context, this integrative approach supports sustainability goals by strengthening conservation strategies for temperate forests under global change.

Spruce (Picea abies (L.) Karst) is one of the most significant coniferous tree species in Romania, covering around 24% of the country’s total forested area. It plays an important ecological and economic role, being widely used in the timber industry and contributing to biodiversity and climate regulation in mountainous regions. The study conducted in UP II Bistra, managed by the Valea Arieșului Forest District, aimed to assess the ecological response of Norway spruce (P. abies) under varying microstationary conditions across five sample plots, each measuring 500 m². The research focused on the influence of ecological factors such as slope exposition and altitude on growth performance and biomass accumulation. Results revealed that trees located on south-west (S-W) facing slopes, at altitudes between 800–1400 m, showed significantly higher biomass values compared to those on north-east (N-E) exposures, despite similar altitude ranges. Among the factors analyzed, slope exposition was identified as the primary driver of phenotypic variability and forest ecosystem functioning at the landscape level. Given that all studied stands were pure and even-aged, the observed growth differences are likely linked to specific local habitat conditions. The superior growth performance observed on south-western slopes is largely due to the spruce’s natural preference for semi-shaded environments, where the balance of sunlight and moisture creates optimal conditions for early development and root establishment. Furthermore, the research supports the conservation of biodiversity in the region by highlighting how varying environmental conditions and forest management practices affect species diversity and ecosystem stability.