Search Results (33)

The effects of torrefaction of the biopellets made from hardwood chip residue (HW), camellia oilseed cake (CO), and pruning remnants of the toothache tree (TA) and mulberry tree (MT) were evaluated. Torrefaction of the biopellets reduced the volatile matter content of biopellets by 18–58% and increased their heating value by 18–58% without negatively impacting durability or fines content. Torrefaction also reduced the initial ignition time of biopellets by 50–59% and prolonged their combustion duration by 15–24%. Regardless of the type of feedstock, all biopellets exhibited mass yields in the range of 60–80% and energy yields ranging from 80–95%. The novelty of this study lies in the application of torrefaction to already-formed biopellets, which enhances pellet quality without the need for binders, and the use of unused forest biomass and wood chip residue from pulp mills. The use of unused forest biomass and wood chip residue from pulp mills for biopellet production not only provides a sustainable and efficient method for waste utilization but also contributes to environmental conservation by reducing the reliance on fossil fuels. Overall, the torrefaction of biopellets represents a promising technology for producing high-quality solid biofuel from a variety of woody biomass feedstocks without compromising pelletizing efficiency. Full article

High-quality pellets are typically produced from coniferous sawdust. However, achieving comparable quality from alternative feedstocks, such as broadleaf wood, often necessitates pre-treatments or additives. Yet, within the framework of small-scale pellet production, local forest enterprises may lack the resources for such treatments and usually produce pellets from the whole trees, including branches, leaves and tops. This can have an impact on the quality of the pellets obtained in this manner. To be classified as high-quality pellets (A1 class), the specific features of the pellet must be higher or fall below the thresholds specified in the EN ISO 17225 standard. In this study, we developed an alternative statistical approach to evaluate pellet quality in comparison to the constant thresholds reported in the technical standard. We applied such an approach to evaluate the quality of pellets produced from the broadleaved species common in the Mediterranean forestry, including European beech (Fagus sylvatica L.), Turkey oak (Quercus cerris L.), Eucalyptus (clone Eucalyptus camaldulensis x C. bicostata), and Poplar clone AF6. In particular, we focused on three variables that are generally the most troublesome for the production of high-quality pellets from the broadleaved species, namely bulk density, ash content, and lower heating value. We found that the beech pellets showed satisfactory bulk density (average effect size of −1.2, with no statistical difference in comparison to the standard’s threshold) and ash content (average effect size of about −5 and significantly lower than the standard’s threshold), but the heating value was significantly lower than the threshold required by the standard (average effect size of about −3). Conversely, other investigated species exhibited notable deficiencies, with turkey oak pellets displaying acceptable heating values. We found a significant improvement in ash content and heating value with increasing stem age within the same species thus suggesting that material derived from thinning interventions might be preferable over coppice-derived biomass for high-quality pellet production. We suggest that future research on the topic should focus on investigating pellets produced from blends of beech and turkey oak biomass. We further recommend a wider application of the proposed statistical approach, considering that it is clear and easy to interpret, and allows for a statistical comparison of the obtained values against the requirements of the technical standard. Full article

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

In recent years, polyhydroxyalkanoates (PHAs) have gained notoriety because of their desirable properties that include proven biodegradability, biocompatibility, and thermal stability, which make them suitable alternatives to fossil-based polymers. However, the widespread use of PHAs is still challenging because of their production costs, which are greatly associated with the cultivation medium used for bacterial cultivation. In Portugal, one-quarter of the forest area is covered by Eucalyptus globulus wood, making its residues a cheap, abundant, and sustainable potential carbon source for biotechnological uses. In this work, eucalyptus bark was used as the sole feedstock for PHA production in a circular bioeconomic approach. Eucalyptus bark hydrolysate was obtained after enzymatic saccharification using Cellic^® CTec3, resulting in a sugar-rich solution containing glucose and xylose. Although with differing performances, several bacteria were able to grow and produce PHA with distinct compositions, using the enzymatic hydrolysate as the sole carbon source. Pseudomonas citronellolis NRRL B-2504 achieved a high cellular growth rate in bioreactor assays (24.4 ± 0.15 g/L) but presented a low accumulation of a medium-chain-length PHA (mcl-PHA) comprising the monomers hydroxydecanoate (HD, 65%), hydroxydodecanoate (HDd, 25%), and hydroxytetradecanoate (HTd, 14%). Burkholderia thailandensis E264, on the other hand, reached a lower cellular growth rate (8.87 ± 0.34 g/L) but showed a higher biopolymer accumulation, with a polyhydroxybutyrate (PHB) content in the cells of 12.3 wt.%. The new isolate, Pseudomonas sp., revealed that under nitrogen availability, it was able to reach a higher accumulation of the homopolymer PHB (31 wt.%). These results, although preliminary, demonstrate the suitability of eucalyptus bark’s enzymatic hydrolysate as a feedstock for PHA production, thus offering an exciting avenue for achieving sustainable and environmentally responsible plastic products from an undervalued forestry waste. Full article

The enormous potential of renewable bioresources is expected to play a key role in the development of the EU’s sustainable circular economy. In this context, inexhaustible, biodegradable, non-toxic, and carbon-neutral forest-origin resources are very attractive for the development of novel sustainable products. The main structural component of wood is cellulose, which, in turn, is the feedstock of nanocellulose, one of the most explored nanomaterials. Different applications of nanocellulose have been proposed, including packaging, functional coatings, insulating materials, nanocomposites and nanohybrids manufacturing, among others. However, the intrinsic flammability of nanocellulose restricts its use in some areas where fire risk is a concern. This paper overviews the most recent studies of the fire resistance of nanocellulose-based materials, focusing on thin films, coatings, and aerogels. Along with effectiveness, increased attention to sustainable approaches is considered in developing novel fire-resistant coatings. The great potential of bio-based fire-resistant materials, combined with conventional non-halogenated fire retardants (FRs), has been established. The formulation methods, types of FRs and their action modes, and methods used for analysing fireproof are discussed in the frame of this overview. Full article

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

United States Army trucks and trailers use an estimated one million board feet (2381 cubic meters) of a critically endangered tropical hardwood, apitong (Dipterocarpus spp.), from southeast Asian rainforests, for wood decking annually. However, their purchasing specifications require the use of domestic hardwoods for decking, floorboards, and platforms. Several US hardwood species, including northern red oak (Quercus rubra), white oak (Quercus alba), hickory (Carya spp.), black locust (Robinia pseudoacacia), and sugar maple (Acer saccharum) could serve as viable substitutes. They have comparable strength properties to apitong, and there is an abundant and sustainable feedstock based on the United States Forest Service Forest Inventory Analysis (USFS FIA) database. The economic impact in New York State of manufacturing the decking panels in Onondaga County from three selected species: hickory, white oak, and black locust, was estimated using IMPLAN. The economic impact could be as high as $27 million, creating 128 full-time equivalent (FTE) jobs. Equally important to providing local and regional economic benefits, domestically sourced decking panels also contributes to the preservation of tropical rainforests, particularly when the entire decking market is considered (beyond the US Army), which includes wood decking consumption by other government agencies at various levels and the private sector. Full article

Typically, coniferous sawdust from debarked stems is used to make pellets. Given the high lignin content, which ensures strong binding and high calorific values, this feedstock provides the best quality available. However, finding alternative feedstocks for pellet production is crucial if small-scale pellet production is to be developed and used to support the economy and energy independence of rural communities. These communities have to be able to create pellets devoid of additives and without biomass pre-processing so that the feedstock price remains low. The features of pellets made from other sources of forest biomass, such as different types of waste, broadleaf species, and pruning biomass, have attracted some attention in this context. This review sought to provide an overview of the most recent (2019–2023) knowledge on the subject and to bring into consideration potential feedstocks for the growth of small-scale pellet production. Findings from the literature show that poor bulk density and mechanical durability are the most frequent issues when making pellets from different feedstocks. All of the tested alternative biomass typologies have these shortcomings, which are also a result of the use of low-performance pelletizers in small-scale production, preventing the achievement of adequate mechanical qualities. Pellets made from pruning biomass, coniferous residues, and wood from short-rotation coppice plants all have significant flaws in terms of ash content and, in some cases, nitrogen, sulfur, and chlorine content as well. All things considered, research suggests that broadleaf wood from beech and oak trees, collected through routine forest management activities, makes the best feasible feedstock for small-scale pellet production. Despite having poor mechanical qualities, these feedstocks can provide pellets with a low ash level. High ash content is a significant disadvantage when considering pellet manufacture and use on a small scale since it can significantly raise maintenance costs, compromising the supply chain’s ability to operate cost-effectively. Pellets with low bulk density and low mechanical durability can be successfully used in a small-scale supply chain with the advantages of reducing travel distance from the production site and storage time. Full article

Solid biofuels, including wood chips, are still the most important feedstock in the structure of primary energy production from renewable energy sources. Wood chips are derived mainly from forests and the wood industry, including sawmills. However, the considerable diversity of chipper types results in great differences in their final production efficiency. The objective of this study was to analyze and evaluate the efficiency of three mobile chippers used in wood chip production by determining their throughput rate, diesel fuel and energy consumption, cost of chipping and greenhouse gas emission, as well as the quality of the chips. By far shortest time (0.82 min. Mg⁻¹) of producing 1 Mg of wood chips was found for the Albach 565 kW chipper. Moreover, the mean time needed for the production of 1 Mg of chips with a chipper of the same make but with a smaller engine (Albach 515 kW) was 8.8% longer. This time was 284.9% longer than when the Bruks chipper was used. However, the highest mean effectiveness of diesel fuel use (expressed as the lowest diesel fuel consumption of 1.41 dm³ Mg⁻¹), the lowest energy consumption (52.02 MJ Mg⁻¹), the lowest cost of diesel fuel use (2.28 € Mg⁻¹) and the lowest GHG emission (4.27 kg Mg⁻¹ CO_2eq) in wood chip production were determined for the Albach 515 kW chipper. In contrast, the poorest parameters were determined for the Bruks chipper. Full article

This paper presents an investigation on the influence of various factors on rolling shear (RS) properties of timber feedstock for cross laminated timber (CLT) available from Australian plantation forest resources. Comparison of RS properties between three softwood species namely southern pine, radiata pine and hoop pine are presented. Furthermore, the effect of modulus of elasticity (MOE), equilibrium moisture content (EMC), aspect ratio, knots and projection length on rolling shear behaviour were investigated. Mean RS modulus for radiata pine, southern pine and hoop pine samples were 74.7 MPa, 87.1 MPa and 99.7 MPa, whilst the RS strength of those species were 2.6 MPa, 3.1 MPa and 3.7 MPa, respectively. Radiata pine samples exhibited the lowest values for RS modulus and strength, almost 30% less than those of hoop pine samples. The study confirmed that the density and MOE had a very weak correlation with RS properties for all pine species. There was an obvious decrease in RS modulus (by 18%) when the woods’ conditioned EMC changed from 8% to 12%. A further 33% decrease was observed when the woods’ conditioned EMC increased from 12% to 16%. However, the percentage increase in RS strength was found to be 23% higher in wood with 12% conditioned EMC while compared against wood conditioned to 16% EMC. RS strength improved with increased aspect ratio; however, RS modulus remained almost unaffected. Moreover, the projection length that resulted in the load passing through the centroid of the specimen resulted in lower RS modulus values, but the presence of knots improved both RS strength and modulus for all three tested species. Full article

Biomass is currently the main renewable energy source (RES) in the EU, particularly in Poland. Solid biomass for energy purposes is primarily sourced from forests, the wood processing industry, and agriculture. A significant source of this energy feedstock could also be short-rotation woody crops (SRWCs), including black locust, poplar, and willow. Since numerous factors determine the SRWC biomass quality, the current study aimed at assessing biomass thermophysical properties and elemental composition depending on the plant species, soil enrichment procedure, and the plant harvest rotation over a consecutive 12-year period of cultivation. The characteristics under study, including the moisture content, ash content, volatile matter, fixed carbon, higher heating value (HHV), and the carbon, hydrogen, nitrogen, sulfur, and chlorine contents, were significantly differentiated by all the main factors, i.e., the SRWC species, the soil enrichment procedure, the harvest rotation, and the interactions between these factors. The SRWC species accounted for the highest percentage of the variation in the biomass moisture content, ash content, HHV, and nitrogen content, while the harvest rotation made the largest contribution to the variation in carbon, hydrogen, and chlorine contents. The black locust biomass was characterized by the significantly lowest moisture content (an average of 38.89%) and the highest sulfur content (an average of 0.033% DM), nitrogen content (an average of 0.91% DM), and chlorine content (an average of 0.032% DM). However, poplar was characterized by the highest HHV (an average of 19.84 GJ Mg⁻¹ DM) and the highest moisture content (56.52% DM), carbon content (56.52% DM), and ash content (an average of 1.67% DM). Willow was characterized by the lowest ash content (an average of 1.67% DM), a medium moisture content, and the lowest nitrogen content (an average of 0.38% DM) and chlorine content (an average of 0.19% DM). Full article

Forest bioenergy value chains can offer attractive opportunities to promote economic development and mitigate climate change. However, implementing profitable and efficient forest biomass value chains requires overcoming barriers that continue to hinder the development of bioenergy systems in several jurisdictions. The objective of this study was to compare the economic, social, and environmental sustainability of various potential configurations of forest bioenergy value chains, including forest biomass supply and bioenergy production chains, in the Capitale-Nationale region of Quebec (Canada), which is a jurisdiction that has considerable forest resources but makes little use of bioenergy. We based our study on the ToSIA model parameterization and compared various policy measures, biomass supply, and logistics scenarios for 2008 and 2030. Our results showed that wood chip and pellet value chains in the Capitale-Nationale region would positively contribute to the regional economy in 2030, even in the absence of subsidies. Moreover, actions to increase biomass feedstock mobilization in 2030 would lead to an increase in gross value added, employment, and energy production in the region compared with 2008 and a greater increase than other considered policy or logistical measures. However, increased biomass feedstock mobilization would also mean higher relative GHG emissions and more fossil fuel energy input per unit of bioenergy than in the other scenarios. Conversely, optimizing biomass feedstock and combustion technologies could help minimize the fossil fuel energy input needed and GHG and some non-GHG pollutant emissions. Overall, our study suggested that implementing policy and logistical measures for forest biomass value chains could make the significant mobilization of forest bioenergy attainable and, in turn, Quebec’s 2030 bioenergy target of 17 petajoules realistic. Full article

The ongoing COVID-19 pandemic has disrupted global economic activity in all sectors, including forest industries. Changes in demand for forest products in North America over the course of the pandemic have affected both primary processors and downstream industries reliant on residues, including wood pellet producers. Wood pellets have become an internationally traded good, mostly as a substitute for coal in electricity generation, with a significant proportion of the global supply coming from Canadian producers. To determine the effect of the COVID-19 pandemic on the Canadian wood pellet industry, economic and market data were evaluated, in parallel with a survey of Canadian manufacturers on their experiences during the first three waves of the pandemic (March 2020 to September 2021). Overall, the impact of the pandemic on the Canadian wood pellet industry was relatively small, as prices, exports, and production remained stable. Survey respondents noted some negative impacts, mostly in the first months of the pandemic, but the quick recovery of lumber production helped to reduce the impact on wood pellet producers and ensured a stable feedstock supply. The pandemic did exacerbate certain pre-existing issues, such as access to transportation services and labour availability, which were still a concern for the industry at the end of the third wave in Canada. These results suggest that the Canadian wood pellet industry was resilient to disruptions caused by the pandemic and was able to manage the negative effects it faced. This is likely because of the integrated nature of the forest sector, the industry’s reliance on long-term supply contracts, and feedstock flexibility, in addition to producers and end-users both being providers of essential services. Full article

Climate change and rising energy costs have led to increasing interest in the use of tree harvest residues as feedstock for bioenergy in recent years. With an increasing use of wood biomass and harvest residues, essential nutrient elements are removed from the forest ecosystems. Hence, nutrient sustainable management is mandatory for planning of intensive forest use. We used soil nutrient balances to identify regions in Germany where the output of base cations by leaching and biomass utilization was not balanced by the input via weathering and atmospheric deposition. The effects of conventional stem harvesting, stem harvesting without bark, and whole-tree harvesting on Ca, Mg and K balances were studied. The nutrient balances were calculated using regular forest monitoring data supplemented by additional data from scientific projects. Effective mitigation management strategies and options are discussed and calculations for the compensation of the potential depletion of nutrients in the soil are presented. Full article

The emerging bioeconomy requires new supply chain paradigms for biomass materials to reach processing centers. Forest bio-hubs can be thought of as networks of collection points to facilitate biomass supply chains that feed from forest to central processing facilities. The design and functionality of forest bio-hubs depends on the form (e.g., vertically and horizontally integrated), and the quality and volume of feedstocks. In this paper we conceptually develop the potential role of forest bio-hubs. We then compare current bio-hub development in three U.S. regions—the Pacific Northwest, the southwest region, and the southeastern U.S. We use a “SWOT” framework to compare strengths, weaknesses, opportunities, and threats for each region. We consider transportation distances, topography, proximity to markets, harvesting methods, and wood products development. Innovation and adaptability would play key roles in forest bio-hub development, especially with dynamic conditions related to markets, wildfire risks, biomass utilization policy, and community socioeconomic factors. Full article