This article presents the results of laboratory examinations concerning the effects of soil bulk density on the growth of sessile oak Quercus petraea Liebl. seedlings. The soil for the study was collected from a nursery plot and then compacted into PCV pots in eight different bulk density levels ranging from 0.81 to 1.32 g cm -3 . Oak seedlings were cultivated in controlled conditions for 76 days after sowing. The growth and mass parameters of particular seedlings together with the parameters of the assimilation apparatus and roots were measured, taking into account the share of various diameter roots in the root system. For the purpose of the experiment, 120 acorns were sowed, of which 73 seedlings were cultured. An analysis of the growth of the sessile oak seedlings revealed that a change in soil density significantly affected root system development, total height of seedlings and dry mass. It was observed that the dry mass of the root system as well as the area and length of the roots decreased with an increase in soil density. Root system reduction was noted, the size of which determines the proper development of the tree and ensures its stability. Besides a decrease in the root system, an increase in soil compaction also resulted in a reduction in the number of roots of a specified diameter. The first to be affected were the smallest roots, i.e., those with diameters up to 0.2 mm, which are responsible for the uptake of mineral components. It was confirmed that even a slight increase in soil compaction might negatively result in the growth of young seedlings, impeding root system development.

The paper presents the results of an analysis of the influence of soil bulk density in a forest nursery plot on the growth and quality parameters of Scots pine and European beech seedlings. Particular density variants were obtained using a tractor device exerting controlled pressure on the soil, while field examinations were performed on an area of ‘Kłaj’ forest nursery in Niepołomice Forest District. Three series of plots were prepared for each species, applying a unit pressure of the values of 50, 100, 150, 200, 250 kPa, corresponding to the dry bulk density in the range of 1.03-1.19 g cm-3, and control plots without the pressure. Seeds of the examined species were sown on the prepared plots, and after 6 months of growth the seedlings were subjected to biometric analysis determining differentiation in root neck diameter, length of the above-ground part and root system, as well as dry mass of particular parts of the plant. The quality of the seedlings was also determined using the method of Schmidt-Vogt. The results obtained show that the change in dry bulk density soil significantly affected most of the growth parameters of the examined seedlings. Especially high negative correlations were obtained for the length and dry mass of the root system. A significant influence of dry bulk density variant on all growth parameters of Scots pine seedlings, and on some parameters of European beech was demonstrated. An increase in soil bulk density clearly caused also a deterioration of European beech seedlings quality

This research was carried out on two experimental plots located in the Rymanów and Nawojowa forest districts. In the second and fifth year after planting, at three and six years of age respectively, survival and height of 25 beech progenies of selected seed stands were measured. Furthermore, we show the effect of beech origin and growth environment (significant ‘provenance × block’ and ‘provenance × test plot’ interactions). Beeches from both experimental plots differed significantly in growth and survival and this difference increased with tree age. The highest provenance heritability was obtained for the tree height after two years of growth in Rymanów. In Nawojowa, the heritability of beech survival reached zero after five years of growth. An evaluation of the stability of beech provenances (genotypes) in terms of survival and height under the habitat conditions of our experimental plots was done using the Finlay and Wilkinson method. The beech provenances of 469- Nawojowa and 452-Lesko (regional standard) were included as a stable basis for reference. A high degree of stability and high average values for the characteristics investigated indicate high progeny quality within these stands.

The effectiveness of different peat-based substrates was compared for the propagation of two mountain tree species (silver fir and European beech). The experiment was set up in the spring of 2006, and seedlings were grown in polystyrene multipots for 2 years. Four types of substrate were applied: (1) a newly prepared 1:1 peat-sawdust mixture; (2) a peat-sawdust mixture which had already been used for five production periods; (3) a peat substrate produced in the ‘Nędza’ container nursery (Rudy Raciborskie Forest District), consisting of peat and perlite; (4) a peat substrate, as described for (3), with added mycorrhizal fungus Hebeloma crustuliniforme. After sowing, polystyrene multi-pots were placed in a transparent tent. During the autumns of 2006 and 2007, for both species and each substrate type, 25 seedlings were randomly selected for measurement of their above-ground height, root length, root collar diameter, above- and below-ground fresh weight. Growth of one-year old and two-year-old seedlings of both species differed depending on their substrate. The application of a mycorrhizal inoculum positively affected seedling establishment, since the best height growth and largest seedlings of both species were grown on substrate (4). The growth of one-year-old fir seedlings in the ‘old’ peat and sawdust mixture (2) was similar to those seedlings grown on the turf substrate (3). Root:shoot allocation differed among the substrates. In fir, root:shoot allocation was approximately equivalent at 1:0.9, whereas for beech it was 1:2 in one-year old seedlings and 1:1.5 in two-year old seedlings.

For the period from the 1st of May to the 30th of October 2014, the water balance for Scots pine, Norway spruce, Pedunculate oak and European beech seedlings in a plantation setting was analysed. The experiment was conducted at the container nursery in the Rudy Raciborskie Forest District, Poland. Water was supplied by natural rainfall as well as a by small-droplet irrigation system and two automatic weather stations combined with 32 rain collectors were used to monitor rainfall throughout this research. Rain gauges were located 25 cm above the metal pallets and 10 cm below the nursery containers. An average of 987 mm∙m−2 of water reached the plantation, of which 53% were provided by the irrigation system. Most water was supplied to the oak field, whereas least was given to the spruce plantations and the irrigation water amounted to 535 liters and 422 liters per square meter, respectively. The amount of water percolating through the substrate was approximately 50–65%, depending on the tree species. An average sum of evapotranspiration at the container nursery was estimated to amount to 520 mm∙m−2 during the growth season leading to a total water balance of +463 mm.

In the past, the entire region of Poland was overgrown by forests. Due to economic changes, the forest cover was reduced to 40% in the 18th century and 21% after the Second World War. After the war, Polish foresters undertook considerable efforts to increase the forest cover to 30.8% by 2015. Polish forests are characterized by the dominance of oligo- and mesotrophic coniferous species (68.7%). This include the pioneer species, Scots pine. It covers approximately 60% of the area. The species composition of Polish forests determined the dominance of artificial regenerations. However, the currently prevailing direction of forest culture is natural regeneration. This tendency is related to “greening” of the forest management, the priority of durability over productivity and culture of multifunctional forests. A natural or seminatural direction of forest culture is being promoted. Renewal of the species such as fir, beech, oak, or spruce from the last stages of succession have always taken place in a natural manner, whereas the statistics are generated by the dominant species preferring open areas during renewal. Currently, the scale of natural regenerations of the pine is increasing. It is increasingly common to value the favorable economic aspect of natural renewal of the species, and the experience of practitioners supported by scientific research increase the likelihood for success. In Poland, the majority of methods of regeneration proceedings (forest cutting) and the law are directed at obtaining and promoting natural renewal. Independent of the concept of natural renewal promotion, the location of Poland in the intermediate climate zone, between the influence of oceanic and continental climates, resulted in the formation of valuable tree stands with high flexibility and tolerance to growth conditions. They are divided into seed stands, excluded stands, and timberlands. Thus, Poland is in possession of a great base for seed collection. At the beginning of 1990s, a rapid need for container seedlings occurred due to numerous disasters (wind-broken trees, gradations). Currently, in Poland, 17 field nurseries are in operation producing 1–10 m seedlings. In 1992, Poland received a loan from the World Bank to conduct afforestations and the “National Program for Increasing the Forest Cover” was started. The main objective of the plan is to increase the forest cover to 30% in 2020 and 33% in 2050. Within the program, it is planned to include vegetation of the natural succession in the area of approximately 80,000 ha.

ABSTRACT:The present paper is about the provenance and family diversity of insect occurrence on the offspring of 58 pedunculate oak (Quercus robur L.) trees representing 5 populations from the Polish range of species. Researches were conducted on the Chrostowa II test plot, located in the Brzesko Forest District (southern Poland). Differences in symptoms of trees inhabitation by Andricus kollari (Hartig, 1843) ♀♀, Andricus lignicolus (Hartig, 1840) ♀♀, Andricus foecundatrix (Hartig, 1840) ♀♀, Biorrhiza pallida (Olivier, 1791) ♀♂, Andricus inflator (Hartig, 1840) ♀♂, Andricus conglomeratus (Giraud, 1859) ♀♀, Andricus quercusradicis (Fabricius, 1798) ♀♀, and Lachnus roboris (Linnaeus, 1758) were evaluated. Approximately 45% of oaks grown at the test site were damaged. The majority of trees were inhabited by A. kollari (35.7%) while the lowest number of trees was inhabited by A. inflator, A. conglomeratus and A. quercusradicis (0.1%). Analysis of variance showed that certain species prefer the offspring of certain provenances. Also a high diversity among families within provenances was found. The effect of the family and provenance was statistically significant on oaks with galls caused by A. kollari, A. foecundatrix and B. pallida share. High heritability values were obtained for A. kollari on the population and family level (0.86 and 0.70 respectively) and for the rest of the species only on the provenance level. The presence of L. roboris was greatly influenced rather by environmental than genetic factors, also being characterized by low heritability values.

Abstract. Phytophthora cambivora (Straminipila, Oomycota) causes root rot and stem canker on several deciduous tree species in Europe. However, very little is known about the variation in susceptibility to P. cambivora colonisation among provenances and families of pedunculate oak (Quercus robur L.). We studied variation in susceptibility of one French and 16 Polish provenances, representing 62 families. Samples were taken from three test plots located in the Brzesko Forest District. Oak susceptibility to P. cambivora was assessed by measuring lesion length following inoculation of excised shoots with two isolates of P. cambivora. There was significant variability in susceptibility among the 17 provenances tested. The highest susceptibility to P. cambivora was apparent in several provenances including Tronçais, Zaporowo, Runowo, Opole and Krotoszyn; while the most resistant provenances originated from Chojnów, Siedlce, Płock, Krotoszyn-90 and Wioska. There was also significant within-provenances variation in susceptibility to P. cambivora.