• Key message: Natural regeneration ofP. abies(L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density.•Context: Norway sprucePicea abies(L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration ofP. abiesin low-elevation mountain forests.•Aims: We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on naturalP. abiesregeneration. We hypothesized that (1) naturalP. abiesregeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration ofP. abies.•Methods: The study was conducted in the Stołowe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m²) for natural regeneration, light availability, soil pH, and understory vegetation assessment.•Results: The highest densities of natural regeneration ofP. abieswere observed in sites with moderate light availability (0.1–0.2 of open sky) and low pH (3.5–4.5), and located relatively far from the riverbank. Cover of 22 understory plant species were correlated with naturalP. abiesregeneration densities, mostly positively.•Conclusion: Different stages of natural regeneration ofP. abiesrevealed different regeneration niches. Most understory plant species (bryophytes and herbs typical of coniferous forests) do not compete with natural regeneration ofP. abies.

Stand density changes due to aging and thinning interventions. At the same time, the social status of trees develops and varies due to different genetic conditions as well as access to nutrients and light. Trees growing in diverse conditions gain their social status in the stand, which, in the end, influences their development and biomass allocation. The objective of this research was to discover if stand density or tree social status has an impact on a tree’s aboveground biomass allocation. The study was carried out in five premature and five mature pine stands, growing in the same soil conditions. The selected sample stands had a different growing density, from low to high. In each sample stand, 10 trees were selected to represent a different social status, according to the Schädelin classification. There were 100 trees felled in total (50 in the premature stands and 50 in the mature stands), for which the dry biomass of the stem, living and dead branches, needles, and cones was determined. The results showed that stand density only had an impact on the branches’ biomass fraction but not the stem and foliage fractions, while social status had an impact on all the fractions. Dominant and codominant trees, as well as those with developed crowns, had a smaller share of the stem and higher share of branches in comparison with trees of a lower social status.