In the context of variable climate conditions, selecting high-quality Sessile oak (Quercus petraea (Matt.) Liebl.) reproductive material is crucial for sustainable forestry. This research aimed to assess the genetic potential of 86 selected plus trees by analyzing seedling morphological characteristics and quality indices. The ultimate goal was to identify the most promising genotypes for establishing seed orchards. Root collar diameter (D), seedling height (H), stem dry mass (SDM), and root dry mass (RDM) were measured under uniform nursery conditions. The following derived indices were calculated: seedling height to root collar diameter ratio (H/D), stem dry mass to root dry mass ratio (SDM/RDM), and Dickson’s quality index (DQI). Descriptive statistics, one-factorial analysis of variance (ANOVA) and Pearson correlation analysis were performed as well. The results showed significant variability in all observed morphological characteristics and quality indices among half-sib families, confirming a strong genetic influence. Correlation analysis indicated strong positive relationships between DQI and all primary morphological characteristics (r≤0.94), confirming DQI as the most effective integrative indicator of seedling quality. The combined ranking of the half-sib families, based on DQI, H/D, and SDM/RDM, identified those with optimal morphological characteristics, including an optimal H/D ratio, balanced SDM/RDM, and a high DQI value. The identified superior half-sib families represent valuable genetic material for the establishment of future seed orchards, thereby contributing to the production of better-quality seedling material and to improved forest ecosystem resilience under climate change.

Norway spruce is one of the most commonly used species for new forest planting in Europe. It is planted in a large number of habitats, often without following the previous results in the success of afforestation. In order to improve Norway spruce afforestation, open field tests were established in which developmental phenophases are monitored. The use of planting material of different provenances, which had not previously been tested for habitat conditions, was often the cause of the decline of newly planted forests. Early budburst of Norway spruce causes losses due to the freezing of terminal buds. Norway spruce testing for different habitat conditions in Bosnia and Herzegovina (B&H) was conducted at two ecologically different localities: Srebrenica (eastern part of B&H) and Drinić (western part of B&H). During 3 years, the budburst on the seedlings originating from 6 populations (Han Pijesak 1, Han Pijesak 2, Foča, Olovo, Kneževo and Potoci) was monitored. The budburst dynamics was monitored in 2013, 2015 and 2016 and it was recorded for each seedling in two progeny tests. Seedlings from the Kneževo population budbursted the earliest. The seedlings would start budburst on different days of the year, depending partly on the temperature sums and their origin. The earliest budburst was recorded in 2013 (119th day of the year in Srebrenica and 121st day of the year in Drinić). During 2015 and 2016, the budburst started later (125th day in Srebrenica and 129th day in Drinić). Temperature cumulants indicate that a smaller sum of temperatures was required for the buburst in the Srebrenica test than in the Drinić test. However, the temperature sums did not clearly indicate the budburst pattern because they were different for each observed year, but the populations ranking was almost the same. This indicates the influence of some other variables on the budburst. The knowing of the data on the budburst dynamics are a prerequisite for a successful selection of starting populations from which planting material is produced and new forests are later planted. Population Kneževo had the earliest budburst but population Han Pijesak 2 had the latest budburst.