Research

22 pages, 4631 KiB

Open AccessArticle

Prediction of Physical and Mechanical Properties of Heat-Treated Wood Based on the Improved Beluga Whale Optimisation Back Propagation (IBWO-BP) Neural Network

by Qinghai Wang, Wei Wang, Yan He and Meng Li

Forests 2024, 15(4), 687; https://doi.org/10.3390/f15040687 - 10 Apr 2024

Viewed by 404

Abstract

The physical and mechanical properties of heat-treated wood are essential factors in assessing its appropriateness for different applications. While back-propagation (BP) neural networks are widely used for predicting wood properties, their accuracy often falls short of expectations. This paper introduces an improved Beluga [...] Read more.

The physical and mechanical properties of heat-treated wood are essential factors in assessing its appropriateness for different applications. While back-propagation (BP) neural networks are widely used for predicting wood properties, their accuracy often falls short of expectations. This paper introduces an improved Beluga Whale Optimisation (IBWO)-BP model as a solution to this challenge. We improved the standard Beluga Whale Optimisation (BWO) algorithm in three ways: (1) use Bernoulli chaos mapping to explore the entire search space during population initialization; (2) incorporate the position update formula of the Firefly Algorithm (FA) to improve the position update strategy and convergence speed; (3) apply the opposition-based learning based on the lens imaging (lensOBL) mechanism to the optimal individual, which prevents the algorithm from getting stuck in local optima during each iteration. Subsequently, we adjusted the weights and thresholds of the BP model, deploying the IBWO approach. Ultimately, we employ the IBWO-BP model to predict the swelling and shrinkage ratio of air-dry volume, as well as the modulus of elasticity (MOE) and bending strength (MOR) of heat-treated wood. The benefit of IBWO is demonstrated through comparison with other meta-heuristic algorithms (MHAs). When compared to earlier prediction models, the results revealed that the mean square error (MSE) decreased by 39.7%, the root mean square error (RMSE) by 22.4%, the mean absolute percentage error (MAPE) by 9.8%, the mean absolute error (MAE) by 31.5%, and the standard deviation (STD) by 18.9%. Therefore, this model has excellent generalisation ability and relatively good prediction accuracy. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

15 pages, 3319 KiB

Open AccessArticle

The Flexural Strength of Three Bamboo Species from Brazil: A Comparative Study of Internal and External Lamina Surfaces Using Static and Dynamic Bending Properties

by Hugo Rocha Scharfenberg, Ana Carolina Borella Marfil Anhê, Victor Almeida De Araujo, Maristela Gava, Fernando Júnior Resende Mascarenhas, Elen Aparecida Martines Morales, André Luis Christoforo, Marcos Massao Shimano and Juliana Cortez-Barbosa

Forests 2024, 15(4), 580; https://doi.org/10.3390/f15040580 - 22 Mar 2024

Viewed by 574

Abstract

Bamboo is already a convenient construction resource, as it offers an efficient structural performance. As this plant has native varieties adapted to different climates and soils of Brazil, bamboo silviculture can be intensified to supply the national industry. Three bamboo species from Brazil [...] Read more.

Bamboo is already a convenient construction resource, as it offers an efficient structural performance. As this plant has native varieties adapted to different climates and soils of Brazil, bamboo silviculture can be intensified to supply the national industry. Three bamboo species from Brazil (Dendrocalamus asper, Bambusa tuldoides, and Phyllostachys aurea) were analyzed for the flexural load capacity applied on the internal and external surfaces. Specimens were prepared without knots and with knots centered at the middle of each sample. In total, 240 samples were tested in terms of static bending and dynamic bending (impact). The results showed a higher flexural elasticity and a higher proportional limit strength of knotted P. aurea. The presence of knots provided higher values of ultimate strength in P. aurea, even reducing the bamboo flexibility. Also, P. aurea exhibited the best characteristic of flexural dynamic energy absorption among the three bamboo species under evaluation. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

13 pages, 26256 KiB

Open AccessArticle

Predicting Wood Density Using Resistance Drilling: The Effect of Varying Feed Speed and RPM

by Vilius Gendvilas, Geoffrey M. Downes, Marco Lausberg, Jonathan J. Harrington and David J. Lee

Forests 2024, 15(4), 579; https://doi.org/10.3390/f15040579 - 22 Mar 2024

Viewed by 616

Abstract

The IML PD series Resi is a device used to assess the drilling resistance of wood. The IML PD series Resi instrument is being widely adopted for commercial wood quality assessment due to its speed, cost-effectiveness, and precision when combined with web-based trace [...] Read more.

The IML PD series Resi is a device used to assess the drilling resistance of wood. The IML PD series Resi instrument is being widely adopted for commercial wood quality assessment due to its speed, cost-effectiveness, and precision when combined with web-based trace processing. Collecting Resi data with fixed feed speed and RPM settings is challenging due to inherent basic density variations within and between tree species. Altering these settings affects the drilling resistance amplitude of the Resi data, impacting basic density predictions. This study introduces the concept of chip thickness to combine feed speed and RPM into a single parameter to minimise the effects of different sampling conditions on the basic density predictions. Regression models, with chip thickness as the regressor variable, account for 97% to 99% of variance in mean Resi outerwood amplitude across six species. The demonstrated adaptability of chip thickness for adjusting feed speed and RPM settings, along with species-specific functions correlating it with Resi amplitude, holds promise for standardizing amplitude values across diverse feed speeds and RPM settings. Optimal sampling conditions needed to predict basic density lie within the 30%–40% amplitude range. To drill a ~30 cm diameter tree, the recommended fastest settings were 200 cm/min and 3500 RPM for Southern Pine (Pinus elliottii var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze)) and Radiata Pine (Pinus radiata (D. Don.)), 200 cm/min and 2500 RPM for Hoop Pine (Araucaria cunninghamii (Mudie)), 50 cm/min and 5000 RPM for Spotted Gum (Corymbia citriodora subsp. variegata (F. Muell.)), 200 cm/min and 4500 RPM for White Cypress (Callitris glaucophylla (Thompson & Johnson)), and 150 cm/min and 3500 RPM for Shining Gum (Eucalyptus nitens (H. Deane & Maiden) Maiden) based on the billets sampled. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

12 pages, 4896 KiB

Open AccessArticle

Predicting Wood Density Using Resistance Drilling: The Effect of Instrument and Operator

by Vilius Gendvilas, David J. Lee, Dominic P. Kain, Chandan Kumar, Geoff M. Downes, Marco Lausberg and Jonathan J. Harrington

Forests 2024, 15(1), 157; https://doi.org/10.3390/f15010157 - 11 Jan 2024

Viewed by 996

Abstract

The IML PD series Resi is an instrument designed to measure the drilling resistance of wood. Use of the IML PD series Resi instrument is rapidly becoming a routine method among Australian forest plantation growers for wood quality assessments. The major driver in [...] Read more.

The IML PD series Resi is an instrument designed to measure the drilling resistance of wood. Use of the IML PD series Resi instrument is rapidly becoming a routine method among Australian forest plantation growers for wood quality assessments. The major driver in the commercial uptake of the IML Resi is that it is fast, cheap, and sufficiently precise for commercial use, particularly when the data are processed through a user-friendly, web-based processor. This study examined whether the accuracy of wood density predictions was impacted by the use of different Resi tools and different operators, which has never been examined before. Seven Resi instruments were evaluated across six sites with two operators on plantation-grown Southern Pine (Pinus caribaea var. hondurensis (Sénéclauze) or hybrids between Pinus elliottii var. elliottii (Engelm) × P. caribaea var. hondurensis) trees. Two types of Resi instruments were used (IML Resi PD-400 and IML Resi PD-500), and all had been recently serviced or were new. The instruments were operated by experienced operators. Constant sampling conditions of feed speed 200 cm/min and 3500 RPM were used. The order of instrument use, and hence the order of operator assessment at each site, was randomized. The variance between Resi instruments was small. The measured mean basic density of 50 mm outerwood cores across all plots was 542 kg/m³, while Resi-predicted basic density varied among instruments between 535 and 547 kg/m³. One Resi instrument underpredicted basic density by 9 kg/m³ and another overpredicted by 5 kg/m³. The operator had no effect on the basic density prediction. Resi PD400 or PD500 instruments gave similar basic density predictions. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

31 pages, 6598 KiB

Open AccessArticle

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

by Rebecca Cherry, Warna Karunasena and Allan Manalo

Forests 2023, 14(9), 1916; https://doi.org/10.3390/f14091916 - 20 Sep 2023

Viewed by 775

Abstract

The evolution toward small-diameter and fast-growing plantation timbers such as the Pinus elliotti var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze) (PEE×PCH) hybrids around the world is producing large volumes of core wood that are falling short of structural sawn timber grading [...] Read more.

The evolution toward small-diameter and fast-growing plantation timbers such as the Pinus elliotti var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze) (PEE×PCH) hybrids around the world is producing large volumes of core wood that are falling short of structural sawn timber grading requirements. Engineered timber products such as cross-laminated timber (CLT) and glue-laminated (glulam) offer potential solutions to value-adding this resource, but the bond performance of this feedstock and the extent to which current standards and guides address its common characteristics for bond performance need to be understood. This study investigated the bond quality and performance of clear defect-free, low stiffness out-of-grade PEE×PCH and evaluated this performance using the pass/fail criteria of the CLT bond performance requirements of three national CLT standards. 5-layer CLT delamination samples and shear block test samples were glued using one-component polyurethane (PUR). This process was repeated for common occurring characteristics in this resource of resin, knots, and pith to understand their impact and inform an evaluation on the need to restrict their inclusion. Clear samples had an average glue line delamination of 2.9% and an average glue line wood failure of 96.7%. Resin achieved 9.3% and 92.6%, respectively. While knots had the lowest performance at 24.4% and 77.4%, respectively. When pith was at or adjacent to the glue line, wood failure occurred through the pith and its immediate surrounding fiber. Shear strength and wood failure tests were carried out on glulam and CLT-oriented samples. CLT knot samples were tested in two load orientations. Glulam-oriented samples in clear, resin, pith, and knots achieved an average shear strength of 8.5 MPa, 8.2 MPa, 7.9 MPa, and 8.2 MPa, respectively, and wood failure of 86%, 85%, 90%, and 69%, respectively. CLT-oriented samples in clear and resin both achieved average shear strengths of 4.0 MPa; 0°-loaded and 90°-loaded pith samples achieved 3.6 MPa and 2.4 MPa, while 0°-loaded and 90°-loaded knot samples achieved 4.2 MPa and 4.7 MPa respectively. Average wood failures were 90%, 89%, 96%, 96%, 83%, and 51%, respectively. PRG320 was found to be the most restrictive standard. Resin, knots, and pith were not addressed in the evaluation of delamination or shear strength in any standard, and PRG320 was the only standard to restrict these characteristics over and above structural grading rules. The amount and type of characteristics present vary considerably in structurally graded wood, and even more so for this out-of-grade resource. It was determined that the negative impact that resin, knots, and pith have on bond quality and bond performance calls for some restriction of their inclusion in order to achieve the author’s interpretation of the intended bond performance requirements of the CLT standards, which currently do not address these characteristics well or at all. A proposed modification to the PRG320 effective bond area was presented as a proactive solution. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

17 pages, 2743 KiB

Open AccessArticle

Microwave Treatments and Their Effects on Selected Properties of Portuguese Pinus pinaster Aiton. and Eucalyptus globulus Labill. Wood

by Fernando Júnior Resende Mascarenhas, Alfredo Manuel Pereira Geraldes Dias, André Luis Christoforo, Rogério Manuel dos Santos Simões and André Eduardo Palos Cunha

Forests 2023, 14(8), 1671; https://doi.org/10.3390/f14081671 - 18 Aug 2023

Cited by 1 | Viewed by 903

Abstract

The most widespread wood species in the Portuguese forest and the most widely utilized are maritime pine (Pinus pinaster) and eucalyptus (Eucalyptus globulus Labill). In the case of eucalyptus, except for the pulping sector, it might have limited usage due [...] Read more.

The most widespread wood species in the Portuguese forest and the most widely utilized are maritime pine (Pinus pinaster) and eucalyptus (Eucalyptus globulus Labill). In the case of eucalyptus, except for the pulping sector, it might have limited usage due to drying issues and low permeability. Microwave (MW) treatment is a technology that has been used to improve wood species’ permeability. Therefore, the present paper aimed to evaluate the MW treatment of both Portuguese wood species and to investigate the effects of different MW treatments on wood’s density, water uptake capability, modulus of rupture (MOR), and modulus of elasticity (MOE). Using small clear wood specimens, two MW powers were used, 700 and 1200 W, and the samples were submitted to successive MW cycles of 2 min till they reached the required dryness. The results showed that each wood species had a different behavior during the MW drying in terms of drying rate, supply, and consumption of energy. In general, with the increase in MW power, the densities of both species decreased and the water uptake increased, as a possible indicator that a certain level of microstructural damage might have occurred. Regarding the mechanical properties of MW-treated maritime pine and eucalyptus wood specimens, under the harshest conditions (MW power of 1200 W), MOR and MOE were reduced compared with the wood sample without MW treatment. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

16 pages, 9725 KiB

Open AccessArticle

The Mechanical Strength Properties, Treatability Retention and Hazard Classification of Treated Small-Clear Fast-Growing Acacia mangium Superbulk at Different Age Groups

by Nur Syahina Yahya, Gaddafi Ismaili, Meekiong Kalu, Mohd Effendi Wasli, Iskanda Openg, Noor Azland Jaimudin, Mohamad Zain Hashim, Ahmad Nurfaidhi Rizalman, Hamden Mohammad and Khairul Khuzaimah Abdul Rahim

Forests 2023, 14(8), 1529; https://doi.org/10.3390/f14081529 - 26 Jul 2023

Viewed by 879

Abstract

The slow growth rate of primer species has affected the supply available to accommodate the market demand. To overcome these problems, a study was carried out to fully utilise fast-growing timber as the primary resource to ensure the demand for timber logs continues. [...] Read more.

The slow growth rate of primer species has affected the supply available to accommodate the market demand. To overcome these problems, a study was carried out to fully utilise fast-growing timber as the primary resource to ensure the demand for timber logs continues. This paper aimed to determine mechanical strength properties, treatability retention, and hazard classification of 7-, 10- and 13-year-old small-clear samples of Acacia mangium superbulk collected from Daiken Plantation Sdn. Bhd. Bintulu, Sarawak, following treatment with 10% copper chrome arsenic. As a result of this study, the maximum strength was obtained from the 10-year-old age group, with the modulus of rupture (MOR), the modulus of elasticity (MOE), and compression parallel to the grain values of small-clear treated Acacia mangium superbulk reaching 118.76 N/mm², 15,020 N/mm², and 57.82 N/mm², respectively. In addition, the treatability retentions obtained were 149.27 L/m³, 147.25 L/m³, and 141.09 L/m³, which were recorded from the 7-, 10-, and 13-year-old samples, respectively. Meanwhile, the dry-salt retentions obtained from the 7-, 10- and 13-year-old samples were 14.93 kg/m³, 14.73 kg/m³, and 14.11 kg/m³, respectively. Hence, this species is classified as moderately difficult to treat under CCA (treatability retention: 80–160 L/m³) and is categorised under the hazard class of H4 (dry salt retention: 12–16 kg/m³). Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

17 pages, 9516 KiB

Open AccessArticle

Mechanical Efficiency and Quality Control Preliminary Analysis of Incompletely Bonded Wood-Based Sandwich Panels

by Emilio Luengo, Francisco Arriaga, Ignacio Bobadilla and Eva Hermoso

Forests 2023, 14(6), 1074; https://doi.org/10.3390/f14061074 - 23 May 2023

Viewed by 950

Abstract

Wood-based sandwich panels are building products composed of two skins attached to a lightweight continuous core in which at least one skin is made of wood-based products, contributing to the use of renewable forest goods. Since the connection between the skins and the [...] Read more.

Wood-based sandwich panels are building products composed of two skins attached to a lightweight continuous core in which at least one skin is made of wood-based products, contributing to the use of renewable forest goods. Since the connection between the skins and the core is often provided by adhesive bonding, its characteristics affect the mechanical behavior of the sandwich and, therefore, must be thoroughly assessed. Full adhesion is often considered the standard situation, although some batches of the commercial product show incompletely glued surfaces, and scarce data is available with regard to their bonding performance. For this reason, analyses were performed using tensile tests with a load perpendicular to the skins and specific shear tests with a load parallel to the longitudinal direction of the panel. The test samples were obtained from wood-based sandwich panels with extruded polystyrene cores and different skin materials. The tensile tests proved to be suitable only for panels with adequate skin material cohesion, their functionality improving as a control method when the glued surface percentage assessment is used together with the tensile strength. The results of the shear tests provided non-linear models relating the effect of the glued surface to the mechanical properties, revealing that the mechanical efficiency of the incompletely bonded specimens is better than that which might be expected if the core only worked in proportion to the glued surface, due to the help of the adjoining non-glued core material. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

21 pages, 6216 KiB

Open AccessArticle

Effect of Alternate Drying Techniques on Cross-Laminated Timber after Exposure to Free-Water Wetting

by Maryam Shirmohammadi and Adam Faircloth

Forests 2023, 14(5), 1007; https://doi.org/10.3390/f14051007 - 12 May 2023

Viewed by 971

Abstract

Cross-laminated timber (CLT) panels are commonly used in mass-timber multistorey constructions due to their prefabrication, construction flexibility, environmental credentials and weight-to-strength ratio advantages compared to competing building materials. However, the long-term durability and service life of these mass timber panels require further understanding [...] Read more.

Cross-laminated timber (CLT) panels are commonly used in mass-timber multistorey constructions due to their prefabrication, construction flexibility, environmental credentials and weight-to-strength ratio advantages compared to competing building materials. However, the long-term durability and service life of these mass timber panels require further understanding of their performance when exposed to free water. Wetting and drying trials were conducted by exposing Radiata pine (Pinus radiata) CLT sections to either free water (pooling on a single surface) or submerged water (all directions exposed) saturation, followed by either ambient or fan drying. The panels exposed to water pooling only reached MC above the FSP up to 40 mm of the panel depth. For submerged panels, the MC reached values above the fibre saturation point (FSP) at depths of 30 to 40 mm penetration on both panel faces. When comparing the ambient and fan-drying panel sections over the same time period, a less uniform MC profile was observed for the ambient drying, whereas the fan-dried panels fell below the FSP faster and with a more consistent MC profile. A complementary study was conducted on a standalone 3.0 × 3.0 m CLT room, where the room was wetted during a simulated pipe burst event. The moisture monitoring of wall and floor panels during fan drying of the room showed that an MC reduction from an excess of 40% to below 20% could be reached in less than 96 h for the panels’ surface; however, the middle sections of the panels dried slower than the surface sections. The CLT structure fan drying required a longer drying time than the CLT sections tested due to the closed sections (overlaps and connected faces) and a lower rate of airflow. The study of drying CLT sections highlighted the product reaching and maintaining MC higher than FSP points and the need for further drying applied to minimise long-term decay development. Further study is recommended to investigate the effects of closed sections (connected faces) and the duration of drying needed for semi-finished and finished buildings. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

15 pages, 7117 KiB

Open AccessArticle

Characterization of Anatomical and Non-Anatomical Properties for the Identification of Six Commercial Wood Species from Vietnamese Plantation Forests

by Alvin Muhammad Savero, Jong Ho Kim, Byantara Darsan Purusatama, Denni Prasetia, Se Hwi Park, Doan Van Duong and Nam Hun Kim

Forests 2023, 14(3), 496; https://doi.org/10.3390/f14030496 - 02 Mar 2023

Cited by 3 | Viewed by 1521

Abstract

This study investigated the anatomical and non-anatomical characteristics of six wood species, Acacia mangium, Acacia hybrid, Dillenia pentagyna, Anacardium occidentale, Hevea brasiliensis, and Melaleuca cajuputi, from a plantation in Vietnam. The anatomical characteristics and non-anatomical characteristics were [...] Read more.

This study investigated the anatomical and non-anatomical characteristics of six wood species, Acacia mangium, Acacia hybrid, Dillenia pentagyna, Anacardium occidentale, Hevea brasiliensis, and Melaleuca cajuputi, from a plantation in Vietnam. The anatomical characteristics and non-anatomical characteristics were observed following the International Association of Wood Anatomists (IAWA) list. All species showed diffuse porosity and non-septate fibers. Exclusively solitary vessels were only observed in M. cajuputi. Vestured pits were observed in A. mangium, A. hybrid, and M. cajuputi, and tyloses were found in A. occidentale and H. brasiliensis. We observed vasicentric axial parenchyma in A. mangium, A. hybrid, A. occidentale, and H. brasiliensis, whereas diffuse axial parenchyma was observed in D. pentagyna and M. cajuputi. Further, prismatic crystals in the axial parenchyma cells existed in A. mangium, A. hybrid, and H. brasiliensis, and raphides in ray cells were observed in D. pentagyna. Silica bodies in ray cells were found in A. occidentale and M. cajuputi. H. brasiliensis exhibited the greatest vessel diameter and ray height, with D. pentagyna exhibiting the greatest fiber length and wall thickness. All the species showed considerable differences in heartwood fluorescence, water and ethanol extract colors, and froth test reactions. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

17 pages, 4415 KiB

Open AccessArticle

Mechanical Properties of Three Bamboo Species: Effect of External Climatic Conditions and Fungal Infestation in Laboratory Conditions

by Asier Elejoste, Juan Luis Osa, Alfonso Arevalillo-Roman, Arantxa Eceiza, Jose Miguel Abascal, Jose Miguel Rico-Martinez, Amaia Butron and Cristina Peña-Rodriguez

Forests 2022, 13(12), 2084; https://doi.org/10.3390/f13122084 - 07 Dec 2022

Cited by 2 | Viewed by 1507

Abstract

Bamboo is a material with good tensile and flexural resistance. As a construction material with structural capacity, using bamboo implies considerable environmental advantages in relation to other typical materials such as steel or concrete. For its correct implementation, it is necessary to define [...] Read more.

Bamboo is a material with good tensile and flexural resistance. As a construction material with structural capacity, using bamboo implies considerable environmental advantages in relation to other typical materials such as steel or concrete. For its correct implementation, it is necessary to define its mechanical properties and durability. Bamboo is susceptible to degradation due to the lack of natural toxins and thin walls, which means that shallow decomposition processes can imply appreciable reductions in its mechanical capacity. The main degrading agents considered in this study were beetles, termites, and xylophagous fungi. The aim of this study was to analyze the durability of three different species: DS, PA, and AA. Durability and mechanical tests results after 6 months of exposure to biotic and abiotic agents were compared with their original properties and chemical composition. In this study, durability was analyzed in two ways. Firstly, the loss of mass due to fungal infection was investigated. The results obtained were based on the standard EN 113 using the fungus CP. Secondly, bending and compressive strength was evaluated after a durability test according to the standard EN 335:2013 for the CU3.1 use class after a 6 month period in the city of Donostia/San Sebastian, Spain. The DS and AA varieties were rated as very durable CD1, while the PA variety is durable CD2, thus proving to be an attractive material for construction. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Graphical abstract

15 pages, 4063 KiB

Open AccessArticle

Evaluation of Yield Improvements in Machine vs. Visual Strength Grading for Softwood Species

by Gonzalo Moltini, Guillermo Íñiguez-González, Gonzalo Cabrera and Vanesa Baño

Forests 2022, 13(12), 2021; https://doi.org/10.3390/f13122021 - 29 Nov 2022

Cited by 2 | Viewed by 1298

Abstract

The current national standard for strength grading in Spain is based on a visual classification, which, for softwood species with small cross-sections (with a thickness equa tol or less than 70 mm), establishes two different visual grades (ME-1 and ME-2). These grades are [...] Read more.

The current national standard for strength grading in Spain is based on a visual classification, which, for softwood species with small cross-sections (with a thickness equa tol or less than 70 mm), establishes two different visual grades (ME-1 and ME-2). These grades are assigned to the strength classes C24 and C18, respectively, for maritime and radiata pines, and C27 and C18 for Scots pine, according to the European standard EN-1912:2012. The production of engineered wood products, such as glulam or cross-laminated timber is increasing worldwide. The machine grading of wood using non-destructive testing provides the industry with a more reliable, fast, and consistent method for grading. With this background in mind, this study presents the yield comparison of machine grading vs. visual grading for those three pine species from Spain. The machine settings were obtained according to the standard EN 14081-2:2019, providing several possible strength grade combinations. Results allow new possibilities for the industry and improve the structural yield of the studied timber, thus increasing the material optimization. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

17 pages, 2808 KiB

Open AccessArticle

Balsam Fir (Abies balsamea (L.) Mill.) Wood Quality after Defoliation by Spruce Budworm (Choristoneura fumiferana Clem.) in the Boreal Forest of Quebec, Canada

by Audrey Lemay, Julie Barrette and Cornelia Krause

Forests 2022, 13(11), 1926; https://doi.org/10.3390/f13111926 - 16 Nov 2022

Viewed by 1068

Abstract

Eastern spruce budworm (Choristoneura fumiferana Clem.) is considered the most important disturbing insect in coniferous stands in eastern North America. During an outbreak, spruce budworm can cause severe defoliation in balsam fir (Abies balsamea (L.) Mill.), which can affect wood properties [...] Read more.

Eastern spruce budworm (Choristoneura fumiferana Clem.) is considered the most important disturbing insect in coniferous stands in eastern North America. During an outbreak, spruce budworm can cause severe defoliation in balsam fir (Abies balsamea (L.) Mill.), which can affect wood properties such as moisture content and mechanical properties. This project aimed to assess the influence of the duration of spruce budworm defoliation on the wood quality of mature balsam fir trees. To do this, we studied sapwood proportion, decay, moisture content, mechanical properties and tracheid dimensions in stands that had suffered three, four or five years of defoliation. We also compared living and dead balsam firs and evaluated the change in wood properties with time. Our results showed that dead balsam firs suffered from a loss of wood quality rapidly after their death, particularly in terms of moisture content and decay in the sapwood. Sapwood proportion was similar between living and dead trees, but the sapwood of dead trees contained more decay and had a lower moisture content than living trees. Mechanical properties and tracheid dimensions were 10% and 4% lower in dead trees than in living trees. We did not observe any major differences in wood properties between the three durations of defoliation, suggesting that wood degradation occurs before that. The study did not make it possible to determine the optimal duration of defoliation to harvest the stands. Full article

(This article belongs to the Special Issue Wood Quality and Mechanical Properties)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Wood Quality and Mechanical Properties

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (13 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI