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We studied the maternally inherited chloroplast DNA polymorphism at three microsatellite loci of 157 Quercus robur trees from 38 native populations in Lithuania. We found high diversity of eight haplotypes from the Balkan lineage A (frequency 0.75) and the “German” subbranch of the Balkan lineage A (freq. 0.12), western and eastern Italian lineages C (freq. 0.05 and 0.06, respectively), and Iberian lineage B (freq. 0.03). The haplotypes were geographically well structured (among population differentiation index PhiPT = 0.30, the p-value &lt, 0.001) that is unexpected for such a small territory as Lithuania. We raised a hypothesis on historical overexploitation of oaks by eliminating certain haplotypes in Lithuania, following a drastic felling of oak forests over the last few centuries.

The use of pedunculate oak (Quercus robur L.), along with other tree species, for the afforestation of heavy metal contaminated lands is an attractive prospect. Little, however, is known of Q. robur tolerance and its antioxidative system response to heavy metal exposure. The main objective of the study was to determine the cadmium-induced changes in antioxidative system of pedunculate oak in an attempt to identify molecular mechanisms underlying Cd tolerance. This may be of great importance in respect of using Q. robur for phytoremediation purposes. As the response of the antioxidative system to heavy metal contamination can vary within species, the research was conducted on oak seedlings from two different regions of origin. Differences in antioxidative system response of seedlings derived from tested regions of origin were noticed both at the transcript and enzyme activity levels. The obtained results indicate that ascorbate peroxidase (APX; EC 1.11.1.11) and superoxide dismutase (SOD; EC 1.15.1.1) play a first barrier role in oak seedlings response to the oxidative stress caused by Cd exposure. Catalase (CAT; EC 1.11.1.6) is involved in reducing the negative effects of prolonged Cd treatment.

Background and Purpose: The declining and dieback of lowland oak forests as the result of global climate change, as well as the attack of various pathogenic organisms, industrial pollution, and other negative effects reduce acorn yield and will continue to do so in the future. As a result of this fact, the areas on which artificial regeneration will be applied by planting seedlings will have to be increased. The artificial regeneration process is more expensive than the natural one, so protection measures need to be applied to minimize the loss of young seedlings. Materials and Methods: Experimental plots were set up in the forest area of Spačva Basin. A completely randomized block design experiment in four repetitions was used, in which four variants of planting and protection of oak seedlings were examined. We tested polypropylene tree shelters and hydrophilic superabsorbent based on maize starch. Heights of the plants were measured by measuring tape, and survival was registered by numbering of dead and living plants. For statistical purposes, we have used analysis of variance (repeated measure ANOVA), which allows us to prove statistically significant difference between morphological traits of studied variants. Results: Two years after planting, the lowest level of survival was found in unprotected seedlings (79.5%), while tree shelters provided the best conditions for seedlings survival (88.75%). In the case with the hydrophilic granules Zeba the result is slightly worse. When analyzing average height in a particular case, significantly higher plants are recorded in cases where the polypropylene tree shelters are used. The average height, with tree shelters (128.27 cm), is more than three times higher than the unprotected seedlings (37.97 cm). The addition of hydrophilic granules did not show a statistically significant difference. In cases where the seedlings were not under the tree shelter protection, the effect of hydrophilic granules was also not statistically significant. Conclusions: Sheltering accelerated the height growth of the planted oaks substantially and also provided best conditions for seedlings survival. During the research period the usage of Zeba did not justify the purpose for which it was applied. Although the first results are promising in order to gain a complete insight into the potential of tree shelters it is necessary to record the changes and maintain the experiment for a further 2-3 years with quantification of other harmful factors that may appear (drought, game etc.) after which a more reliable judgment regarding their usefulness could be provided.

Three of the most frequently used sigmoidal growth curves from the Richards family are the logistic model, Gompertz model and Richards model. They are used in the analysis of organismal growth over time in many disciplines/studies and were proposed in many parameterisations. Choosing the right parameterisation is not easy. The correct parameterisation of the model should take into account such parameters that are useful to describe the analysed growth phenomenon and are biologically relevant without additional calculations. In addition, each parameter of the model only affects one shape characteristic of each growth curve, which makes it possible to determine standard errors and confidence intervals using statistical software. Growth curves in germination dynamics studies should provide information on topics such as the length of the lag in onset of germination, the maximum germination rate and, when it occurs, the time at which 50% of seeds will germinate and the final germination proportion. In this article, we present three parameterisations of the logistic, Gompertz and Richards models and indicate two parameterisations for each model, corresponding to the above-mentioned issues. Our proposition is parameterisation by taking into account the maximum absolute growth rate. Parameterisations indicated as useful for germination dynamics are characterised by the fact that each parameter has the same meaning in every model, so its estimates can be compared directly amongst the models. We also discussed the goodness-of-fit measures for nonlinear models and in particular measures of nonlinear behaviour of a model’s individual parameters as well as overall measures of nonlinearity. All described models were used to study the dynamics of the epicotyl emergence of pedunculate oak. After checking the close-to-linear behaviour of the studied model parameters and by taking into account the criteria of model selection (AICc of each growth curve and the residual variance [RV]), the best model describing the dynamics of epicotyl appearance of pedunculate oak was the Richards curve.

Ovo istraživanje obuhvaća opažanja fenološke varijabilnosti od 28 provenijencija hrasta lužnjaka u bosansko­hercegovačkom pokusu provenijencija u Žepču. Pokus je baziran na slučajnom blok sustavu sa tri (3) ponavljanja, gdje je svaka provenijencija u svakom bloku predstavljena sa 36 biljaka, osim provenijencija Drvar, Mutnica, Zvornik i Vinac, koje su djelomično zastupljene u pokusu. Proces listanja praćen je tijekom 2012. i 2013. godine, od kraja ožujka do početka svibnja. Praćeno je pet (5) fenofaza listova koje su za hrast kitnjak razradili Derory i dr. (2006.).Analiza fenoloških faza pokazala je da postoje statistički značajne razlike između ispitivanih provenijencija. Razlike su potvrđene za početak, trajanje i završetak pojedinih fenoloških faza listanja između provenijencija, što ukazuje na genetsku varijabilnost između populacija i zavisnost fenoloških faza od vremenskih uvjeta.U ovom istraživanju nije bilo moguće napraviti razliku između provenijencija na osnovi najranijeg pojavljivanja faza. Provenijencija Bijeljina nešto ranije ulazi u fazu B u 2012. godini, dok u 2013. godini u fazu B ulazi u isto vrijeme kao i ostale provenijencije. Provenijencija Bosanska Dubica kasni s ulaskom u sve faze u obje godine, i kašnjenje u odnosu na ostale provenijencije u prosjeku iznosi 7-10 dana. S obzirom na lokaciju populacije Bosanska Dubica u planinskim uvjetima možemo pretpostaviti da se radi o kasnoj formi.Dobiveni rezultati već sada mogu biti korišteni u programu oplemenjivanja hrasta lužnjaka, kao i u očuvanju genetske varijabilnosti uz pomoć in situ i ex situ metoda. Dobivene rezultate treba koristiti za planiranje, repopulaciju i reintrodukciju hrasta lužnjaka u Bosni i Hercegovini. Ovo istraživanje treba nastaviti kako bi se dobila detaljnija slika o fenologiji hrasta lužnjaka i utvrdila eventualna prisutnost ranih i kasnih formi, uzimajući u obzir i učinke klimatoloških uvjeta., Our research of Phenological variability of 28 provenances of pedunculate oak in the Bosnian and Hercegovinian test of provenances in Žepce. The experiment is based in the accidentally random block system with three (3) repetitions, where each provenance in each block is represented by 36 plants (except provenances Drvar, Mutnica, Zvornik and Vinac, which are partially represented in the experiment). We have observed the process of leafing during years 2012 and 2013 and from the end of March to beginning of May. We followed five (5) phenofazes of leafing that were developed for sessile oak by Derory et al. (2006). The analysis of phenological phases has shown that there are statistically important differences between the investigated provenances. The differences have been confirmed for the start, duration and end of certain phenological phases during leafing in the provenances and it points to a genetic variability between the populations and the dependence of phenological phases on the weather conditions.In this research, based on the earliest appearance of the phases no differentiation between any of the provenances could be made. Bijeljina provenance entered phase B slightly earlier in 2012, while in 2013 it entered phase B at the same time as all the other groups. With the Bosanska Dubica provenance we observed lateness with all the phases in both years, however when compared to the other groups it averages a delay of 7-10 days and considering the location is in a mountainous conditions we can safely confirm that it is a matter of late form.It should be noted that the obtained results already have great possibility of implementation in breeding programme of pedunculate oak as well as in conservation of genetic variability with in situ and ex situ methods. The obtained results should be used for planning, repopulation and reintroduction of pedunculate oak in Bosnia and Hercegovina. This research should be done further and in more depth to obtain an even more details picture about the phenology of pedunculate oak and further research would help to establish the early and late forms while taking the weather and its effects into consideration.

AIM: The strength of species interactions is traditionally expected to increase toward the Equator. However, recent studies have reported opposite or inconsistent latitudinal trends in the bottom-up (plant quality) and top-down (natural enemies) forces driving herbivory. In addition, these forces have rarely been studied together thus limiting previous attempts to understand the effect of large-scale climatic gradients on herbivory. LOCATION: Europe. TIME PERIOD: 2018–2019. MAJOR TAXA STUDIED: Quercus robur. METHODS: We simultaneously tested for latitudinal variation in plant–herbivore–natural enemy interactions. We further investigated the underlying climatic factors associated with variation in herbivory, leaf chemistry and attack rates in Quercus robur across its complete latitudinal range in Europe. We quantified insect leaf damage and the incidence of specialist herbivores as well as leaf chemistry and bird attack rates on dummy caterpillars on 261 oak trees. RESULTS: Climatic factors rather than latitude per se were the best predictors of the large-scale (geographical) variation in the incidence of gall-inducers and leaf-miners as well as in leaf nutritional content. However, leaf damage, plant chemical defences (leaf phenolics) and bird attack rates were not influenced by climatic factors or latitude. The incidence of leaf-miners increased with increasing concentrations of hydrolysable tannins, whereas the incidence of gall-inducers increased with increasing leaf soluble sugar concentration and decreased with increasing leaf C : N ratios and lignins. However, leaf traits and bird attack rates did not vary with leaf damage. MAIN CONCLUSIONS: These findings help to refine our understanding of the bottom-up and top-down mechanisms driving geographical variation in plant–herbivore interactions, and indicate the need for further examination of the drivers of herbivory on trees. This study was carried out with financial support from the French National Research Agency (ANR) in the frame of the Investments for the Future Programme, within the Cluster of Excellence COTE (Continental To coastal Ecosystems: evolution, adaptability and governance) (ANR-10-LABX-45). E.V.C. was funded by the BiodivERsA (BiodivERsA is a network of national and regional funding organisations promoting pan-European research on biodiversity and ecosystem services, and offering innovative opportunities for the conservation and sustainable management of biodiversity) project SPONFOREST (Unraveling the potential of spontaneous forest establishment for improving ecosystem functions and services in dynamic landscapes) (BiodivERsA3-2015-58). info:eu-repo/semantics/publishedVersion

Kadar naravna obnova ni možna ali uspešna, se najpogosteje poslužujemo umetne obnove s saditvijo. Zaradi visokih stroškov saditve se v praksi uporabljajo vse manjše gostote saditve, ki pa ne dajejo vedno želene kakovosti debel. V tej raziskavi smo analizirali v letih 2011 in 2020 izmerjene rastne in kakovostne parametre izbrancev doba iz štirih naravno in šestih umetno obnovljenih sestojev, ki ležijo v treh največjih gozdnih kompleksih nižinskih dobovih gozdov v Prekmurju (Hraščica, Ginjevec in Črni log). Izbranci doba so v naravno osnovanih sestojih dosegli značilno manjši prsni premer in višino ter višje razmerje H/D kot izbranci v umetno osnovanih sestojih. Večina znakov prihodnje komercialne kakovosti je nakazovala ugodnejši razvoj na izbrancih v naravno obnovljenih sestojih. V teh smo zaznali v poprečju 50 visokokakovostnih izbrancev/ha, v umetno obnovljenih sestojih pa v povprečju za polovico manj. Najmočnejši pozitivni učinek na kakovost izbrancev sta izkazali gostota saditve oziroma gostota naravnega podmladka ter zastiranje drevesne in grmovne plasti. V umetno obnovljenih sestojih smo zaznali značilno boljšo kakovostno strukturo v sestojih z večjo gostoto saditve (nad 5000/ha) v primerjavi s tistimi z manjšo gostoto saditve (pod 5000/ha). Zato priporočamo, da se manjše gostote saditve preizkusijo na način skupinske saditve, ki je v nekaterih raziskavah pokazala obetavne rezultate. Whenever natural regeneration is not possible or successful, we usually resort to artificial regeneration with planting. Due to high planting costs, low-density planting is used in practice, however, this does not always ensure the desired quality of the trunk. In this study, we have analysed the growth and quality parameters of the crop pedunculate oak trees, which were measured in 2011 and 2020, from four naturally and six artificially regenerated stands in the three largest forest complexes of lowland pedunculate oak forests in Prekmurje (Hraščica, Ginjevec and Črni log). The crop pedunculate oak trees from naturally established stands have reached a statistically significant lower diameter at breast height and height as well as a higher H/D ratio than those crop trees from the artificially established stands. Most signs of future commercial quality have indicated a more favourable development of the crop trees from naturally regenerated stands. In these, we detected an average of 50 high-quality crop trees/ha, and in artificially regenerated stands, on average, half less. Planting density and the density of naturally seedlings as well as cover of the tree and shrub layer have proven to have the strongest positive affect on the quality of the crop trees. In the artificially regenerated stands, we have observed a significantly better quality structure in stands with higher planting density (above 5000/ha) than in stands with lower planting density (under 5000/ha). For this reason, we recommend trying lower-density planting in the form of group planting that has shown promising results in some studies.

Extreme weather conditions, namely droughts, heat waves, heavy rains, floods, and landslides are becoming more frequent globally and in Serbia as a result of climate change. Generally, various parts of human society are affected by changing climate conditions. Forest ecosystems are one of the most sensitive systems to weather and climate. In that sense, small changes may lead to large disturbances including forest decline, outbreaks of insect pests and diseases and eventually mortality. In Serbia, the average temperature in forest ecosystems of the most important and abundant forest tree species has risen for more than 1°C in the last thirty years (1990-2019) in comparison to the previous period (1961-1990). During the last thirty years, the northern and western parts of Serbia experienced an increase in precipitation as opposed to the southern and eastern parts of the country. If one takes a closer look at the climate within a particular forest stands, it would seem that the effect of precipitation decrease is stronger in less humid parts of a tree species range. In this paper, we discuss various aspects of climate change impacts on forests and forestry, including forest ecology, genetics, physiology, pests and diseases, ground vegetation, monitoring, reporting and verification system, climate change litigation and perspectives of forests in the 21st century in Serbia.

Spraying herbicides to reduce weed competition is a usual practice in agricultural regions. However, tree tending under agroforestry or forest plantations is hampered by the extensive use of these pesticides. Here, we assessed the survival, symptoms expression and growth of pedunculate oak (Quercus robur) saplings after spraying different herbicides at recommended doses in two seasons: winter and spring. Three independent herbicide trials were carried out on oak sapling plots (E_WINTER 2013, E_SPRING 2012, E_SPRING 2013) in Ayacucho, province of Buenos Aires, Argentina. Plants were kept under uniform conditions in a nursery for about three months. We alternatively tested the herbicides (doses in sub-index, cc.ha-1 or g.ha-1) flumioxazin (FLUM100), glyphosate (GLIF2000, 4000, 6000), metsulfuron-methyl (METS8), dicamba (DIC120), propaquizafop (PROP500, 1000), flurochloridone (FLUO1000, 1500, 4000), atrazine (ATR2000, 4000), acetochlor (ACET2000), imazethapyr (IMAZE500, 1000) and imazapyr (IMAZA33, 100). At the end of each trial all plants survived, regardless of treatment, although the symptoms varied depending on the trial and product. Glyphosate associated with chlorosis, necrosis and deformation, propaquizafop with necrosis, and dicamba, flurochloridone, imazethapyr and imazapyr with chlorosis. ATR2000 and FLUO1500 treatments advanced the re-sprout phases. In terms of growth, saplings sprayed with IMAZE1000, IMAZA100 and GLIF6000 had lower total dry weight than the control (CT) (p

Insect herbivory is an important ecological process that affects plant populations, communities and ecosystems. The distribution and abundance of insect herbivores and their resulting activity are shaped by a multitude of drivers, intrinsic or extrinsic to the host plant, that act at different spatial scales and often in concert. A widely used classification distinguishes between bottom-up forces where herbivore activity is influenced by the distribution and dynamics of the resource stock (including the defenses), and top-down forces where herbivore activity is constrained by drivers of mortality (e.g. predators, pests). Both bottom-up and top-down forces are involved in the trophic cascades that inevitably accompany plant-herbivore interactions in natural plant populations, yet their relative importance can vary greatly depending on the particular study context, and the underlying biological mechanisms remain poorly understood.I investigated the ecological drivers shaping the relationships between Pedunculate oak (Quercus robur) and its insect herbivores across different spatial scales. In particular, I examined the effects of the ecological neighbourhood, the landscape context, tree genetic relatedness and climate on herbivore activity. A major aim of my thesis was to evaluate the relative importance of bottom-up and top-down forces in shaping oak-herbivore relationships.The thesis is structured in three main chapters corresponding to independent manuscripts that are either published (chapter 1), under review (chapter 2) or under preparation (chapter 3) at the moment of submitting the thesis document. In chapter 1 I investigated the relationship between herbivory and the community and activity of insectivorous birds in oak stands that differed in size and connectivity. I found that herbivory, bird predation and bird communities were influenced by landscape characteristics, but neither predation on herbivores nor bird communities had a significant effect on herbivory. In chapter 2 I investigated the relationship between oak genotype, leaf defences and herbivory in the same stands. I found that insect herbivory and leaf defences were not only influenced by landscape characteristics but also by the genotype of the tree, and that insect herbivory decreased with increasing concentration of leaf defences. Finally, in chapter 3 I investigated the effect of large-scale climate variability on the interactions between plants, herbivory and bird predation in oak trees along a latitudinal gradient. I found that climatic factors influenced insect herbivory as well as leaf nutritional traits, while they did not influence leaf defences and bird predation. Furthermore, insect herbivory was only influenced by bottom-up forces (e.g. leaf nutritional traits and leaf defences) and these effects on herbivory varied among herbivore feeding guilds, while neither other traits nor top-down forces affected insect herbivory.Overall, these results help improve our understanding of the different ecological forces shaping insect herbivory and their bottom-up and top-down drivers in natural tree populations. Future studies of plants-herbivores-predator interactions should take into account that these are simultaneously influenced by host plant genotype, landscape characteristics and climate. Finally, the thesis also illustrates the value of citizen science approaches that can combine scientific research with much-needed environmental education.; L'herbivorie par les insectes est un processus écologique important qui affecte la dynamique des populations de plantes, les communautés et les écosystèmes. La distribution et l'abondance des insectes herbivores et l'activité qui en résulte sont façonnées par une multitude de facteurs, intrinsèques ou extrinsèques à la plante hôte, qui agissent à différentes échelles spatiales et souvent de concert. Une classification largement utilisée fait la distinction entre les forces ascendantes, telles que l'activité des herbivores est influencée par la distribution et la qualité des ressources (incluant les défenses), et les forces descendantes, telles que l'activité des herbivores est limitée par le contrôle exercé par les ennemis des herbivores (prédateurs, parasitoïdes). Les forces ascendantes et descendantes sont toutes deux impliquées dans les cascades trophiques qui accompagnent inévitablement les interactions plantes-herbivores dans les populations naturelles de plantes, mais leur importance relative peut varier considérablement selon le contexte particulier local, et les mécanismes biologiques sous-jacents restent mal compris.J'ai étudié les facteurs écologiques qui façonnent les relations entre le chêne pédonculé (Quercus robur) et ses insectes herbivores à différentes échelles spatiales. En particulier, j'ai examiné les effets du contexte du paysage, de l’apparentement entre les arbres et du climat sur l'activité des herbivores. Un des principaux objectifs de ma thèse était d'évaluer l'importance relative des forces ascendantes et descendantes dans la structuration des relations chêne-herbivores.La thèse est structurée en trois chapitres principaux correspondant à des manuscrits indépendants qui publiés (chapitre 1), en cours de révision (chapitre 2), ou en préparation (chapitre 3) au moment de la soumission du document de thèse. Dans le chapitre 1, j'ai étudié la relation entre l'herbivorie et la communauté et l'activité des oiseaux insectivores dans les chênaies qui diffèrent en taille et en connectivité. J'ai constaté que l'herbivorie, la prédation des oiseaux et les communautés d'oiseaux étaient influencées par les caractéristiques du paysage, mais que ni la prédation sur les herbivores ni les communautés d'oiseaux n'avaient d'effet significatif sur l'herbivorie. Dans le chapitre 2, j'ai étudié la relation entre le génotype du chêne, les défenses chimiques des feuilles et l'herbivorie dans les mêmes peuplements. J'ai constaté que l'herbivorie des insectes et les défenses chimiques étaient non seulement influencées par les caractéristiques du paysage, mais aussi par le génotype de l'arbre, et que l'herbivorie des insectes diminuait avec la concentration des défenses foliaires. Enfin, au chapitre 3, j'ai étudié l'effet de la variabilité climatique à grande échelle sur les interactions entre les plantes, l'herbivorie et la prédation des oiseaux dans les chênes selon un gradient latitudinal. J'ai découvert que les facteurs climatiques influençaient l'herbivorie des insectes ainsi que les caractéristiques nutritionnelles des feuilles, alors qu'ils n'influençaient pas les défenses foliaires et la prédation des oiseaux. De plus, l'herbivorie des insectes n'était influencée que par des forces ascendantes dont l’importance variait selon les guildes d’insectes.Dans l'ensemble, ces résultats aident à améliorer notre compréhension des différentes forces écologiques qui façonnent l'herbivorie par les insectes et de leur variabilité dans les populations naturelles d'arbres. Les études futures sur les interactions plantes-herbivores-prédateurs devraient tenir compte du fait que celles-ci sont influencées simultanément par le génotype de la plante hôte, les caractéristiques du paysage et le climat. Enfin, la thèse illustre également la valeur des approches de science citoyenne qui peuvent combiner la recherche scientifique avec une éducation scientifique et à l’environnement bien nécessaires.

Cessation of xylem formation or wood growth (CWG) and onset of foliar senescence (OFS) are key autumn phenological events in temperate deciduous trees. Their timing is fundamental for the development and survival of trees, ecosystem nutrient cycling and the seasonal exchange of matter and energy between the biosphere and atmosphere, and affects the impact and feedback of forests to global change. A large-scale experimental effort and improved observational methods have allowed us to compare the timing of CWG and OFS for different deciduous tree species in Western Europe, particularly in silver birch, a pioneer species, and European beech, a late-succession species, at stands of different latitudes, of different levels of site fertility, for 2 years with contrasting meteorological and drought conditions, i.e., the low moderately dry 2017 and the extremely dry 2018. Specifically, we tested whether foliar senescence started before, after or concurrently with CWG. Onset of foliar senescence and CWG occurred generally between late September and early November, with larger differences across species and sites for OFS. Foliar senescence started concurrently with CWG in most cases, except for the drier 2018 and, for beech, at the coldest site, where OFS occurred significantly later than CWG. The behavior of beech in Spain, the southern edge of its European distribution, was unclear, with no CWG, but very low wood growth at the time of OFS. Our study suggests that OFS is generally triggered by the same drivers of CWG or when wood growth decreases in late summer, indicating an overarching mechanism of sink limitation as a possible regulator of the timing of foliar senescence.

The aim of this thesis is to evaluate the growth, production and yield parameters of oak stands on floodplain habitats in the region of Kojetín. On the forest management unit Foundation of Dr. Leopold Prečan were investigated in four stands with more than 50% representation of oak (Quercus robur L.) aged between 120 and 130 years. The numbers of crop oak in the stands ranged from 40 to 110 pcs∙ha-1. The basal area ranged from 40.8 to 45.8 m2∙ha-1 in the examined stands. High volume values of the medium strain were also recorded, ranging from 5.51 to 9.37 m3. The stock of oak stand was found in the range of 569 to 904 m3∙ha-1. The yield per hectare was set at 51,400 to 88,000 €∙ha-1. The main recommendation is the transition to multi layer oak management and increasing species diversity.

Istraživanja su obavljena u nizinskom dijelu Varaždinske županije, u šumi posebne namjene „FOPER“, g. j. „Zelendvor odsjek 13c na oko 3 km udaljenosti od rijeke Drave na nadmorskoj visini od 190 m, u području gdje su sađene pretežito kulture smreke, borovca i bagrema iako je stanište pogodno za sadnju i uzgoj hrasta. S obzirom na promijenjene ekološke i klimatološke prilike osnovana je 2012. godine trajna pokusna ploha veličine 2,00 ha. Na plohi su posađene trogodišnje (2 + 1) sadnice hrasta lužnjaka (Quercus robur L.) i hrasta kitnjaka (Quercus petraea L.) i to na dva načina. Jedan dio u razmaku sadnje 3 x 3 m u polipropilenskim štitnicima. Drugi dio razmaka sadnje 2 x 2 m uobičajenim načinom (bez štitnika). Cijela je površina podijeljena na 24 pod plohe približnih površina. Na jednoj plohi nalazi se jedna vrsta drveća. Raspored vrsta je naizmjeničan od plohe do plohe. Upotrijebljen je randomizirani oblik metode, sa 4 bloka i 3 ponavljanja. Visine biljaka mjerene su 5 godina uzastopce za vrijeme mirovanja vegetacije. Prsni promjeri mjereni su na kraju promatranog razdoblja kada su biljke bile više od 1,30 m. Učešće i intenzitet pepelnice utvrđivan je tri godine tijekom ljetnih mjeseci. Cilj istraživanja je proučavanje rasta i razvoja sadnica hrasta lužnjaka i hrasta kitnjaka na prostoru gdje do sada nije bilo uobičajeno saditi navedene vrste, iako za to postoje ekološko gospodarski uvjeti. Istraživanja ukazuju kako je broj biljaka nakon 5 godina izmjere smanjen je za 14%. Kod hrasta lužnjaka smanjen je za 4 do 8%, a kod hrasta kitnjaka za 17 do 22%. Visine i prsni promjeri stabala u štitnicima značajno su veći bez obzira na vrstu drveća. Visine i prsni promjeri hrasta lužnjaka značajno su veće od hrasta kitnjaka. Nije utvrđena povezanost između visina stabala i prisutnosti pepelnice., The research was carried out in the lowland region at a distance of about 3 km from the Drava River at an altitude of 190 m, in an area where mostly spruce, white pine and black locust are planted, although the habitat is suitable for planting and growing oak. Considering the changed ecological and climatological conditions, an experimental plot of 2.00 ha was established. Three-year-old (2 + 1) seedlings of pedunculate oak (Quercus robur) and sessile oak (Quercus petraea) were planted on the plot according to two different methods. The first group was planted at a distance of 3 x 3 m in polypropylene shelters. The second group was planted at a distance of 2 x 2 m in the regular way (without the shelters). The entire area was divided into 24 plots of approximately the same size. Each plot contained only one tree species. The arrangement of species alternated between the plots. A randomized block design was used, with 4 blocks and 3 replicates. Tree heights were measured for 5 consecutive years not during the growing season. Breast height diameters were measured at the end of the observed period. The impact and intensity of powdery mildew has been observed for three years during the summer months. The aim of the research is to study the growth and development of pedunculate oak and sessile oak seedlings in an area where these species were not commonly grown, although there are adequate ecological and economic conditions. After 5 years of measurement, the number of plants was reduced by 14%. In pedunculate oak the number of trees was reduced by 4 to 8%, and in sessile oak by 17 to 22%. The height and breast height diameters of the trees grown within the shelters were significantly higher regardless of the tree species. The height and breast height diameter of pedunculate oak trees was significantly larger than of sessile oak trees. No correlation was found between tree height and the presence of powdery mildew.

Pedunculate oak (Quercus robur L.) is economically and ecologically one of the most important tree species in lowland forests of Southeastern Europe, and it is endangered by numerous biotic and abiotic factors. In this study, we investigated the effect of drought and herbivore attack of gypsy moth (Lymantria dispar L.) on two families of young oak seedlings subjected to the following treatments: drought (D); gypsy moth (GM); both drought and gypsy moth (D+GM) and control (Ø) for a period of 15 days followed by a 7-day recovery period. During both treatment and recovery, physiological parameters - net photosynthesis (A), transpiration (E), stomatal conductance (gs), sub-stomatal CO2 concentration (Ci), water use efficiency (WUE), nitrate reductase activity (NRA) and chlorophyll content (Chl) were measured. Our results showed significant effects of stress factors on physiological processes in oak seedlings which could have potential impact on forest regeneration. Also, differences in the reaction between investigated families indicated the need for breeding and selection of more resistant progenies and provenances of pedunculate oak., Hrast lužnjak (Quercus robur L.) predstavlja jednu od ekonomski i ekološki najznačajnijih drvenastih vrsta u jugoistočnoj Europi, čiji je opstanak znakovito ugrožen promjenama okoliša koje se najčešće očituju u poremećaju vodnog režima i napadima kukaca. Imajući u vidu činjenicu da oba negativna čimbenika dovode do poremećaja fizioloških procesa u biljkama i da često utječu na biljke zajedno, cilj ovoga pokusa bio je ispitati utjecaj pojedinačnog i zajedničkog djelovanja suše i napada kukaca na fiziologiju hrasta lužnjaka i mogućnost različite reakcije uvjetovane porijeklom sadnica.U ovom smo radu ispitivali utjecaj suše i napada gubara (Lymantria dispar) na klijance hrasta lužnjaka porijeklom iz dvije familije polusrodnika koji su bili naklijani u kontroliranim uvjetima i potom izloženi sljedećim tretmanima: suša ( D); gubar (GM); suša i gubar (D+GM) te kontrola (Ø) u trajanju od 15 dana, nakon čega je slijedio oporavak biljaka u trajanju od 7 dana. Krajem tretmana i nakon oporavka, izvršena su mjerenja fizioloških parametara – stopa neto fotosinteze (A), stopa transpiracije (E), stopa provodljivosti puči (gs), intercelularna koncentracija CO2 (Ci), učinkovitosti korištenja vode (WUE), aktivnosti nitrat-reduktaze (NRA) i sadržaja klorofila.Rezultati mjerenja fizioloških parametara prilikom induciranog Kod tretiranih klijanaca A opala je za 42-61% u odnosu na kontrolni tretman (Graf 1) a u isto vrijeme, zabilježen je porast Ci u svim tretmanima, što ukazuje na metaboličku limitiranost fotosinteze, osobito ako se uzme u obzir da nije zabilježeno signifikantno smanjenje provodljivosti puči u svim tretmanima. Inducirani stres je različito utjecao na aktivnost nitrat-reduktaze koja je bila smanjena samo kod familije 2 u svim tretmanima. Period oporavka biljaka (Graf 2) nije doveo do povećanja intenziteta fotosinteze kod ispitivanih sijanaca hrastova u obje familije, ali je zabilježena razlika u pogledu razine njene limitiranosti. Kod familije 2 limitiranost je bila uvjetovana zatvorenošću puči (smanjena vrijednost gs), dok je kod familije 7 ona i dalje bila metaboličke prirode (visoke vrijednosti Ci). Oporavak je uvjetovao povećanje razine aktivnosti nitrat-reduktaze, što ukazuje na postepeni oporavak biljaka. Analiza varijance utjecaja tretmana, familije i perioda oporavka (Tablica 1) pokazala je znakoviti utjecaj porijekla sjemena na sve ispitivane parametre osim intenziteta neto fotosinteze (p>0.001), dok je utjecaj tretmana bio signifikantan kod svih ispitivanih parametara (p>0.001) Period oporavka je imao signifikantan utjecaj (p

Svi objekti reflektiraju, apsorbiraju ili emitiraju elektromagnetsko zračenje ovisno o sastavu, stvarajući jedinstvene uzorke koje zovemo spektralni potpisi ili endmemberi. Čisti spektralni uzorci definiraju se u idealnim terenskim ili laboratorijskim uvjetima, gdje je spektar refleksije dobiven uporabom spektroradiometra fokusiranog na jednu površinu. Prema istraživanjima, većina spektralno čistih uzoraka odnosi se na istraživanja minerala. Spektralni potpisi vegetacije, za razliku od spektralnih potpisa minerala, su dinamični (u spektralnoj, prostornoj i vremenskoj rezoluciji), znatno zahtjevniji za prikupljanje i dokumentiranje, te ih treba s oprezom ugraditi u spektralne knjižnice. Postoji nekoliko spektralnih knjžnica (većih i manjih) koje su organizirane po poglavljima, a sastoje se od uzoraka koji imaju dovoljan broj analiza i dokumentaciju za utvrđivanje kvalitete spektra. U ovome istraživanju izdvojeni su spektralni potpisi za nekoliko vrsta u Hrvatskoj: hrast lužnjak (Quercus robur L.), običnu bukvu (Fagus sylvatica L.), običnu jelu (Abies alba Mill.), običnu smreku (Picea abies L.), bijelu imelu (Viscum album L. ssp. Abietis (Weisb.)) i žutu imelu (Loranthus europaeus Jacq.). Svrha istraživanja je bila uspostaviti spektralnu knjižnicu za buduća istraživanja primjene hiperspektralnih skenera pri detekciji vrsta drveća.Za prikupljanje spektralnih potpisa korišten je hiperspektralni linijski skener ImSpector V9, koji snima vidljivi i bliži infracrveni dio spektra od 430 do 900 nm. Osim njega korišten je i senzor sunčevog zračenja FODIS, kako bi dobili prosječnu vrijednost sunčeve insolacije u trenutku snimanja. Snimanje je provedeno u kontroliranim uvjetima. Uzorci su postavljeni na kružnu podlogu sa naznačenom podjelom za svakih 45 stupnjeva točno u centru optičke osi skenera, te su rotirani kružno. Spektralne snimke su zatim obrađivane u softveru ImageJ gdje su izdvojeni podaci za daljnju analizu.Nakon obračuna srednjih vrijednosti po vrstama napravljene su usporedbe između vrsta. Dobiveni rezultati pokazali su preklapanja u vidljivom dijelu spektra, dok u bližem infracrvenom dijelu spektra vrste diferenciraju jedna od druge, odnosno rezultati pokazuju kako postoji razlika između spektralnih krivulja uzoraka.Provedenim istraživanjem definirani su postupci uzimanja uzoraka i dobiveni spektralni potpisi za istraživane vrste (endmemberi). Spektralni potpisi postali su dio spektralne knjižnice, a najznačajniji rezultat istraživanja je mogućnost primjene za detekciju vrsta na hiperspektralnim snimkama., All objects reflect, absorb or emit electromagnetic radiation depending on the composition, creating unique patterns called spectral signatures or endemembers. Pure spectral samples are defined in ideal field or laboratory conditions, where the spectrum of reflection is obtained using a spectroradiometer focused on one surface. According to researches, most spectral-pure samples refer to mineral exploration. Spectral signatures of vegetation, unlike minerals, are dynamic (in spectral, spatial and temporal resolution), considerably demanding for collecting and documenting, and need to be incorporated with caution in spectral libraries. There are several spectral libraries (bigger and smaller) that are organized by chapters which consist of samples that are adequately reviewed and documented to determine the spectrum quality. In this study, the spectral signatures for several species in Croatia were isolated: Oak (Quercus robur L.), Common Beech (Fagus sylvatica L.), Silver fir (Abies alba Mill.), Norway spruce (Picea abies L.), White-berried mistletoe (Viscum album L. ssp. Abietis (Weisb.)) and Yellow Mistletoe (Loranthus europaeus Jacq.). The purpose of the research was to establish a spectral library for future research into hyperspectral scanners for tree species detection.For collecting spectral signatures, the hyperspectral line scanner ImSpector V9 was used to capture the visible and near infrared spectrum (430-900 nm). In addition, the FODIS solar radiation sensor was used to obtain the average value of the solar insolation at the time of recording. Recording was performed under controlled conditions. Samples were placed on the circular base with the indicated division for every 45 degrees exactly in the center of the optical axis of the scanner and were rotated circularly. Spectral images were then processed in ImageJ software where data was extracted for further analysis.After calculation of the mean values by species, comparisons were made between species. The obtained results showed overlaps in the visible part of the spectrum. In the near infrared part of the spectrum they differentiate from one another, apropos the results show that there is a difference between the spectral curves of the samples.The research carried out defines sampling procedures and obtained spectral signatures for the investigated species. Spectral signatures have become part of the spectral library, and the most significant result of the research is the ability to detect the species on hyperspectral images.

Background/Objectives: One of the most pressing problems of the forestry profession nowadays represents a frequent absence of seed crops of forest tree species. In changed ecological conditions, fructification and periodicity of crops are disrupted, and thus the regeneration of forests becomes increasingly questionable. The objective of the project is monitoring seed crops pedunculate oak and european beech in quantity and quality to determine the production potential of stands and new genetic tests will complement the results of the knowledge of genetic diversity, adaptation and use, and circulation forest reproductive material with regard to provenance. Research started in 2015 under the project by Croatian Science Foundation (IP-11- 2013-8131) in four registered european beech seed stands. Now, with the project IP-2018-01-8189, research is carried out in the same beech seed stands (plus additional one) and four pedunculated oak forest stands. Material/Methods: The aim is to apply the same research methodology on both project species. The size of each experimental plot is 60x80 m. Seed yield is estimated based on seed traps, by visual scoring of seeding intensity and from the air with the drone. During autumns the seeds are collected from selected trees. Seed analyses are performed in the Laboratory for Seed Testing of the Croatian Forest Research Institute. In future, procedures for optimum seed storage will be created. Also, field trials for ex situ conservation of their genetic resources will be established. Results: Monitoring of the dynamics and the amount of seed production in the period from 2015 till 2019 was noticed absence and irregularity of beechnuts production. 2016 and 2018 were years with crop in that period. Beechnuts were collected from five selected trees in each plot. Nets for collecting the beechnuts were placed at 1 m above ground covering whole projection area of their crowns. The floor area of nets for the collection of whole seed crop ranges from 40 to 170 m2. The total amount of seed collected at all localities is 245 kg in 2016 and 168 kg in 2018 kg. ISTA (International seed testing association) methods were used for testing seed quality. 1000 seed weight (TSW), moisture content, viability and germination test were assessed. The results showed high variability within and between the populations. Continuous monitoring of the crop of european beach in the coming years will lead to better predictions of the results and recommendations for the use of seeds. Monitoring of the crop of pedunculate oak begun in 2019 and the results are expected during this autumn and winter. Conclusion: Overall, the research results will prescribe the seed manipulation method from the moment of seed collection in forest stands, through seed processing and treatment stages, until storage in the refrigerator. The research will provide a better insight into the genetic diversity of the surveyed species. By establishing new experiments, we will establish the intrapopulation and interpopulation variability of different seed and plant characteristics to improve and ensure the preservation of gene pool. The research will be of great importance for science, the Croatian economy, and implementation in forestry practice. *This work has been fully supported-supported in part by Croatian Science Foundation under the project (IP-11-2013-8131). Research and data processing is continued by the project (IP-01- 2018-8189).

Pedunculate oak is a species of major economic importance in Polish forests. This species seedlings constitute 18.9% of the nursery production in the country. One of the most widespread fungal disease these oaks face is the oak powdery mildew induced by Erysiphe alphitoides. Nursery production is on the lookout for environment−friendly means of plant protection as well as growth simulators capable of raising levels of productivity. Our objectives was to assess two preparation treatments regarded as biostimulators (registered as fertilisers under the names Apol−Humus and Apol−Hum Chelat) in the raising of seedlings of pedunculate oak in bare−root nursery conditions. The experiment included 6 variants with seedlings treated with the above agents, protected against mildew in the traditional way using Falcon 460 EC, treated with fertiliser and fungicide at the same time, or left as control specimens with no measures taken. All preparations were applied by means of foliar spraying 5 times in the course of the season. Survival of seedlings was then assessed at the season end, along with biometric features like root−collar diameter, length of main root and stem, dry mass of leaves and stem, and degree of oak powdery mildew attack. Results indicated curtailment of mildew infection of oak seedlings thanks to both of the biostimulators, albeit to a more limited extent than when fungicide was applied. No stimulation of seedling growth was achieved, however, though the most favourable biometric parameters characterised the oaks supplied with both biostimulator and fungicide. Significantly higher survival rate was noted for oaks offered effective protection against mildew, in the variants with the fungicide or with simultaneous application of Apol−Humus or Apol−Hum Chelat with Falcon. The research points to the two biostimulators under study (based on natural components) being suitable for use in the nursery production of pedunculate oak seedlings, with it being presumed that either or both can allow for reduction in amount of fungicide necessary to be used to safeguard seedlings against mildew., Sylwan 164 (4): 292-299

To preserve the sustainability of Quercus robur forests, which is at risk due to the disturbed natural regeneration, human assisted sowing of acorns or planting of oak seedlings is often performed. However, the success of these methods depends greatly on the use of high-quality sowing and planting material. Thermotherapy is thus often employed to decrease the acorn mycobiota and maintain their quality during the storage. The aim of this study was to test the impact of acorn thermotherapy, followed by a short-term storage at −1 °C or 3 °C, on the quality of related oak seedlings, which was assessed based on the easily observable morphological characteristics. Height, root collar diameter and seedling form were measured or noted for the 1284 and 1190 seedlings at the age of four months and three years, respectively. It was found that acorn thermotherapy affirmatively affected seedling height, especially at the early growth stage. Positive impact on other seedling attributes could not be decisively confirmed because of the lack of the continuity of the effect (not visible in both younger and older seedlings) and the prevailing impact of other factors. Different acorn thermotherapy conditions (temperature and duration) and short-term storage temperatures appeared to be associated only with the occurrence of stem forking at the earlier stage of seedling growth.

Osnivanje uzgojnih staza u svrhu jednostavnijega rada njege pomlatka i učinkovitije kontrole u Hrvatskoj, prvi je puta napravljeno 1977. godine u Šumariji Đurđenovac (Sabljak 1990) i Šumariji Cerna. Od tada se postupno proširilo kao prihvaćena tehnologija rada uglavnom u slavonskim podružnicama Hrvatskih šuma, dok je u ostalima slabo prihvaćeno. Hrvatske šume d.o.o. do danas nisu analizirale učinkovitost ove tehnologije, već je odluka o njezinu provođenju ili ne provođenju prepuštana Upravama šuma podružnicama, pa čak i šumarijama. Suština tehnologije odnosi se na formiranje pravilne mreže izvoznih putova okomitih na glavni put ili makadamsku cestu širine 3 m te okomito na njih uzgojnih staza širine 1,5 m. Proizvodna površina između staza različitih je širina u pojedinim UŠP-ima, ali najčešće iznosi 5 m. Mreža se formira u godini prvoga uzgojnog zahvata nakon dovršnoga sijeka (prije popunjavanja sadnicama ili njege pomlatka). Radnicima je rad sa staza jednostavniji i lakši, a posebice je učinkovita kontrola. S druge strane, pokosi se između 24 i 29 % već pomlađene površine, što je osnovni argument protivnicima ove tehnologije. U ovome radu predlaže se iskušati i drukačije razmake i položaje uzgojnih staza. Izvozni putovi izrađuju se kad i uzgojne staze, a koriste se za izvoženje drvnoga materijala od vremena početka proreda pa do kraja ophodnje. Razmak osi izvoznih putova u odjelima dimenzija 750 × 750 m je 37,5 m, čime se površina odjela podijeli na 20 jednakih dijelova. U odjelima drukčijih dimenzija razmak varira, najčešće između 40 i 50 m, a povećanje razmaka umanjuje učinkovitost izvoženja drva s njih. Stoga bi pokusno svakako trebalo ispitati i drukčije razmake osi izvoznih putova, na prvome mjestu onaj od 25 metara. Budući da o ovoj problematici kod nas ima iznimno malo pisanih materijala, a tehnologija je u primjeni dugi niz godina, ovaj rad ima za cilj opisati postojeće stanje, navesti dobre i loše strane osnivanja mreže izvoznih putova i uzgojnih staza te pokrenuti raspravu s konačnim ciljem definiranja optimalnoga načina rada, a posebice njegova unificiranja i primjene u svim šumama hrasta lužnjaka u nas., The establishment of silvicultural trails in young pedunculate oak forests for the purpose of simplifying work of tending young stands and more effective control of done work in Croatia was first made in 1977 in forest area managed by Forest Office Đurđenovac (Sabljak 1990) and Forest Office Cerna. Since then, it has gradually expanded as an accepted technology of work mainly in the Slavonian Forest Administrations of the Croatian Forests ltd., while in other Forest Administrations it was not accepted. Croatian Forests ltd. still have not analyzed the effectiveness of this technology, and the decision of its implementation has been left to the Forest Administrations, even Forest Offices. The technology is based on the formation of a 3 m wide regular network of haulage tracks perpendicular to the forest road and silvicultural trails 1.5 m wide parallel to the same forest road. The production area between the trails is different in width in different Forest Administrations, but most often 5 m. The grid is formed in the year of the first intervention after the final cut (before filling with seedlings or tending). It is easier to work when trails exist, and the control of a done work is especially effective. On the other hand, it is cut down between 24 and 29 % of already rejuvenated surfaces, which is the basic argument for the opponents of this technology. The article proposes to try different ways and positions of silvicultural trails. Haulage tracks are made simultaneously with the silvicultural trails and are used to haul wood material from the beginning of the thinning process to the end of the rotation period. The haulage tracks axis distance in the 750 × 750 m dimension forest compartments is 37.5 m, which divides the compartment’s surface into 20 equal segments. In compartments with other dimensions the spacing varies usually between 40 and 50 m, and the increasing of spacing between the haulage tracks reduces the efficiency of hauling. Therefore, it would be worthwhile testing the different distances between the axis of the haulage tracks, in the first place that one of 25 meters. Since this issue has very little written material in our country, and technology has been in use for many years, this article aims to describe the present situation, to indicate the good and bad sides of the establishment of haulage tracks and silvicultural trails grid, and to initiate a discussion with the ultimate goal of defining the optimal way of work and especially its unification and application throughout the pedunculate oak area in Croatia.

Background and Objectives: Summer droughts are expected to increase in central and western Europe both in terms of frequency and intensity, justifying studies on longer term legacies of drought stress on tree species and their hybrids. Materials and Methods: We studied the longer-term after effects of water withholding and re-watering in the first growing season of potted seedlings from the sympatric species Quercus robur L., Q. petraea (Matt.) Liebl. and their morphological intermediates. Phenology, growth, and plant architecture were examined after a cut-back of the stems at the end of the third growing season. Results: The legacy of the first-year water limitation is faded in the phenological response. Nonetheless, leaf senescence occurred later in offspring from Q. robur than in offspring from Q. petraea at the end of the fourth growing season and leafing out tended to be later in the subsequent growing season. Offspring from the intermediate forms displayed variable phenological responses. Height and radial growth were still affected by the drought stress in a taxon-dependent way, with the offspring from Q. petraea displaying growth reduction both in height and diameter, whereas offspring from Q. robur did not show any differences anymore between control and treated plants, demonstrating better post-stress recovery in Q. robur. Offspring from morphological intermediates responded again in a variable way. Although the number of reshoots after cutting back the stems was not affected anymore by the drought treatment in the first growing season, the number of side shoots on the reshoots was still reduced in the drought treated group of plants, independent of the taxon of the mother tree. Conclusions: Together, our results demonstrate the longer-lasting effects of drought stress on oak saplings with regard to growth and plant architecture, with the first being taxon dependent.

This paper presents an analysis of the climatic factors affecting tree-ring growth in pedunculate oak (Quercus robur L.), one of the most important species of Hungarian forests. A 221-year oak chronology was elaborated, covering the period 1789 to 2009 AD. The daily climate data for a ~110 year stretch offered a detailed insight into the climate-growth relations. The correlation function reached a maximum (r > 0.4) in the case of precipitation in May-August, providing evidence that water availability is the main factor driving the oak growth in the eastern part of the Great Hungarian Plain. Although there was no significant linear relation with temperature in the long term, moving window correlation analysis revealed that temperature response changed substantially over the course of the 20th century. While positive correlation with winter temperature was characteristic in the first decades, later the response to summer temperature strengthened remarkably, reaching r = -0.569 by the end of the analysed period (years 1978-2007). While the vulnerability of oak to drought stress is common across Europe, in southern and central Europe high summer temperatures impair tree growth. The enhanced sensitivity of pedunculate oaks to the water balance in the eastern part of the Great Hungarian Plain allows to surmise the presence of an evolving tendency towards drought risk and vulnerability in the case of these oak stands.

Logging operations using heavy machinery effect changes in soil characteristics due to compaction; such conditions can negatively influence seedling development. In stands managed on the basis of close-to-nature silviculture or continuous cover forestry, successful establishment of natural regeneration after logging is important to ensure the proper functioning of a forest ecosystem, to promote soil recovery, and to prevent and mitigate land degradation processes (such as soil erosion, mudflow, waterlogging, and landslides) related to soil compaction and rutting. This work aimed to assess the early response of Quercus robur seedlings to soil compaction during the first 1.5months after germination. The study was carried out in a controlled environment using 8 L containers filled with natural alluvial soil. Three levels of soil compaction were applied in a laboratory using a compression-testing machine placed on the top surface of the soil in the containers. The morphological traits of the seedling shoot and root systems were analysed to compare 3 compaction levels. There were significant differences in seedling traits among the treatments, and they indicated that increasing levels of compaction reduced early seedling growth after emergence. Compaction had a larger impact on the root system, particularly the development at depth (root system depth, and main root length), compared with the shoot system. Our results suggest that compaction affects seedling root system growth following the first growth stages after germination; thus, compaction represents an additional critical factor for seedling establishment, particularly in environments where early growth is crucial for overcoming the dry season.

The goal of this work was to study the temporal stability of the climate/growth relationship of 15 pedunculate oak trees in Wrocław, SW Poland. Furthermore, pointer years were defined and the span of their meteorological conditions was assessed. The tree-ring widths were measured with an accuracy of 0.01 mm using LINTABTM 6 and the TSAP-Win software. The site chronology covered 128 years from 1887 to 2014. The tree rings were on average 3.56 mm wide and ranged from 2.10 to 5.43 mm. Their variation was significantly influenced by temperature and precipitation. Tree-ring widths from 1965 to 2014 were most influenced (positively) by June precipitation in the year previous to the formation of the rings. From 1915 to 1964, the tree-ring widths were most strongly and negatively influenced by November precipitation recorded in the previous year. Ten pointer years were identified, three of which were positive and seven negative. Both in the group of positive pointer years (1917, 1966 and 1982) as well negative years (1923, 1951, 1953, 1960, 1981, 1989 and 2009), we were unable to determine variation patterns of temperature and precipitation. Research on the TRW series of pedunculate oaks on flood protection embankments should be continued to better understand the effect of climate conditions on annual tree growth., Cilj rada bio je proučiti vremensku stabilnost odnosa klime i rasta 15 stabala hrasta lužnjaka u Wrocławu, u jugozapadnoj Poljskoj. Nadalje, određene su pokazne godine i procijenjen raspon meteoroloških uvjeta među njima. Širine godova mjerene su s točnošću od 0,01 mm primjenom softvera LINTABTM 6 i TSAP-Win. Kronologija staništa obuhvatila je 128 godina, od 1887. do 2014. Godovi stabala imali su prosječnu širinu 3,56 mm, a ona se kretala u rasponu od 2,10 do 5,43 mm. Na varijacije širine godova znatno su utjecale temperature i količine oborina tijekom promatranog razdoblja. Na širinu godova od 1965. do 2014. najviše su utjecale (pozitivno) oborine u lipnju u godini koja je prethodila formiranju goda. Od 1915. do 1964. na širine godova najviše su utjecale, i to negativno, oborine zabilježene u mjesecu studenome prethodne godine. Utvrđeno je deset pokaznih godina, tri pozitivne i sedam negativnih. U skupini pozitivnih godina (1917., 1966. i 1982.), kao i negativnih (1923., 1951., 1953., 1960., 1981., 1989. i 2009.), nije bilo moguće odrediti model promjene temperature i količine oborina. Radi boljeg razumijevanja učinka klimatskih uvjeta na godišnji rast stabala, potrebno je nastaviti istraživanje o nizovima širine godova stabala hrasta lužnjaka koja rastu na nasipima uz rijeku.

Climate change has a significant impact on natural ecosystems, particularly on floodplain forests that are among the most transformed ecosystems in the world. The climate sensitivity of dominant species is likely to play a key role in determining the susceptibility of flooded forests to climate changes. Here, we use dendrochronological approaches and local climate records from 1880 to 2015 to assess the response in pedunculate oak (Quercus robur L.) trees growing in a floodplain of the Dnipro River near Kyiv to climatic variables. Correlation analysis reveals the strongest positive association of the Q. robur tree-ring width chronology with May–June precipitation, May–June temperature, and May self-calibrating Palmers drought severity indices (scPDSI). The moving-window correlation analysis points to positive association with the scPDSI after the 1950s, when local river regulation was implemented. The positive correlation with current March precipitation is the least expected change in the oak growth-to-climate relationship that occurred in the aftermath of human alterations in the local river and regional climate changes. This study discusses the probable ecological consequences and ecophysiological mechanisms of observable climate-to-growth relationships and their temporal stability