Denisa Sedmáková

In high-mountain Norway spruce stands, contrasting tree health and strong within site growth divergence may alter climate sensitivity and obscure climate reconstructions when trees are analysed together. We tested whether blue intensity (BI) chronologies, developed for all trees or separately by health status, provide stronger climatic signals than tree-ring width (TRW) chronologies. We established 12 plots and sampled neighbouring canopy trees of similar size and social position but contrasting health status (healthy vs. declining or dead). High resolution tree-ring images were used to develop indexed TRW and BI chronologies and assess their temperature sensitivity. During 1961–1990, BI showed stronger correlations with temperature than TRW, whereas in recent period 1991–2022 TRW became more strongly related to temperature in healthy trees. In declining or dead trees, BI retained a stronger temperature signal than TRW. These findings indicate that tree health and recent warming may alter the climate-growth relationships and that BI and TRW provide complementary information for climate reconstruction.

Forest plantations, including those of Norway spruce, are increasingly threatened by drought in Central Europe. One of the measures understating this threat might be the use of drought-mitigative additives at planting. The effects of induced water limitation and the application of hydrogel Agrisorb and commercial ectomycorrhizal fungi (EMF) inoculum Ectovit on the development of 2 + 1 spruce seedlings were estimated in this study. The root systems of 2 + 0 seedlings were treated with the additives, along with their spring transplantation into peat-filled pots. The seedlings were then exposed throughout the entire growing season either to full watering (FW)—volumetric soil water content 70%, reduced watering (RW)—water content 40%, periodic watering (PW)—substrate rehydrated to 70% after drying to the wilting point (21%), or remained non-watered (NW). Survival, growth and chlorophyll fluorescence of the seedlings decreased proportionally to the increased drought intensity, while the highest root-to-shoot ratio and EMF colonization of roots occurred under PW and RW, respectively. NW seedlings died after 9 weeks of desiccation, whereas the EMF inoculum prolonged the survival time by one week. Ectomycorrhizas were formed predominantly with native EMF in all the treatments; nevertheless, compared with the uninoculated control, the formation of a treatment-specific EMF root morphotype and increased EMF colonization under PW and RW were observed on the inoculated seedlings. Both the EMF inoculum and the hydrogel increased survival under PW by approximately 15% but did not significantly affect growth, regardless of the watering regime. These results are limited to the experimental conditions and suggest a more dominant effects of the watering regimes compared with the additives tested.

Gap dynamics are driving many important processes in the development of temperate forest ecosystems. What remains largely unknown is how often the regeneration processes initialized by endogenous mortality of dominant and co-dominant canopy trees take place. We conducted a study in the high mountain forests of the Central Western Carpathians, naturally dominated by the Norway spruce. Based on the repeated forest inventories in two localities, we quantified the structure and amount of deadwood, as well as the associated mortality of standing dead canopy trees. We determined the basic specific gravity of wood and anatomical changes in the initial phase of wood decomposition. The approach for estimating the rate of gap formation and the number of canopy trees per unit area needed for intentional gap formation was formulated based on residence time analysis of three localities. The initial phase of gap formation (standing dead tree in the first decay class) had a narrow range of residence values, with a 90–95% probability that gap age was less than 10 or 13 years. Correspondingly, a relatively constant absolute number of 12 and 13 canopy spruce trees per hectare died standing in 10 years, with a mean diameter reaching 50–58 cm. Maximum diameters trees (70–80 cm) were represented by 1–4 stems per hectare. The values of the wood-specific gravity of standing trees were around 0.370–0.380 g.cm⁻³, and varied from 0.302 to 0.523 g.cm⁻³. Microscopically, our results point out that gap formation is a continuous long-lasting process, starting while canopy trees are living. We observed early signs of wood degradation and bacteria, possibly associated with bark beetles, that induce a strong effect when attacking living trees with vigorous defenses. New information about the initial phase of gap formation has provided a basis for the objective proposal of intervals and intensities of interventions, designed to promote a diversified structure and the long-term ecological stability of the mountain spruce stands in changing climate conditions.

Forest–steppe ecosystems represent a heterogeneous small-patch landscape important as a biodiversity hotspot and habitat for many endangered species. In this work, we examine threatened forest–steppe communities using structural indices, browsing intensity and indices that consider herbivorous game preferences. The study aims to assess the abundance of natural regeneration and the browsing intensity in relation to different stand structures and to identify woody species threatened by selective browsing at three study sites on the Krupina Plateau in the southern part of central Slovakia. At each study site, three circular permanent research plots (PRPs), each 500 m² in size, were established for stand structure analysis. Within each PRP, nine circular subplots with a radius of 2 m were established for detailed analysis of natural regeneration. The results of this study suggest that forest patches in the forest–steppe mosaic suffer from a long-term lack of natural regeneration, which is induced mainly by increasing aridity and ungulate pressure. Positive effects on the amount of natural regeneration were noted in association with the aggregated structure of forest patches and the presence of dead wood. Differentiated stand structure influenced the regeneration number in a negative way and at the same time significantly increased browsing intensity. In relation to a more advanced regeneration, shrubs had a protective effect against browsing. The feeding preferences of the animals can positively modulate the species composition and eliminate the imbalances in the regeneration in favor of the increasingly rare Quercus pubescens Willd.

Curly birch (Betula pendula Roth. var. carelica [Merklin] Hämet-Ahti) is a disappearing representative of the Betula genus facing a regeneration failure in a large part of its natural distribution in Europe. The unique long-term study of clonal replications originating in heterogeneous environments enabled the evaluation of long-term survival and phenotypic stability of progenies in seed orchard to assess the conservation and commercial potential of heterovegetative propagation. Seventy-eight geographic sources (95 clone origins) representing the south distribution edge in East-Central Europe were analysed for species variation in survival, growth form, bark colour, and stem quality of parent trees and their vegetative progeny, and the effects of four parental site origin characteristics. The survival rate was 73% after 28–33 years of growth. Retention of curly-grained wood was high, the curly-grained wood structure is heritable and thus clonally efficiently achievable (only 3.5% of grafted individuals showed no occurrence of figured wood structure). The phenotypic expression of curliness manifested on the trunks as bulges, stem growth forms (tree/shrub) and stem technical quality showed a lower degree of stability (coincidence) between the parent trees and heterovegatively propagated progenies. Despite this, the conservation potential of seed orchard is very high, especially when stabilization of the stem growth forms affecting the survival and commercial value of progenies can be probably achieved by a more careful selection of scions. Overall, heterovegetative orchards seem to be a very promising method for the long-term conservation of curly birch populations, which, in addition to their great biological and ecological value, have considerable commercial potential.

Sustainability and the optimal provision of the various ecosystem services is an essential task in forest management. In this study, we deal with the optimization of forest tending to achieve the maximal long-term provision of financial incomes from wood at a minimal level of ecological risks for selected small ownership unit. The methods of interactive decision maps and reasonable goals (IDM/RGM) were connected with a modern forest growth simulator to investigate the four-dimensional optimization space and to produce the complete set of Pareto optimal solutions. The four different types of forest owners as potential decision-makers were simulated, and precise management goals in multidimensional target space were defined. Then, the optimal tending system for each forest owner in three stands, differing by the degree of the naturalness of the species composition, was detected. The multi-criteria analysis suggests that predominantly economically oriented forest management still prevails in the Czech and Slovak Republics, which can be as a source of conflicts among forest owners and other stakeholders. The existence of trade-offs between biodiversity, ecological stability and wood production and different owners’ demands must be taken into account. The possibility of balancing the management risks and wood provision according to the owner’s and other stakeholders’ demands with the aid of the easy-to-apply IDM/RGM methods (and the careful assistance of a specialist experienced in multi-criteria optimization) was introduced. At the same time, the application of real integrative management in small forest areas was demonstrated in practice. After the change of paradigm in forest management, the applied methods should prevent increasing conflicts among owners and society in former socialist countries, which have undergone a fundamental transformation in terms of forest ownership in recent decades.

Forest management mimicking natural processes represents an approach to maintain mixed, uneven-aged stands at small spatial scales. The reliance on natural processes, especially on natural regeneration leads to the use of gap-based regeneration as a fundamental silvicultural technique. As a baseline for such management, we investigated mixed forest in unmanaged National Nature Reserve Sitno in the Western Carpathians, which harbours extraordinary diversity on a rather small scale. To quantify the impact of gaps on gap-filling processes and to assess the role they play in recently observed changes in tree species composition we established a large (2.5 ha) permanent research plot and surveyed the status of natural regeneration, forest structure, tree species composition, and disturbance regime. Our research highlights the long-term and contemporary difficulties in the establishment of Quercus petraea (Matt.) Liebl and Fagus sylvatica (L.). Based on the provided evidence, the native tree species diversity in one of the few preserved old-growth multi-species beech-oak forest remnants is not likely to persist, what could have many implications for future ecosystem functioning. Our results suggest that variation in gap size is an important factor contributing to composition of tree species composition of natural regeneration. The recent intermediate-scale disturbance pattern dominating the old-growth beech-oak forest is beneficial to canopy recruitment of species less shade-tolerant than Fagus sylvatica, as Acer pseudoplatanus (L.), Acer platanoides (L.), and Fraxinus excelsior (L.). We discuss possible factors behind observed shifts in tree species composition and limitations for application of gap dynamics to forest practice in managed beech-oak forest systems. Overall, results of this study may help to design silvicultural measures promoting mixed-species forests to deliver a range of desired ecosystem services.

As long-lived, slow-growing tree species, European yew (Taxus baccata L) has considerable potential for dendrochronological use. The increasing probability of decline and the worsening of yew health status endanger the species diversity of temperate forests. In 2015-2017, we sampled adult yew populations with scattered occurrence in limestone beech forests (Fagetum dealpinum), in which yew trees exhibit the top growth performance. Altogether, 150 trees were sampled (294 cores) at four localities. By using the general linear model, we investigated the interactions between stem and crown status, sex and growth performance of yew trees. Based on the previous results and innovative measures of competition and canopy closure, we explored the promotion of silviculture care for female over the male trees and formulated exact release cutting rules. The results demonstrate divergent growth trends between male and female trees and the pronounced negative effects of crown and stem damage on growth performance of European yew. Expected decreases in radial growth of damaged female trees in comparison with male ones is less confirmed. Despite this, making silviculturel treatments for females as a priority is recommendable. Our findings can improve the effectiveness of forest management and restoration activities in European temperate forests, where yew adults are threatened by the higher degree of shading and herbivory pressure.