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The purpose of the research is to analyse the successful creation of an artificial pine forest by seeding and develop recommendations for the guaranteed reproduction of pine stands in Northern European Russia. In recent decades, there has been a steady decline in the share of pine stands and their replacement with low-value and low-yielding tree species. We surveyed 12 permanent sample plots that were laid out in various variants of forest crops. The taxation parameters were obtained by a standard analysis of the experimental data. The evaluation parameters of the stands vary within the following limits: the average diameter of the pine trees varied from 21.9 to 30.9 cm; the total basal area of the pine varied from 19.1 to 38.8 m2∙ha-1; the average height of the pine varied from 20.1 to 26.8 m; the number of growing trees varied from 754 to 1 952 ha-1; the pines varied from 382 to 762 ha-1; the growing stocks of stands varied from 416 to 608 m3∙ha-1. The distribution of pine trees by thickness steps showed that all the studied samples were close to the normal distribution curve. The results of the correlation and multidimensional analyses showed that the creation method of the forest crops had a significant impact on the value of the taxation parameters. It was found that the best options for growing pure pine stands that can be recommended for practical production are plots with a large share of soil cultivation and the size of the seedbed.

The collection of forest products by indigenous communities is the main cause of deforestation and a major obstacle to efficient forest management. This study develops a time allocation model for a representative household living in the peripheries of the forest. It is assumed that the household allocates their labour time between three activities: agriculture, forest product extraction, and off-farm activities. Households maximize their net income subject to the available forest resources. Using the Optimal Control Theory and applying the unique and global maxima, the results of the comparative static and dynamic analyses suggest that higher agricultural efficiency, agricultural output prices, and higher off-farm wages maximize the forest stock. Besides that, knowledge of forest extraction and farming may also yield the higher equilibrium of forest stock while higher forest and input prices encourage forest resource extraction. The result from the tobit analyses of a socio-economic survey from the Malakand Division forest in Pakistan provides supportive empirical evidence.

Wood-inhabiting macromycete (WIM) communities in the ecosystem of uneven-aged spruce stands growing on former agricultural land were investigated in relation to the supply of wood substrate, degree of wood rot, and selected climatic and ecological conditions. Altogether, 58 WIM species were detected at research plots during 2016-2018. The abundance of fruiting bodies and WIM species richness increased from the youngest to the oldest forest stands. The highest numbers of fruiting body abundance were recorded for Gymnopus perforans (11 756), Hypholoma fasciculare (2 971), Coprinellus disseminatus (326), Exidia pithya (318) and Panellus mitis (147). The influence of stand age on WIM abundance was highly significant (P < 0.001), WIM abundance was not affected by precipitation (P > 0.05). The relationships between abundance and air temperature (P < 0.001), species richness and precipitation (P < 0.001), species richness and air temperature (P < 0.001) were highly significant. The most frequent damage to trees was caused by insects and forest animals (81%), which resulted in a high occurrence of resin secretion (70%). The total volume of coarse wood debris (CWD) and the decay rate were not statistically dependent. We confirmed the occurrence of Heterobasidion annosum s.s., H. abietinum s.s., H. parviporum s.s., Armillaria ostoyae s.s. and A. cepistipes s.s. by use of molecular genetic analyses.

Pests and diseases can cause a variety of reactions in plants. In recent years, the boxwood dieback has become one of the essential concerns of practitioners and natural resources managers in Iran. To control the boxwood dieback spread, the early detection and disease distribution maps are required. The boxwood dieback causes a range of changes in colour, shape and leaf size with respect to photosynthesis and transpiration. Through remote sensing techniques, e.g. satellite image processing data, the variation of thermal and visual characteristics of the plant could be used to measure and illustrate the symptoms of the disease. In this study, five common vegetation indices like difference vegetation index (DVI), normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), simple ratio (SR), and plant health index (PHI) were extracted and calculated from Landsat 8 satellite image data from six regions in the Gilan province, located in the northern part of Iran out of 150 maps over the time period 2014‒2018. It turned out that among the aforementioned indices, based upon the results of the models, SR and NDVI indices were more useful for the disease spread, respectively. Our disease progression model fitting criteria showed that this technique could probably be used to assess the extent of the affected areas and also the disease progression in the investigated regions in future.

Roads with the low standard level are often more susceptible to soil loss and production of sediment during rainfall events. The main aims of this research were to investigate the relationships between the standard level of the road and soil loss and determine the most effective road attributes in soil loss. Therefore, 30 road segments were selected in Bahramnia forest district, Golestan Province. These segments were classified into low standard, medium standard and high standard levels based on longitudinal slope, coverage on cut slopes, distance from runoff origin to culvert, traffic volume, and surfacing quality. A rubber bar was installed at the end of each segment to divert runoff into a sediment trap. In each trap, a series of wooden pins marked the locations for repeated elevation measurements of trapped sediment. Sediment volume was measured after each rainfall event. Results of the study showed that the most effective road attributes in soil loss were distance from runoff origin to trap and depth of ditch. Soil loss from road segments increased with the decreasing standard level of segments but this relationship was moderately strong (correlation coefficient: -0.45). An average amount of soil loss from low level standard road segments was 6.56 t.ha^-1.year^-1 while an amount of soil loss for high level standard roads was 2.66 t.ha^-1.year^-1. Indeed, by improving the road attributes and standard level, less sediment is produced from road segments.

Forest fires are a major environmental issue because they are increasing as a consequence of climate change and global warming. The present study was aimed to model forest fire hazard using the ordered weighted averaging (OWA) multi-criteria evaluation algorithm and to determine the role of human, climatic, and environmental factors in forest fire occurrence within the Golestan National Park (GNP), Iran. The database used for the present study was created according to daily classification of climate changes, environmental basic maps, and human-made influential forest fire factors. In the study area, the forest fires were registered using GPS. Expert opinions were applied through the analytic hierarchy process (AHP) to determine the importance of effective factors. Fuzzy membership functions were used to standardize the thematic layers. The fire risk maps were prepared using different OWA scenarios for man-made, climatic, and environment factors. The findings revealed that roads (weight = 0.288), rainfalls (weight = 0.288), and aspects (weight = 0.255) are the major factors that contribute to the occurrence of forest fire in the study area. The forest fire maps prepared from different scenarios were validated using the relative operating characteristic (ROC) curve. Values of forest fire maps acquired from scenarios of human, environment, climate factors and their combination were 0.87, 0.731, 0.773 and 0.819, respectively.

Site conditions (topography, aspect, moisture availability, humus thickness, light exposure, and grazing activities) play a vital role in the germination and regeneration process. The research was conducted in the Himalayan moist temperate forest. The research site was divided based on the silvicultural system (group selection system and single-tree selection system) into 148 plots and 150 plots, respectively. The group selection system was examined on the site of 2 ha which was clear-felled under a project in the 1980's. The present study examined the impact of silvicultural systems on regeneration. The frequency table was used, and relative frequency was calculated for the species and silvicultural system, density per m2 was also calculated. Diversity indices were calculated through taxa, dominance, Simpson's index, Shannon index, evenness, equitability, and fisher alpha. Ten taxa were found in both silvicultural systems, with individual repetition of 17 and 15 taxa, respectively. Group selection is more compact visibly as compared to the single-tree selection system. The single-tree selection system is more diversified in species composition, stand structure, moisture availability, and less humus availability. The study also highlights future predictions for the conservation of these forests, which are highly sensitive and a hotspot for wildlife and climate change phenomena. Silvicultural practices such as silvicultural system, cleaning, weeding, thinning operations are regularly practiced, which can reduce the negative impact on these productive forests.

This study investigated the influence of site conditions on the physical and morphological properties of hawthorn (Crataegus azarolus L.) wood grown in Zagros forests of Iran. Hawthorn is a valuable woody species in Iran's Zagros forests with data deficiency in its wood properties. To our best knowledge, there is no study on the properties of hawthorn wood. Twenty-seven mature trees were randomly chosen and sampled at three altitude levels (1 800-2 000, 2 000-2 200, and 2 200-2 400 m) in the Bazoft region of Chaharmahal Va Bakhtiari, Iran. Dry wood density, volumetric shrinkage, fibre length, fibre diameter, cell wall thickness were then determined. Multivariate analysis of variance (MANOVA) was conducted to evaluate significant differences between the mean values of studied wood properties at different altitude levels and slope classes. Moreover, the relationships between the above-mentioned properties and some site conditions (temperature, precipitation, altitude, and slope) as well as growth parameters of trees (tree height, DBH, age, crown dimensions, volume, etc.) were studied by principal component analysis (PCA). The results indicated that trees growing at the second altitude level had the highest oven-dry density values, and those at the third altitude level had the lowest ones. Results also indicated a significant effect of altitude levels on fibre length, fibre diameter, and cell wall thickness. In contrast, a significant difference was found between the mean values of fibre diameter at different slope classes. PCA indicated that altitude, precipitation, and temperature are the most important environmental site variables affecting the wood characteristics.

Variations in seasonal responses in water relations and total carbohydrate content (TCC) in one-yearold shoots from precommercially thinned (PCT) and unthinned Anatolian black pine stands were assessed during three seasons (sampling in May, July and September) in 2015-2017. Three different treatments were established: unthinned control with 4 941 stems.ha-1 and two thinned spacing levels (2-2.5 and 3-3.5 m) where 2 133 stems.ha^-1 and 1 093 stems.ha^-1 were left, respectively. Differences in osmotic potential at turgor loss point (Ψπ_TLP) between the thinned and unthinned plots appeared only during a water shortage (September) in the second season, with the thinned stands showing lower Ψπ_TLP than the unthinned stands. Seasonal variation in terms of Ψπ_TLP was detected in the 3-3.5 m spacing trees. PCT were effective on osmotic potential at full turgor (Ψπ₁₀₀), relative water content (RWC), symplastic water at saturated point per dry weight of the shoot and dry weight fraction. In both the thinned and unthinned plots, a gradual decline was observed in RWC from May to September in all three years. Generally, although TCC was found to be higher in the 3-3.5 m spacing, control plots were also high in carbohydrates in some periods. Results reflect the ability of this species to survive in changing environments by PCT during dry periods in the three studied seasons. Although PCT has an effect on water potential components and TCC, it is not clear exactly how effective the PCT density is in osmotic adjustment.

The aim of the study was to confirm and compare efficiency of methods enhancing the vitality of Scots pine and Norway spruce seeds: soaking in water, cold stratification, additional moistening and incubation according to IDS method. The examined parameters included water content in the seeds, germination energy, mean germination time and germination capacity before the seed treatment, after its treatment by the tested methods and after drying. Results show that all the tested methods accelerate germination of seeds; cold stratification is the most efficient and recommended method for Scots pine and soaking of seeds in water is the most efficient and recommended for Norway spruce. The best results in spruce were also obtained with cold stratification (comparable with soaking in water) but the method is complicated, longer-lasting and more costly than soaking in water.

Forest dimensional structure and tree species composition strictly define ecosystem resilience, success of its functioning and development. Spatial structure of forest compartments provides an additional information on the forest stand heterogeneity. The aim of this study is to examine structural patterns (both spatial and nonspatial ones) in European oak (Quercus robur L.) urban forests located in Kyiv city, Ukraine. We compared two middle-aged (~ 80 years) and two mature (~ 180 years) oak stands in terms of structural metrics collecting a data from geo-referenced trees on the established permanent sample plots. Younger stands reached similar tree diameter diversity (9.07 and 10.45 vs. 11.42 and 14.05 of Shannon indices), while the compositional diversity was driven by the dominance of either oak or European hornbeam (Carpinus betulus L.). We have not found any differences in the species mingling and deadwood distribution indices except a clear occurrence pattern for the stand located near roads. Herewith, the largest distance between the plot and park pathways was an indicator of changed spatial variation and tree dimensional differentiation within one middle-aged stand. We hypothesize that human impacts can alter structural development in urban deciduous forests providing both positive (gap formation, deadwood occurrence and ecosystem complexity) and negative (shifts in compositional and successional trajectories) effects on such forest stands.

The influence of three types of treatment on seedling survival percentage, growth and Armillaria infestation of Fagus sylvatica L. (FAGUS), Abies alba Mill. (ABIES) and Picea abies (L.) H. Karst. (PICEA) seedlings were tested in this study: (i) inoculation with the Ectovit^® preparation containing ectomycorrhizal fungi (INOCUL), (ii) Ectovit^® preparation + Conavit^® fertilizer (INOCUL + FERTILIZ) and (iii) the untreated group (CONTROL). The selected sample contained 100 seedlings per each tree species and treatment type (900 seedlings in total). Besides that, 18 months after planting, 10 living seedlings per each species and treatment (90 seedlings in total) were sampled to evaluate root dry mass and Armillaria infestation. The data were statistically evaluated by frequency analysis, analysis of variance and Kruskal-Wallis test. The overall seedling survival percentage was very low, probably due to extreme drought and high temperatures, with significantly lower results for the ABIES INOCUL + FERTILIZ and PICEA INOCUL + FERTILIZ groups. All tested growth characteristics (seedling height increment, root collar diameter increment, seedling shoot dry weight, root dry mass) were significantly higher in PICEA seedlings. Root collar diameter increment showed significant differences within each species and inconsistent results. Armillaria was detected only in the PICEA CONTROL group as rhizomorphs identified as A. ostoyae. The results suggest that the artificial mycorrhizal preparation can be an efficient method of preventing Armillaria infestation, especially in spruce seedlings.

Simulation of the runoff-rainfall process in forest lands is essential for forest land management. In this research, a hydrologic modelling system (HEC-HMS) and artificial neural network (ANN) were applied to simulate the rainfall-runoff process (RRP) in forest lands of Kasilian watershed with an area of 68 square kilometres. The HMS model was performed using the secondary data of rainfall and discharge at the climatology and hydrometric stations, the Soil Conservation Service (SCS) for simulating a flow hydrograph, the curve number (CN) method for runoff estimation, and lag time method for flow routing. Further, a multilayer perceptron (MLP) network was used for simulating the rainfall-runoff process. HEC-HMS model was used to optimize the initial loss (IL) values in the rainfall-runoff process as an input. IL reflects the conditions of vegetation, soil infiltration, and antecedent moisture condition (AMC) in soil. Then, IL values and also incremental rainfall were applied as inputs into ANN to simulate the runoff values. The comparison of the results of simulating the RRP in two scenarios, using IL and without IL, showed that the IL parameter has a high effect in increasing the simulation performance of the rainfall-runoff process. Moreover, ANN predictions were more precise in comparison with those of the HMS model. Further, forest lands can significantly increase IL values and decrease runoff generation.

This article encompasses the impacts of disturbance, regeneration potential of conifers and the dynamics of tree species seedlings along the spatial scale in Murree forest. The seedling status preferably of conifers along with associated broadleaved dominant tree species is determined by a quantitative evaluation of diversity functions. An empirical approach is applied to predicting the future of seedlings under stress as well as the current hypothetical appearance of seedlings in the forest. The need of analysing diversity of this forest is due to highly disturbed conditions there, and this paper is designed to know the recent trends of species diversity in the area. Species diversity and species abundance at a seedling level are estimated by using standard formulas of diversity measurements. Thirty stands are used for the evaluation of seedling abundance in highly disturbed conditions with the examination of diversity in the area. Seedling density is too low in the forest whereas diversity is also in poor condition. Seedlings from four conifers with three broadleaved species in different stands indicated the low density of future trees. The mean density.ha^-1 of pine seedlings is consecutively low in Pinus wallichiana (16 ± 2), Pinus roxburghii (11 ± 3), Cedrus deodara (9 ± 3), Abies pindrow (8 ± 3). The correlation coefficient is as low as 0.76, 0.66 and 0.61 in Pinus roxburghii, Cedrus deodara and Abies pindrow, respectively, while Pinus wallichiana showed a significant correlation, i.e. P > 0.5. Hence, this study claims that the survival of the forest is threatened as seedling density and diversity are too low. This forest needs serious attention towards preventing and conserving pines and other associated species seedlings for the existence of this forest in future.

Despite recent issues, Norway spruce remains the most important commercial tree species which might be demanded henceforth for its broadly utilizable wood. Even before foresters faced both the bark beetle outbreaks and spruce decline, spruce monospecific stands were known to be prone also to other damage due to snow and wind. On this basis, measures that help prevent such failures were looked for, which resulted in the establishment of international IUFRO experimental series focused on impacts of different thinning regimes on stability and production of spruce stands. The thinning treatments differed in numbers of trees removed and retained on the site when dominant height of crop trees was reached or allowable cut in non-crop trees was accumulated. Also effects of different width of skid trails were tested. The study summarizes the results from the two IUFRO experiments in the Czech Republic. Effects of thinning regimes on spruce were found positive though thinning reduced the total volume production of wood while improving crop-tree stability which enhanced production safety. Different widths of skid trails had no effect on wood increment. Early thinning of spruce can be used to prevent their damage. No such measure, however, can alleviate the spruce decline.

The aim of the article is to describe the issue of determining the characteristics and parameters of raw timber natural losses due to shrinkage at long-term storage, defining the theoretical basis for creating standards, and verify its finding by means of a case study in raw timber storing. This issue is very topical in forestry practice in the Czech Republic as well as in other countries. The lower and upper limits of the standards were calculated, and the proposed mean value was grouped according to woody plants that reflected the most frequent commercial usage with respect to subsequent processing. Subsequently, experimental verification was carried out on a representative sample of 2 209.99 m3 of raw timber of Norway spruce (Picea abies /L./ H. Karst.) at selected forest administrations. Furthermore, the article addresses the related accounting and tax issues of the standards of natural losses of raw timber. Currently, no legislation mandates an entity to establish standards.

Fire is considered one of the major natural hazards that damages European forests and causes losses for forest owner. The forest fires endanger the financial stability of forest enterprises, which may cause their economic decline. One possibility how to cover these losses is to insure forest land against this kind of specific risk of forest land management. The aim of the present paper is to analyse possibilities of forest fire insurance for forest owners and enterprises in the Slovak private insurance market. The market analysis was based on document analysis of general terms and insurance conditions of chosen private insurance companies and interviews with insurance agents. The results show that forest owners and enterprises have only few options for forest property insurance concerning the specific risk of forest fires. Only one commercial insurance company provides such forest fire insurance product for forest owners. This insurance covers material damage to forest land and timber damage.

Improving the quality of sorting wood waste is the main problem in the timber industry from the point of view of saving energy resources and preserving the environment, associated with the intensity of forest harvesting. Depending on the required quality characteristics, the sorting of wood chips makes it possible to determine their further use in production or utilization as a fuel. This paper presents the results of the development of a novel approach to sorting wood chips on a conveyor belt using machine learning and scanning technology. The proposed methodology includes functions to analyze the fractional size distribution among wood chips and rot detection. It shows that once a defective unit is detected, the quality control system will automatically remove it from the conveyor belt while it is moving. The minimization of wood waste will reduce logging intensity and increase the profitability of lumber enterprises.

As labour for manual tree planting becomes scarcer, regeneration costs are steadily increasing in Nordic forestry. Today's intermittently advancing tree planting machines provide excellent silvicultural results, but are expensive to operate because of poor productivity. In contrast, continuously advancing planting machines, thanks to high productivities, are increasingly being regarded as a solution to these runaway regeneration costs. The Silva Nova was a historical, continuously advancing tree planting machine with high productivity. However, Silva Nova's weaknesses included high labour costs (it required two operators) and the random nature of how it chose planting spots. In contrast, SuperSilva, a purely conceptual modernisation of Silva Nova, involves both automation and microsite identification to make the machine more efficient. We used discrete-event simulation to analyse the stocking rate and spatial distribution of tree planting with SuperSilva. The simulation results showed that introducing sensors for identifying suitable microsites will allow continuously advancing planting machines (like SuperSilva) to plant seedlings in a numerically and spatially adequate manner on moraine soils. Hence, these sensors will increase the competitiveness and versatility of tree planting machines. Unfortunately, such reliable and robust sensor technology (unaffected by a wide variety of operating conditions) is not yet commercially available.

The paper deals with the determination of the amount of logging residues including merchantable timber volume (brush) left in the beech stands for further use. Logging residues were recorded in all types of intentional felling starting with intentional improvement felling up to 50 years and ending with intentional regeneration felling. The potential amount of biomass left was divided into the share of brush and the share of small wood. The parameter was monitored for 3 years and all measured values were then statistically evaluated and related to 1 m3 of intentional felling in beech stands. A partial goal of this publication is characterization of economic impacts of the proposal for processing the recorded volume of logging residues left in the beech stands on the forest branch in Smolenice. The economic impacts are characterized in two proposed and mutually compared scenarios. The first scenario considers framework contractors for logging works with their own machines, i.e. by assignments, as a mediation of service invoiced for the assumed amount (m3) forwarded to the roadside landing, with the ownership of the forwarded dendromass belonging to Lesy SR (Forests of the Slovak Republic). Then, the dendromass is sold from the roadside landing to customers who are going to transport and process it at their own expense. The second scenario considers sales of assumed amounts of left dendromass including brush to customers who will provide for its transport and processing on the identified roadside landing within a set deadline under obligation to return the site to its original condition if there is possible damage. In this case, Lesy SR would be only a control body supervising labour quality and set-up technological procedures.

Understanding the forest response to ongoing climate change is crucial in forest management strategies under anticipated climate adversity. To understand the retrospective growth dynamics of Jeffrey pine (Pinus jeffreyi Grev. & Balf.), tree-ring chronology from the subalpine forest in the Lake Tahoe Basin, California was correlated with air temperature, precipitation, and Palmar Drought Severity Index (PDSI). The years 1757, 1782, 1886, 1859, 1876, 1920, 1929-30, 1977, 1988-89, 2001-02, 2008, and 2014 were some of the years with noticeable low growth. There was robust growth in 1747-49, 1792, 1828, 1866-68, 1913, 1969, 1984, 1998, and 2011. Ring width index (RWI) and basal area increment showed a recent growth increase. Climate-growth response analysis revealed the growth-inhibiting influence of the hot and dry summer. More pronouncedly, warm and wet winter was found to be conducive to tree growth in the following year. A significant growth correlation with the previous year climate (stronger with PDSI) and its absence in current spring may be suggestive of potential growth stimulation by predicted warmer and longer growing season in the future. However, since the RWI chronology consisted mostly of mature trees and because the old cambial age tends to have signal divergence, further studies incorporating younger trees and cohabitant species would provide deeper insights into the growth-climate response.

Understanding the various processes and relationships that take place in forest ecosystems is generally possible only through long-term observations. This is especially true of the biological production of forests, through the in-depth exploration of their structure. In Hungary the black walnut (Juglans nigra L.) is one of the most valuable exotic tree species, mainly because of its very valuable wood, with fine tissues and unique colour, for furniture industry. Generally, the species is established by manual seeding, and can also be regenerated well by coppice shoots, but not by natural seeding. Black walnut regularly produces seeds from the age of 25-30 years and its rotation age is 70-80 years. It is also used outside forests due to the very decorative stem and crown shapes. In this paper, out of the stand structure factors, the relationships between age and height (r² = 0.7205), age and diameter (r² = 0.7719), age and number of stems per ha (r² = 0.3485) as well as between diameter and number of stems per ha (r² = 0.4595), all considered important for cultivation technology, were examined (based on the data collected in 34 black walnut stands, age of 7 to 67 years). We also analysed the diameter distributions in two black walnut stands with tending operations, reporting them as a case study. Its future role may be increased mainly on sandy soils of better quality, therefore the more accurate exploration of the structure of black walnut stands growing under such conditions can be considered as gap-filling.

In January 2019 the forest industry in Ukraine adopted European standards for measuring and grading of round wood based on mid-point diameters, which caused major discrepancies from traditionally used estimates of timber volume using top diameters. To compare methods of merchantable wood volume estimation, we investigated the stem form inside bark for two dominant tree species in Ukraine, i.e. Scots pine (Pinus sylvestris L.) and common oak (Quercus robur L.). We used tree stem measurements to fit stem profile equations, whereas simulation was applied to derive log taper. We found that Newnham's (1992) variable-exponent taper equation performed well for predicting stem taper for both tree species. Then, we simulated the structure of harvested wood, so that it replicated annual distribution of logs by their length and diameters. As a result, the average log taper was estimated at 0.836 / 0.855 cm.m^-1 and 1.180 / 0.121 cm.m^-1 for pine and oak, respectively. The study also indicated that log taper varied along stems. The higher rates of diameter decrease were found for butt logs, for which the taper was 2.5-3.5 times higher than its average for the whole stem. The results of our study ensure the stacked round wood volume conversion between estimates obtained using top and mid-point diameters.

The regeneration of forest trees is affected by the presence, dispersion pattern and specifications of parent trees. These effects were investigated and modelled in hardwood forests in the north of Iran. To do so, at first, fifty plots, each with a total area of 0.1 ha, were identified. Four subplots with a radius of two meters were then stabilized in each plot. The height and the root collar diameter of all the cherry seedlings were measured. Likewise, the diameter, basal area, and distance from the plot centre were appraised in the parent trees. The correlation and regression analyses were performed to evaluate the effects and to construct the models, respectively. The results showed that there was a positive and significant relationship between the presence, abundance, mean diameter, and total basal area of parent trees and the presence and abundance of seedlings. The logistic regression showed that the models based on the mean diameter of parent trees and abundance of parent trees could significantly predict the presence of regeneration. Only in 10% of the sample plots was the regeneration recorded without the presence of a parent tree. Due to the small number of established seedlings, while maintaining the existing parent trees, especially large trees, it is necessary to consider the proper management methods to promote and protect their regeneration. We recommend completing the natural regeneration of wild cherry by artificial regeneration and creating well-dimensioned canopy gaps.

One of the most important issues indicating the quality and quantity of forest ecosystems is the distribution of natural disturbances resulting in canopy gaps (CGs). The present study was conducted in one of the Hyrcanian beech forests in northern Iran in summer 2018. The gap areas were classified into small (< 200 m²), medium (200‒500 m²) and large gaps (500-1 000 m²) on the basis of full inventory. The univariate Ripley's L-function was used for introducing the CG spatial pattern. Furthermore, mark correlation function (MCF) and density function (DC) in turns were used for verifying the correlation and frequency of CG size classes in each pattern. The results showed patterns of the gaps in each size class and integrated by the three size classes, they were random and cluster, respectively. Furthermore, the MCF revealed that the gap size classes were independently located in the clusters. The total frequency of the small, medium and large gaps in turns was 32, 49 and 19%, respectively. Although the density share of medium and small gaps in turns was more frequent than the large gap density in the study forest, the results of DC indicated that the frequency of each gap size class was random within each cluster, regardless of their density share. Based on the natural gap aggregations, the base circular mosaic with an area of 5 000 m² can be introduced for monitoring and specifying the forest stand dynamics.

Coppice management is an ecologically important silvicultural practice to provide the quicker and higher potential of wood biomass production for industrial demands. Understanding morphological and anatomical responses of coppiced trees could help to determine the quantity and quality of wood and thus provide better management of coppiced tree plantations for short-time biomass production. However, there is a little investigation in morphological and anatomical adaptation in different fast-growing tree species. The present study, therefore, studied how morphology and anatomy vary between two fast-growing coppices of Populus nigra L. (black poplar) and Salix alba L. (white willow). Each coppiced tree was grown in a similar habitat and was at a similar age. However, each coppiced tree showed different morphological and anatomical plasticity in their stems in response to environmental factors. Poplar coppices showed better anatomical properties due to greater vessel diameter, fibre length, fibre width, fibre wall thickness, and ray height; however willow coppices had better morphological plasticity which had higher average stem height and ring width. The results suggest that willow coppices had the greater height growth potential even at 2 years of age than poplar coppices.

The present study is focused on European beech (Fagus sylvatica L.) growth in eastern Bohemia in the Broumovské stěny National Nature Reserve, Czech Republic. The objective of this research was to develop an evaluation of European beech radial growth in relation to solar activity (number of sunspots), air temperature in the growing season, annual precipitation and air pollution (SO₂ depositions). The highest positive significant correlation coefficient was found between radial growth of European beech and number of sunspots, followed by the correlation with air temperature in the growing season. The radial growth showed a negative significant correlation with SO₂ depositions. The correlation of the radial growth indicates that precipitation and sunspots have a lower correlation coefficient with beech growth than seasonal temperature during an air pollution disaster in the 21st solar cycle. Radial growth, precipitation total and air temperature in the growing season were processed by spectral analysis for the evaluation of periodic cycles. The 7.5- to 11-year cycles were observed in air temperature and in sunspot cycles. Precipitation and air temperature in the growing season indicate a higher frequency at 3.7-year cycles. The long-term periodicity of radial growth was influenced by both solar activity and fluctuations of growing-season air temperature.

The brown marmorated stink bug, Halyomorpha halys Stål, 1855 (Hemiptera: Heteroptera: Pentatomidae), is recorded from Slovakia for the first time based on a 5^th instar larva collected in the town of Štúrovo, Slovakia. The current distribution, economic importance and biology of the species are briefly reviewed. During the visit to Štúrovo, a mass occurrence of adults and larvae of the southern green stink bug, Nezara viridula (Linnaeus, 1758) (Pentatomidae), so far captured in Slovakia in 2014 only as a single specimen, was also observed. This observation confirms the presence of N. viridula as an established species in southern Slovakia. Both species are important pests to a large number of crops (vegetables, fruit trees, decorative plants, etc.) and can cause considerable economic losses.

Soil samples from 100 cultivated and natural sites were assessed for the presence of entomopathogenic nematodes. Heterorhabditid nematodes were recovered from three soil samples during spring months, with the overall positive sample rate of 3%. The isolates of entomopathogenic nematodes were identified as three different strains conspecific with Heterorhabditis bacteriophora (Heterorhabditidae). They were found from natural sites and vineyard, while no recovery occurred from intensively cultivated agricultural fields. The morphometrical characteristics of infective juveniles and males showed differences between all Croatian strains and from the original description. Heterorhabditis bacteriophora ISO9 was bioassayed on Lasioptera rubi (Cecidomyiidae) (the raspberry gall midge) larvae at different nematode concentrations under laboratory conditions. The significantly highest mortality was observed in treatments with 50 and 200 infective juveniles per insect larvae within 8 days after inoculation. This is the first report of entomopathogenic nematodes of the family Heterorhabditidae from Croatia, and susceptibility of L. rubi larvae to entomopathogenic nematodes. The Croatian strain H. bacteriophora ISO9 was proved to possess strong insecticidal properties against L. rubi larvae.

This paper presents the first record of the oleander aphid (Aphis nerii Boyer de Fonscolombe, 1841; Hemiptera: Aphididae) in Slovakia, and also one of the most northern record of this natural pest on the invasive common milkweed (Asclepias syriaca Linnaeus.; Apocynaceae) in Central Europe. Modern social media crowdsourcing has achieved comprehensive distribution data in the horticultural community, and a total of 35 new distribution sites were discovered in 28 Slovak settlements, one new site in Austria, and one in the Czech Republic. It was further established that the oleander aphid could survive in anthropogenic refuges during the winter months.