Abstract: The density of seedlings in a nursery affects their growth parameters and subsequently their adaptation to the growth conditions of their planting sites. Density is especially important in the case of deciduous seedling species, such as pedunculate oak, as it significantly influences their size and leaf size during the production season. The research was conducted in 2015 and 2016 at the container nursery in Nędza (Rudy Raciborskie Forest District). The aim of the study was to investigate the effect of reduced density on the growth of pedunculate oak seedlings in Hiko V265 containers. Approximately three months after sowing in each container the seedlings were sorted into tall (TS) and short seedlings (SS). Subsequently, the TS seedlings were transferred to a new container until reaching 50% capacity. This provided double the growing space for the transplanted seedlings in the second half of the production season. Each year seedlings were analyzed at 14 dates in total in two−week intervals. During the first five dates one container was selected, and after sorting, two containers (one with TS and one with SS) were selected during the remaining nine dates. On each date seedling height, root collar diameter, the dry weight of the roots, shoots, leaves, and total seedlings were measured. Each seedling was assessed to determine three indices of its breeding suitability including: sturdiness quotient (SQ), shoot−to−root ratio (S/R) and Dickson quality index (DQI). The study found that the SS seedlings that were retained in the container after sorting were on average characterized by a lower height and root collar diameter than the TS seedlings. However, by the end of the production season the SS seedlings reached the required quality class. Both the sorted seedling groups exhibited a comparable sturdiness quotient and shoot−to−root ratio during the growth season, whereas only the TS seedlings had a higher Dickson quality index. Overall, the study results support the idea of reducing seedling density in a container during the production season by transferring the tallest seedlings to new containers. This procedure significantly increased the number of good−quality seedlings (by more than 100%) compared to the method without this process.
Key words: growth, Hiko container, quality indicators, seedling efficiency

Abstract: Engraver beetles Ips spp. (Coleoptera: Curculionidae: Scolytinae) are one of the main factors causing tree dieback in European forests. During the last 50 years, Ips beetles killed more than 150 million m³ of forest in Europe, affecting ecosystems on a large scale and causing significant economic losses. In this paper, we investigated the relationship between the habitat disturbance of pine tree stands and the effects of pine engraver beetles infestation resulting in tree crown dieback. We utilized a UAV equipped with a SENOP multispectral camera, which captured images at a resolution of 10 cm, to accurately ascertain the extent of pest infestation. We mapped the tree stands in the Miradz Forest District (Poland) planted on sites formerly drained by the Konin lignite mines. We examined the undergrowth vegetation in varying habitat conditions to assess the habitat degradation level. In transects 50 meters wide we identified clusters of trees infested by the engraver beetles. We found the fertile oak−hornbeam forests to be most sensitive to the infestation of Ips engraver beetles. The probability of expansion in those habitats is 2−3 times higher than in a nutrient−poor pine forest. Susceptibility to the expansion of the Ips beetles increases with the disturbance level of the undergrowth and the presence of non−forest plant species, mainly from the Epilobietea class, followed by the disappearance of species associated with preserved habitat continuity – ancient forest species. UAV monitoring and vegetation data indicating habitat degradation level can be helpful tools for successful monitoring and prevention of infestations by Ips beetles.
Key words: biodiversity, forest degradation, insect pest monitoring, Ips outbreak, unmanned aerial vehicles

Abstract: To examine effects of soil drought stress on the production of potentially stress−related compounds in current−year seedlings of Fagus crenata, we collected seeds from two sites in the northern region of mainland in Japan. We then germinated and grew them in well−watered (watered once every two days) or water−stressed (no watering) conditions in an environmental chamber for ca. two weeks. The concentrations of biochemical compounds in leaves were estimated to be in the range 0.81−3.44 µmol/gDW and 2.70−5.73 mg/gDW for free−proline and total flavonoids, respectively. Negative associations were found between the seedlings’ height at the start of the experiment and concentrations of free−proline and total flavonoids in leaves. After accounting for the effect of height, there was no significant difference between the two sites with respect to the concentrations of free−proline and total flavonoids in leaves of seedlings. The concentrations of free−proline in leaves of seedlings from both sites were higher under water−stressed conditions than in wellwatered, whereas there were no differences between the two conditions for total flavonoids, irrespective of sampling site. These results suggest that the concentrations in leaves vary depending on biochemical compounds examined as well as properties of individual plants relating to their metabolism, and that free−proline participates, at least in part, in a rapid acclimation response to short−term drought stress in current−year beech seedlings.
Key words: Fagus crenata seedling, free−proline, growth experiment, soil drought, total flavonoids

Abstract: Pine marshy forests Vaccinio uliginosi−Pinetum Kleist 1929 are associations included in Natura 2000 areas. They are at the highest risk of dismemberment due to global climate change. The study assessed the possibility of regeneration and genetic variability of Scots pine in a marshy forest habitat. The research was carried out in the Polesie National Park on the Durne Bagno and Lake Moszne peatbog. In the examined locations the phytocenosis of pine marshy forest was characterized. Subsequently the density of pine seedlings was estimated and their height measured. The genetic variability of the pine regeneration was estimated using the ISSR technique. Based on the research results, it was concluded that the regeneration potential of pine was low. On average, 200 regeneration plants were inventoried per hectare, and their average height was 26.34 cm. Significantly more pine regeneration was recorded (123 plants) in Lake Moszne, with an average height of 6.99 cm. By contrast, only 36 pine trees were inventoried in Durne Bagno, but their height was 45.69 cm. Scots pine genetic variability was similar in both locations. The percentage of polymorphic loci was 74.24. The average number of alleles per locus reached 1.685 and the effective number of alleles per locus was 1.405. The expected heterozygosity and Shannon index were 0.239 and 0.362, respectively. The phytocenosis was scarce, but characteristic of the Vaccinio uliginosi−Pinetum habitat. In total, 17 species were inventoried, of which 11 occurred in both locations. Light, humidity and habitat fertility indices were characteristic of this type of habitat and amounted to 6.98, 7.70 and 1.53, respectively. No relationship between undergrowth vegetation and the Scots pine regeneration was found. A negative effect of bog blueberry Vaccinium uliginosum L. on the number of pine regeneration was demonstrated only in the Durne Bagno location. Shading of the tree and shrub layer did not suppress the growth of Scots pine regeneration or undergrowth vegetation. Based on the study results, we concluded that the current state of preservation of pine marshy forests in the Polesie National Park was satisfactory. The presence of pine in the shrub layer allowed to conclude that the survival of seedlings in pine marshy forests was possible and could lead to their transition to the next developmental phases. However, as a result of the ongoing climate change and those predicted in the near future, we recommend constant monitoring of the habitat in order to maintain its sustainability.
Key words: conservation, genetic variability, ISSR markers, natural regeneration, Pinus sylvestris, Vaccinio uliginosi−Pinetum

Abstract: The forests of Świętokrzyski National Park are an example of changes in tree species composition of stands which mainly occur spontaneously. The main forest−forming species in this area was the European silver fir Abies alba Mill. with a mixture of European beech Fagus sylvatica L. Both species seem to be beneficiaries of the climate changes occurring in this part of Europe: an increase in average temperature with a slight decrease in precipitation in upland and mountainous areas. This study aimed to analyse the changes occurring in the species compositions of stands in Świętokrzyski National Park from 1925 to 2014. As data from long−term studies of permanent sample plots characterising changes in the park area were not available, we used 299 random sample points distributed evenly over the study area and stand descriptions in which the points were located during the inventory periods. Inventory data from the years 1925, 1954, 1971, 1997 and 2014 were used. Data from the forest management plans were compiled into a database and processed to determine the role of species in each stand layer to indicate the forest−forming role of the species. The forest−forming role of the two species studied was linked to the forest habitat type, moisture variant, forest type and forest condition. Spatial analysis was based on a numerical terrain model, from which derived layers were calculated and their scores were attributed to their forest−forming role. An attempt was also made to analyse the relationship of the forest−forming role with a topographic moisture index, but no significant results were found for the generalized data within the boundaries of the forest stands. The widespread and persistent dominance of fir in the forest ecosystems of the study area was confirmed. In the case of beech, a correlation between its forest−forming role and altitude was observed. Up to a height of 480 m above sea level, its forest−forming role increases and then decreases at higher elevations. The results can be used to project the extent of regeneration of fir and beech forests in the Świętokrzyskie region.
Key words: European beech, forest habitat type, map analysis, Silver fir

Abstract: Pedunculate oak and sessile oak Quercus robur and Q. petraea are of significant economic importance in Central Europe, but they are also species with an important ecological function. Therefore, forest management in oak forests should consider both timber production and environmental goals. The aim of the present study was to assess the occurrence of valuable Natura 2000 forest habitats in managed oak forest stands, the distribution and connectivity of their patches, and also the age of the oak stands. The analyses included forest stands with a dominance of native oak species located in SW Poland. Spatial analysis was performed with ArcGIS 10.7 software, and the age of trees was analysed with Statistica 12. In total, 66% of the area of managed oak stands was occupied by Natura 2000 habitats. The largest area was recorded for oak−hornbeam forests (9170), and the smallest for oak steppic woods (91I0). The area of Natura 2000 habitats was similar within and outside Special Areas of Conservation (SACs). The oak stands that did not represent Natura 2000 forest habitats had a larger area outside the SACs. Moreover, oak stands representing Natura 2000 forest habitats formed a greater number of forests larger than 5 ha. Oak stands not representing Natura 2000 forest habitats were more fragmented and dispersed. The mean age of trees in oak stands was significantly higher for Natura 2000 habitats. Forest stands of most oak−hornbeam forests (9170), acidophilous oak forests (9190) and oak steppic woods (91I0) were older than 80 years. Riparian mixed forests (91F0) were more frequently represented by younger forest stands. The study revealed that the old−age oak stands which formed larger and more compact forests, mainly within SACs, were the most valuable within managed oak stands. These forest stands mostly represented Natura 2000 habitats. However, the coherence of the Natura 2000 network was also improved by the Natura 2000 habitats located outside SACs. As a result of forest stand logging and regeneration, patches of Natura 2000 habitats are expected to lose their specific structure and functions. Therefore, it is important to preserve at least fragments of old forest stands to facilitate the regeneration of the forest community. The ranges of Natura 2000 habitats should be designated based on the presence of model habitat patches and the surrounding vegetation representing dynamic phases of plant communities.
Key words: forest fragmentation, native oak species, natural habitats, old forest stands, Special Areas of Conservation