<abstract><title style='display:none'>Abstract</title> The paper proposes and justifies an alternative concept of aggregation of forest site types in higher units for purposes of differentiation of forest management. Analysis of variance was performed for both: the natural occurrence of tree species in reserves, as well as the production potential of tree species measured on the representative plots according to Zlatnik´s altitudinal vegetation zones and edaphictrophic series. Based on the results of this analysis, an aggregation of forest site types was suggested along the elevation gradient of climatop, and along the edaphic-trophic and the edaphic-hydric gradients of edaphotop. By intersection of such created 32 categories of geotope with the basic formation groups of forest habitats by Braun-Blanquet geo-botanical school, 53 reconstructive geo-biotopes were formed. The proposed unit was compared using the F-test, Akaike information criterion (AIC), and the index of classification efficiency (EQ) with current typological units in terms of its ability to describe the variability of the analyzed parameters. Finally, the qualitative association of the compared classification models with the European classification systems was assessed. Based on the results obtained, it can be concluded that the site unit geo-biotop is at least comparable with currently used unit MGFT, with the number of categories lower by 72%.</abstract>

The concept of geo-biotope as a possible superior site unit for
differentiation of forest management

Národné lesnícke centrum-Lesnícky výskumný ústav Zvolen, Stredisko lesníckej ochranárskej služby, Lesnícka 11, SK-969 23 Banská Štiavnica

Technická univerzita vo Zvolene, Lesnícka fakulta, T. G. Masaryka 20, SK-960 53 Zvolen

Parasitic wasps (Hymenoptera) of the European oak bark beetle larvae (<italic>Scolytus intricatus</italic> Ratz., Coleoptera: Scolytidae)

Národné lesnícke centrum - Lesnícky výskumný ústav Zvolen, T. G. Masaryka 22, SK - 960 92 Zvolen

Národné lesnícke centrum - Ústav lesných zdrojov a informatiky Zvolen, Sokolská 2, SK - 960 52 Zvolen

Odvodenie 3-D modelu povrchu korún lesného porastu a detekcia korún stromov z leteckých snímok s vysokým rozlíšením

<abstract xml:lang="en"><title style='display:none'>Results of harvesters and forwarders operations in Slovakian forests</title>Paper deals with performance, consumption of fuel and negative effects of harvester technologies on remaining stand at some workplaces in Central Slovakia.Measurements were performed at OZ (affiliated state forest enterprise) Beňuš, Kriváň, Čierny Balog and ProPopulo Poprad Ltd. Harvester and forwarder Valmet 911.1/6 + Valmet 840.1/8, John Deere (JD) 1070 D + JD 810 D, JD 770 D + JD 810 D and JD 1270 D + 1110 D were used. The results show that during wheeled harvesters operation on the slopes with inclination to 40% it is possible to reach that number of mechanically damaged trees could be on average below 10%. Using statistical verification it was found that treatment intensity influences significantly damage to remaining stand.Harvester JD 1070 D operating in tending felling reached an average performance only 2.3 m3.h-1 with average volume of tree 0.14 m3 and slope inclination within 10%. We found that it is possible to reduce to a half the costs of the production of 1 m3 of wood by proper technological preparation of the workplace and modifying the technical parameters of machine according to the parameters of stand where harvesters would operate.</abstract>

Results of harvesters and forwarders operations in Slovakian forests

The dynamics of vegetative phenophases observed at the autochton population of Norway spruce (<italic>Picea abies</italic> [L.] Karst.) in Slovakia

<abstract>
<title style='display:none'>Abstract</title>
We are currently witnessing significant global changes in climate conditions. We cannot change the natural conditions, but with regard to sustainable landscape management, we can increase our knowledge of tree species and adapt forest management to them. Surprisingly, one of the most affected tree species in Central Europe today is Scots pine (<italic>Pinus sylvestris</italic> L.). The following literature review summarizes over 200 studies from 1952–2022 regarding Scots pine across its entire range while addressing various topics in the ecology and management of this taxon. It is a tree species with a large natural range, nearly covering the entire Eurasian area. In the Czech Republic, it is the second most important tree species in terms of industrial wood production. Scots pine is characterized not only by a significant genetic variability of its populations but also by its wide ecological plasticity. Typically, it grows on sandy soils, poor habitats, and stony scree–but also in peat bogs. The wide habitat valence justifies the economic significance of this species, both in terms of its high production potential (mean annual increment of up to 10.8 m3 ha-1 yr-1) but also its wide range of use. However, in the light of climate variations, the practices of Scots pine silviculture are also gradually transforming from the traditional reforestation by clear-cutting to a more natural system–shelterwood felling. In view of climate change, its range of distribution is changing, as with other species, but Scots pine remains a very resistant tree species, depending on the habitat.
</abstract>

Importance and potential of Scots pine (<italic>Pinus sylvestris</italic> L.) in 21st century

<abstract>
<title style='display:none'>Abstract</title>
With prolonged periods of drought and temperature extremes becoming more frequent, the stress on Norway spruce has increased, as its ecological optimum is in colder and more humid environments. However, it is a tree species with a good adaptability, due to its great geographic and intraspecific variability. In this study, we tested the sensitivity of chlorophyll <italic>a</italic> fluorescence tools for the early detection of drought and heat stress, as well as their combined effect, in four Slovak Carpathian provenances, under controlled laboratory conditions. Responses in photosynthetic parameters of fast and slow (light response curves) kinetics of chlorophyll <italic>a</italic> fluorescence were analysed in spruce seedlings under four treatments: control, drought, heat, and combined drought + heat. Heat and drought + heat stresses led to the decrease of photosynthetic efficiency to a greater extent than in the case of only individual drought stress. The less sensitive parameter impacted by the stresses was the maximum quantum yield of PSII photochemistry (Fv/Fm), while the more sensitive parameters were: the performance index based on absorption of light energy (PIABS), the effective quantum yield of the PSII (ΦPSII), and the coefficients of non-photochemical fluorescence quenching (NPQ, qN). The significant variability in responses of individual provenances was also observed. Seedlings from two studied provenances responded better to these abiotic stresses (Pa-680 and Pa-1500); however, Pa-1500 provenance from the highest altitude showed the best ability of resistance to soil drought stress, as well as to high temperature effect. This rapid screening of photosystems II efficiency showed the importance of the selection of more resistant populations to concurrent stresses as one of the measures to mitigate climate change impacts.
</abstract>

Soil drought stress and high-temperature effects on photosystem II in different juvenile spruce provenances

<abstract>
<title style='display:none'>Abstract</title>
Drought is one of the abiotic factors that negatively affect the productivity of laurel (<italic>Laurus nobilis</italic> L.). Increasing water scarcity in arid and semi-arid regions is pushing the physiological limits of woody species, necessitating strong resistance to drought. Studies should be conducted on the effects of drought stress not only on forest trees but also some medicinal and ornamental species, and ways to increase their resistance should be explored. This study was carried out to determine the effect of drought stress on seedling growth and some physiological and biochemical properties in laurel. The seedlings were subjected to drought stress for about 4 months with three different irrigation regimes: watering once every 2–3 days (control), every 15 days, and every 30 days. Morphological properties (root collar diameter, height, dry weight, stem: root ratio, and number of leaves), physiological properties (midday xylem water potential and photosynthesis properties), and biochemical properties (photosynthetic pigments, total carbohydrate, and proline contents) were determined. Results have shown that drought stress has a negative effect on root collar diameter, seedling height, and dry weight. Likewise, leaf number and midday xylem water potential decreased due to increased drought stress. Furthermore, the net photosynthesis rate, stomatal conductance, and transpiration rate of the least irrigated (30th day) seedlings were quite low compared to those of control seedlings. The differences in chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid contents were also found to be statistically significant. Total carbohydrate and proline contents showed the highest values for the least irrigated seedlings and the lowest values for controlled irrigation seedlings. Our results reflect the improved tolerance capacity of laurel to increased drought stress.
</abstract>

Drought effects on growth, biochemical changes and leaf gas exchange in laurel (<italic>Laurus nobilis</italic> L.)

<abstract>
<title style='display:none'>Abstract</title>
This paper provides characteristic and a comprehensive overview of the adaptation strategies of sessile oak (<italic>Quercus petraea</italic> [Matt.] Liebl.) in the context of global climate change (GCC). The GCC is primarily manifested by increasing air temperatures and changing precipitation distribution. It poses a significant challenge to tree species including sessile oak, affecting its capacity for adaptation and survival. Despite the challenge, sessile oak shows significant drought tolerance due to its deep-reaching root system, which allows the tree to use available water more efficiently. Other adaptive strategies include the establishment of mixed stands that increase the resilience and biodiversity of the ecosystem. Adjustments of stand density through tending interventions play a significant role, helping to improve the stress resistance of stands. Additionally, coppice forest cultivation is applied on extremely dry sites. The sessile oak is also significant for its ecological plasticity – its ability to thrive on versatile soil and climatic conditions makes it a promising tree species for future forest management. Mixed stands with sessile oak and other tree species can enhance the ecosystem services of forests and also increase their endurance to GCC events. However, sessile oak faces several challenges, including the increasing risk of damage from pests and pathogens that require targeted measures for its protection and sustainable cultivation. The literature review suggests that a comprehensive understanding of sessile oak’s ecological requirements and interactions with the environment is crucial for its successful adaptation to GCC and the formulation of effective strategies for its protection and use in forest management.
</abstract>

Sessile oak (<italic>Quercus petraea</italic> [Matt.] Liebl.) and its adaptation strategies in the context of global climate change: a review

<abstract>
<title style='display:none'>Abstract</title>
On the one hand, the European beech (<italic>Fagus sylvatic</italic>a L.) is the tree of the future due to ongoing climate changes, on the other hand, there are questions about its expansion and economic use as a replacement for the declining Norway spruce (<italic>Picea abies</italic> [L.] Karst.). This literature review examines 140 studies summarizing basic research on beech in the context of climate change. As a climax tree species, beech is becoming dominant again in parts of its original range at the middle and higher altitudes of Central Europe, following spruce. It is a shade-loving species that can thrive in various types of mixed forest stands. To cultivate beech, close-to-nature methods, shelterwood, or selection management are optimal. The occurrence of the beech seed year is influenced by factors such as precipitation, temperature, drought, and air pollution. Although beech is generally considered resistant to abiotic and biotic factors, it often needs protection against hoofed game browsing in the earliest stages of development. As climate change progresses, it is essential to cultivate beech in areas rich in precipitation and nutrients where it can thrive even under more extreme conditions. In optimal conditions, beech has shown intensive regeneration in recent years, aggressively displacing other tree species. However, with insufficient precipitation and prolonged periods of drought, beech loses its vigor, production, and ability to compete. For adaptation to climate change, it is recommended to select appropriate beech provenance, promote natural regeneration, and cultivate structurally differentiated stands through positive-selection thinning from above.
</abstract>

European beech (<italic>Fagus sylvatica</italic> L.): A promising candidate for future forest ecosystems in Central Europe amid climate change

<abstract>
<title style='display:none'>Abstract</title>
This study aims to analyse the phenological dynamics of tree species in response to changes in climatic conditions over the last two climate-normal periods (CLINO 1961−1990 and 1991−2020). We focused on the main climax tree species (<italic>Quercus</italic> species, <italic>Fagus sylvatica</italic> L., <italic>Abies alba</italic> Mill., <italic>Picea abies</italic> [L.] Karst., and <italic>Pinus mugo</italic> Turra) dominating eight altitudinal forest vegetation zones (FVZ) and alluvial forests of Western Carpathians and adjacent lowlands in Central Europe. The phenological phases analysed in this study were first leaf (BBCH11) and general leaf colouring (BBCH94) for deciduous species, and the onset of new shoots (BBCH10) for evergreen conifers. The results of partial correlations confirmed that temperature is the main driving factor explaining the shifted onset of phenological phases for the species considered. Furthermore, deciduous species growing in the lower (and warmer) FVZ showed a certain level of drought sensitivity related to the earlier BBCH94. The identified trends in phenology were species-specific and differed between the individual FVZs. The most pronounced shifts toward the earlier BBCH10 and BBCH11 were found in the upper FVZ of the vertical distribution range of species. The presented results will support our understanding of the mechanisms underlying environmental control of tree phenology. This is crucial for predicting how the growing season of trees will be constrained by climate change-induced conditions in individual FVZ.
</abstract>

Significant phenological response of forest tree species to climate change in the Western Carpathians

<abstract>
<title style='display:none'>Abstract</title>
The growth performance of short-rotation woody coppice (SRWC) is strongly influenced by successful establishment in the initial months after planting. Future climates, expected to be warmer due to elevated atmospheric CO2 (eCO2), may bring about more frequent soil droughts alongside increased vapour pressure deficit (eVPD). Hence, this growth chamber experiment aimed to explore the interactive effects of eVPD, eCO2, and soil drought on growth and physiology traits of juvenile hybrid poplars under warmer climates. Our findings with juvenile hybrid poplar J-105 revealed that eVPD resulted in reductions in leaf area (–21%), root (–20%) and stem biomass (–9%), as well as in net assimilation (–15%), stomatal conductance (–26%), and transpiration (–13%). However, these decreases were relatively minor compared to the compensating effect of eCO2, which generally exerted a stronger influence than eVPD. While soil drought emerged as the primary growth-limiting factor in our study, elevated VPD is not expected to pose a significant additional threat to central European SRWC plantations of juvenile hybrid poplars under future conditions of ongoing climate change.
</abstract>

Elevated CO2 concentration alleviates the negative effect of vapour pressure deficit and soil drought on juvenile poplar growth

<abstract>
				<title style='display:none'>Abstract</title>
				 The paper presents information on the projected drought exposure of Central Europe, describes the anticipated dynamics of the regional forests, and identifies measures facilitating the adaptation of forests to climate change-induced drought risk. On the basis of an ensemble of climate change scenarios we expect substantial drying in southern Slovakia and Hungary, while such trends were found to be less pronounced for the Czech Republic and Austria. In response to these climate trajectories, a change in species composition towards a higher share of drought tolerant species as well as the use of drought resistant provenances are identified as paramount actions in forest adaptation in the region. Adaptation to aggravating climate change may need to use artificial regeneration to enrich local gene pools and increase the drought tolerance of stands. Increasing risks from pests, pathogens and other disturbances are expected as a result of more frequent and severe droughts, underlining the need to put a stronger focus on risk management principles rather than on indicators of productivity in silviculture and forest planning. A consolidation of disturbance monitoring systems and a broader use of pest dynamics and hazard rating models are paramount tools to facilitate this adaptation process in forest management. The effectiveness of all the suggested measures needs to be controlled by efficient forest monitoring systems, the consolidation of which seems to be a timely task. Systematic and long-term implementation of the presented measures should increase forest stability and resilience, and further secure the sustainable provision of ecosystem services under climate change.
			</abstract>

National Forest Centre - Forest Research Institute Zvolen, T. G. Masaryka 2175/22, SK – 960 92 Zvolen, Slovakia

Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129

University of West Hungary, Institute of Environmental and Earth Sciences, Pob. 132, H – 9401 Sopron, Hungary

University of Natural Resources and Life Sciences, Institute of Silviculture, Peter-Jordan-Straße 82, 1190, Vienna, Austria

Technical University Zvolen, Forestry Faculty, T. G. Masaryka 24, SK – 960 53 Zvolen, Slovakia

Eötvös Loránd University, Department of Meteorology, Pázmány P. s. 1/A, H – 1117 Budapest, Hungary

Climate change increases the drought risk in Central European forests: What are the options for adaptation?

<abstract><title style='display:none'>Abstract</title>In time of climate change, close-to-nature silviculture is growing in importance as a tool for future forest management. The paper study the tree layer and natural regeneration of monospecific Norway spruce (<italic>Picea abies</italic> [L.] Karst.), trough mixed spruce-beech to dominant European beech (<italic>Fagus sylvatica</italic> L.) forests in Jizerské hory Mts., the Czech Republic. In the locality, shelterwood and selection system have been applied since 2000. The research objectives were to evaluate production parameters, structural diversity, species richness, natural regeneration dynamics and radial growth of individual tree species in relation to climatic factors and air pollution. The stand volume on permanent research plots amounted to 441 – 731 m3 ha−1 in initial stage of transformation. Natural regeneration showed high expansion of beech and decrease of spruce compared to mature tree species composition. Radial growth of spruce was in significant negative correlation with SO2 and NOX concentrations compared to no effect on beech increment. Moreover, spruce was more sensitive to significant years with extreme low radial growth. Beech was more stable in radial growth. Spruce was more resistant to air pollution and climatic stress in mixed stands. Low temperature was limiting factor of radial growth together with climate extremes (such as strong frosts and more frequent droughts) and biotic factors (bark beetle, beech scale). Close-to-nature management supporting admixed tree species should lead in future to diversification of stand structure toward higher species, spatial and age structure to mitigate negative effect of climatic change.</abstract>

Adaption of Norway spruce and European beech forests under climate change: from resistance to close-to-nature silviculture

<abstract><title style='display:none'>Abstract</title> Knowledge of the structure and dynamics of near-natural mixed forests is a key factor for ecologically oriented management of forest ecosystems. The development of these model forests mostly takes place continually without any pronounced disturbances. Natural regeneration can be locally limited by ungulate browsing. The paper was focused on the structure and development of forest stands with emphasis on natural regeneration in relation to ungulates in Černý důl Nature Reserve and Trčkov National Nature Reserve situated in the Orlické hory Mts., Czech Republic. The case study was conducted in a spruce-beech-fir forest stand on four permanent research plots (PRP) of 0.25 ha in size. PRP are situated in the same stand and in comparable site and stand conditions, but two PRP has been protected against game by fencing since 1985-1989. The stand volume ranged from 478 to 565 m3 ha−1 in age 143 - 156 year. The results showed that the diversity of tree layer was higher by 19.8% (48.0% in species richness) in the stands protected by fence. In the phase of natural regeneration, the species composition, stand structure and number of recruits were poorer on unfenced PRP (7,990 recruits ha−1) compared to fenced PRP (13,160 recruits ha−1). Admixed silver fir and rowan were completely eliminated by browsing (to 94 - 100% of individuals). Growth analyses statistically confirmed that ungulates were a significant limiting factor for successful forest development (P &lt; 0.001).</abstract>

Structure and dynamics of spruce-beech-fir forests in Nature Reserves of the Orlické hory Mts. in relation to ungulate game

<abstract>
<title style='display:none'>Abstract</title>
The structure and health status of waterlogged or peaty spruce (<italic>Picea abies</italic> [L.] Karst.) forests in the summit parts of the Krkonoše Mts. in the Czech Republic were studied in 1979–2014. The objective was to evaluate the stand structure, dead wood, trend of the health status and productivity on four permanent research plots (PRP) in relation to air pollution (SO2 and NOx concentrations) and climatic conditions (temperatures and precipitation amounts). Stand structure was evaluated on the base of the measured parameters of individual trees on PRP. The health status of trees was evaluated according to foliage, and their vitality was assessed according to their radial growth documented by dendrochronological analyses. The radial growth was negatively correlated with SO2 and NOx concentrations. Stand dynamics during the observation period was characterised by increased tree mortality, the presence of dead wood and reduction of stand density from 1983 to 1992, while the most severe impairment of health status and stand stability occurred in 1982–1987. The foliage mass of living trees has been gradually increasing since 1988, but no pronounced improvement of tree vitality was documented after the decrease in SO2 concentration. However, particularly physiologically weakened spruce trees were attacked by the European spruce bark beetle (<italic>Ips typographus</italic>). The process of forest damage is manifested not only by foliage reduction but also by symptoms of various necroses on the assimilatory organs. In terms of climatic data, the weather in April had the most important effect on radial growth. Diameter increment showed positive statistically significant correlation with temperature in growing season, but the precipitation effect was low.
</abstract>

Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, CZ – 165 21 Prague, Czech Republic

Structure, development and health status of spruce forests affected by air pollution in the western Krkonoše Mts. in 1979–2014

<abstract><title style='display:none'>Abstract</title>The negative effect of air pollution on mountain spruce stands culminated in the 70s – 90s of the 20th century, when an extensive dieback and disturbance of stands occurred in the Krkonoše Mts., the Czech Republic. Dendrochronological analysis was used on ten permanent research plots established in 1976–1980 to document the dynamics of radial increment of Norway spruce (<italic>Picea abies</italic> [L.] Karst.). The objective was to determine the effect of SO2, NOX and O3 concentrations and precipitation and temperatures on spruce radial growth in climax forests, waterlogged forests and cultivated forests. The results document the strong depression of diameter increment in the period 1979–1991 caused by synergism of climatic extremes and high SO2 pollution in the 80s and 90s of the 20th century. After 2000 climate had prevailing effect on radial growth. Spruce increment was in positive correlation with temperature, particularly with temperature in the growing season and annual temperature of the current year. In general, temperature had a more significant effect on increment than precipitation, mainly in climax and peaty spruce stands. Diameter increment was in significant negative correlation with SO2 and NOX concentrations in all types of stands. Overall, peaty spruce stands were the most vulnerable to air pollution stress. Low radial increments were caused also by climate extremes, historically by strong frosts and winter desiccation in early spring, nowadays in time of climatic changes by extreme drought. Spruce stands have the ability of quickly responding by tree-ring width to both negative and positive impulses related with air pollution and climate.</abstract>

Tree-ring widths as an indicator of air pollution stress and climate conditions in different Norway spruce forest stands in the Krkonoše Mts.

<abstract><title style='display:none'>Abstract</title>Norway spruce (<italic>Picea abies</italic> [L.] Karst.) and silver fir (<italic>Abies alba</italic> Mill.) are main tree species of Central Europe that are currently highly vulnerable in times of global climate change. The research deals with the effect of climate and air pollution on radial growth of silver fir and Norway spruce in mixed age-varied (56 – 146 years) forests in the Jeseníky Protected Landscape Area, the Czech Republic. The objectives were to evaluate biodiversity, structure and production, specifically interaction of radial growth of fir and spruce to air pollution (SO2, NOX, tropospheric ozone) and climatic factors (precipitation, air temperature). Concentration of SO2 and NOX had negative effect on radial growth of fir, while radial growth of spruce was more negatively influenced by tropospheric ozone. Fir showed higher variability in radial growth and was more sensitive to climatic factors compared to spruce. On the other hand, fir was relatively adaptable tree species that regenerated very well when the pressure of stress factors subsided (air pollution load, Caucasian bark beetle, frost damage). Low temperature was a limiting factor of radial growth in the study mountainous area, especially for fir. Fir was significantly sensitive to late frost, respectively, spruce to winter desiccation and spring droughts with synergism of air pollution load. Generally, older forest stands were more negatively influenced by air pollution load and climatic extremes compared to young trees.</abstract>

Effect of climate and air pollution on radial growth of mixed forests: <italic>Abies alba</italic> Mill. vs. <italic>Picea abies</italic> (L.) Karst.

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