In mast‐seeding species, strong annual variation in seed production is assumed to drive seed fate and ultimately plant recruitment. However, the effects of temporal variation in seed crops on spatial patterns of seed rain and recruitment are poorly understood, in part because of limited data on fine‐scale spatial variation of seed deposition. To investigate how mast‐seeding affects spatial variation in seed rain, we analysed a 15‐year data set on seed rain and population dynamics in a montane old‐growth forest (2 plots with 81 seed traps per ha), dominated by European beech Fagus sylvatica and, to a lesser degree, Norway spruce Picea abies and European silver fir Abies alba . Using geostatistical methods and point process modelling, we modeled 1) the relationship between annual seed crop and spatial heterogeneity of seed rain, 2) the temporal stability of seed rain hotspots and 3) the spatial relation of seed rain and recruitment into the population. The results illustrate the interaction between temporal and spatial variation in seed production and its consequences for population dynamics of mast‐seeding trees. The signature of annual variation in seed rain fades with seedling mortality over time in all three focal species. For beech, the cumulative probability of seed arrival over the whole study period drives spatial seedling and sapling dispersion patterns – mediated by light competition with older trees; seedling density was most strongly reduced by sapling density, while saplings were most frequently found in areas of low adult density. Such decoupling of spatial processes across life history stages, combined with spatial heterogeneity may play a larger role in driving stand‐level spatial dynamics than previously assumed.

Key message: The disturbance of a research plot by a windstorm allowed us to study the role of the seedling bank in the regeneration processes. The released advance regeneration dominated among the saplings; taller individuals retained their position until the end of the study. Pioneer species occurred sporadically. Seven years after the disturbance, the windthrow was covered by a dense thicket of young trees. Context: The dominant role played by advance regeneration in natural regeneration processes after intense wind disturbances is still a matter of dispute. Aims: We took advantage of a windstorm in one of our research plots to study the role of the seedling bank released by the disturbance in the regeneration processes. Methods: We collected data in 70 plots, recording the survivorship of seedlings, annual height growth, and signs of browsing. The height ranking was analyzed with Kendall’s concordance coefficient, and the height growth rates were compared using Dunn’s test. Results: The density of seedlings increased from 6.7/m² in 2008 to 8.1/m² in 2010 and then decreased to 1.2/m² in 2015. The density of saplings increased continuously from 0.14 to 1.9/m². The highest size differentiation occurred in sycamore maple; the individuals which were taller before the windstorm retained their position until the year 2015. The only species that was recruited mainly from germinants was European hornbeam. Conclusion: The advance regeneration released by the windstorm played a major role in the regeneration process, while pioneer species occurred only sporadically. Seven years after the disturbance, the windthrow was already covered by a dense thicket of young trees.

Tree regeneration is a key demographic process influencing long‐term forest dynamics. It is driven by climate, disturbances, biotic factors and their interactions. Thus, predictions of tree regeneration are challenging due to complex feedbacks along the wide climatic gradients covered by most tree species. The stress gradient hypothesis (SGH) provides a framework for assessing such feedbacks across species ranges, suggesting that competition between trees is more frequent under favourable conditions, whereas reduced competition (i.e. positive interactions) is more likely under climatic stress. Moreover, tree life‐history strategies (LHS) may shed light on how and whether the SGH explains regeneration of different tree species. To address these topics, we developed statistical models based on >50,000 recruitment events observed for 24 tree species in an extensive permanent plot network (6540 plots from 299 unmanaged European temperate, boreal and subalpine forests) covering a wide climatic gradient. We found that the effects of Leaf Area Index (as a proxy for competition) on tree recruitment changed along climatic gradients but in a species‐specific manner. Competition predominates, with its intensity decreasing under stressful conditions for most species, as predicted by the SGH. However, positive interactions were only evident for a few species. Additionally, the ability of the SGH to explain patterns of competition and positive interactions across the gradients differed among species, with some differences and exceptions that may be related to varying LHS. Synthesis. Our study shows that competition between trees toward climatic stress decreases systematically but depends on species stress tolerance to climate and shade. These findings explain within‐ and between‐species differences in tree recruitment patterns in European temperate forests. Moreover, our findings imply that projections of forest dynamics along wide climatic gradients and under climate change must accommodate both competition and positive interactions, as they strongly affect rates of community turnover.

The EU Biodiversity Strategy 2030 aims to better protect natural ecosystems with high biodiversity and climate change mitigation potential. To achieve this goal, it is crucial to identify forests worth protecting, such as those characterized by long continuity and old age. Here, we propose a robust approach that combines historical maps from the mid‐19th century with remote sensing data to identify areas that have been forested for over 150 years, aiming to reduce the need for detailed and time‐consuming field investigations in potential conservation areas. We tested this approach in a 20,000 km ² region in the Polish Carpathians, an area likely containing many unprotected forests of high conservation value, where historical maps from the mid‐19th century are representative of much of Central Europe. Our results showed that an area of approximately 4200 km ² has been continuously forested since at least the mid‐19th century. Currently, 50% of these forests are outside protected areas, representing an important conservation opportunity. More generally, our approach can support the identification of valuable forests worth protecting before they are lost and provide useful insights for policymakers and stakeholders in the ongoing debate on the challenges of improving forest conservation in the Carpathians, and Europe more widely.