The most extensive study to be carried out in Poland, and one of only a few worldwide, regarding the influence of location, tree age and forest habitat type on the basic fuel properties of silver birch (Betula pendula Roth.) wood was conducted in 12 Forestry Districts of the Polish State Forests. The field study included trees in three age groups of approximately 30, 50 and 70 years. The research was carried out in a fresh broadleaved forest (FBF) habitat type, where in Poland silver birch stands predominate in respect of coverage area and merchantable volume. Additionally, for five selected Forestry Districts, a comparative study was conducted in a fresh mixed broadleaved forest (FMBF), the second most important habitat of this tree species. A total of 306 test trees were examined. For every sample, calorific value and contents of ash, carbon, hydrogen, nitrogen, sulphur and chlorine were determined. The results indicated a statistically significant influence of location on the calorific value (p = 0.0001) and on the contents of ash (p < 0.0001), carbon (p < 0.0001), hydrogen (p < 0.0001), nitrogen (p < 0.0001) and chlorine (p < 0.0001) in the analysed wood. Moreover, statistically significant differences were observed between values of ash content (p = 0.046) and of calorific value (p = 0.0026) depending on the forest habitat type. Tree age was found to have no significant influence on the calorific value of silver birch wood.

The article presents the results of a so far most extensive study on the effect of tree age on variation of the chemical structure of silver birch wood carried out in Poland. Field studies took place in 12 forestry districts distributed throughout the country. In each district, study sites were selected with stands aged approximately 30, 50, and 70 years in fresh broadleaved forest habitats, as well as in five districts in fresh mixed broadleaved forest habitats. Analyses were made of the contents of substances soluble in cold and hot water, ethanol and 1% NaOH, as well as the contents of cellulose, lignin, pentosans and ash, and the pH, of wood from 306 silver birch trees. Tree age was shown to have a significant effect on the contents of cellulose, pentosans, ash, and substances soluble in 1% NaOH. In the case of the other characteristics, age was found to have no significant effect. The cellulose content was lowest in 30-year-old stands and increased with tree age. Similar observations were made regarding ash content. Contents of pentosans and substances soluble in 1% NaOH were highest in the wood of the youngest trees. Since birch wood is used by the pulp and paper, board and energy industries, the knowledge of its chemical composition, depending on the age of the trees, can be of potential practical importance for its further application.

We report on the most extensive study to date in Poland concerning the variability in the chemical composition of silver birch (Betula pendula Roth.) wood depending on the forest habitat type and the location of the forest stand. The research was carried out in 12 forest districts, on two habitat types where silver birch forest stands predominate in respect of coverage area and merchantable volume. Chemical composition analysis was performed on 51 samples from 306 test trees aged approximately 30, 50 and 70 years. In the examined sample material, the sum of the main chemical components for individual locations varied from 89.26 to 91.57%. The content of substances soluble in water and ethanol ranged from 2.30 to 4.03%, and the ash content was measured at between 0.09 and 0.25%. The results showed that the location had a significant influence on the contents of substances soluble in cold water (p = 0.0015), hot water (p = 0.0005), ethanol (p \ 0.0001) and 1% NaOH (p = 0.0014), as well as on the contents of cellulose (p = 0.04), lignin (p = 0.002), pentosans (p = 0.04) and ash (p \ 0.0001) and on the pH value (p \ 0.0001). Notable influence of location on the contents of secondary constituents of birch wood, especially those extractable with water and ethanol, was recorded for the test plots in north-eastern Poland. The obtained results may form a basis for assessment of the industrial utility of birch wood, as well as the optimisation of traditional methods of utilisation and the development of new such methods that are ecological and sustainable.

This work contains the preliminary results of research into the technical quality of the wood from Scots pine trees of diverse genetic origin, grown on an experimental plot at the Forest Experimental Station in Rogów. The following are the parent stands, numbered: 5 (the Tucholskie Forest 130 m a.s.l.), 7 (the Napiwodzko–Ramuckie Forest 145 m a.s.l.), 10 (the Piska Forest 145 m a.s.l.), 12 (the Biała Forest 95 m a.s.l.), 13 (the Namysłowsko–Ostrzeszowskie Forest 190 m a.s.l.), 15 (the Knyszyńska Forest 165 m a.s.l.), and 16 (the Nowotarskie Forest 590 m a.s.l.). The tested wood was obtained in 2018 from trees aged 52 years. The research material came from 100 trees in total. After felling, two logs approximately 0.5 m in length were cut from each tree. The height on the tree from which the material was taken ranged from breast height (1.3 m) to approximately 2.5 m. Next, planks were cut from the logs in a north–south direction; these were precisely described and then left to season. The work included the measurement and statistical analysis of one physical property, wood density (kg/m3), and of the following mechanical properties: compressive strength along the fibres, Rc12 (MPa); static bending strength, Rg12 (MPa); modulus of elasticity under static bending, Eg12 (MPa); and indices of strength quality of the tested mechanical properties, JRc12, JRg12, and JEg12 (km). The origin of the logs was shown to have a significant influence on wood density, compressive strength, static bending strength, and modulus of elasticity under static bending. The highest mean density was found for trees originating from stand 10 (537 kg/m3). The highest values of compressive strength were obtained for trees originating from stands 5 (45 MPa), and the highest static bending strength and modulus of elasticity under static bending were obtained for trees originating from stand 12 (102 and 9825 MPa, respectively).

This work presents the findings of a study concerning variability in the basic density of silver birch ( Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m) and in Giżycko forest district on the FMBF habitat type (548 kg m). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.Betula pendula–3–3

A timber market occupies a very particular position within the economic reality. Trading of commodities such as precious timber is, indeed, strongly conditioned by the carrying capacity and the silvicultural potential of the forest ecosystem. Timber markets in Poland are characterized by a controlling position of the State Forests, and one of the possible forms of wood sale is the system of submission. A submission usually implies that small quantities of wood with unusual features are being offered to a specific group of customers. The paper presents the sale results and prices of veneer wood commercialized in submission systems and in other forms of timber sale in the territory of Krosno during the years 2000−2019. It is one of the oldest submission markets in Poland, where the most expensive log ever in Poland was sold (13,000 USD/log—close to 7000 USD/m3). The Regional Directorate of State Forest (RDSF) of Krosno is located in the south-eastern part of Poland and manages a forest area of approximately 400,000 hectares. Annual timber harvesting amounts to 2 million m3, of which less than 2000 m3 annually is allocated to the submissions. The data cover a 20-year continuous time series and allow tracing changes in the wood volume offered to the market, the species population structure, and price trends for individual species. The data are being discussed against the background of the economic situation and in relation to the average prices obtained from other methods of sale. Beech was the most sold, but the demands for oak and sycamore appeared to be particularly high during the period of observation. The unity prices can be very variable even for wood from the same species, especially for sycamore. The prices are generally demand-driven and show strong influences from furniture industries and fashion. A rising demand for high quality timber and logs of big dimensions has been noticed. The submission system results in substantial economic benefits for the forest management and the region as a whole.

Struktura włókien drewna brzozy brodawkowatej (Betula pendulaRoth.) w północno-wschodniej Polsce

The subject of the research, which is the Polish managed part of Białowieża Forest together with Białowieża National Park, a remnant of primeval forests, is one of the most valuable forest areas in Europe. This article presents the history of the use of these forests. The assortment and species structure of the harvested timber was analyzed in detail for the Białowieża, Browsk, and Hajnówka Forest Districts from 2008 to 2017. The research is based on data from the State Forests Information System (SILP) and Forest Management Plans (PUL), as well as Nature Conservation Programs (POP). The volume of harvested timber was diversified. In 2011–2013, it was limited by a decision of the Minister of the Environment from 110,000 m3 in 2010 to 48,500 m3. This contributed to the increase of the European spruce bark beetle gradation, causing the death of spruce stands. By an annex to the Forest Management Plan issued in 2016, the Minister of the Environment increased the amount of the timber harvest. In 2017, it amounted to almost 190,000 m3, where 91% of the harvested volume was spruce, but the wood was markedly inferior in technical quality compared to previous years. Such a large increase in harvesting aroused the opposition mainly of environmental organizations and the European Commission. In April 2018, the EU Court of Justice decided that Poland violated EU law by increasing the number of felled trees in Białowieża Forest. After this decision, the Minister of the Environment repealed the earlier decision, the basis for conducting the increased wood harvesting in Białowieża Forest. Changes in the timber harvested in terms of volume, quality, and assortment, are due to the specificity of managing environmentally valuable areas. This relates to the many limitations on commercial forestry, which must take into account the need to protect nature and the legal acts regulating timber harvesting.