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• the percentage of release signals typically ranged between 5 and 30% per decade; • release frequency per decade was over-dispersed compared to the random (Poisson) model; • cadences of increasing/decreasing tree growth lasted between 24 and 54 years (30 years on average); • stand-level fluctuations in tree growth were small compared to the total variation in tree increment; • a mixed-severity disturbance regime suggests unsteady gap-phase dynamics. Disturbances have been recognized as a key factor shaping the species composition, structure and dynamics of natural forest ecosystems. In Europe, where forests driven by spontaneous processes have survived in relic form, knowledge about natural disturbance regimes is still fragmentary. To expand this knowledge, we reconstructed stand-level growth and analyzed the spatio-temporal pattern of release signals in the increment chronologies of individual trees as indicators of disturbance events in the Western Carpathians (Central Europe). The study was carried out in five old-growth forests formed by Fagus sylvatica L., Abies alba Mill. and Picea abies (L.) H. Karst. Depending on the stand, the analyses included tree-ring series of 84–193 trees sampled over areas of 5.9–13.6 ha and aimed at determining (1) the spatio-temporal pattern of disturbance severity over the last two centuries, (2) whether disturbances have been synchronized in time across the study sites and (3) whether disturbances have induced pulsed dynamics of stand development manifested as fluctuations in radial tree increment at the level of entire stands. In the period 1850–2010, the percentage of decades with the proportion of released trees < 10, 10–20, 20–30 or more than 30% was 38, 41, 14 and 7%, respectively, and no instances of severe disturbances simultaneously impacting an extensive area and releasing the vast majority of trees were found. The release events were only weakly synchronized at the between-stand level. The spatial distribution of released trees varied over the decades, with a shift toward spatial independence for the most severe disturbances. At the stand level, the interchanging periods of increasing/decreasing tree growth lasted between 24 and 36 years, with the exception of one stand in which this period lasted 54 years. The revealed fluctuations in tree growth attributable to changes in stand density were relatively small and accounted on average for 7% of the total variation in annual tree increments. This suggests that local level disturbances introduce structural heterogeneity and strongly modify tree growth, but at the stand level, their effect is dispersed and causes only minor fluctuations. An over-dispersion of decadal release frequencies compared to the random model and spatial correlation of disturbing events on the one hand, and the lack of extensive disturbances, frequent occurrence of multiple releases in tree life histories, and small fluctuations in the reconstructed growth at the stand level on the other hand, suggest a disturbance regime which goes beyond random processes in a strict sense and is thus not entirely compatible with the classical model of gap-phase stand dynamics. [ABSTRACT FROM AUTHOR]

In Europe, concerns regarding the provision of ecosystem services from forests, such as biodiversity, has led to a widespread conversion from even-aged to close-to-nature forest management. These concerns have also led to a demand for quantifying stand structure, dynamics, and species diversity in order to evaluate ecosystem status and devise management action. In this study, species distribution, species association, and size diversity in a semi-natural, unmanaged beech forest in Denmark were analyzed using spatial indices including uniform angle index, mingling index, and differentiation index and spatial functions including pair correlation function, bivariate pair correlation function, mark variogram, and the Wiegand scheme. To analyze the spatial patterns of tree species, two plots, one in a less disturbed part of the forest and the other in a more recently disturbed part, was selected. Based on the spatial functions, all species showed a clustered pattern as a result of forest dynamics. Fagus sylvatica L. was segregated from other species and was more likely to form pure groups. In contrast, Ulmus glabra L.- Fraxinus excelsior L. and Ulmus glabra L.- Acer psedoplatanous L. showed positive association. All species in the less disturbed part of the forest showed positive spatial correlation of tree diameters, probably as a result of gap-phase dynamics. However, a lack of spatial correlation of tree diameters was observed for beech and elm trees in the more recently disturbed part of the forest. Our results indicated that spatial functions using stem-mapped data provide more reliable results and additional insights into the stand structure than neighborhood based indices. The study findings can be used to align forest management practices with goals of protecting biodiversity in managed forest. [ABSTRACT FROM AUTHOR]

The interest to assess the relationship between forest gap characteristics and topography features has been growing in the last decades. However, such an approach has not been studied in undisturbed mixed sessile oak–beech old-growth forests. Therefore, the present study carried out in one of the best-preserved sessile oak–beech old-growth forests in Europe, aims to assess the influence of topographic features (slope, altitude and aspect) on (i) some characteristics of canopies and expanded gaps (surface, diameter and perimeter) and (ii) the proportion of beech and sessile oak as bordering trees, gap fillers and gap makers. Through a complete gap survey on an area of 32 ha, 321 gaps were identified and mapped. The largest gaps and also the highest gap frequency (140) was found in the slope class (15.1–20°), while the gap frequency increased with altitude, with 99 gaps being recorded at 601–650 m a.s.l. The size and perimeter of the canopy and expanded gaps, as well as the number of gap makers, were negatively related to the slope and altitude. The expanded gap to canopy gap size ratio decreased with the slope and was positively related to the altitude, while a significant negative decrease in gap filler density with altitude was encountered. The sessile oak participation ratio as bordering trees forming the gap increased not only with the altitude but also with the slope. The topography plays an important role in the formation of gaps as well as in the characteristics of the future stand. This study provides valuable insights into the relationship between canopy gap characteristics and topography, which is useful information for forest owners that pursue the design of forest management toward nature-based solutions. [ABSTRACT FROM AUTHOR]

European beech-dominated forests are crucial for maintaining biodiversity in forested mountain landscapes of the European temperate zone. This paper presents the results of research and assessment of management strategy for mountain beech-dominated forests in the Jeseníky Mountains (Czech Republic). Our approach is based on combining research on historical development of the forest ecosystem, assessment of its current state, and predictions of future dynamics using a forest growth simulation model. Using such a method makes it possible to understand the current state of the mountain beech-dominated forest ecosystem and predict its future development as a response to specific management strategies. The application of this method is therefore appropriate for assessing the suitability of selected management strategies in mountain protected areas. Our results show that a non-intervention management for mountain beech forest in the next 80 years complies with the Natura 2000 requirement to maintain the existing character of the forest habitat. Thus, the current management plan for the beech-dominated forests in the Jeseníky Mountains does not require significant corrections in the context of its conservation targets (i.e. maintaining biodiversity and current character of the forest ecosystem dominated by beech). The results of this study suggest that combining the knowledge on historical development with forest growth simulation can be used as a suitable support tool to assess management strategies for forest habitats in protected areas. [ABSTRACT FROM AUTHOR]

Questions Are the structural characteristics of natural beech forests predominant on small monitoring plots representative of the large-scale features of these forests? Do the findings of our large-scale investigation support the hypothesis that this primeval beech forest is shaped by fine-scale processes, or is there evidence that high-severity disturbance events have affected its structure? Location Ukrainian Carpathians, Uholka- Shyrokyi Luh, the largest primeval beech forest in Europe, covering 102.8 km2. Methods On 314 (500 m2) circular plots, systematically distributed across the forest, all living and dead trees with a DBH ≥6 cm were assessed. Lying deadwood, tree regeneration, the size of canopy gaps and the number of canopy layers were recorded. Spatial analyses were conducted using Moran's I. Dendrochronological analysis was used to reconstruct tree ages and growth patterns. Results The forest is characterized overall by a density of 435.0 ± 12.2 ha−1 (mean ± SE) living trees, a basal area of 36.6 ± 0.8 m2·ha−1, a volume of living trees of 582.1 ± 13.5 m3·ha−1 and a total deadwood volume of 162.5 ± 8.4 m3·ha−1. Beech is the dominant species (97.3 ± 0.7%, by basal area), interspersed with mostly deciduous species with moderate shade tolerance. The forest canopy is multi-layered, with a high abundance of old trees, and with canopy gaps rarely larger than the crown projection area of a few trees. Conclusions The results lend support to findings from small monitoring plots, but our landscape approach allows a reliable estimation of key forest characteristics such as basal area and standing volume, which tend to be overestimated in studies on subjectively placed small monitoring plots. We conclude that disturbance events of moderate or higher severity have left only few discernible traces in forest structure or species composition. All findings suggest that this forest is characterized by a mainly small-scale disturbance regime, leading to a homogeneity of forest characteristics of the living stand at larger spatial scales and causing only minor fluctuations around the average values of forest parameters observed. [ABSTRACT FROM AUTHOR]

A major goal of the Convention on Biological Diversity (CBD) is to improve the protection of biodiversity. One approach to meet this goal is the implementation of strictly protected forest reserves (SPFRs). Many countries have adopted this approach and set target values for SPFRs, for example Germany aims to set aside 5 % of the forest area by 2020 (BMU, Strategie zur Biologischen Vielfalt, ). The contribution of SPFRs to biodiversity conservation cannot be assessed without considering the quality or conservation value of these areas. One challenge lies in the selection of specific criteria to evaluate this contribution of existing SPFRs. For Central Europe we reviewed these specific evaluation criteria and their ecological theory and evidence underpinning their relevance for an assessment as well as the interrelations between criteria. In addition, we present a framework for the integration of these criteria into an evaluation process. To identify criteria typically used or recommended for the evaluation of SPFRs, we analyzed the international conventions and reviewed the scientific literature on biodiversity conservation, specifically on area selection, status assessment and gap analysis. Since nearly all criteria were interrelated and operate at different scales, we developed a coherent evaluation framework to integrate them. Within this framework the criteria cover the fundamental aspects: space (completeness and connectivity), time (habitat continuity and persistence), and function (naturalness, rarity/threat and representativeness). This approach, once it is complemented by indicators, may be used to evaluate the extent to which individual SPFRs as well as a system of SPFRs contribute to the protection of natural forest biodiversity at a national level. It may be particularly relevant for Central European countries with a similar ecological, historical and political context. [ABSTRACT FROM AUTHOR]

This paper deals with the existence and identification of a common European growth cycle. Univariate Markov switching autoregressions are used for individual countries in order to detect changes in the mean growth rate of industrial production. A Markov switching vector autoregression model is then used to identify a common cycle in Europe. Three important results are obtained: we find a common unobserved component governing European business cycle dynamics, suggesting the existence of a common business cycle; we propose a dating of the business cycle, both for an index of industrial protection and GDP, and both chronologies appear to be consistent; and finally we retrieve an important set of stylized facts and relate these with those reported for the US. Finally two further issues are investigated: first, the contribution of the European business cycle to the individual country cycles; and second, we undertake an impulse response analysis to investigate the response of each individual country to European expansions and recessions. [ABSTRACT FROM AUTHOR]