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Recent studies have revealed that European beech ( Fagus sylvatica L.) has significantly increased its growth in Central Europe during the last century but recently started to decline at the edge of its southern distribution. Climate scenarios predict an increased frequency of severe drought events in the future, which is supposed to cause a decline of beech forests even towards the northern edge. Whether the management has the potential to mitigate the negative effects of climate warming has not been fully addressed yet. In order to fill the knowledge gap, we compiled data from 29 long-term research plots (LTRP) at 8 sites across the western Carpathian Mountains (Eastern Europe). The LTRP were established in 1958–84 and measured every 4–5 years till 2015. Development of forest stand attributes including top height (h top ), mean quadratic diameter (d q ), mean annual tree volume increment (iv̅), periodic annual volume increment (PAIV), mean annual basal area increment (BAI), and total yield production (TY) was compared with the simulations by the Slovakian yield models developed in the 1980s based on data from the period before recent climate change. Results were additionally confronted with the growth of beech forests in a larger Central European region. Results showed an increase of TY since the 1960s compared to the simulated TY, starting from the same value, ranging from 5% to 40% and mainly depending on site quality and average annual temperature. The largest increase was found on less productive sites, which was in line with the previous findings in recent literature. Interestingly, beech TY in the Western Carpathians was found to be lower by −11% on average compared to beech forests in Central Europe (Germany). Moreover, while an increase in the BAI continues in unmanaged forests, it has recently slowed down in forests managed by “free crown thinning” and it even started to decrease in less productive forests where heavy thinning from below was applied. Finally, our results showed that the responses of beech BAI to climate variation significantly depended on tree class. [ABSTRACT FROM AUTHOR]

The paper summarises the results concerning the effects of cultivation of Douglas-fir (Pseudotsuga menziesii /Mirb./ Franco), especially in the last decades, on the intensity of production as well as non-production forest functions in the conditions of the Czech Republic and Slovak Republics. It analyses the research outcomes from the point of volume and value production in comparison with other native tree species, from the point of species effects on the soil and on the ground vegetation diversity, and from the point of stability and cultivation in the last period. The main aim was to compare this species with Norway spruce, which can be replaced by Douglas fir in suitable conditions. Douglas fir can have a favourable impact on the amount and the value of timber production, as well as on the soil and the biodiversity of ground vegetation. The stability of forest stands can also be considerably supported in this way. Hence, Douglas-fir represents a suitablealternative to Norway spruce at lower and middle altitudes and it can contribute to greater competitiveness of the Czech as well as Slovak forestry. [ABSTRACT FROM AUTHOR]

The paper deals with assessment of the long-term experiment (45 years of investigation) in beech (Fagus sylvatica L.) stand with delayed tending started at stand age of 60 years. The research was performed on four partial plots by different methods of their management: (i) plot with heavy thinning from below (C degree according to the German forest research institutes from 1902), (ii) plot with the free crown thinning (thinning interval of 5 years), (iii) plot with the free crown thinning (thinning interval of 10 years) and (iv) control plot (with no thinning). From qualitative point of view, the best results according to the number of target (crop) trees were found on plots tended by the free crown thinning (thinning interval of 5 years), and the worst on plots with heavy thinning from below and/or plot with no tending (control plot). Consequently, the results showed lower number of target (crop) trees in comparison with our assumption and/or the model developed for beech stands in the past. On the other hand, from quantitative point of view, the best results were achieved on plot tended by heavy thinning from below, followed by the plot with the free crown thinning (thinning interval of 5 years). [ABSTRACT FROM AUTHOR]

Individual tree growth and yield models precisely describe tree growth irrespective of stand complexity and are capable of simulating various silvicultural alternatives in the stands with diverse structure, species composition, and management history. We developed both age dependent and age independent diameter increment models using long-term research sample plot data collected from both monospecific and mixed stands of European beech (Fagus sylvatica L.) in the Slovak Republic. We used diameter at breast height (DBH) as a main predictor and other characteristics describing site quality (site index), stand development stage (dominant height and stand age), stand density or competition (ratio of individual tree DBH to quadratic mean diameter), species mixture (basal area proportion of a species of interest), and dummy variable describing stand management regimes as covariate predictors to develop the models. We evaluated eight versatile growth functions in the first stage using DBH as a single predictor and selected the most suitable one, i.e., Chapman-Richards function for further analysis through the inclusion of covariate predictors. We introduced the random components describing sample plot-level random effects and stochastic variations on the diameter increment, into the models through the mixed-effects modelling. The autocorrelation caused by hierarchical data-structure, which is assumed to be partially reduced by mixed-effects modelling, was removed through the inclusion of the parameter accounting for the autoregressive error-structures. The models described about two-third parts of a total variation in the diameter increment without significant trends in the residuals. Compared to the age independent mixed-effects model (conditional coefficient of determination, R c 2 = 0.6566; root mean square error, RMSE = 0.1196), the age dependent model described a significantly larger proportion of the variations in diameter increment ( R c 2 = 0.6796, RMSE = 0.1141). Diameter increment was significantly influenced differently by covariate predictors included into the models. Diameter increment decreased with the advancement of stand development stage (increased dominant height and stand age), increasing intraspecific competition (increased basal area proportion of European beech per sample plot), and diameter increment increased with increasing site quality (increased site index) and decreased competition (increased ratio of DBH to quadratic mean diameter). Our mixed-effects models, which can be easily localized with the random effects estimated from prior measurement of diameter increments of four randomly selected trees per sample plot, will provide high prediction accuracies. Our models may be used for simulating growth of European beech irrespective of its stand structural complexity, as these models have included various covariate variables describing both tree-and stand-level characteristics, thinning regimes, except the climate characteristics. Together with other forest models, our models will be used as inputs to the growth simulator to be developed in the future, which is important for decision-making in forestry. [ABSTRACT FROM AUTHOR]