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This paper aims to numerically assess the cavitation damage of hydrodynamic machines and hydraulic components and its development in time, based on cavitation erosion tests with samples of used materials. The theoretical part of this paper is devoted to the numerical simulation of unsteady multiphase flow by means of computational fluid dynamics (CFD) and to the prediction of the erosive effects of the collapses of cavitation bubbles in the vicinity of solid surfaces. Compressible unsteady Reynolds-averaged Navier–Stokes equations (URANS) are solved together with the Zwart cavitation model. To describe the destructive collapses of vapor bubbles, the modeling of cavitation bubble dynamics along selected streamlines or trajectories is applied. The hybrid Euler–Lagrange approach with one-way coupling and the full Rayleigh–Plesset equation (R–P) are therefore utilized. This paper also describes the experimental apparatus with a rotating disc used to reach genuine hydrodynamic cavitation and conditions similar to those of hydrodynamic machines. The simulations are compared with the obtained experimental data, with good agreement. The proposed methodology enables the application of the results of erosion tests to the real geometry of hydraulic machines and to reliably predict the locations and magnitude of cavitation erosion, so as to select appropriate materials or material treatments for endangered parts. [ABSTRACT FROM AUTHOR]

Insect infestation triggers multiple defense responses in plants, both locally at the infection site and systemically throughout the plant, including the production of feeding deterrents, toxins, defensive proteins, enzymes, and secondary metabolites. Our study aimed to compare the endogenous levels of antioxidative enzymes, photosynthetic pigments, phytohormones, total phenols, and flavonoids in bark-beetle-infested and uninfested trees. We evaluated the surviving trees in bark-beetle-infested stands, assessing both the condition and defense of uninfested and infested beech (Fagus sylvatica), pine (Pinus sylvestris), and fir (Abies alba) trees. Sampling was performed at six affected sites in the Czech Republic, targeting trees that were resilient to significant health deterioration caused by abiotic and biotic factors. The results showed different levels of most of the measured compounds in the three species. Among all the tested species, photosynthetic pigment levels showed the strongest association with infestation status, which was generally lower in the infested plants. For chlorophyll a, extremely significant reductions were observed from 123 ± 20.6 to 101 ± 17.9 μg/g dry weight (DW) in pine, from 231 ± 33.1 to 199 ± 22.2 μg/g DW in beech, and from 60 ± 5.66 to 51.3 ± 6.27 μg/g DW in fir. In contrast, enzymatic activities indicated only isolated instances of significant association, whereas antioxidative properties (total phenolic content, flavonoids, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity) were not significantly associated with infestation status. There was a statistically significant increase in glutathione reductase activity in infested fir and pine trees. However, this difference was not statistically significant in beech. In contrast, a significant increase in superoxide dismutase activity was detected in infected beech trees. Phytohormones have emerged as the most diverse group of analyzed compounds. Cytokinins were the most distinct, with many of them being significantly increased in infested pines, whereas both beech and fir showed only one significant association. Additionally, derivatives of jasmonic acid also showed a distinct pattern of change associated with bark beetle infestation, with the levels of three out of the four analyzed jasmonates being significantly decreased in infested pines, whereas no effects were observed in beeches and firs. Notably, many phytohormones were significantly elevated in the infested pine, whereas both beech and fir exhibited only one significant association. Overall, the data showed that pines responded differently to bark beetles than to beeches or firs. The greatest changes in phytohormones were observed in pine, whereas the most significant changes in photosynthetic pigments were observed in beech and fir trees. [ABSTRACT FROM AUTHOR]

The study evaluates the results of a long-term research trial lasting 50 years in two research plots established in the 1970s aimed at solving the decline of the silver fir in the Czech Republic. A total of 103 different provenances occurring naturally across 12 countries were planted in research plots No. 67, Černovice (Českomoravská vrchovina), and No. 77, Nové Hrady (Novohradské hory). The total tree height, diameter at breast height (DBH) and assessment of the health status of all trees in the area were measured with the same methodology. Subsequently, the volume of large wood was calculated by the volume equation, and the growing stock per hectare was recalculated. Based on our analysis of average height growth, it was found that trees with the best growth came from provenances that included the Czech provenances CZ 70 - Ždírec nad Doubravou, CZ 82 - Vizovice, CZ 42 - Lukov, CZ 76 - Nýrsko, Suchý Kámen, and CZ 53 - Opočno. The last three mentioned provenances also dominated in other growth parameters (DBH and volume of large wood). Of the foreign provenances, D 146 - Schwarzwald mit Baar, S 9 - Kriváň, and S 6 - Čierny Váh produced trees that showed above-average values. The smallest growth in height was found in the trees from the provenances BG 132 - Rila, Borovets, F 104 - Departement de ľ Aude, I 228 - Vallombrosa, A 93 - Wörschachwald. Although some trees of Italian provenance achieve above-average volume, due to high mortality, they are not suitable for economic use in the forests of the Czech Republic. Based on the European zoning for forests, the units from the Central European region (3.11.0 - České Polabí, 3.32.0 - Schwarzwald with foothills and Baar, and 9.14.0 - Southern Apennine Mountains) were the best rated in all parameters. Specimens from 9.12.0 - Mountain forest of the northern Apennines, and 4.05.0 - Vosges showed the lowest parameters. [ABSTRACT FROM AUTHOR]

Th e paper deals with growth and prosperity of 25 provenances of grand fi r from Washington, Oregon, Idaho and Montana (USA), and from Vancouver (British Columbia, Canada) tested in the international provenance research trial No. 212 – Drahenice (Czech Republic; N49° 31‘ 10‘‘, E13° 57‘ 20‘‘, 570 m a.s.l., acidic beech site). Biometric measurements took place at the age of 41 years; qualitative features were visually assessed according to the IUFRO methodology. Th e best overall assessment of both production and quality shows provenance 12041 – Oyster Bay (BC). Other provenances with high growing stocks, i.e. 12005 – Bear Mountain (WA), 12038 – Clearwater (ID), 12043 – Sproat Lake (BC) and 12044 – Kaye Road (BC) showed some qualitative shortcomings (lower vitality, worse stem shape or thicker branches). Th e worst both in production and quality were provenances 12020 – Crescent Creek (OR) and 12011 – Clear Lake (WA). Th e results confi rm the suitability of the current setting of the rules for the transfer of reproductive material from North America to the Czech Republic. [ABSTRACT FROM AUTHOR]

Th is study examines the variability of Scots pine provenances in four Czech research plots from the same series of experiments conducted in 1972. 121 provenances from the Czech Republic and Slovakia were evaluated in terms of growth and morphological characteristics. Th e quantitative traits measured for each tree were its tree height and DBH. Th e stem volume was also calculated according to the volume equation (Petráš, Pajtík 1991). Among the qualitative traits, stem form, health status, branch thickness in the crown, stem damage, stem twist, stem clearing, stem cross-section, and taper were evaluated. Th e large variance in growth characteristics of provenances does not specify the suitability of a particular reproductive material for a given area. Slovak provenances even from a relatively small land unit (Šaštín area) planted in the same research plot have diff erent quantitative and qualitative traits. However, the evaluation of the test plots of Scots pine in Bohemia showed impaired growth performance of most of the Slovak provenances. Th erefore, it is necessary to test more provenances from a larger area of the Scots pine range to obtain the possibility of using a wider range of reproductive material of the tree in our conditions. In the long term, further provenance trials with new reproductive material are needed to assess suitability under changing natural conditions [ABSTRACT FROM AUTHOR]

Th e paper contains the evaluation of 9 European black pine provenances on the research trial No. 41 – Roblín (Czech Republic) at the age of 51 years. Th e tested provenances originated from Bosnia and Herzegovina, Serbia, Croatia, Bulgaria, Greece, France and Slovakia. Th e evaluation is based on an assessment of following factors: total height, dbh, stem form, health state, defoliation, diameter of main branches, stem damage, crown density, twisted growth, stem nature pruning, cross-section, and taper. Obtained data sets were statistically analysed. Th e best growth both in quantitative and qualitative traits was recognised for the provenance 9 – Les Barres, Oise (France), which was excellent in height growth, health status and stem shape, and also for the Serbian provenance 2 – Crni Vrh, Titovo Užice, which excelled not only in growth rate, stem shape and health status, but also in diameter of main branches. Less suitable provenance seem to be 3 – Prušačka Rjeka, Banja Luka from Bosnia and Herzegovina (worse growth, stem nature pruning, cross-section and taper) and Croatian 5 – Južna Kandija, Osijek (worse growth, stem shape, and health). Th e most important for explaining the diff erences between provenances were the diameter at the breast height, crown density and defoliation. [ABSTRACT FROM AUTHOR]

The lack of high-quality local reproductive material, which makes it impossible to reforest large clearings after the calamity, results in the search for other suitable sources. Extensive testing of the spruce provenances in various conditions started as early as in 1960s and lasts until today. The presented study is focused on research plots from the series 1984/86–1990 with the Norway spruce’s progenies of certified units of category IIA taken within the whole territory of the Czech Republic. On two selected research plots Úsov and Jedovnice evaluation of both quantitative (tree height, DBH) and qualitative traits (stem form, stem damage, defoliation and health state) was performed. Measured provenances in young middle age growing in the conditions with a lack of precipitation showed initial growth and morphological differentiation. The highest growing stock as for the Úsov plot was achieved by provenance 46 – Janovice, Karlov pod Pradědem 2, and in the Jedovnice plot it was provenance 50 – Rožnov pod Radhoštěm, Horní Bečva. Low defoliation and overall good health state on both plots indicate resistance to external abiotic and biotic factors. In both research plots it was possible to define sets of above-average, average and below-average evaluated provenances. In summary, provenances originated from the Vysočina, Jeseníky and Beskydy mountains thrived in both plots. At the beginning of the 1980s, there was a mast year of Norway spruce, enabling the collection of seeds from 53 recognized units of category IIA (Table 1), which were considered to be the best stands in the given conditions. The obtained seeds were sown in eleven forest nurseries in the spring 1984. In the years 1986–1990, 23 research plots were established in total. The aim of the paper is to assess the variability of growth, phenotypic characteristics and health state of Norway spruce provenances in the research plots Jedovnice and Úsov at the age of 35 years. The evaluation provides an overview of the behaviour of spruce provenances in relevant site conditions and their possible grouping according to similar growth features. In all cases, 49 spruce provenances were planted on the established research plots, but four each time (different according to localities) were not planted due to the cultivation of different amounts of planting stock. Each research plot reaches a size of 1.96 ha, and the distribution of provenances was performed by a double grid system of 7 × 7 provenances with four repetitions. The plots of interest in Úsov and Jedovnice were measured in 2019 at the age of 35, where quantitative and qualitative indicators of volume production were evaluated, and resistance of provenances to abiotic harmful effects, respectively. From the biometric data, the tree height and DBH were measured. Based on the results of measurements of heights and DBH, the stem volume (o.b.) was calculated using the volume equation. The evaluation of qualitative features (stem form, stem damage, defoliation, and health state) focused on resistance to negative influences was also performed (Table 2). When comparing heights (Fig. 1 and 2) and standing volumes (Table 3 and 4), there was a significant differentiation compared to the values of DBH (Fig. 3 and 4). In the case of qualitative indicators, only slight amount of variability was observed. The health status and defoliation of spruce in the research plots point to good vitality, even though the bark calamity has already manifested itself in the surrounding forest stands. Most trees are without stem damage, but there are some provenances with prevailing damaged stems in the top part. On the Jedovnice plot, a completely straight stem form predominates, while on the Úsov plot, once slightly bent form is more pronounced. PCA method taking into account significant dendrometric and morphological features gives good results only for research plot Úsov. The data show a strong relationship between tree height, stem form and DBH, and also between health state and the number of growing individuals (Fig. 5). Partial clustering of provenances according to natural forest areas was found. The evaluation of provenance plots in Central Moravia showed that significant differentiation among provenances was found especially in heights and standing volumes. Both plots were dominated by provenances from the Vysočina, Jeseníky and Beskydy mountains. For qualitative traits, the selected characteristics have not manifested themselves significantly due to the young age of experimental material. For the next phase of research, there is supposed to add more morphological characteristics, which can be evaluated only at older age. [ABSTRACT FROM AUTHOR]

The common yew (Taxus baccata L.) is classified as a highly endangered plant species according to the valid national legislation. Wild or at least historical cultural occurrences of this species have been preserved only in some areas of the Czech Republic, including the Lusatian Mountains. In this region, the issue of yew has been given increased attention for two decades. In 1999, a targeted inventarization of species occurrence sites was started. The yew gene pool is protected and the population reinforcement by plantings at selected forest sites is carried out. The subjects of interest are 14 potentially autochthonous ± isolated yew localities in the Lusatian Mountains and 3 localities of undoubtedly cultural origin. Selected quantitative and qualitative characteristics of all known yew individuals were measured. More attention is focused on the issue of natural regeneration, seedlings ecesis and sex ratio. The results correspond well with the findings of other authors. Yew, even in advanced age, is characterized by a significant increase in thickness and good vitality. The species responds very positively to supportive measures of regulatory conservation management. [ABSTRACT FROM AUTHOR]

The work deals with the evaluation of three Norway spruce provenance research plots within the age 40-50 years. Totally, 65 provenances from several regions of Norway spruce were measured at two different altitudes (North Moravia) and under the conditions of former air pollution load (North Bohemia). The plots are part of the GDR-CSR 1972/76-77 series established in cross-border cooperation with Germany. The evaluation included heights, DBH, defoliation, stem form, stem damage and health state. The best volume production was achieved in both research plots by provenances of German origin, namely 41 Hainsbach (Červená Voda research plot) and 39 Bütterbächel (Mnichov), whose origin altitudes roughly correspond to the altitudes of the research plots on that they proved successful. With the exception of two Austrian provenances (49 Granitz, 50 Fastenberg) on the Červená Voda plot, the provenances from Belarus and Austria show the slowest growth on research plots Červená Voda and Mnichov. The fastest growths show the provenances from Poland with one exception (59 Borki) on the plot Červená Voda and one exception (58 Iłava) on the plot Mnichov. Czech, Slovak and German provenances growth intensity was mostly moderate or slightly above average. Two homogeneous groups according to origin have been differed: (1) Alpine, Rhodopean and Russian-Scandinavian, (2) Hercynian-Carpathian. The best growth performance appeared in the provenances of the Hercynian-Carpathian sub-region, the worst in the North-European provenances. [ABSTRACT FROM AUTHOR]

The paper deals with the growth and phenotypic characteristics of Norway spruce in three separate core zones of the Gene Conservation Unit (GCU) No. G102-1 Trčkov-Šerlišský kotel-Vrchmezí in the Orlické hory/Eagle Mts. at the Czech-Polish border. The research was carried out in representative stands of all three parts of the GCU, which were selected in the direction from their core towards the periphery and outside the border. In total, 15 stands were evaluated. In each stand, dendrometric measurements and phenotypic surveys were performed on representative sets of sample trees. Tree growth characteristics reached their maximum in the core zones of all three parts of GCU, but also in the exceptionally high-quality stand T2.1, whose above-average parameters influenced the results of analyzes. Another stands, V2 and T2, situated relatively close to the core zones, were found of rather average quality according to cluster analysis, however. In the statistical analysis, the stands V3.1, V3, V3.2 and T2.1 proved to be most outlying, because of their lower (V3.1, V3) or exceptionally high (T2.1, V3.2) production and quality. In summary, according to the best growth parameters of trees, three parts of GCU can be sorted in descending order as follows: Trčkov, Vrchmezí, Šerlišský kotel. It can be concluded that the most valuable groups of trees are located in the central parts of GCU, and thus represent an important genetic resource to be protected from negative effects of a gene flow from surrounding lower quality inferior stands. Results of this study could be used for an objectification of the method of incorporation the stands into GCU complexes. In particularly questionable cases, it is recommended to use also molecular-genetic methods for this purpose. [ABSTRACT FROM AUTHOR]

Douglas-fir is one of the most promising introduced tree species in Czech forests. The aim of the study was the evaluation of the two oldest experiments established in the Moravia region in 1959 on two localities: (i) Horní Lhota and (ii) Studená Loučka wiTh11 and 9 provenances, respectively. On the trials, basic quantitative characteristics were evaluated, obtained results from boThtrial were then compared. Also, an ocular assessment of basic qualitative traits was performed. On the trial Horní Lhota, there were found differences especially among growing stocks of individual provenances. Provenances from Oregon were found to be slightly above average in (i), while provenances from Washington were slightly above average in (ii). However, the Studená Loučka trial showed slightly worse evaluated characteristics compared wiThthe Horní Lhota trial. The universal optimal provenance for boThtrials was not found, the growing stock was influenced by the different number of trees in boThtrials. [ABSTRACT FROM AUTHOR]

The main goal of the presented study was to evaluate genotypes of unique population of grey poplar (Populus × canescens Aiton Sm.), which has been selected for its valuable parameters and limited reproduction ability by classical methods of vegetative propagation for gene pool preservation and restoration at Dyjákovice village (South Moravia Region, Czech Republic). Nuclear microsatellite (SSR) analyses using 14 SSR markers together with phenotype characterization determined that 90 sampled trees of female bias belonged to one clone. According to these results, the collection of grey poplars has been extended for 155 individuals in totally including both female and male bias (120 and 35, respectively) to discriminate their genetic diversity. Our data revealed occurrence of 6 unique genotypes among all female samples while higher genetic variability pattern exhibited male samples among which 27 genotypes have been detected. These findings about species genetic identity as well as genetic variability indicate the importance of SSR method for selection of valuable grey poplar genotypes as a source of reproductive material for further reforestation. [ABSTRACT FROM AUTHOR]

Paper documents the effects of grand fir (Abies grandis /Dougl. ex D.Don/ Lindl) on the basic characteristics of the soil chemistry and nutrient dynamics. The amount of the surface humus and basic chemical characteristics of the horizons F+H, Ah, Bv (soil pH, soil adsorption complex characteristics, total carbon and nitrogen content, C/N ratio, exchangeable acidity characteristics, plant available and total nutrient contents) were compared at two localities in young stands (38 years) of grand fir, Norway spruce and European beech on the territory of the Central Bohemia (altitude 340 and 435 m a. s. l., mean annual precipitation 660 mm, mean annual temperature 876;C, fresh to waterlogged oak-beech and beech sites). Results documented relatively slight differences among stands as a result of different species cultivation. Th is was determined by the site conditions and young age of particular stands. However, some positive effects of the grand fir were visible and relevant, especially higher soil reaction and soil adsorption complex characteristics. Forestry research should bring this species into focus more frequently. [ABSTRACT FROM AUTHOR]

The article evaluates 27 provenances of three subspecies of lodgepole pine on the Kovařska research plot (Krušne hory Mts.). The plot is part of a series of three established plots in various stand conditions. Two plots were already evaluated and the findings were published. At 34 years of age, we evaluated height, DBH, trunk shape, trunk forking, branch thickness, bark type, mortality and defoliation. A total of 1,147 trees were measured. Above-average growth was achieved predominantly by the provenances of Pinus contorta subsp. latifolia (Engelmann ex S. Watson) Critchfield from middle elevations. In the Pinus contorta subsp. contorta Douglas ex Loudon, only the 2099 Port Orford provenance from Oregon demonstrated favourable results, and in the Pinus contorta subsp. murrayana (Balfour) Engelmann it was 2098 Chemult. High mortality was demonstrated mainly in the P. c. subsp. murrayana provenance from high mountainous elevations in California and P. c. subsp. contorta from coastal regions of Oregon. Provenances from middle elevations had relatively lower mortality, especially P. c. subsp. latifolia. The pines usually were of good quality although this was not the case for defoliation and branch thickness. In comparing all plots of the series, growth was fastest at the Sofronka location in western Bohemia and slowest at the south Bohemian Mlaka location. Only the best provenances of lodgepole pine can equal the domestic Scots pine (Pinus sylvestris Linnaeus). [ABSTRACT FROM AUTHOR]

The paper deals with evaluation of the lodgepole pine research provenance plot in the pine site conditions in Třeboň (Southern Bohemia, Czech Republic) at the age of 34 years. Based on the evaluation of specific quantitative and qualitative traits (height, DBH, stem volume, tree stock, mortality, defoliation, stem form and height of stem forking, branch thickness, and bark type), provenances were assessed in terms of their production capacity and utilization on extremely dry sandy soils. The lowest defoliation (20-25 %) has been recorded in the case of provenances No. 2089 Manzanita, No. 2235 Calling Lake and No. 1902 Mile 86, most others did not exceed a level of 50 %, but four provenances had a high needle loss (71-79 %). From the volume production point of view, the provenance No. 2089 Manzanita (P. c. subsp. contorta) from the Oregon coast and No. 2091 Mount Hood (P. c. subsp. latifolia) from Oregon Cascades, demonstrated their high production ability. The best-growing provenance No. 2089 Manzanita corresponds through its growth characteristics to the fourth relative site class of domestic Scots pine, which confirms that proper selection can find suitable provenances that can fulfill the production function even in poor and dry site conditions. [ABSTRACT FROM AUTHOR]