Abstract: One of the adverse effects of global warming is the growing threat of drought. Periods of water deficit together with high temperatures are the main abiotic stresses negatively affecting the function of plants. The projections of climate change indicate an increase in temperature and a decrease in precipitation in the future. The predicted increase in the intensity and frequency of droughts is supposed to have negative effect on physiological and physical characteristics of seeds of forest trees. This study aims to determine the impact of the 2015 drought on the phenotypic characteristics of cones and seeds from Scots pine orchards located in western Poland. Five clonal seed orchards, each composed from plus−trees representing one Scots pine provenance, were included in the study. Collected material provided data about the length and width of cones and seeds, as well as the frequency of full and empty seeds per cone. Analyses indicated a signifi− cant impact of drought on the biometric characteristics of the seeds, which were generally smaller. Dimensions of cones were not affected, but mass of cones grown during drought was slightly lower. The number of seeds in cone ripened during the drought was lower, but the relative number of empty seeds was not affected. Generally, provenances represented by plus−trees were not differentiating average values of analysed variables.
Key words: climate change, drought, Scots pine, seed orchard

Abstract: At present, I. duplicatus (Sahlb.) creates extensive outbreaks in the Czech Republic. Established methods used to protect against Ips typographus (L.) and check its spread, are not effective against Ips duplicatus. The aim of the survey was to verify the possibility of protecting forest against I. duplicatus by using chemical treatment or by injecting protected standing spruce trap trees. Thirty−four trees inside an area with an outbreak of I. duplicatus (East Czech Republic) were randomly chosen in a stand of spruce. The stems of 10 spruces (i) were treated with alfa−cypermethrin insecticide up to a height of 4 m and a device for collecting dead bark beetles was attached to these trap trees. Eight spruces (ii) were injected with imidacloprid (1% solution), and the rest of the trees (iii) were used as a control. Pheromone lures were applied on these trees, with two items on every type of trap tree. Five naturally infested trees I. duplicatus located outside the area of influence of the pheromone lure were included in the analysis (iv). Infestation of the spruce trees was calculated from the density of entry holes on the stem (i, iii, iv) or the number of collected dead bark beetles (ii). Naturally attacked trees had the highest density of entry holes. Standing trap trees treated with alpha−cypermethrin had a lower infestation density than injected trees. The pheromone lure attracted I. duplicatus to the bottom of the stem, away from the naturally infested crown section. Treatment with insecticide to a height of 4 m was insufficient, because varying infestation rates of standing trap trees ranged from thousands to just a few individuals of bark beetle adults. These standing trap trees were also infested in the treated section. The dispersion of the infested trees within the group was uneven. Injection by imidacloprid had a low efficacy in protecting trees against development of a new generation of bark beetle.
Key words: alpha−cypermethrin, imidacloprid, Ips typographus, standing trap trees

Abstract: The Białowieża Forest District is one of the three forest districts managing the Białowieża Primeval Forest. With an area of 12,586 ha, this district accounts for approximately 20% of the entire Polish area of the Białowieża Primeval Forest. The forest district also includes many forms of nature protection that appear in Polish legislation, including Natura 2000, nature reserves and species protection zones. Additionally, the district is protected under international agreements as part of the UNESCO World Heritage Site ‘Białowieża Forest’. Over the last 100 years, the forest stands of the Białowieża Primeval Forest have experienced numerous changes in the population dynamics of the spruce bark beetle, where outbreaks resulted in the insects colonizing live trees – mainly spruces. In the last decade (2012−2021), the spruce bark beetle outbreak also occurred in the Białowieża Forest District between 2013−2017. In this case, the size of the outbreak was largely influenced by introduced formal and legal restrictions which made it impossible to take active measures to prevent the reproduction of the spruce bark beetle. This led to a catastrophic development of the outbreak, resulting in about 2 million m³ of trees being infested in the forest districts – including over 0.7 million m³ of spruces and pines in the Białowieża Forest District. The aim of this study was to describe the activity of the spruce bark beetle between 2012−2021 in the Białowieża Forest District, and to analyse the collected data in relation to nature reserves, stands over 100 years old (based on Prof. Tomasz Wesołowski’s criterion) and stands up to 100 years old. In the analysed 10−year period, the greatest volume of infested trees occurred in stands over 100 years old (395,761 m³), then in stands up to 100 years old (195,059 m³) and lastly in nature reserves (141,526 m³). The peak of the outbreak in the forest district occurred in 2016, when 200,761 infested trees with a volume of 224,674 m³ were registered. Using the collected data, the volume of infested trees was also characterized according to forest habitat types, age classes of stands and any changes that took place in this respect during the 10−year period. The highest volume of trees infested in 2012−2021 was found in the habitats of fresh mixed broadleaved forest (LMśw), fresh mixed coniferous forest (BMśw) and fresh broadleaved forest (Lśw), where the values were 229,143 m³, 186,276 m³ and 176,455 m³, respectively. In the initial phase of the outbreak, the spruce bark beetle mainly infested old spruce forests in the 6^th and older age classes. At a later stage, from 2016 onwards, the mass of the infested younger stands, i.e., age classes II, III and IV, clearly increased. Giving up the practice−proven methods of reducing the bark beetle population led to the breakdown of tree stands over thousands of hectares. This resulted in threats to the existence of many species of plants, animals and fungi along with their habitats. Forest fire risk also increased, increasing the need to periodically prohibit access to the forest to implement work in the field of public safety. Management of such a valuable entity as the Białowieża Primeval Forest requires great caution and prudence in making decisions on protection methods. This should consider both the aspects related to passive protection, i.e., the protection of natural processes, as well as active protective measures for the protection of habitats and species.
Key words: infested tree, Norway spruce, habitat type, protection form

Abstract: The aim of this study is to estimate the area with forest vegetation that does not yet meet the criteria formulated in the FAO/UN definition (minimum height 5 m, minimum canopy cover 10%, minimum area 0.5 ha), but will potentially meet them in the future (5 years or more, depending on the individual site conditions), which means that (according to the definition) they also represent forest areas. The study was conducted in the Białowieża Glade. Tree species were classified individually and then divided into two groups: those that will reach a height of 5 m in the future and those that will not (grey willow, hawthorn). Hyperspectral (reduced with MNF transformation) and ALS−based features were used for classification with the SVM algorithm. Classification accuracy based on ALS data was better than that of hyperspectral data for indi− vidual species but similar for the two species groups – 95.5% (Kappa 87.5%). Information about species and height was used to perform the classification of a fishnet layer into ‘forests’, ‘potential forests’ and ‘non−forests’, with an accuracy of 96% (Kappa 87.7%). A map of forests and potential forest vegetation was created in the form of a thematic map, taking into account height, canopy cover, area of the complex and land use. This study provides new solutions in the context of cli− mate change, deforestation and the need for reporting the forest area by individual countries (including Poland) to the FAO/UN.
Key words: species, classification, hyperspectral data, ALS data, potential forest area, reporting, FAO/UN forest definition

Abstract: Various factors, such as availability of light, water, nutrients and soil properties have impact on plant growth. Macroelement content in the seedlings affects their biometric features (such as height and weight) which in turn affects the likelihood that the seedling would survive and thrive later in the forest. This research focuses on analyzing how changes in bulk density of the substrate affect the selected biometric features and the content of macroelements in different parts of the Scots pine Pinus sylvestris L. seedlings (needles, shoot and root). This paper presents the results of research carried out using Scots pine seedlings grown in 120 cm³ containers. The seedlings grew at 9 different peat substrate bulk densities (ranging from 0.208−0.342 g·cm^–3). Here, we have determined the macroelements (N, P, K, S, Ca and Mg) content of individual parts of the seedlings (needles, shoot, root system) and substrate furthermore their selected biometric features (height of the above ground plant, dry weight of needles, shoot, root system, length of fine roots). It was found that higher bulk density of the substrate had a limiting effect on the uptake of most macroelements by seedlings and on the examined biometric features. The analysed macroelement content in the assimilation apparatus was compared to the optimal values given in the literature and it was shown that the best concentration of peat substrate for the cultivation of Scots pine seedlings, in terms of this criterion, is in the range of 0.103−0.117 g·cm^–3 dry bulk density.
Key words: Pinus sylvestris, bulk density, macronutrients, fine roots, nursery container, seedling morphology

Abstract: In Poland, Pissodes castaneus (De Geer), the small banded pine weevil, is increasingly common in young Scots pine Pinus sylvestris L. stands weakened by various biotic (root diseases, deer) and abiotic (drought, hail, etc.) factors. In Europe, an increasing threat to young P. sylvestris stands by this pest has been observed since the early 2000s, most likely due to ongoing climate change. It seems that weakening of young trees by droughts may have contributed to the increase in pest numbers. The intensification of damage caused by P. castaneus, as well as the lack of effective protection methods, justified conducting research on the insects co−occurring with P. castaneus on P. sylvestris, with special emphasis on its natural enemies. The 3−5−year−old P. sylvestris trees colonized by P. castaneus were collected in 2015−2017 at three locations in Central Poland. All these trees were weakened mainly by drought. Their roots and stems were divided into sections according to their diameters and kept in the laboratory until the emergence of associated insects was complete. A total of 13 species of Coleoptera and 2 species of Hymenoptera were collected from the trees colonized by P. castaneus. Among the co−occurring insects (not trophically related to the pest), the Curculionidae family was most numerous, in which Pityogenes bidentatus (Herbst) dominated, with a proportion of almost 90% of the collected insects, followed by Pogonocherus fasciculatus (De Geer) (5% share) and Magdalis phlegmatica (Herbst) (2%). Only two co−occurring species were found in the fragments of the stems with a diameter >3 cm: Rhagium inquisitor (L.) and P. bidentatus. In stems <1 cm only Ernobius nigrinus (Sturm) and M. phlegmatica were observed. Most species (5) were observed in stems 1−3 cm in diameter: Phaenops formaneki Jacobs, Anthaxia quadripunctata (L.), Chrysobothris igniventris Reitt, P. fasciculatus, and P. bidentatus. P. castaneus occurred over the entire height of the stems. The share of natural enemies of P. castaneus was negligible – less than 3%. In this group of insects, the parasitoid Coeloides melanostigma Strand was the most numerous (1.4%), followed by the predators Crypturgus pusillus (Gyll.) and Corticeus linearis (Fabr.), both with 0.5% share. The results indicate that predatory insects and parasitoids have little influence on the number of P. castaneus. Several beetles and larvae of Hylobius abietis (L.) were reared from the roots of trees colonized by P. castaneus. This publication is the first report on the occurrence of this species on weakened but still living P. sylvestris young trees.
Key words: co−occurrence, Hylobius abietis, natural enemies, reforestations, pine weevils, thickets