Wood Loss Research Articles

Study of microwave hardwood board modification and drying: experiments and technical-economic assessment

The very low permeability of many hardwood species causes problems during lumber drying. These include very long drying times, drying defects, large material losses after drying, high energy consumption, and expensive drying processes. Jarrah (Eucalyptus marginata) is a species which very difficult to dry. Microwave (MW) wood modification and MW drying can provide an increase in wood permeability and solve some hardwood drying problems. Two 60 kW MW conveyor plants at frequencies 2.45 and 0.922 GHz were used for experiments. The study of MW Jarrah (29x87mm) board drying after pre-drying MW modification showed that it is possible to dry boards in the moisture content range from 70 to 10% during 147-159 hours (6 -7 days) using the cycle method of MW power application. Such intensive MW drying does not bring perceptible damage to the wood and provides low variability of moisture content in the board cross sections. The shorter drying times reduce associated capital, space, energy and labor costs whilst the reduction in drying defects can increase yields. A short time of MW drying provides an opportunity to develop conveyor systems for hardwood sawn timber drying. Economic assessment of MW Jarrah board drying showed that a specific drying cost ranges from US$ 50 to $277/m3 at electricity prices from US$0.08 to $0.32/kWh. The electricity costs form the largest share in total specific drying costs - 44 to 82%. Jarrah boards are expensive product and MW drying costs can be acceptable for industry taking into consideration savings provided by fast drying and wood loss reduction.

Multifaceted and dual-edged native Trichoderma strains from subabul rhizospheric soil to combat Fusarium wilt disease – a sustainable approach

ABSTRACT Fusarium wilt and gummosis disease is a major concern in Subabul plantations, resulting in quantitative and qualitative wood losses to the paper and pulp industry. Growers currently rely on agrochemicals, which are not environmentally safe. Therefore, developing a sustainable control strategy employing biocontrol agents is necessary. For this, the investigation was performed to identify native Trichoderma strains from Subabul rhizospheric soil having antagonistic, disease control efficiency, and PGPR attributes. Six antagonistic Trichoderma (TR1 to TR6) strains were isolated and their efficacy was tested against Fusarium in-vitro by dual plate technique and volatile metabolites. Among these, Trichoderma strains TR1 and TR2 were found efficient in counteracting the growth of F. equiseti (70–90% inhibition) compared to control. The effectiveness was primarily attributed to the increased production of volatile metabolites, siderophores, and the ability to solubilise the nutrients (P and K). Further, six potent Trichoderma strains were identified as T. asperellum (TR1, TR2, TR3, TR6), and T. hamatum (TR4, TR5) through rDNA ITS gene sequencing and phylogenetic analysis. These isolates were mass-multiplied, formulated using Talc powder followed by bio-priming in rooting media. The application of Trichoderma into rooting media reduced the wilt disease caused by artificial inoculation of F. equiseti. Further, TR1 and TR2 were found promising with conferred protection against wilt, enhanced survival rate (10–15%), and improved growth compared to untreated control. Application of adapted TR1 and TR2 antagonists in rooting media during clonal multiplication has the potential wilt control efficiency, enhanced survival rate, and plant growth promotion in Subabul.

Chemical Composition as the Indicator of Thermally Treated Pine (Pinus sylvestris L.) Wood Colour

This study aimed to determine the influence of increased temperature on the mass loss, chemical composition, and colour of pine wood because of the lack of such information. The colour was measured on samples of wood, extracted sawdust, holocellulose, and lignin isolated from the extracted sawdust of pine heartwood and sapwood. A wood sample labelled 20 °C was considered as wood with the original composition. Subsequently, we verified the measured values with the proposed mixing colour model. Pine heartwood and sapwood samples were thermally treated at temperatures of 100, 150, 200, 220, 240, and 260 °C for 1, 3, and 5 h. It was found that sapwood degraded faster than heartwood. The thermal treatment of wood increases lignin content and decreases holocellulose content, especially at 260 °C. The maximum extractive content of 3.60% was at 1 h and a temperature of 260 °C for both parts of the wood. Lightness values decreased with increasing temperature and time of treatment. The coordinate a* of heartwood showed a positive slope until one hour of treatment duration and a temperature of 240 °C. Then, it decreased for the subsequent duration of treatment. The same course was shown for the coordinate b* of sapwood at a temperature of 200 °C. The proposed model of mixing colours proved that changes in both parts of a wood-extracted substance, holocellulose, and lignin content, were responsible for the changing colour of extracted wood.

FORESTRY AND STAND MENSURATION CHARACTERISTICS OF OAK STANDS IN RECREATIONAL AND HEALTH FORESTS OF THE LEFT-BANK STEPPE

The study of forestry and stand mensuration characteristics of oak stands in the recreational and health forests of the Left-Bank Steppe was carried out based on forest management materials. The distribution of oak stands in recreational and recreational forests of the region by location, origin, forest types, age groups and classes, health status classes, and relative completeness was analyzed. Indicators of the use of forest site capacity by modal oak stands within forest areas of green zones around settlements (forestry part of forests of green zones) were calculated. It was found that oak groves in the recreational and recreational forests of the Left-Bank Steppe occupy an area of more than 73 thousand hectares or 39% of the total area of recreational and recreational forests of the Left-Bank of Ukraine. Artificial oak plantations predominate, the share of which is 52.9%. Sprouted oak stands occupy 42.5% of the area, and natural seeded stands occupy 4.6%. The largest reserve (195 m3·ha–1) is characterized by natural seed stands. Forests in the conditions of dry birch and sapwood predominate — 25,9 thousand hectares, which is 35.4% of the total area of oak stands in study region. In terms of area and stock, medieval plantations prevail, the share of which is 60.7% of the total area and 56.6% of their total stock. The predominance of oak stands growing according to the II and III site classes (62.7%) and characterized by a relative completeness of 0.7–0.8 (63.7%) was noted. It was established that the relative completeness of oak stands, starting from the VII age class, gradually decreases. The rate of use of forest plant potential by oak trees within the forests of green zones around settlements (forestry part) compared to local highly productive stands amounts to 76%. Losses of wood due to the insufficient degree of use of land fertility were estimated at 916.7 thousand m3.

Methods for economic assessment of forest resource degradation: A systematic review

Forest degradation is one of the challenges facing the planet today. Several methods have been used to measure forest degradation, including spatiotemporal model analysis, satellite analysis, remote sensing, time series data, geospatial techniques, and most recently aerial drone imagery. However, few studies have used economic valuation methods to assess forest degradation. Therefore, this research aimed to identify the methods used the economic assessment of forest degradation. This systematic review was carried out using PRISMA guidelines. Research articles on the economic valuation of forest resource loss, published from 2015 to 2022, were electronically collected from three databases. Three independent reviewers, with the third acting as referee, inventoried articles, extracted data, and assessed the risk of bias in the articles included in the study. A total of 10,095 articles were identified, including one article from the grey literature. Only five articles met the eligibility criteria. A qualitative content analysis was performed on the extracted data. The selected articles used various methods. However, only a few articles used the contingent valuation method, even though this is indicated for estimating the highest economic value of forests. Based on forest functions, the articles evaluated erosion due to the absence of trees, wood loss, recreation areas and externalities due to forest loss, air quality, water regulation, food supply, and wildlife. The main limitation of this review was the small number of studies included, which may have affected the findings. The study protocol is registered in PROSPERO under the number CRD42021223242

In vitro antagonist activity of cedar Trichoderma species against three cedarwood lignivorous fungi

Cedarwood lignivorous fungi cause significant damage to cedar groves. In Morocco, the losses of cedar wood are estimated at more than 30% due to these fungi, which cause two primary diseases known as M'jej and Saboune. In this study, we are interested in the isolation and molecular identification of parasitic fungi and trichoderma species in the cedar groves of Tazekka National Park and Azrou forest, as well as the biological control of these lignivorous fungi by Trichoderma species. The molecular characterization identified three phytopathogenic fungi: Paecilomyces maximus, Pleurostoma richardsiae, and Alternaria tenuissima. Under in vitro conditions, Trichoderma species (Trichoderma lixii, Trichoderma simmonsii, and Trichoderma viridescens) were more effective. They significantly inhibited the mycelial growth of the studied pathogens through the production of volatile metabolites and mycoparasitic capacity. A maximum percentage exceeding 73 % was recorded. In addition, the direct confrontation tests showed a great capacity of Trichoderma isolates to colonize the medium in competition with the pathogenic fungi, with colonization percentages that reached 81.25 %. In general, Trichoderma agents significantly inhibited the growth of pathogens through various inhibition mechanisms, including colonization of the space, mycoparasitism, or the production of volatile or diffusible metabolites. An in-vivo study is recommended to take advantage of this ecological biocontrol solution.

Sound transmission loss of vertical building partitions designed to meet shear structural requirements

Vertical partitions often include structural building elements designed to meet shear requirements. Shear partitions are designed to resist lateral load due to wind or seismic activity and are required in many regions throughout North America. Nightingale et al. completed a 70-assembly series quantifying the effect of shear OSB on the sound transmission loss (STL) of both wood- and steel-framed single-stud assemblies in the National Research Council Canada (NRCC) research report NRCC-45018. This research study builds on the NRCC research with a test of over 200 wood and steel assembly partitions. This research study includes single-, staggered-, and double-stud framing as well as various forms of shear treatment such as OSB Plywood installed on one or both sides of the partition, attachment with various nail attachment patterns, and steel strapping. The effect of these partition elements on the STL will be presented and discussed. Additionally, the effect of sound isolation treatment, such as additional mass, resilient channels, resilient sound isolation clips, and constrained-layer damping will be presented and discussed.

Effect of unilateral surface compression technique and heat treatment on industrial application performance of poplar

The utilization of unilateral surface compression technique offers significant advantages such as reduced volume loss of wood and energy consumption, making it highly promising for widespread applications. This work focused on fast-growing poplar (Ctrl) as research subject. The unilateral surface compression technique was employed to prepare compressed wood (USW), while superheated steam was utilized to suppress rebound effects (resulting in the formation of US＆HW). The results showed that the combination of densification and heat treatment technology significantly enhanced the application performance of wood. Compared to Ctrl, the densified area exhibited a significant reduction in the volume of cell cavities, with a stepped distribution evident on the VDP. Furthermore, heat treatment resulted in a decrease in the relative amount of hydroxyl in the wood, as well as a slight increase in crystallinity. This effectively reduced deformation in dense wood, resulting in a 20.02% reduction in its recovery rate, without causing excessive damage to the VDP. Additionally, Heat treatment resulted in a darker wood color, reduced glossiness, increased roughness, and further increase the water contact angle of the compressed wood. The mechanical performance of US＆HW achieved an excellent grade, with a score of 48, while all six processing performance grades of US＆HW exceeded Grade 3, surpassing those of both USW and Ctrl. The finishing performance of the US＆HW was good, although slightly lower than that of USW in terms of ball impact performance. And the adhesion, hardness and abrasion resistance indexes of the paint film meet the requirements of excellent products in the standard.

Correlation analysis between mass loss of wood due to thermal modification and equilibrium moisture content of thermally modified wood

This study was conducted to determine the correlation between the mass loss (ML) of wood due to thermal modification and the equilibrium moisture content (EMC) of thermally modified wood. After thermal modification of larch lumber under various temperature and time conditions, ML according to treatment temperature and time was measured, and the (EMC) of the thermally modified wood was evaluated for each treatment condition. As the treatment temperature increased and the treatment time became longer, the ML of wood due to thermal modification increased. In addition, as the treatment temperature increased, the difference in EMC between the non-treated wood and the thermally modified wood tended to increase. Finally, a robust logarithmic correlation was observed between the ML due to thermal modification and the EMC of the thermally modified wood. These results suggest that the EMC of thermally modified wood can be predicted by simply measuring the weight of wood before and after thermal modification.

Wood resistance of Magonia pubescens (Sapindaceae), Dalbergia nigra, and Machaerium amplum (Fabaceae) to Nasutitermes sp. (Blattodea: Termitidae).

Termites of the genus Nasutitermes sp. (Blattodea: Termitidae), which feed on cellulose, may cause wood to become brittle and fragile. This study aimed to evaluate the natural resistance of three native wood species: Magonia pubescens (Sapindaceae), Dalbergia nigra and Machaerium amplum (Fabaceae) to attack by Nasutitermes sp. termites and to investigate the relationship between resistance, extractive content, and oven-dry density. Samples of each wood species were subjected to a forced feeding process with Nasutitermes sp. termites for 30 days. Following the exposure, the oven-dry density, extractive content, percentage of wood loss, and termite mortality were determined for each sample. Dalbergia nigra exhibited resistance to termite attack and had the highest extractive content at 13.14%. Conversely, M. amplum had the highest wood loss at 5.37% and the lowest extractive content at 1.94%. Both species showed a negative correlation between wood loss and extractive content, but no correlation with wood density. Magonia pubescens had the highest density at 0.90 g/cm3. Macherium amplum and M. pubescens caused 100% termite mortality, while D. nigra caused 40% mortality.

Enhancing fire resistance in wood with high-water retention silica gel: A promising flame-retardant solution

This study aims to evaluate the water retention and flame-retardant properties of silica gel prepared using anionic polyacrylamide (HPAM), gluconate-delta-lactone (GDL), and aluminum citrate (AlCit). Silica gel samples were synthesized with sodium silicate (8 wt%), sodium bicarbonate (4 wt%) and varying concentrations of HPAM (0.2-0.8 wt%) and GDL (0.1-0.3 wt%). The prepared gels were characterized using XPS, XRD, FTIR, and TGA. Optimal water retention capacity was achieved with 0.4 wt% HPAM and 0.2 wt% GDL. Compared to traditional gels, silica gel has more surface water molecules due to additional hydrophilic groups and the amorphous nature of silica. At high temperatures, silica forms a layer with the charcoal from treated wood combustion, inhibiting oxygen penetration and minimizing further combustion. After combustion at 500?C, the mass loss of wood treated with silica gel is 36-53% less than untreated wood, indicating greater weight retention and demonstrating silica gel's effectiveness in preventing continued burning.

Durability of heat-treated Paulownia tomentosa and Pinus koraiensis woods in palm oil and air against brown- and white-rot fungi

This study aimed to evaluate and compare the effects of oil- and air-heat treatments on the durability of Paulownia tomentosa and Pinus koraiensis woods against Fomitopsis palustris and Trametes versicolor. The wood samples were treated in palm oil and air at 180, 200, and 220 °C for 2 h. The weight loss, morphology, crystalline properties, and chemical compounds of untreated and heat-treated wood after fungal attack were investigated. The significant difference in weight loss between oil- and air-heat-treated samples was shown at 220 °C. Heat-treated wood exposed to white-rot fungus showed a lower weight loss than that exposed to brown-rot fungus. The cell components in the untreated- and heat-treated Paulownia tomentosa and Pinus koraiensis at 180 °C were severely damaged due to fungal exposure compared to those at 220 °C. A fungal effect on the relative crystallinity was observed in heat-treated wood at 180 °C, whereas the effect was not observed at 220 °C. Following brown-rot fungus exposure, untreated- and heat-treated wood at 180 °C showed a notable change in the Fourier transform infrared (FTIR) peaks of polysaccharides, whereas no noticeable change in lignin peaks was observed. Heat-treated wood at 220 °C showed no noticeable change in the FTIR spectra owing to brown-rot fungus exposure. Exposure to white-rot fungus did not noticeably change the FTIR spectra of untreated and heat-treated wood.

Antifungal protection of beech wood using plant extracts

In this research, the antifungal efficacy of dry plant extracts of Chinese cinnamon bark (Cinnamomum cassia L.), Rtanjski tea herb (Satureja montana L.) obtained by water extraction and extract of Thyme herb (Thymus serpyllum L.) obtained by ethanol-water extraction was investigated against the fungi Coniophora puteana and Serpula lacrymans, which cause brown rot, and the fungus Trametes versicolor, which causes white rot of hardwood and conifers. Five different concentrations of plant extracts were tested, and water was used as a solvent. Samples of beech wood (Fagus sylvatica ssp. moesiaca (Maly) Czeczott.) were treated by the immersion method with solutions of plant extracts and exposed for 60 days to the action of the test fungi. The smallest mass loss (%) of beech wood when affected by each of the test fungi was in samples treated with Thymus serpyllum extract at a concentration of 25%, followed by Satureja montana at the same concentration. Cinnamomum cassia bark extract did not show significant antifungal activity against the test fungi at any concentration. The obtained results can affirm the use of dry plant extracts as ecologically acceptable agents in the preventive protection of non-resistant wood species against rotting fungi.

In-situ growth of hexaconazole/polydopamine/hexadecyltrimethoxysilane in multi-scale structured wood to prepare superhydrophobic wooden materials with decay resistance

Using the layered channels of wood and its unique mesoporous microstructure, hexaconazole, polydopamine (PDA), and hexadecyltrimethoxysilane (HDTMS) were grown and deposited in-situ on the surface and interior of wood. Using this method, a superhydrophobic wood composite with decay resistance was prepared. Hexaconazole inhibited wood fungal decay, and the mass losses of wood were 0 and 0.06% with a retention of 140 g/m3 after laboratory decay tests for 12 weeks by using Trametes versicolor and Gloeophyllum trabeum, respectively. More importantly, through the oxidative self-polymerization of PDA, the adhesive PDA anchored hexaconazole nanoparticles to form a stable core–shell structure that increased the surface roughness of wood. In addition, based on the association of PDA with hydrophilic –OH groups in cellulose and hemicelluloses in wood, long-chain HDTMS was deposited on the surface of wood to form a superhydrophobic multifunctional wooden material with a water contact angle (WCA) of 154°. Based on its multifunctional and inherent durability, the wood also showed good chemical stability and resistance to UV, high- temperature, and high-humidity environments.

Moisture content estimation of green softwood logs of three species based on measurements of flexural vibration

The moisture contents of sugi (Cryptomeria japonica), todomatsu (Abies sachalinensis) and hinoki (Chamaecyparis obtusa) logs were estimated using a method of moisture content estimation proposed in our previous study. In the course of estimation, it was revealed that the regression line of the correlation between specific dynamic Young’s modulus (E/ρ) and tangent loss (tan δ) of green wood was different from that of moisture-conditioned wood and showed species dependency, both of which are not previously reported. Regression lines at the fiber saturation point (FSP) were constructed for each species by measuring E/ρ and tan δ from the flexural vibration of green small specimens and correcting the E/ρ values at their own moisture contents into E/ρ values at the FSP. The correlation of green wood in this study was different from that reported in previous studies of moisture-conditioned wood near the FSP. The correlations of sugi and hinoki were similar, whereas those of sugi and todomatsu were different despite no previous report of species dependency in air-dried wood. The moisture contents 86 logs (not those used to prepare small specimens) were estimated using regression lines of each species. The standard deviation of the difference between the estimated moisture content and the measured moisture content was 15.7%. A systematic error of 25.9% in moisture content was attributed to the different methods of specimen support used for small specimens and logs.

Preservatve Potentials of Datura metel Seed Oil on Triplochiton scleroxylon Wood (Schumann)against Fungal Attack

This experiment was carried out to evaluate the potential of extracted Datura metel seed oil as a bio wood preservative against fungi attack as reports have shown bio-preservatives to be toxic free and environmentally friendly. The oil was extracted from the seed by Soxhlet apparatus using N-Hexane and ethanol solvents and using volume-to-volume method of dilution kerosene (at 50%) was added to increase its quantity thereafter. The phytochemical screening of the seed of Datura metel revealed the presence of tannins, alkaloids, flavonoids, saponins and phenols. Wood samples of Triplochiton sceleroxylon were cut to 20 × 20 × 60mm and the dimensioned wood samples were soaked for 72 hours in the seed oil extract hence preservative absorption rate and percentage weight loss of wood was determined on exposure to a purely cultured Sclerotium rolfsil (brown rot fungi) and Pleurotus ostreatus(white rot fungi). Data obtained were subjected to analysis of variance at α0.05 and the results showed the highest value of mean weight loss of 18.29% while the samples exposed to brown rot fungi has a mean value of 14.12% and white rot a lowest mean value of 12.72%. The highest absorption was observed to be 92.73 kg/m at 100 % concentration level of D,metel extract. Based on the results obtained, the seed-oil extracts of Datura metel have the potential of being an effective wood preservative.

Energy value of silver fir (Abies alba) and Norway spruce (Picea abies) wood depending on the degree of its decomposition by selected fungal species

Negative environmental impacts related to climate change and social pressure to raise the rotation age of forests contribute to the quality deterioration of harvested wood, including its decomposition by fungi. This paper presents the results of laboratory experiments investigating the decomposition of Norway spruce (Abies alba) and silver fir (Picea abies) wood by selected species of decay fungi: Hericium flagellum and Bondarzewia mesenterica (causing white rot) as well as Rhodofomes roseus (causing brown rot). The decay process affects wood density, elemental composition, net calorific value, as well as the amount and price of the energy contained in the wood. Wood density was measured conventionally using an electronic caliper and laboratory balance. Energy parameters were determined using elemental analyzer and combustion calorimeter. Wood decay was found to adversely affect energy content per unit of wood at a given volume, thus leading to higher prices per unit of energy. Over the 120 days of the experiment, wood parameters were not affected considerably by Hericium flagellum or Bondarzewia mesenterica. Of the three examined fungal species, Rhodofomes roseus caused the highest weight loss of wood and the greatest decrease in its oven-dry density (spruce - a decrease from 409 to 214 kg m−3; fir - a decrease from 420 to 306 kg m−3), unfavorably reducing energy content per 1 m3 of wood (spruce – decrease by 3.8 GJ m−3; fir – decrease by 2.3 GJ m−3) and raising the unit price of energy.

Vanillin/silica microencapsulation for wood preservation

Abstract Vanillin is an antifungal and environmentally friendly compound. In this study, vanillin and silica microcapsules (VSM) were microencapsulated using the sol-gel method and then impregnated into wood. Scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDXA) and transmission electron microscopy (TEM) were used to characterize the morphological structure and distribution of VSM in wood. Fourier transform infrared spectroscopy (FTIR) was used to study the intermolecular interactions between VSM and wood. The antifungal performance of the VSM-treated wood was evaluated. The study revealed that VSM had good sustained-release performance and decay resistance. Mass losses of VSM-treated wood after leaching and exposure to Trametes versicolor (L.) Quel. and Gloephyllum trabeum (Pers.) Murrill decreased from mass losses of 20.8 % and 15.9 % of the control group to 9.2 % and 6.4 %, respectively. VSM treatment disrupted the mycelium of T. versicolor and G. trabeum, inhibited their respiratory metabolism, and the ligninase-laccase enzyme activity of T. versicolor. Meanwhile, MOR and MOE of VSM-treated wood were 96.7 MPa and 12.3 GPa which were 28.8 % and 11.5 % higher than the control group, respectively.

Effect of Abrasive Grain Size on the Abrasion Volume Loss of Subfossil and Recent Oak Wood in Three Characteristic Sections

Subfossil wood is a valuable and rare material often used for production of expensive furniture and decorative artistic items of unique beauty. Its mechanical and tribological properties are still being studied and are considered specific due to the particular conditions of its long-lasting formation in aqueous sediment sludge. Various elements that have been impregnated into the wood tissue over many years make the machining and grinding of this type of wood rather difficult compared to normal recent wood. The main objective of this study was to determine the influence of the abrasive grain size of sandpaper on the abrasion volume loss of recent and two subfossil oak samples in three characteristic sections (cross, radial, and tangential). The results showed that the average size of abrasive grains and the orientation of the wood structure have an influence on the abrasion volume loss of all three samples. The phenomenon of the critical size of abrasive grains was observed in all samples and on all sections. As the size of abrasive grains increased to the critical size, the abrasive volume loss of the sample increased simultaneously. The lowest abrasion volume loss was observed on recent oak. In all samples, the lowest volume loss was measured on the cross sections, and the tangential and radial sections had mutually equal values. It was also found that the increase in the size of abrasive grains to a critical value resulted in the increasing value of the absolute difference between the abrasion volume loss of the cross, radial, and tangential section samples, while the relative relations between the abrasive volume loss values of three different sections (C/R, C/T, R/T) within the same grit of sandpaper remained quite similar.

Climate change, greenhouse gases and the bioeconomy

According to existing estimates, by the middle of the twentieth century, due to intensive deforestation and large losses of wood, as well as as a result of qualitative changes in the economy and nature management, hydrocarbon reserves (gas, oil) and coal became the basis of energy supply. Intensively developing industrial production, construction, transport, agriculture, as well as the intensification of land use and forestry, combined with the growing population of the planet, began to have a significant impact on the planet’s climate, in particular, in the form of warming due to the “greenhouse” effect.