The heat supply systems energy efficiency improvement requires the use of increasingly complex methods. The basic ways to reduce heat consumption is by using better thermal insulation, although they have more and more limited possibilities and need relatively large financial outlays. Good effects can be achieved by the better heat source adaptation to the conditions of a specific facility supplied with heat. However, this requires research that identifies the effectiveness of such solutions as well as the tools used to describe selected elements of the system or its entirety. The article presents the results of tests carried out for a gas boiler room supplying heat to a group of residential buildings. The goal was to build a model that would forecast the day range in which the maximum gas consumption occurs for a given day. Having measurements of gas consumption in subsequent hours of the day, it was decided to build a forecasting model determining the part of the day in which such a maximum would occur. To create the model the random forest procedure was used along with the mlr (Kassambara) package. The model’s hyperparameters were tuned based on historical data. Based on data for another period of boiler room operation, the results of the model’s quality assessment were presented. Close to 44% efficiency was achieved. Tuning the model improved its predictive ability.

We talk to Dr. Bogdan Jaroszewicz, head of the Białowieża Geobotanical Station of the University of Warsaw, about how planned logging in the Białowieża Forest will damage not only the forest itself but also Poland’s image around the globe.

Wherein lies the essence of the two-year dispute over the management and protection of the commercial forest stands in the Białowieża Primeval Forest?

Turning conflict into cooperation.

Forest stand decomposition of the Silesian Beskids which is followed by the tree cutting has been observed since the beginning of the 21st century. Changes in forest management due to the introduction of heavy machines for forest work mainly for skidding have been observed in the Silesian Beskids for the last decade. The paper presents results of a three-year investigation of erosion gullies forming in mountain forest after the skidding performed with use of heavy equipment. In the Wilczy Potok catchment comprising an area of above 100 ha 40 gullies were identified. The measurement of the length and depth of gullies showed that the total volume of soil and rock material removed from the catchment area due to erosion accelerated by skidding exceeded 9 000 m3. The year erosion rate for deep gullies was found to be 10%. The presented results show that necessary protective actions and preventive measures should be taken to mitigate the soil degradation processes.

Celem pracy było poznanie zawartości Mn, Zn, Cu, Pb, Ni, Cr, Cd w glebach leśnych Parku Krajobrazowego "Podlaski Przełom Bugu". Badania pierwiastków śladowych w glebach były prowadzone na obszarze rezerwatu "Lęg Dębowy" oraz "Stary Las". Zawartość pierwiastków śladowych oznaczono metodą ASA w roztworze uzyskanym po mineralizacji prób glebowych w mineralizatorze mikrofalowym w stężonym kwasic azotowym oraz 30% nadtlenku wodoru. Badane gleby nic są zanieczyszczone metalami ciężkimi. Średnia geometryczna zawartość pierwiastków w badanych glebach tworzyła następujący szereg: Mn (229) > Zn (23, I) > Pb ( 15,0) > Cr ( 11,6) > Cu (7,4) > Ni (6,4) > Cd (0, 11) mg-kg:' s.m. Stwierdzono, że pierwiastki śladowe kumulowały się głównie w poziomach organicznych i mineralno-organicznych. Analiza statystyczna wykazała wysoce istotne korelacje pomiędzy badanymi metalami a zawartością części splawialnych i iłu koloidalnego oraz pomiędzy zawartością Mn, Zn, Cu, Pb, Cd a węglem organicznym.

Almost half (47%) of Latvian forest areas (3611 thousand ha) are considered degraded or partly improved by the hydro-technical drainage. The degradation is caused by very poor soil aeration due to waterlogged conditions. The location of waterlogged forests in Latvia is neither uniform nor occasional. Comparison of the abundance of waterlogged forests and the amount of atmospheric precipitation showed that the waterlogged forests are mainly located in areas with least precipitation. This hydrological phenomenon is connected with water discharge in drainage ditches: even during the dry summers of the years 1963, 1964, 1975, 1976 and 2002 in the drained forests with deep peat soils water flowed continuously in 1 m deep ditches and the discharge exceeded the amount of precipitation. Using the data from 182 sample plots in drained forests with the peat layer depth of 4.2 m, it was found, that coniferous forests are most productive in areas where the peat layer is most dense. One of the possible explanations for this phenomenon is that the most intensive paludification and formation of most dense peat layer are characteristic for the areas with intensive water discharge from confined aquifers. This discharge provides necessary mineral nutrients for the forest soil regardless of the peat layer thickness. The forest productivity may increase several times due to the enhancement of water movement in soil and to improved soil aeration by hydro-technical drainage. Also the flow regime of rivers connected with the drained areas changes considerably, mitigating extremely high and low flow events.

The human factor in Białowieża.

When ordinary people visit Poland’s forests, they are most afraid of encountering a big mammal – a wolf, boar, or bear. But the greatest dangers are actually posed by more inconspicuous animals: ticks and snakes.

On the need to change perceptions of the Białowieża Primeval Forest’s value.

How do bark-beetle outbreaks begin, how do they spread? What are the key factors that affect their population dynamics? Ongoing research has provided some understanding and knowledge, although many questions still remain to be answered fully.

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

The study of groundwaters was carried out in two different forest ecosystems of Słowiński National

Park: Vaccinio uliginosi-Betuletum pubescentis and Empetro nigri-Pinetum in the period of 2002-2005. Differences were found in the position of the groundwater table and in the concentrations of nitrogen and phosphorus

compounds in the investigated forest associations. In the Vaccinio uliginosi-Betuletum pubescentis association

the groundwater table was found on average at a depth of -73.3 cm, while in Empetro nigri-Pinetum at -90.2

cm. No statistically significant effect of precipitation on the position of the groundwater table was found in

this study. Statistical calculations (U Mann-Whitney test) for groundwaters in the analyzed forest associations

showed statistically significant differences in the dynamics of concentrations of total nitrogen (T-N), organic

nitrogen (Norg.), nitrate nitrogen (N-NO3

), total phosphorus (T-P), organic phosphorus (Porg.) and the level of

groundwaters.

The aim of the research was to study the influence of different tree stands on topsoil magnetic susceptibility and heavy metal contamination in the soil. The study was performed in the old park in Pruhonice (near Prague) in the Czech Republic. On the relatively small area of Pruhonice Park, five different coniferous tree species (pine, spruce, blue spruce, fir, Douglas fir) and five deciduous species (beech, red oak, common oak, hornbeam, birch) were found, growing in small clusters on the same geological background. Also other natural and anthropogenic factors such as distance from industrial and urban sources of pollution, type of soil, climate, etc. were similar. The magnetic susceptibility was measured directly in the field. Twenty topsoil cores 0.3 m long (2 under each tree species) were collected and also soil samples from under each tree (litter horizon) were taken. The magnetic susceptibility values of the topsoil profiles and of litter layer samples were obtained. Heavy metal analyses of surface samples (litter horizon) were also carried out. The field magnetic susceptibility (K) data are more or less comparable to the laboratory data (x). High heavy metal contents corresponding to high magnetic susceptibility values are observed in the litter horizon. A positive correlation between magnetic susceptibility and some heavy metals was observed. The results suggest that the type of forest may also influence the values of magnetic susceptibility and heavy metal content. Generally higher magnetic susceptibility values were observed in the coniferous forest, except for the surface layer (litter horizon) where the K values are lower than in the deciduous forest.

Forests may play important role in partial neutralization of CO2 emission. To maximize their potential it is unavoidable to divide them into forests that will be allowed to evolve toward natural state and forest predisposed for timber production, supplemented with forest plantations. Natural forests store almost twice more carbon in biomass and soil than managed forests, and carbon contained in wood from plantations and timber-producing forests will be frozen long time in wooden constructions. Gasification of wood debris instead of burning will allow for production of biocarbon that added to soil will residue there through decades, and will decrease necessary amount of artificial fertilizers, which production is an important source of carbon dioxide. Forests evolving to natural state will be less prone to fire and hurricanes, and will better protect biodiversity. Presented project is not contradictory to the project “The Forest Carbon Farms” of State Forests, but allows to reach better results in shorter time and likely at lower cost.

Treating a sick forest: evidence-based medicine?

New types of models can help us better predict how well species will be able to adapt to climate change.

Machine learning methods, such as the random forests algorithm, have revolutionized how we analyze growing volumes of data. The algorithm can be usefully applied in studying… real forests.

How can we best describe the living space of given species? Are geographical criteria sufficient, or do we need more dimensions to specify an ecological niche? What can we learn from such analyses?

The story of bark-beetle outbreaks in the Šumava National Park, in the Czech Republic along the German and Austrian borders, provides some insight into the impact of stable/unstable zonation regimes on efforts to fight the beetle, as well as a better understanding of what may be described as the “paradoxes of sanitary cutting.”

Professor Krzysztof Spalik, Chairman of the PAS Committee for Environmental and Evolutionary Biology, tells us why the Białowieża Forest should be allowed to renew itself on its own.

The aim of the study was to specify the current status and direction of transformations of leaf beetle assemblages taking part in the rapid process of succession of vegetation towards the types of forest communities occurring in the Krzemionki Opatowskie reserve. At five sampling sites (in five plant associations) 30 species of Chrysomelidae were recorded. Five typical forest species (Chrysomela populi, Pyrrhalta viburni, Calomicrus pinicola, Altica brevicollis and Cryp-tocephalus labiatus) accounted for 16.67% of the number of species and 12.85% of the number of individuals caught in the reserve. The forest association richest in species (18) was Querco ro-boris-Pinetum (Que_Pin). This was followed by Tilio-Carpinetum association (Til_Car, 15 spp.), and then a mosaic of Tilio-Carpinetum and Querco roboris-Pinetum (Til_Car/Que_Pin), and Peucedano-Pinetum (Peu_Pin) (11 spp. each). The fewest number of species (10) were noted in Potentillo albae-Quercetum (Pot_Que). The most similar were the fauna of Potentillo albae--Quercetum (Pot_Que) and Querco roboris-Pinetum (Que_Pin) (55.08% similarity). The most distinct was the fauna of Peucedano-Pinetum (Peu_Pin). We can conclude that the structure of the leaf beetle assemblages in the forest associations studied in the reserve is at present an adaptive mixture of faunas characteristic of all the intermediate successional stages of vegetation, changing in this area in a relatively short time. The considerable diversity of fauna is the result of an ‘eco-tone in time’, i.e. the continuous presence of open-land species, which until recently had dominated here, accompanied by forest species characteristic of the current habitat types.

Changes in the land use structure, which are observed in recent years, generally indicate their negative impact on ecological quality considered in the landscape scale. Therefore, the aim of this study was to determine whether such a trend also applies to protected areas, such as land-scape parks (LP). As research areas four parks located within the Roztocze and Solska Forest (Poland) were selected. Three factors were analyzed as an surrogate indicators of the ecological quality: the degree of anthropogenic transformation of land cover forms, landscape diversity and the degree of landscape fragmentation. The study included data for the years 2004 and 2012 and was based on the GIS and orthophotomaps analysis. The results showed a lack of general trends for the whole analyzed region. The impact of changes in the land use structure on the ecological values can be defined as positive for Krasnobród LP and South Roztocze LP. In the case of Szczebrzeszyn LP and Solska Forest LP the impact is difficult to determine due to the different results obtained on the basis of selected indicators. Therefore, in order to totally illustrate the analyzed dependence the landscape structure in other periods of time should be analyzed, as well as the correlations between the defined changes and a variety of natural and cultural considerations.

In this study, emulsified kerosene was investigated to improve the flotation performance of ultrafine coal. For this purpose, NP-10 surfactant was used to form the emulsified kerosene. Results showed that the emulsified kerosene increased the recovery of ultrafine coal compared to kerosene. This study also revealed the effect of independent variables (emulsified collector dosage (ECD), frother dosage (FD) and impeller speed (IS)) on the responses (concentrate yield (γC %), concentrate ash content ( %) and combustible matter recovery (ε %)) based on Random Forest (RF) model and Genetic Algorithm (GA). The proposed models for γC %, % and ε% showed satisfactory results with R2. The optimal values of three test variables were computed as ECD = 330.39 g/t, FD = 75.50 g/t and IS = 1644 rpm by using GA. Responses at these experimental optimal conditions were γC % = 58.51%,  % = 21.7% and ε % = 82.83%. The results indicated that GA was a beneficial method to obtain the best values of the operating parameters. According to results obtained from optimal flotation conditions, kerosene consumption was reduced at the rate of about 20% with using the emulsified kerosene.