Wood Quality Research Articles

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

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.

The miR159a-CfMYB37 module regulates xylem development in Chinese cedar (Cryptomeria fortunei Hooibrenk)

Cryptomeria fortunei is the indigenous evergreen coniferous timber species in southern China, valued for its superior wood quality, which frequently finds industrial applications. MiRNAs (microRNAs) can be involved in regulating various aspects of plant growth, and more and more studies have explored miRNAs related to growth and development, but among them, the ones on C. fortunei are relatively rare. In this study, we screened miRNAs that were differentially expressed during vascular cambium development, and chose miR159a and CfMYB37 as candidate genes for cloning and functional validation. The results showed that miR159a had CfMYB37 as a target gene and that there was a distinct negative regulatory relationship between miR159a and CfMYB37 in C. fortunei. 35 S::miR159a plants were taller than WT and had thicker stems than WT, and miR159a encouraged the growth of xylem cells and lignin. While 35 S::mCfMYB37 plants had the opposite phenotype to 35 S::miR159a plants, with considerably lower lignin content and xylem cell layer number compared to WT, 35 S::CfMYB37 plants lacked a distinctive phenotype. This suggests that the miR159-CfMYB37 module can control plant growth and xylem development. For the following investigation of C. fortunei's growth and vascular cambium development as well as the enhancement of its wood qualities, this work serves as a crucial theoretical foundation.

Wood Quality Analyzing System

This paper presents a comprehensive approach to optimizing furniture design processes and facilitating wood identification through the development of a mobile application. The application is designed to provide users with intuitive tools and resources for informed decisionmaking in furniture design and wood selection. The first component of the mobile application focuses on optimizing furniture design through furniture size and quality consideration. This encompasses the creation of an intuitive user interface that enables users to specify their furniture design preferences, including material selection criteria. A comprehensive wood database is meticulously curated, furnishing users with comprehensive details on wood sizes, qualities, and thicknesses, thereby aiding in material selection and waste reduction initiatives. Algorithms are employed to recommend optimal wood sizes, considering factors such as material selection, waste reduction, and cost analysis. Visual representation tools are included, allowing users to preview furniture designs with different wood options, facilitating informed decisionmaking. Furthermore, feedback mechanisms have been integrated to enable users to provide feedback on recommended wood sizes and qualities, thereby facilitating continuous enhancement and refinement of recommendations. The second component aims to identify the type of wood by its appearance. Image processing features have been developed to precisely extract visual characteristics from wood sample images, thereby aiding in the identification of wood species. Machine learning models are trained to classify wood species based on visual characteristics obtained from images, thereby enhancing the precision of identification. User interaction tools have been designed to ensure ease of use and accessibility for users in capturing and submitting wood sample images. Within the application, educational resources and materials are provided to help users learn about different wood species, aiding their understanding and selection process.

Planting density and mechanical site preparation effects on understory composition, functional diversity and planted black spruce growth in boreal forests

Mechanical site preparation (MSP) is used prior to planting to control competing vegetation and enhance soil conditions, particularly in areas prone to paludification. Tree planting density can be adapted to the management context and objectives, as it influences yield and wood quality. However, the combined effects of MSP and planting density on understory vegetation composition, functional traits, and diversity remain uncertain. We thus conducted a study in the Clay Belt region of northwestern Quebec, Canada. After careful logging, the study area was divided into nine sites, each receiving one of three treatments: plowing, disc trenching, or no preparation. Sites were further divided into two, with black spruce (Picea mariana [Mill.] Britton, Sterns & Poggenb.) seedlings planted at either a low planting density of 1100 seedlings ha-1 or a high planting density of 2500 seedlings ha-1. After nine years, we assessed understory composition, diversity, key functional traits, sapling density and growth of planted trees. Careful logging alone led to a higher density of naturally established conifers compared to plowing or disc trenching. The interaction between planting density and MSP significantly influenced understory diversity and composition in plowed plots. Understory composition was affected by the soil C/N ratio, coniferous species, and deciduous species density. The growth of black spruce was notably enhanced with higher planting density in the plow treatment only. Neither planting density nor MSP alone affected tree height and diameter. Our results suggest that combining plowing with high-density planting can enhance stand growth and improve forest productivity. These findings guide future research on paludified forests.

Genetic selection for growth, wood quality and resin traits of potential Slash pine for multiple industrial uses.

This study aims to understand the genetic basis of key industrial traits in Slash pine (Pinus elliottii Engelm. var. elliottii) to enhance improvement efficiency. Detailed analyses were conducted on inter-family differences, genetic parameters, correlations, and breeding values (BVs) for growth, wood properties, and resin traits of Slash pine planted in Changle Forest Farm of Hangzhou, leading to the identification of elite families. It indicates that growth traits are primarily influenced by environmental effects, while wood properties exhibit a significant impact of genetic effects. The variation in resin traits arises from both genetic and environmental effects. Notably, Beta-pinene exhibits the highest variability and genetic gains among the traits analyzed. The family heritability ranges for growth, wood properties, and resin traits are 0.543-0.794, 0.870-0.885, and 0.285-0.695, respectively. Significant positive correlations are evident between growth and resin traits, while a negative correlation is observed between growth and wood properties. Elite families identified through single-trait and multi-trait combined selection are 8-126 for growth traits, 2-325 and 0-373 for wood properties, and 8-131 for resin traits. The average genetic gains for these elite families are 7.44%, 7.17%, and 8.84%, respectively. These findings provide valuable insights for high-generation breeding of Slash pine and lay a genetic foundation for formulating effective breeding strategies for conifers.

Influence of spacing between trees on wood and charcoal quality indicators

Influence of spacing between trees on wood and charcoal quality indicators

Evaluation of Mechanical Properties and Surface Quality of Wood from Bosnia and Herzegovina Exposed to Outdoor Conditions

Evaluation of Mechanical Properties and Surface Quality of Wood from Bosnia and Herzegovina Exposed to Outdoor Conditions

History and Prospects of Development of Low-Rise Wooden Buildings in Cities of the North of Russia

Low-rise timber buildings are an important part of Arctic cities. This is due to a number of factors: the traditions of using wood in construction, accessibility and simplicity, mastery of the technology of processing wood as a building material, the ability to quickly construct buildings from ready-made elements, high thermal qualities of wood. The modern emergency low-rise wooden building fund has discredited itself, which has led to an increase in the construction of capital multi- apartment buildings using technologies from cities in central Russia. Currently, economics, ecology, and the development of modern technologies dictate the need to revive low-rise wooden residential buildings at a new qualitative level, including the development of a new typology of residential buildings that meet the diverse modern requirements of the population of Arctic cities.

Estimating wood quality attributes from dense airborne LiDAR point clouds

Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest inventories. We present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing trees. Unlike object reconstruction methods, our approach is based on simple metrics computed on vertical slices that summarize information on point distances, angles, and geometric attributes of the space between and around the points. Our models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser scans. We show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation scenarios. Our approach provides a simple, clear, and scalable solution that can be adapted to different situations both for research and more operational mapping.

Process modeling and simulation of Gmelina arborea (GmW) and Mansonia altissima (MaW) wood drying

This study simulate the process modeling of drying characteristics of Gmelina arborea (GmW) and Mansonia altissima (MaW) wood under the influence of various process variables such as drying time, drying temperature, and airflow velocity. GmW and MaW moisture desorption isotherms, kinetics, and thermodynamics were also studied. Five (5) thin-layer and desorption isotherm drying models were used to model the moisture ratio and water activity data from the process. According to the anatomical analysis, the GmW sample has an average lumen size of 147.44 m, indicating a high moisture content. The results showed that the Guggenheim, Anderson, and de Boer (GAB) model with the lowest sum of squared error value (0.046) demonstrated the best-fit to the experimental desorption data for GmW samples and the Henderson-P model for MaW samples, while the Demir et al. model emerged as the best kinetics model fit for describing the moisture desorption isotherm and thin-layer drying kinetics. GmW effective diffusivity (Deff) values ranged from 3.671 × 10−8 to 5.378 × 10−8 m2/s and MaW effective diffusivity (Deff) values ranged from 2.923 × 10−8 to 4.678 × 10−8 m2/s. GmW and MaW activation energies were 252.702 kJ/mol and 313.604 kJ/mol, respectively. The thermodynamic studies revealed that the heat and mass transfer coefficients varied linearly with temperature, as the change in enthalpy (ΔH) and change in entropy (ΔS) decreased while the Gibbs free energy (ΔG) increased. The results obtained from this study demonstrated that the proposed drying process modeling and simulation approach could be successfully applied to investigate the wood drying phenomena. The information can be used to reduce the drying costs and improve the wood quality.

A framework for wood quality assessment using DenseNet algorithm

A framework for wood quality assessment using DenseNet algorithm

Glycosyltransferases and Xylan Biosynthesis in Poplar: Genetic Regulation and Implications for Wood Quality

Glycosyltransferases and Xylan Biosynthesis in Poplar: Genetic Regulation and Implications for Wood Quality

Wood Research at the University of Sopron – Physical-mechanical Properties

This study series shows research fields and results in wood science of the University of Sopron, Hungary. In this paper, we review several studies regarding the physical-mechanical properties of wood, including some properties of Turkey oak grown in different stands, showing that it should be planted among other species in same stand to achieve optimal wood quality. Research in the field of the firewood plantations has shown that it is necessary to choose the right species of poplars, in a given area. Paulownia and some invasive species grow rapidly, so they have great potential as raw materials and there are significant differences between paulownia varieties. Based on their densities, box elder, tree of heaven and green ash can be substituted for the noble species. Basswood can be well impregnated with paraffin, making it a good choice for pencils. Low-quality noble oak logs have the potential to be used in structural elements as lamellae, improving the yield and decreasing the loss in the wood industry. Black locust, sessile oak, beech, poplar, larch and spruce were subjected to different mechanical test methods at different moisture contents. Their properties decreased with increasing moisture content between 12% moisture content and FSP for all six wood species, but the ratio of changes varied, depending both on the measurement method and on the species.

Genetic parameters and correlations in growth and wood density traits of Balfourodendron riedelianum based on provenance and progeny testing

Abstract Balfourodendron riedelianum is an important timber species of South America used in civil construction and carpentry. Knowing the genetic variation, heritability and correlation between traits is an essential prerequisite for guiding selection of the best genotypes in tree improvement. In this study, growth (diameter and height) and wood density (mean, pith, middle and bark position) traits were investigated in 30-year-old trees planted in a B. riedelianum provenance and progeny test established in two sites, Luiz Antônio (LA) and Pederneiras (PE), in São Paulo State (Brazil). ANOVA results showed significant differences between sites for all traits, among provenances and families for wood density traits in the LA site and among families for growth traits in PE. Provenance x site and family x site interactions were significant for almost traits, and genetic correlation between sites was low for all traits (0.17–0.20). Genetic variation (CV g) was higher (4.0–5.4 %) and mean family heritability (h m 2) was lower for growth (0.12–0.20) compared to wood density (CV g: 2.3–3.8%, h m 2: 0.31–0.59) traits. Genetic correlation was significantly positive and ranged from moderate to high between growth traits (0.47–0.68) and between wood density traits (0.42–0.83) and non-significant between growth and wood density (-0.22–0.30) traits. An analysis of different radial positions showed that heritability tended to increase from pith to the bark position. Our results show a lower environmental effect on wood density traits, allowing the possibility of selecting superior provenances and families with high wood quality in breeding programs in both sites.

Does forest stand density affect soil microbial communities?

Forest management aims to maintain sustainable production of quality wood while limiting increased competition between trees for light, water, and nutrients. Thinning is a widely used silvicultural practice to reduce plants competition for resources while still exploiting the wood. The investigation of the effects of forest management on stand functioning typically centers on the above-ground compartment, overlooking the alterations and influences exerted on below-ground biotic factors. Within the soil matrix, biological mechanisms are mainly governed by microbial communities. Many studies have focused on the effects of thinning on soil microbial communities (SMC), evidencing contrasted effects. Conversely, stand density effects on SMC are less documented. The aim of this study is therefore to focus on the effects of stand density (SD) on SMC biomass, gene abundance, functional diversity, and activity, according two sylvicultural practices: dynamic (low SD) and conservative (medium SD) in a temperate Quercus petraea Stand (QS) in Europe Forest. We hypothesized that dynamic silviculture (low-SD) could promote soil SMC biomass, abundance, functional diversity, and activity. Our results showed that dynamic silvicultural practices in oak forests reduced the abundances of bacteria, archaea and fungi were reduced by 43 %, 29 % and 34 %, respectively. SMC functional diversity was reduced by 10 % in dynamic forestry stands. On the contrary, dynamic silvicultural practices increased soil microbial activity by 13 to 47 %, depending on the carbon source added, compared with conservative silviculture. Our results were incremented with an extensive number of biotic and abiotic environmental variables that had contrasting effects on SMC, and there is no single factor, which alone can explain all the SMC responses. Our results seem to advocate dynamic silvicultural practices in oak forests to promote soil microbial activity. However, it remains to be seen what the long-term effects will be of the reduced abundance and functional diversity of SMCs observed jointly in low-SD.

The relationship of growth characteristics and wood quality on the experimental plot of larch

Europski ariš (Larix decidua Mill.) pokazao je vrlo dobar rast i prilagodljivost ekološkim uvjetima u Bosni i Hercegovini. Cilj istraživanja je utvrditi varijabilnost morfoloških svojstava ariša na pokusnoj površini kod Kaknja, te varijabilnosti u početku osržavanja, kao i postojanje korelacija između ovih svojstava. U sjemenskoj sastojini ariša, osnovanoj sadnicama starosti 2+0 1979. godine, napravljena je trajna pokusna površina od 0,45 hektara i na njoj mjerene su visine i promjeri stabala 2002. i 2020. godine, te izračunate temeljnica i volumen. Stabla su 2020. godine bušena na prsnoj visini Preslerovim svrdlom kako bi se odredio udio osrženosti. Izračunate su prosječne vrijednosti svih svojstava. Zatim je odabrano po deset, pet i jedno najbolje stablo po svojstvima promjera, visine, temeljnice, volumena i izračunate razlike između prosječnih vrijednosti za deset stabala i ukupnog prosjeka, prosjeka za pet stabala i ukupnog prosjeka, te razlike između maksimalnih i prosječnih vrijednosti za istraživana svojstva. Također je izračunavat Pearsonov koeficijent korelacije između svih istraživanih svojstava. Prosječan promjer stabala starih 41 godinu bio je 24,6 cm, prosječna visina 21,8 m. Rezultati istraživanja osrženosti su pokazali da ariš prosječno počinje osržavati pri starosti od 14 godina. Pearsonov koeficijent korelacije za 2020. godinu pokazuje da postoji negativna korelacija između početka osržavanja prema svim ostalim svojstvima, odnosno stabla koja ranije osržavaju imaju veće vrijednosti svojstava rasta. Rezultati će biti korišteni u procesima individualne selekcije ariša sa dobrim visinskim i debljinskim prirastom i ranim osržavanjem.

Population structure and genetic diversity in Eucalyptus pellita based on SNP markers.

Eucalyptus pellita has the characteristics of rapid growth and high resistance. However, there is little research on molecular breeding of E. pellita, which is essential to shortening breeding life and selecting quality varieties. Therefore, a crucial step before selective breeding can be carried out to increase the wood quality of E. pellita is identifying genetic diversity and population structure using single nucleotide polymorphism (SNP) markers. In this study, the genetic diversity of 1st generation 196 E. pellita families from 23 geographically defined was assessed using 1,677,732 SNP markers identified by whole genome resequencing. SNP annotation showed that the ratio of non-synonymous to synonymous coding mutations was 0.83. Principal component analysis (PCA), phylogenetic tree, and population structure analysis permitted the families to be categorized into three groups, one of which (G2) contains most of the Indonesian (IDN) and Papua New Guinea (PNG) families. Genetic relationship analysis showed that IDN was closely related to PNG. Genetic diversity analysis showed that He, PIC, I, and H mean values were 0.2502, 0.2027, 0.3815, and 0.2680, respectively. PCA analysis classified various provenances in QLD into two categories (G1 and G3). The genetic diversity of G3 was higher than that of G2. The results of genetic differentiation (Fst) showed that PNG region was divided into two groups (PNG1 and PNG2), the Fst (0.172) between QLD and PNG2 region was higher than QLD and PNG1, and the Fst (0.024) between IDN and PNG1 is smaller than IDN and PNG2. A Mantel test revealed a positive correlation between the genetic and geographic distance of E. pellita. This study has a certain reference value for genetic identification, germplasm preservation, and breeding of E. pellita. Also, it provides a basis for subsequent association analysis to explore excellent alleles and introduction.

A comparative study on quantitative anatomical characteristics of compression, lateral, and opposite woods in Agathis loranthifolia and Pinus merkusii

Quantitative anatomical characteristics and their radial variation in compression (COW), lateral (LAW), and opposite (OPW) woods of Agathis loranthifolia and Pinus merkusii stem woods growing in Indonesia were observed and compared to understand wood quality. The length, diameter, wall thickness, and lumen diameter of tracheids and ray height and numbers were observed using optical microscopy. In both species, COW had the shortest tracheid length, smallest tracheid and lumen diameter, thickest cell wall, and highest ray numbers among the parts, while LAW and OPW showed comparable or variable values in quantitative characteristics. In A. loranthifolia, COW had the highest ray height, whereas, in P. merkusii, it had the lowest uniseriate and fusiform ray heights. No significant difference was observed in ray numbers and heights between LAW and OPW. In both species, the tracheid length and lumen-to-diameter ratio in COW, LAW, and OPW tended to increase from near the pith to near the bark while the wall-to-diameter ratio decreased. The ray heights of all parts increased with increasing distance from the pith, whereas the ray number decreased.

Cambial Age Influences PCD Gene Expression during Xylem Development and Heartwood Formation

Heartwood formation is an important ontogenetic stage in Scots pine (Pinus sylvestris L.). The amount of heartwood determines the proportion of functionally active sapwood in the total trunk biomass as well as the quality of wood. The key criterion for heartwood formation is the death of xylem ray parenchyma cells. Previously, models that described the patterns of heartwood formation, depending on the cambial age, were derived from Scots pine trees of different ages. The cambial age is the number of annual xylem layers at the core sampling site at a certain trunk height. We studied the features of the occurrence of programmed cell death (PCD) processes during the xylem differentiation and heartwood formation of 80-year-old Scots pine trees, depending on the cambial age, under the lingonberry pine forest conditions in the transition area of the northern taiga subzone and tundra. We have shown that the distance from the cambial zone to the heartwood boundary does not change significantly with stem height. As the cambial age increases, the lifespan of the formed xylem ray parenchyma cells increases and the activity of PCD genes decreases during the formation of both (1) xylem (in the outer layers of sapwood) and (2) heartwood (in the inner layers of sapwood and transition zone). We hypothesized that the decisive factor in the PCD initiation during heartwood formation is the distance of the xylem ray parenchyma cells from the cambial zone. The younger cambium forms wider annual increments, and therefore the xylem ray parenchyma cells in these parts of the trunk reach the distance from the cambial zone earlier, which is necessary for PCD initiation.

A method for identifying and segmenting branches of Scots pine (Pinus sylvestris L.) trees using terrestrial laser scanning

Abstract Terrestrial laser scanning (TLS) has been adopted as a feasible technique to characterize tree stems while the characterization of trees’ branching architecture has remained less explored. In general, branching architecture refers to the spatial arrangement of branches and their characteristics that are important when exploring the eco-physiological functioning of trees or assessing tree biomass and wood quality. Our aim was to develop a point cloud processing method for identifying and segmenting individual branches from TLS point clouds. We applied a Cartesian-to-cylinder coordinate transformation and a simple morphological filtering for stem surface reconstruction and stem-branch separation. Then branch origins were identified as their intersections with the stem surface, and individual branches were segmented based on their connectivity with the branch origins. The method, implemented in MATLAB and openly available, was validated on a 0.4-ha mature and managed southern boreal forest stand. The branch identification performance was assessed based on visual interpretation of 364 randomly sampled stem sections from 100 Scots pine (Pinus sylvestris (L.)) trees that were inspected for branch identification accuracy. The results showed that the branches could only be identified up to the height where the stem could be reconstructed. For 90% of the trees, this threshold ranged between 59.3% and 81.2% relative tree heights. Branches located below this threshold were identified with a recall of 75%, a precision of 92%, and an F1-score of 0.82. Based on our study, it appears that in a managed Scots pine stand, most of the branches can be identified with the developed method for the most valuable stem part eligible for logwood. The findings obtained in this study promote the feasibility of using TLS in applications requiring detailed characterization of trees. The developed method can be further used in quantifying the characteristics of individual branches, which could be useful for biomass and wood quality assessment, for example.