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Keywords = pine and birch wood

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17 pages, 1783 KiB  
Article
Nature-Based Solutions in Sustainable Cities: Trace Metal Accumulation in Urban Forests of Vienna (Austria) and Krakow (Poland)
by Mateusz Jakubiak, Ewa Panek, Krzysztof Urbański, Sónia Silva Victória, Stanisław Lach, Kamil Maciuk and Marek Kopacz
Sustainability 2025, 17(15), 7042; https://doi.org/10.3390/su17157042 - 3 Aug 2025
Viewed by 70
Abstract
Forests are considered one of the most valuable natural areas in metropolitan region landscapes. Considering the sensitivity and ecosystem services provided by trees, the definition of urban forest ecosystems is nowadays based on a comprehensive understanding of the entire urban ecosystem. The effective [...] Read more.
Forests are considered one of the most valuable natural areas in metropolitan region landscapes. Considering the sensitivity and ecosystem services provided by trees, the definition of urban forest ecosystems is nowadays based on a comprehensive understanding of the entire urban ecosystem. The effective capturing of particulate matter is one of the ecosystem services provided by urban forests. These ecosystems function as efficient biological filters. Plants accumulate pollutants passively via their leaves. Therefore, another ecosystem service provided by city forests could be the use of tree organs as bioindicators of pollution. This paper aims to estimate differences in trace metal pollution between the wooded urban areas of Vienna and Krakow using leaves of evergreen and deciduous trees as biomonitors. An additional objective of the research was to assess the ability of the applied tree species to act as biomonitors. Plant samples of five species—Norway spruce, Scots pine, European larch, common white birch, and common beech—were collected within both areas, in seven locations: four in the “Wienerwald” Vienna forest (Austria) and three in the “Las Wolski” forest in Krakow (Poland). Concentrations of Cr, Cu, Cd, Pb, and Zn in plant material were determined. Biomonitoring studies with deciduous and coniferous tree leaves showed statistically higher heavy metal contamination in the “Las Wolski” forest compared to the “Wienerwald” forest. Based on the conducted analyses and the literature study, it can be concluded that among the analyzed tree species, only two: European beech and common white birch can be considered potential indicators in environmental studies. These species appear to be suitable bioindicators, as both are widespread in urban woodlands of Central Europe and have shown the highest accumulation levels of trace metals. Full article
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28 pages, 4600 KiB  
Article
Utilization of Coniferous and Deciduous Tree and Paper Ashes as Fillers of Rigid Polyurethane/Polyisocyanurate (PU/PIR) Foams
by Joanna Liszkowska, Magdalena Stepczyńska, Andrzej Trafarski, Justyna Miłek and Tomasz Karasiewicz
Materials 2025, 18(5), 1165; https://doi.org/10.3390/ma18051165 - 5 Mar 2025
Viewed by 1319
Abstract
Five series of rigid polyurethane–polyisocyanurate (RPU/PIR) foams were obtained. They were modified by ashes from burning paper (P) and wood: conifers (pine—S, spruce—S’) and deciduous trees (oak—D, birch—B). The ash was added to rigid polyurethane–polyisocyanurate foams (PU/PIR). In this way, five series of [...] Read more.
Five series of rigid polyurethane–polyisocyanurate (RPU/PIR) foams were obtained. They were modified by ashes from burning paper (P) and wood: conifers (pine—S, spruce—S’) and deciduous trees (oak—D, birch—B). The ash was added to rigid polyurethane–polyisocyanurate foams (PU/PIR). In this way, five series of foams with different ash contents (from 1 to 9% wt.) were obtained: PP, PS, PD, PS’, PB. The model foam (reference—W) was obtained without filler. The basic properties, physico-mechanical, and thermal properties of the ashes and obtained foams were examined. It was specified, among other things, the cellular structure by scanning electron microscopy (SEM), and changes in chemical structure by Fourier-transform infrared spectroscopy (FTIR) were compared. The obtained foams were also subjected to thermostating in a circulating air dryer in increased temperature (120 °C) for 48 h. Ash tests showed that their skeletal density is about 2.9 g/cm3, and the pH of their solutions ranges from 9 to 13. The varied color of the ashes affected the color of the foams. SEM-EDS tests showed the presence of magnesium, calcium, silicon, potassium, aluminum, phosphorus, sodium, and sulfur in the ashes. Foam tests showed that pine ash is the most beneficial for foams, because it increases their compressive strength three times compared to W foam and improves their thermal stability. All ashes cause the residue after combustion of the foams (retention) to increase and the range of combustion of the samples to decrease. Full article
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13 pages, 2909 KiB  
Article
Utilization of Pine and Birch Juvenile Wood for Low-Density Particleboard Production
by Rafał Czarnecki, Dorota Dukarska, Jakub Kawalerczyk and Arkadiusz Filipski
Materials 2025, 18(5), 1140; https://doi.org/10.3390/ma18051140 - 4 Mar 2025
Cited by 1 | Viewed by 975
Abstract
This study investigated the effect of using juvenile pine and birch wood for the production of particleboards with lowered density, glued with urea-formaldehyde (UF) resin. The wood used was characterized by a number of annual rings ranging from 5 to 13, which ensured [...] Read more.
This study investigated the effect of using juvenile pine and birch wood for the production of particleboards with lowered density, glued with urea-formaldehyde (UF) resin. The wood used was characterized by a number of annual rings ranging from 5 to 13, which ensured that only juvenile wood was used in the study. In addition to the basic characteristics of the wood particles obtained from this type of raw material, the density profiles of the manufactured particleboards, the internal bond, bending strength, modulus of elasticity, swelling, and water absorption after short-term water exposure (2 h) were also investigated. The results were compared to particleboards made from industrial wood particles from mature wood. It was found that particleboards made from juvenile pine wood exhibited higher internal bond than those made from juvenile birch wood. The bending strength of boards made from both types of juvenile wood was comparable to that of industrial particleboards; however, the modulus of elasticity of the particleboards made from juvenile pine was lower, which indicates reduced stiffness. These particleboards also showed higher swelling and water absorption, which may limit their durability under humid conditions. In contrast, birch boards exhibited lower internal bond, but their bending strength and modulus of elasticity were similar to those of industrial particles-based particleboards. Birch boards also showed slightly better water resistance than pine particleboards made from juvenile wood. However, their swelling remained higher than that of industrial particleboards. Overall, particleboards made from juvenile wood, especially birch, show good potential for further research. Full article
(This article belongs to the Special Issue Modern Wood-Based Materials for Sustainable Building)
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11 pages, 2074 KiB  
Article
Valorization of Forest Biomass Through Pyrolysis: A Study on the Energy Potential of Wood Tars
by Jakub Brózdowski, Magdalena Witczak, Klaudia Sikorska, Izabela Ratajczak, Magdalena Woźniak, Monika Bartkowiak, Grzegorz Cofta, Grażyna B. Dąbrowska and Magdalena Zborowska
Energies 2025, 18(5), 1113; https://doi.org/10.3390/en18051113 - 25 Feb 2025
Cited by 2 | Viewed by 812
Abstract
Forest biomass is a renewable source of environmentally friendly material—wood. However, wood processing generates large amounts of by-products, including branches. These byproducts are often used as firewood; however, they can be used much more effectively. In this study, the pyrolysis of two woods, [...] Read more.
Forest biomass is a renewable source of environmentally friendly material—wood. However, wood processing generates large amounts of by-products, including branches. These byproducts are often used as firewood; however, they can be used much more effectively. In this study, the pyrolysis of two woods, namely birch and pine, was proposed. The liquid products of pyrolysis were studied by FTIR spectroscopy, and the heating value of these products was evaluated. In order to find the optimal pyrolysis temperature from the point of view of the calorific value of the product, the process was carried out at four temperatures: 450, 500, 550, and 600 °C. The liquid product yielded three fractions, from which two were analyzed, namely the dense tar fraction and light liquid fraction. FTIR analysis results clearly demonstrated that samples from different fractions differ from one another, yet the results within the same fraction are remarkably similar. The tar fraction was characterized with a higher gross calorific value between 42 to 50 MJ/kg, while the liquid fraction gross calorific value was between 29 and 39 MJ/kg; in general, pine wood yielded products with higher calorific values. The pyrolysis of small wood industry by-products is an interesting method of utilization, yielding not only a liquid product with good calorific properties, but also a solid product, namely biochar, which may be used in carbon storage or used as a soil amendment. Full article
(This article belongs to the Special Issue Biomass to Liquid Fuels)
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22 pages, 2862 KiB  
Article
Short-Term Ground Vegetation Responses to Fertilization in Latvian Forests: Effects on Species Richness and Diversity
by Guna Petaja, Didzis Elferts, Arta Bārdule, Zaiga Anna Zvaigzne, Dana Purviņa and Ilona Skranda
Environments 2025, 12(2), 47; https://doi.org/10.3390/environments12020047 - 4 Feb 2025
Viewed by 968
Abstract
This study investigated the impact of forest fertilization on ground vegetation in deciduous and conifer stands across different forest site types (forests with drained mineral soils, forests with drained organic soils, and dry upland forests), stand age groups (young, middle-aged, and pre-mature), and [...] Read more.
This study investigated the impact of forest fertilization on ground vegetation in deciduous and conifer stands across different forest site types (forests with drained mineral soils, forests with drained organic soils, and dry upland forests), stand age groups (young, middle-aged, and pre-mature), and fertilizer types (ammonium nitrate (NH4NO3) and wood ash alone, and both together). Ground vegetation was surveyed one to three years after fertilizer application, with the projected ground cover of individual species in the moss and herb layers determined. Thus, results reflect short-term impact of fertilization. Species richness and diversity (Shannon diversity index, H′) were compared between fertilized and control (unfertilized) plots. The results show that species diversity in the moss layer of silver birch stands was significantly affected by fertilization, while species richness was significantly influenced by the interaction between fertilization and forest site type. Differences between control and fertilized plots in birch stands suggest a potentially negative response of the moss layer to fertilization. In contrast, no significant effect of fertilization was observed in Norway spruce stands, where site type and stand age emerged as significant factors. In Scots pine stands, where NH4NO3 was applied alone, fertilization had a significant impact on both species richness and diversity in the herb layer. In the moss layer, a marginally significant effect was found for the interaction between fertilization and stand age. NH4NO3 alone appeared to enhance herb layer richness, although its effect on species diversity was more variable. Our study highlights the context-dependent nature of fertilization effects on species richness and diversity in Latvian hemiboreal forest ecosystems. Full article
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18 pages, 3774 KiB  
Article
Weathering Resistance of Wood Following Thermal Modification in Closed Process Under Pressure in Nitrogen
by Juris Grinins, Guntis Sosins, Ilze Irbe and Janis Zicans
Forests 2025, 16(1), 132; https://doi.org/10.3390/f16010132 - 12 Jan 2025
Cited by 1 | Viewed by 788
Abstract
The wood of Scots pine (Pinus sylvestris), silver birch (Betula pendula), and European aspen (Populus tremula) was thermally modified in nitrogen under pressure. Three commercial linseed oil-based coatings without or with brown and grey pigments were applied [...] Read more.
The wood of Scots pine (Pinus sylvestris), silver birch (Betula pendula), and European aspen (Populus tremula) was thermally modified in nitrogen under pressure. Three commercial linseed oil-based coatings without or with brown and grey pigments were applied to the specimens. Specimens were placed outside, and weathering stability was assessed for 3 months. The test measured total surface colour change (ΔE) and colonization by wood dicolouring fungi. Following the test, all uncoated specimens demonstrated poor colour fastness and resistance to fungal growth. All tested coatings were unsuitable for protecting untreated wood from dicolouring fungi. The transparent coating was inefficient since it did not significantly prevent untreated or TM wood from fading, and fungal resistance was increased only for a few TM regimes. The colour fastness of specimens with pigmented coatings was enhanced. Specimens with a grey coating exhibited the lowest ΔE and remained consistent throughout the test period. TM specimens with coloured surfaces exhibited greater fungal resistance. However, not all TM aspen and birch regimes had a sufficient growth mark (rating 0 or 1). TM aspen was less resistant to fungi, whereas TM pine displayed very strong fungal resistance across all TM regimes. Full article
(This article belongs to the Special Issue Improving the Service Life of Wood: Durability and Preservation)
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17 pages, 12952 KiB  
Article
Assessment of Changes in Selected Features of Pine and Birch Wood after Impregnation with Graphene Oxide
by Izabela Betlej, Sławomir Borysiak, Katarzyna Rybak, Barbara Nasiłowska, Aneta Bombalska, Zygmunt Mierczyk, Karolina Lipska, Piotr Borysiuk, Bogusław Andres, Małgorzata Nowacka and Piotr Boruszewski
Materials 2024, 17(18), 4464; https://doi.org/10.3390/ma17184464 - 11 Sep 2024
Cited by 1 | Viewed by 1032
Abstract
In this work, pine and birch wood were modified by graphene oxide using a single vacuum impregnation method. The research results indicate that the impregnation of wood with graphene oxide increases the crystallinity of cellulose in both pine and birch wood, and the [...] Read more.
In this work, pine and birch wood were modified by graphene oxide using a single vacuum impregnation method. The research results indicate that the impregnation of wood with graphene oxide increases the crystallinity of cellulose in both pine and birch wood, and the increase in crystallinity observed in the case of birch was more significant than in the case of pine. FT-IR analyses of pine samples impregnated with graphene oxide showed changes in intensity in the absorption bands of 400–600, 700–1500 cm−1, and 3200–3500 cm−1 and a peak separation of 1102 cm−1, which may indicate new C-O-C connections. In the case of birch, only some differences were noticed related to the vibrations of the OH group. The proposed modification also affects changes in the color of the wood surface, with earlywood containing more graphene oxide than latewood. Analysis of scanning electron microscope images revealed that graphene oxide adheres flat to the cell wall. Considering the differences in the anatomical structure of both wood species, the research showed a statistically significant difference in water absorption and retention of graphene oxide in wood cells. Graphene oxide does not block the flow of water in the wood, as evidenced by the absorbability of the working liquid at the level of 580–602 kg/m3, which corresponds to the value of pure water absorption by wood in the impregnation method using a single negative pressure. In this case, higher graphene oxide retention values were obtained for pine wood. Full article
(This article belongs to the Section Advanced Materials Characterization)
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20 pages, 2824 KiB  
Article
The Effect of Wood Species on Fine Particle and Gaseous Emissions from a Modern Wood Stove
by Henna Rinta-Kiikka, Karna Dahal, Juho Louhisalmi, Hanna Koponen, Olli Sippula, Kamil Krpec and Jarkko Tissari
Atmosphere 2024, 15(7), 839; https://doi.org/10.3390/atmos15070839 - 16 Jul 2024
Cited by 4 | Viewed by 2191
Abstract
Residential wood combustion (RWC) is a significant source of gaseous and particulate emissions causing adverse health and environmental effects. Several factors affect emissions, but the effects of the fuel wood species on emissions are currently not well understood. In this study, the Nordic [...] Read more.
Residential wood combustion (RWC) is a significant source of gaseous and particulate emissions causing adverse health and environmental effects. Several factors affect emissions, but the effects of the fuel wood species on emissions are currently not well understood. In this study, the Nordic wood species (named BirchA, BirchB, Spruce, SpruceDry, Pine and Alder) were combusted in a modern stove, and the emissions were studied. The lowest emissions were obtained from the combustion of BirchA and the highest from Spruce and Alder. The fine particle mass (PM2.5) was mainly composed of elemental carbon (50–70% of PM2.5), which is typical in modern appliances. The lowest PAH concentrations were measured from BirchA (total PAH 107 µg/m3) and Pine (250 µg/m3). In the ignition batch, the PAH concentration was about 4-fold (416 µg/m3). The PAHs did not correlate with other organic compounds, and thus, volatile organic compounds (VOCs) or organic carbon (OC) concentrations cannot be used as an indicator of PAH emissions. Two birch species from different origins with a similar chemical composition but different density produced partially different emission profiles. This study indicates that emission differences may be due more to the physical properties of the wood and the combustion conditions than to the wood species themselves. Full article
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18 pages, 1891 KiB  
Article
Properties of Forest Tree Branches as an Energy Feedstock in North-Eastern Poland
by Mariusz Jerzy Stolarski, Natalia Wojciechowska, Mateusz Seliwiak and Tomasz Krzysztof Dobrzański
Energies 2024, 17(8), 1975; https://doi.org/10.3390/en17081975 - 22 Apr 2024
Cited by 6 | Viewed by 1374
Abstract
Tree branches from forest tree harvesting for the timber industry are an important energy feedstock. Solid biofuel in the form of wood chips, produced from branches, is an excellent renewable energy source for generating heat and electricity. However, the properties of wood chips [...] Read more.
Tree branches from forest tree harvesting for the timber industry are an important energy feedstock. Solid biofuel in the form of wood chips, produced from branches, is an excellent renewable energy source for generating heat and electricity. However, the properties of wood chips as a solid biofuel produced from forest tree branches can vary greatly depending on the species from which they have been produced. Therefore, this study aimed to assess the thermophysical properties and elemental composition of fresh branches harvested from nine tree species (pedunculate oak, silver birch, European ash, common aspen, grey alder, Norway maple, Scots pine, European larch and Norway spruce) over three consecutive years (2020–2022). The branches of the tree species most commonly found in Polish forests (Scots pine) were characterized by the highest heating value (an average of 20.74 GJ Mg−1 DM), the highest carbon content (an average of 55.03% DM), the lowest ash (an average of 0.60% DM) and nitrogen contents (an average of 0.32% DM), and low sulfur (an average of 0.017% DM) and chlorine contents (an average of 0.014% DM). A cluster analysis showed that the branches of all three coniferous tree species (Scots pine, Norway spruce and European larch) formed one common cluster, indicating similar properties. The branches of the European ash were characterized by the lowest wood moisture content (an average of 37.19% DM) and thus the highest lower heating value (an average of 10.50 GJ Mg−1). During the three years of the study, the chlorine and ash contents of the branches of the tree species under study exhibited the highest variability. Full article
(This article belongs to the Section A4: Bio-Energy)
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16 pages, 664 KiB  
Article
Chemical Composition and Mechanical Properties of Wood after Thermal Modification in Closed Process under Pressure in Nitrogen
by Juris Grinins, Guntis Sosins, Prans Brazdausks and Janis Zicans
Materials 2024, 17(7), 1468; https://doi.org/10.3390/ma17071468 - 22 Mar 2024
Cited by 4 | Viewed by 1410
Abstract
In this study, silver birch (Betula pendula) and Scots pine (Pinus sylvestris) wood planks (1000 × 100 × 25 mm) were thermally modified in pilot-scale equipment. Research extended our knowledge of the thermal modification (TM) process in a closed [...] Read more.
In this study, silver birch (Betula pendula) and Scots pine (Pinus sylvestris) wood planks (1000 × 100 × 25 mm) were thermally modified in pilot-scale equipment. Research extended our knowledge of the thermal modification (TM) process in a closed system under nitrogen pressure, as well as how process parameters affect the chemical composition and mechanical strength of wood. Various TM regimes were selected—maximum temperature (150–180 °C), modification time (30–180 min), and initial nitrogen pressure (3–6 bar). Chemical analyses were performed to assess the amount of extractives, lignin, polysaccharides and acetyl group content following the TM process. The mechanical properties of TM wood were characterized using the modulus of rupture (MOR), modulus of elasticity (MOE), and Brinell hardness. The MOR of both studied wood species following TM in nitrogen was reduced, but MOE changes were insignificant. The Brinell hardness of TM birch wood’s tangential surface was much higher than that of the radial surface, although Scots pine wood showed the opposite pattern. TM birch and pine wood specimens with the highest mass loss, acetone soluble extractive amount, and the lowest xylan and acetyl group content had the lowest MOR and Brinell hardness. Full article
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12 pages, 1934 KiB  
Article
Comparative Transcriptome Analysis Explores the Mechanism of Angiosperm and Gymnosperm Deadwood Degradation by Fomes fomentarius
by Yulian Wei, Jianbin Xue, Jiangtao Shi, Tong Li and Haisheng Yuan
J. Fungi 2024, 10(3), 196; https://doi.org/10.3390/jof10030196 - 4 Mar 2024
Cited by 2 | Viewed by 1864
Abstract
In forest ecosystems, most of the soil organic matter is derived from trees, as deadwood lignocellulose and wood-decaying basidiomycetes are the most important decomposers of lignin and cellulose. Fomes fomentarius is one of the most common white-rot fungi colonizing angiosperm trees and is [...] Read more.
In forest ecosystems, most of the soil organic matter is derived from trees, as deadwood lignocellulose and wood-decaying basidiomycetes are the most important decomposers of lignin and cellulose. Fomes fomentarius is one of the most common white-rot fungi colonizing angiosperm trees and is often found in birch deadwood but seldom in pine deadwood. To reveal the mechanism through which F. fomentarius selects angiosperms as its preferred host trees, birch and pinewood sticks were selected for culturing for two months. The weight loss, cellulose and lignin degradation rates, activities of degrading enzymes, and transcriptome analyses of two degradation models were compared and analyzed. The results showed that F. fomentarius-degraded birchwood with higher efficiency than pinewood. A GO enrichment analysis found that more upregulated genes related to the top 30 terms showed a molecular function related to degradation, and most genes belonged to the CAZymes family in F. fomentarius-degraded birchwood. However, pinewood degradation did not show these phenomena. A KEGG pathway analysis also indicated that, for the same pathway, more upregulated genes were involved in birchwood degradation caused by F. fomentarius than in pinewood degradation. Full article
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15 pages, 2684 KiB  
Article
Water-Related Properties of Wood after Thermal Modification in Closed Process under Pressure in Nitrogen
by Guntis Sosins, Juris Grinins, Prans Brazdausks and Janis Zicans
Forests 2024, 15(1), 140; https://doi.org/10.3390/f15010140 - 9 Jan 2024
Cited by 5 | Viewed by 1378
Abstract
Silver birch (Betula pendula) and Scots pine (Pinus sylvestris) wood boards (1000 × 100 × 25 mm) were thermally modified in a 340 L pilot-scale device in nitrogen with a special focus on increasing dimensional stability and reducing hydrophilicity. [...] Read more.
Silver birch (Betula pendula) and Scots pine (Pinus sylvestris) wood boards (1000 × 100 × 25 mm) were thermally modified in a 340 L pilot-scale device in nitrogen with a special focus on increasing dimensional stability and reducing hydrophilicity. The research expands our understanding of the TM process in a closed system under pressure of nitrogen and its impact on the water absorption capabilities of wood. Several thermal modification (TM) parameters were tested, including temperature (160–180 °C), maximum temperature duration (30–180 min), and TM chamber initial pressure (3–6 bar). TM wood dimensional changes, mass loss (ML), equilibrium moisture content (EMC), and anti-swelling efficiency (ASE) were determined to characterize the TM process intensity and evaluate the hydrophilicity. Birch wood exhibited a higher ML (5.9%–12%) than pine wood (2.6%–9%) after TM. TM caused a shrinkage in the tangential, radial, and total volume of both wood species. The TM birch wood ASE values varied from 22% to 69%, while the pine wood ASE was 27% to 58%. The cell wall total water capacity (CWTWC) of TM wood was greatly reduced. The EMC and volumetric swelling (VS) of TM birch and pine wood were 29% to 67% lower, respectively, at all relative humidities (65, 75, and 95%). Full article
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22 pages, 5698 KiB  
Article
Estimation of the Short-Term Impact of Climate-Change-Related Factors on Wood Supply in Poland in 2023–2025
by Jan Kotlarz and Sylwester Bejger
Forests 2024, 15(1), 108; https://doi.org/10.3390/f15010108 - 5 Jan 2024
Cited by 2 | Viewed by 2180
Abstract
In this study, we analyzed in situ data from the years 2018–2022 encompassing entire forest plantations in Poland. Based on data regarding stand density and the occurrence of fungal, water-related, climate-related, fire, and insect factors that may intensify with climate changes, we determined [...] Read more.
In this study, we analyzed in situ data from the years 2018–2022 encompassing entire forest plantations in Poland. Based on data regarding stand density and the occurrence of fungal, water-related, climate-related, fire, and insect factors that may intensify with climate changes, we determined the correlation between their occurrence and the decline in wood increments for six tree species: pine, birch, oak, spruce, beech, and alder. Subsequently, we identified age intervals in which the species–factor interaction exhibited statistically significant effects. Next, we developed neural network models for short-term wood increment predictions. Utilizing these models, we estimated a reduction in wood supply harvested in accordance with the plans for the years 2023–2025 assuming a tenfold greater intensity of factors than in 2022. Findings indicate: birch: water-related factors may reduce wood production by 0.1%–0.2%. This aligns with previous research linking drought to birch wood decline, highlighting its sensitivity to water-related issues. Oak: fungal and insect factors could decrease wood production by up to 0.1%. Prior studies emphasize the significant influence of fungal diseases on oak health and regeneration, as well as the impact of insect infestation on wood production. Alder: water-related factors may lead to a slight reduction in wood production, approximately 0.02%. The impact is significant within specific age ranges, indicating potential effects on harvesting. Pine: water- and climate-related factors may result in up to a 0.05% reduction in wood production. Pine, a key forest-forming species in Poland, is notably sensitive to these factors, especially as it nears harvesting age. Spruce: insects, fungi, and climate-related factors could lead to a reduction in wood production of up to 0.2%–0.3%. Analyses demonstrate sensitivity, resulting in a noticeable growth differential compared to the typical rate. Short-term predictions based on neural networks were developed, acknowledging their suitability for short-term forecasts due to uncertainties regarding long-term factor impacts. Additionally, our study discussed modeling wood increments in divisions well below the harvesting time, emphasizing that the influence of current and 2023–2025 factors on wood increments and supply may only manifest several decades from now. These results imply important indications for the economic and financial performance of the wood industry. Full article
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13 pages, 3918 KiB  
Article
Off-Gassing and Oxygen Depletion in Headspaces of Solid Biofuels Produced from Forest Residue Biomass
by Kazimierz Warmiński, Klaudia Anna Jankowska, Agnieszka Bęś and Mariusz Jerzy Stolarski
Energies 2024, 17(1), 216; https://doi.org/10.3390/en17010216 - 30 Dec 2023
Cited by 1 | Viewed by 1314
Abstract
As living standards improve worldwide, the demand for energy increases. However, climate changes and decreasing fossil fuel deposits have increased interest in renewable energy sources, including pellets produced from forest residues. This study aimed to compare changes in concentration of gases (CO, CO [...] Read more.
As living standards improve worldwide, the demand for energy increases. However, climate changes and decreasing fossil fuel deposits have increased interest in renewable energy sources, including pellets produced from forest residues. This study aimed to compare changes in concentration of gases (CO, CO2, O2, volatile organic compounds—VOCs) in enclosed headspaces above pellets produced from deciduous (oak OA, birch BI) and coniferous (pine PI, spruce SP) dendromass and selected types of commercial pellets during their storage. The experiment measured the concentration of gas released from the pellets in storage daily for 14 days. The highest mean CO concentration was found for PI pellets (1194 ppm), and the lowest was for OA (63.3 ppm). Likewise, the highest CO2 concentration was noted for PI pellets (4650 ppm), and the lowest was for BI (1279 ppm). The largest VOC amount was released in the headspace above PI (88.8 ppm), and the smallest was above BI (4.6 ppm). The oxygen concentration was the lowest as measured for PI (minimum 16.1% v/v) and for SP (19.3% v/v). The threshold limit value (8 h) for CO was exceeded for all the pellets under analysis and, in the case of CO2, only for PI after day 10 of incubation. The study findings are extremely important from a scientific (but mainly from a practical) perspective because of the safety of storing and transporting wood pellets. The knowledge of autooxidation processes in those biofuels can help organize their logistics and storage and result in proper warehouse ventilation and monitoring of noxious gases. Full article
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20 pages, 4546 KiB  
Article
Changes in Commercial Dendromass Properties Depending on Type and Acquisition Time
by Mariusz Jerzy Stolarski, Michał Krzyżaniak, Ewelina Olba-Zięty and Jakub Stolarski
Energies 2023, 16(24), 7973; https://doi.org/10.3390/en16247973 - 8 Dec 2023
Cited by 4 | Viewed by 1098
Abstract
Forest dendromass is still the major raw material in the production of solid biofuels, which are still the most important feedstock in the structure of primary energy production from renewable energy sources. Because of the high species and type diversity of production residues [...] Read more.
Forest dendromass is still the major raw material in the production of solid biofuels, which are still the most important feedstock in the structure of primary energy production from renewable energy sources. Because of the high species and type diversity of production residues generated at wood processing sites, as well as at logging sites, the quality of commercial solid biomass produced there has to be evaluated. The aim of this study was to assess the thermophysical characteristics and the elemental composition of ten types of commercial solid biofuels (pinewood sawdust; energy chips I, II, and III; veneer sheets; shavings; birch bark; pine bark; pulp chips; and veneer chips), depending on their acquisition time (August, October, December, February, April, and June). Pulp chips had the significantly lowest moisture content (mean 26.92%), ash content (mean 0.39% DM—dry matter), nitrogen (N) content (mean 0.11% DM), and sulfur (S) content (mean 0.011% DM) and the highest carbon (C) content (mean 56.09% DM), hydrogen (H) content (6.40% DM), and lower heating value (LHV) (mean 13.61 GJ Mg−1). The three types of energy chips (I, II, and III) had good energy parameters, especially regarding their satisfactory LHV and ash, S, and N content. On the other hand, pine and birch bark had the worst ash, S, and N contents, although they had beneficial higher heating values (HHVs) and C contents. Solid biofuels acquired in summer (June) had the lowest levels of moisture and ash and the highest LHV. The highest moisture content and the lowest LHV were found in winter (December). Full article
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