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Sweetgum (Liquidambar styraciflua) is an excellent short-rotation woody crop species for producing hardwood pulp and biofuel feedstock on marginal sites. A recent development which may improve growth is the production of hybrid sweetgum (L. formosana x styraciflua) clones. We compared the productivity and attributes, e.g., wood specific gravity and stand growth, of operational plantations of hybrid sweetgum clones to improved native sweetgum half-sib families in 36 stands in Oklahoma, Texas, and Louisiana, U.S. The least square means (LSMean) of wood specific gravity was significantly greater for hybrids clones than the half-sibs (0.49 vs. 0.46 g/cm3), and the hybrid clones had less taper which necessitated developing genotype-specific volume and biomass equations. Despite having less fertilizer inputs on average, the hybrids had greater standing green stem biomass than the half-sibs at an age of 8.5 years (LSMean of 73.3 vs. 51.9 Mg/ha). The hybrids as a group also exhibited greater green biomass growth during the 2022 growing season when compared to the half-sibs at 8.5 years (LSMean of 15.8 vs. 11.4 Mg/ha/y). Therefore, the hybrids provide growth and wood quality advantages that may provide an opportunity to increase productivity and profitability of hardwood SRWC plantings. [ABSTRACT FROM AUTHOR]

Pinus pinaster is a very important species for the Galician wood industry. A genetic breeding program was started in the 1980s to select plus trees based on growth and straightness. In this study, we estimated genetic parameters, juvenile-mature correlations and genetic gains in basic density (BD) and the dynamic modulus of elasticity (MOEd) in Galician breeding families, as well as their relation to volume, straightness, and tree slenderness. All traits were measured at a tree age of 12 years in three half-sib progeny trials. Wood quality traits were also measured at 24 years in two other trials. All progeny trials followed a randomized complete block design and the data were analyzed using several mixed-model approaches. The individual heritability of MOEd remained stable at both ages (~ 0.39) but decreased with age for BD (from 0.44 at age 12 to 0.24 at age 24). The high juvenile-mature correlations (0.51 for BD, 0.57 for MOEd) observed support the viability of early selection for both traits at 12 years. Both wood quality traits correlated positively with each other and weakly with volume, straightness and tree slenderness. Selecting a minimum number of the best families, based on volume or any wood quality trait, would generate genetic gains for the selecting trait and prevent genetic losses of non-selecting traits. We also identified specific families showing positive genetic gains for all traits. The research indicates that either or both of these wood quality traits could be included as new selection criteria in the Galician breeding program. [ABSTRACT FROM AUTHOR]

Trees in breeding programmes are often selected at 1/4–1/3 of rotation, called 'early selection', which is typically between 8 and 10 years in radiata pine. However, differences between populations and genotypes selected for either basic density or wood stiffness are already apparent at age 2. We report the application of very early screening techniques for wood properties in the New Zealand Radiata Pine Breeding Programme deployment populations. Approximately 3000 trees representing three populations with 92 families and 10 clones were grown in a common garden trial, leaning for 21 months to separate compression and opposite wood. The trees were harvested and analysis carried out separately by wood type. The trial showed the existence of large variability in wood properties at early age, in some cases similar to variability near rotation age, and moderate to high degree of genetic control ( 0.35 ≤ h 2 ≤ 0.71 ). The genetic association between traits was strong, particularly between wood stiffness and longitudinal shrinkage ( - 0.69 ) and between longitudinal and volumetric shrinkage (0.83), suggesting that improving stiffness would also have a strong effect on improving dimensional stability. Basic density was also associated with stiffness and shrinkage, but with lower predictive capacity. These results can be used for roguing deployment populations-which already contain superior growing trees-and quickly upgrade the wood quality of seeds and clones currently available to New Zealand forest growers. We discuss necessary modifications to turn this research work into operation to screen any new material before commercial release. [ABSTRACT FROM AUTHOR]

There is currently no quality sorting of harvested hardwood timber in Norway on a national scale. Medium- and high-quality logs including those from birch (Betula pubescens Ehrh., B. pendula Roth) are thus not utilized according to their potential monetary value. Increased domestic utilization of quality birch timber requires that the quality of harvested logs be properly assessed for potential end uses. A preferred sorting procedure would use visually detectable external log defects to grade roundwood timber. Knots are an important feature of inner log quality. Thus, the aim of this study was to evaluate whether correlations between branch scar size and knot features could be found in Norwegian birch. Using 168 knots from seven unpruned birch trees, external bark attributes often showed strong correlations with internal wood quality. Both length of the mustache and length of the seal performed well as predictors of stem radius at the time of knot occlusion. The presence of a broken off branch stub as part of an occluded knot significantly increased the knot-effected stem radius, proving that the practice of removing branches and branch stubs along the lower trunk is a crucial measure if quality timber production is the primary management goal. [ABSTRACT FROM AUTHOR]

The research conducted on kraft cooking of for different chip sizes is often not representative for the industrial process since the chip size fractions were made of high-quality wood without impurities. We evaluated the effects and the potential of cooking non ideal spruce chip fractions after industrial chipping and screening. The chips were classified according to SCAN 40:01, and the respective fractions were cooked under the identical conditions to mimic the effect of a joint cooking in the industrial digester. For the undersized chips we found higher bark content, a lower screened yield, a higher Kappa number, lower fiber length and lower tensile strength. For the oversized chips, the fiber length and tensile index were also considerably lower. A lower wood quality due to high knot content in the larger fractions was found to be the reason for that. Based on the data obtained from the experiments and literature, different process options for increased yield and reduced chemical consumption are discussed, e.g., separate cooking of different chip fractions. Improved chip screening seems to be the process improvement with lowest costs and highest impact. [ABSTRACT FROM AUTHOR]

Scientific information on the ash quality of Tachigalis vulgaris wood may reveal nutrient export mechanisms in energy forests and also insights into the wood quality for thermochemical conversions. This study aimed to evaluate the nutrient export and technological implications of ashes in the combustion of T. vulgaris grown in different planting spacings (4.5 m2;6.0 m2; 7.5 m2; 9 m2; 10.5 m2; 12.0 m2). The levels of inorganic elements were determined for 7-year-old trees cultivated in experimental plantations across the eastern Amazonia region. The element contents were used to obtain the export of nutrients and to calculate the fouling index (FI), basic to acidic compound ratio (B/A), sintering index (SI), slag viscosity index (SR), bed agglomeration index (BAI), and alkali index (AI). The most exported nutrients were Ca (18.7 kg/ha), P (13.9 kg/ha), and K (6.6 kg/ha). The FI, B/A, SI, and SR indices suggested deposition problems in the boilers for all planting spacings. However, BAI and AI indicated a low propensity to form fouling and slag. The spacing significantly influenced the P export. Planting spacing of 12 m2 demands increased P fertilization to maintain plantation productivity. The low ratio between alkaline earth and alkaline elements and high P2O5 values in the ash of T. vulgaris are disadvantageous. However, the high Al2O3 level and low ash content may contribute to the increase in the melting temperature of the ash. The study revealed that Tachigali vulgaris is a suitable species for wood production in energy forests. [ABSTRACT FROM AUTHOR]

The main mode of transport in Brazil is the road; however, the railroad has a freight rate 39% lower, which demonstrates its economic potential. Railroad ties are essential in railroads, and for many years, native wood was used as raw material. For environmental and economic reasons, it is important to identify reforested wood species with fast growth that may be used as ties. Thus, the present study aimed to evaluate the quality of Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus saligna, and Corymbia maculata woods for use as railway sleepers according to the NBR 7511 standard (ABNT, 2013) and compare them with the material inspection procedure PIM 14 (2016) of the National Department of Transportation Infrastructure (DNIT). It was observed that the wood of the species C. maculata presented the closest conditions for use as ties, probably due to its high density, which is directly reflected in the specific mass and mechanical properties of hardness and shear. However, this species showed less dimensional stability, due precisely to its high density and thus larger cell wall diameters. Successive to the good performance of C. maculata, the E. saligna was the second species that was best fit for use as ties, but it was not classified for two properties: traction and the sum of the properties: (B) hardness in MPa, (C) shear resistance in MPa, (D) normal strength resistance in MPa, (E) fracture toughness in MPa, respectively B + C + D + E. Nevertheless, it is the one that best presents dimensional stability. The other woods did not meet the minimum levels for use as ties. [ABSTRACT FROM AUTHOR]

The Legume family (Leguminosae or Fabaceae), is one of the largest and economically important flowering plants. Heartwood, the core of a tree trunk or branch, is a valuable and renewable resource employed for centuries in constructing sturdy and sustainable structures. Hongmu refers to a category of precious timber trees in China, encompassing 29 woody species, primarily from the legume genus. Due to the lack of genome data, detailed studies on their economic and ecological importance are limited. Therefore, this study generates chromosome-scale assemblies of five Hongmu species in Leguminosae: Pterocarpus santalinus, Pterocarpus macrocarpus, Dalbergia cochinchinensis, Dalbergia cultrata, and Senna siamea, using a combination of short-reads, long-read nanopore, and Hi-C data. We obtained 623.86 Mb, 634.58 Mb, 700.60 Mb, 645.98 Mb, and 437.29 Mb of pseudochromosome level assemblies with the scaffold N50 lengths of 63.1 Mb, 63.7 Mb, 70.4 Mb, 61.1 Mb and 32.2 Mb for P. santalinus, P. macrocarpus, D. cochinchinensis, D. cultrata and S. siamea, respectively. These genome data will serve as a valuable resource for studying crucial traits, like wood quality, disease resistance, and environmental adaptation in Hongmu. [ABSTRACT FROM AUTHOR]

Sex has a significant effect on various traits among dioecious plants. In this analysis of the sex effect on the radial growth and wood density of numerous 20-year-old trees of Populus deltoides growing in a common garden, male trees performed better than the females in radial growth, but sex did not significantly affect wood density. Growth rate and wood density were weakly negatively correlated. Sex selection is also critical for controlling seed-hair pollution from P. deltoides plantations. However, because the juvenile period of P. deltoides lasts for years, a reliable technique to determine the sex of juveniles has been needed. Here we developed a marker-aided technique to discriminate the sexes of P. deltoides seedlings. This study provides essential information on target traits and a highly desirable genetic toolkit for accelerate breeding programs for this important tree species. [ABSTRACT FROM AUTHOR]

Key message: In Tachigali vulgaris planting, the 3.0 × 3.0 m spacing reduced variability in wood properties and increased the proportion of medium-density wood, while forking increased the proportion of low-density wood. Promising Amazonia species for forest energy crops require further investigation into how silviculture affects wood quality. This study sought to investigate how planting spacing and stem type (forked and non-forked) affect the basic wood density, X-ray density, and heartwood development of Tachigali vulgaris in a homogeneous plantation in Amazonia. The experiment was established with initial planting spacings of 3.0 × 1.5 m, 3.0 × 2.0 m, 3.0 × 2.5 m, 3.0 × 3.0 m, 3.0 × 3.5 m, and 3.0 × 4.0 m. 102-month-old trees were harvested for the work. Disks sampled along the stem height were tested for wood basic density and density measured by X-ray densitometry (air-dry density by growth ring) analyses. Disks obtained at the 1.3 m height were photographed and submitted to image manipulation for heartwood/sapwood analysis. The lowest average wood density was 0.512 g cm−3 in the 3.0 × 1.5 m spacing, and the highest was 0.538 g cm−3 in the 3.0 × 4.0 m spacing. Among non-forked trees, 66% had medium-density (≥ 0.500 g cm−3) and 34% low-density (< 0.500 g cm−3) wood. In contrast, forked trees had only 55% of trees with medium-density wood. The X-ray density profiles reduced from 0.713 to 0.582 g cm−3 in the increasing longitudinal direction and from 0.393 to 0.973 g cm−3 in the radial direction. Forking did not influence the heartwood proportion (60.03–61.54%). The 3.0 × 3.0 m spacing favored the wood quality concerning density class and variability, while the widest spacings improved heartwood formation. The forking increases the chances of low-density wood and its variations along the stem. Thus, future genetic studies should focus on this phenomenon to increase the productivity of Tachigali vulgaris energy forests. [ABSTRACT FROM AUTHOR]

Fuel quality is an important measure to assess as conventional fuel resources have been depleted at an alarming rate over recent years. For centuries, wood-based biofuels have been used extensively as the primary fuel source for boilers or heating plant operations. In a heating plant scenario, operating temperature, moisture content, gas usage, emission controls, etc., play a significant role in fuel quality assessment. Additionally, the advent of solar energy and its popularity in drying applications has provided ample opportunities to explore wood solar drying. Hence, improving the wood-based biofuel quality by implementing solar drying strategies has caught research attention in recent decades. However, there is a lack of well-documented review on the classifications of wood solar drying systems and the various modeling and simulation approaches that evolved in recent years for their performance optimization. This work reviews extant wood fuel quality problems and regional and technical challenges worldwide. Further insights into the possible solutions (through modeling or simulation) to enhance wood-based fuel quality by adopting solar drying technologies are discussed briefly. Notably, a case study of real-time data assessment of wood chips as biofuel in a boiler plant in Miskolc, Hungary, is presented. The outcomes of this review would serve as a benchmark and aid industries and researchers in further exploring wood solar drying potential. [ABSTRACT FROM AUTHOR]

Genomic selection methods are particularly useful for traits that are difficult or expensive to measure. We investigated the impact of using predictor growth traits and/or genomic information to increase the breeding value (BV) predictive accuracies for target scarcely recorded wood quality traits in an open-pollinated Eucalyptus grandis population. The performance of single- and multiple-trait single-step genomic best linear unbiased prediction and conventional pedigree-based models were compared in terms of the predictive accuracies (PA) of estimated BV for the target traits. We also derived the contributions of the BV for candidate trees to better understand our results. The inclusion of predictor traits in both, the training and the validation sets, together with genomic information, improved the PA (up to 17.7%) for pulp yield and cellulose. However, significant improvements in PA were not observed when predictor traits were recorded only in the training set or when the impact of genomic information alone was assessed. Changes in the PA were explained by the variations in the maternal contributions, contribution/s from all the predictor/s trait/s, and from genotyped trees. We conclude that there is not a "universal" rule regarding the use of genomic information and records on predictor traits. However, assessing the contributions to the BV of validation trees may help to better design how to benefit from predictor traits in forest tree breeding. [ABSTRACT FROM AUTHOR]

Wood processing is one of the most widely used in agriculture and industry. Low precision and high time delay of machine learning in wood defect detection are currently the main factors restricting the production efficiency and product quality of the wood processing industry. An SPP-improved deep learning method was proposed to detect wood defects based on the basic framework of the YOLO V3 network to improve accuracy and real-time performance. The extended dataset was firstly established by image data enhancement and preprocessing based on the limited samples of the wood defect dataset. Anchor box scale re-clustering of the wood defect dataset was carried out according to the defect features. The spatial pyramid pooling (SPP) network was applied to improve the feature pyramid (FP) network in YOLO V3. The validity and real-time performance of the proposed algorithm were verified by a randomly selected test set. The results show that the overall detection accuracy rate on the wood defect test dataset reaches 93.23% while the detection time for each image is within 13 ms. [ABSTRACT FROM AUTHOR]

Basic wood density is an excellent indicator of quality, it is correlated with numerous physical, physiological and mechanical characteristics of a species and is a good descriptor of wood quality and important indicator of tree performance in community ecology. An accurate method is thus needed to estimate wood density. The standard way is to calculate the ratio of the oven-dried mass of a wood sample divided by its green volume, but wood characteristics within and between growth rings are highly variable; the density can vary in the longitudinal and the radial directions. The present study investigates the longitudinal and radial fluctuations in the basic density of Abies cephalonica Loud and Pinus halepensis Mill. Four logs were cut from four different trees for each species and 16 discs were formed (two discs from each log, one at the base and one at the top). Each disc was cut into cubes where their distance from the pith was measured and then sorted into 2 cm wide concentric zones. The results revealed a mild decreasing trend in basic density from the foot of the trunk upward for both species. The pith in both species also seems to have a relatively high density, which in the immediate next growth rings decreases only to resume increasing toward the bark. [ABSTRACT FROM AUTHOR]

Key message: Near-infrared hyperspectral imaging allows to build suitable wood density maps for 6-year-old Eucalyptus grandis trees. Robust age–age correlations from wood density maps suggest feasible early tree selection for wood density. Wood is a heterogenous material whose properties vary over time, making it difficult to predict the wood properties at a given age of trees in the future. The site and climate are also factors affecting wood heterogeneity. To improve the accuracy of early selection of trees in drier sites, it is thus important to study inter-annual variations in wood density in conditions of contrasting water availability. We tested the use of near-infrared hyperspectral imaging (NIR-HSI) to assess inter-annual wood density and predict wood density at a future age to evaluate the accuracy of early selection of Eucalyptus grandis trees for wood density and to see if a drier site influences early selection. We sampled 38 six-year-old trees growing under two different water regimes: (i) 37% throughfall reduction (–W), to simulate a dry site, and (ii) undisturbed throughfall (+ W). NIR-HSI images were used to build high-resolution wood density maps of the whole cross section. After the annual growth rings were delimited, the average wood density at each age and in growth ring was extracted to evaluate juvenile–mature correlations in the wood. The NIR-HSI images calibrated with a locally weighted partial least square regression (LWPLSR) model, using raw spectra, performed well in predicting the wood density of the whole cross section. Correlations for wood density between ages 1–3 and 5–6 were strong (r = 0.85 to 0.94), while correlations between rings 1–3 and 4–5 were moderate to strong (r = 0.51 to 0.87). In − W plots, juvenile–mature correlations were slightly lower than in + W plots. Our results suggest that early E. grandis selection for wood density is feasible to predict wood density at 6 years of age. [ABSTRACT FROM AUTHOR]

This paper deals with mathematical modeling of mold growth on wood. The logistic growth equation is used to model mold growth phenomena in changing environmental conditions. Microscopic mold coverage fraction is used in the logistic equation to represent mold development on a material surface over time. The current state-of-the-art dynamic Finnish mold growth model is used as the reference model for development of the logistic mold growth model. The optimal values of mold growth coefficient are estimated by simulations of mold growth under constant environmental conditions and by finding the best agreement with the Finnish mold growth model using mathematical optimization methods. It is shown that the mold growth coefficient can be approximated as a function of relative humidity, temperature, wood species and the quality of the surface. The model parameters are then verified by a comparison with the Finnish mold growth model. In this case, cyclic step changes of constant relative humidity are used. Finally, the logistic mold growth model is compared with published experimental observations of mold growth. The discrepancy of mold growth models and experimental mold growth data, and possible improvements are discussed. [ABSTRACT FROM AUTHOR]

Reforestation with species of the Eucalyptus genus provides the main biomass source for energy purposes in Brazil. However, the country's northern region lacks such crops to meet the demand of the second-largest national steel pole. The species is a promising source of biomass, as it is native to the region and grows at high rates. Thus, this research aimed to evaluate the effect of planting spacing (4.5, 6.0, 7.5, 9.0, 10.5, and 12 m2 per plant), tree age (87 and 102 months) and stem forking on dendrometric variables and wood basic density of T. vulgaris trees from a trial plantation located in Eastern Amazonia. The commercial volume, basic density, form factor, and dry wood mass of trees were determined. The forked trees had a higher volume (0.2492 m3) and dry wood mass (112.88 kg) than non-forked trees (average volume of 0.1573 m3 and 73.66 kg of dry wood mass). At 87 months, wood basic density was found higher in wide spacings (9 and 12 m2 plant− 1). At 87 months, the non-forked and forked trees presented basic densities of 0.505 and 0.474 g cm− 3, respectively. The forked trees at 102 months spaced by 9 m2 had a basic density > 0.500 g cm− 3, a desirable parameter for charcoal production. Thus, this study confirmed the relevance of planting spacing, age, and stem type on the basic density of T. vulgaris, supporting future studies to define the best silvicultural practices and decision-making on the species by forest companies located in Amazonia. [ABSTRACT FROM AUTHOR]

Elevated concentration of heavy metals has been reported in Brachystegia longifolia trees attributed to pollution emanating from a copper mine in Mufulira, Zambia. This study investigates the growth response of B. longifolia to copper mining pollution induced growth stress. Wood discs were extracted at breast height from eight sampling sites established along a transect up- and downwind of the mine, representing polluted and unpolluted areas. The annual ring width was measured using a LINTAB supported by TSAP-Win software. Significant decreases were observed in B. longifolia radial growth on polluted sites compared to control sites. The tree growth reduction was attributed to Cu and Fe phytotoxicities through a multivariate analysis and the reduced growth manifested in a decreased ring width in response to heavy metal stress on polluted sites. This study demonstrates that B. longifolia trees are vulnerable to copper mining pollution and that the mining activities affect the wood quality negatively. [ABSTRACT FROM AUTHOR]

Tectona grandis L.f. (teak), though considered a paragon among timber species, raises several questions on quality parameters when grown on farmlands. The growth characteristics and important wood quality parameters such as equilibrium moisture content, density, shrinkage, static bending strength and stiffness, compressive strength parallel and perpendicular to grain, hardness, nail and screw holding powers of 24–25-year-old teak from intensively managed block (Bim), partially managed line (Lpm) and unmanaged block (Bum) plantations grown under agroforestry practices (AFP) were studied. Overall growth rate of teak trees of Bim was greater than Lpm and Bum. Few wood quality parameters of Bum were comparatively better than Bim and Lpm. However, teak from three AFP exhibited lower wood quality parameters compared to average values of forest teak. Superiority of Bum is reflected mainly in density and bending strength compared to Bim and Lpm. Other properties like compressive strength, hardness and nail and screw holding powers were almost comparable among three AFP. Flexural strength, compression parallel to grain and hardness of Bim and Lpm were found to be comparable. Average wood properties of both managed plantations were lower than Bum. There was no significant effect observed in specific gravity of wood when age of trees increased from 12 to 24 years. Although, Bum exhibited better or comparable properties to Bim and Lpm, average growth was significantly lower than managed plantations. Selective harvesting of Bum at pole stage may support optimal resource utilization, reduce inter-tree competition and provide an option to further delay felling of unharvested residual trees. Delayed harvesting of teak may provide more optimal economic utilisation as strength parameters are predicted to improve with increased maturity. If a decision to enhance financial returns is warranted, commercial felling could be initiated for Bim among the three options, due to its higher growth rate and moderate wood properties which can translate into higher returns. The outcome of the present study may be useful to stakeholders for taking appropriate management decisions for optimal utilization of the farm grown teak bioresource. [ABSTRACT FROM AUTHOR]

One of the goals of the European Union's agroforestry plans is to alleviate the shortage of timber in Europe caused by the growing demand for hardwoods and the declining import of tropical timber. The study shows which tree species can be considered in agroforestry systems in Europe, and which of them can be used as raw material for the wood industry and what quality of wood can be produced in agroforestry systems. Since 2005, the European Union has been officially encouraging farmers to plant the crops in an agroforestry system and parallel try to produce trunks for high quality timber. By analysing the current economic developments of the European Union, especially Horizon 2020, our study provides an overview of what can be expected by the participants of the agroforestry sector and the related primary wood industry in the European Union now and in the future. In addition to the distribution analysis, indices describing projects have also been created. Rank correlation was used to examine the relationship between them. Possible decision mechanisms were also outlined using a custom-built expert software system. [ABSTRACT FROM AUTHOR]

Genomic selection (GS) is poised to revolutionize eucalypt tree improvement by shortening breeding cycles and increasing selection intensities. This could be particularly valuable for alternative, non-mainstream Eucalyptus species that are still in the initial stages of breeding. Eucalyptus benthamii is important for its adaptation to frost-prone subtropical regions. In this work, we compared seven genomic prediction models, six Bayesian and one frequentist GBLUP (Genomic Best Linear Unbiased Prediction) with the conventional pedigree-based ABLUP approach. Models were evaluated for their ability to estimate heritabilities and predict wood quality traits (wood density, extractives, lignin, and carbohydrates content) and volume growth in 77 open-pollinated families of Eucalyptus benthamii. We also evaluated predictive abilities and heritabilities using variable numbers of SNP in the models. Heritabilities ranged from 0.09 (extractives content) using Bayesian Lasso (BL) to 0.55 (wood density) using ABLUP. Predictive abilities (PA) ranged from 0.12 (for volume using ABLUP) to 0.44 (for wood density using three Bayesian models). All seven genomic models performed similarly well and better than the pedigree model for all traits, except extractives content. Subsets of 5000–7000 SNPs yielded heritabilities and PAs nearly as large as using all 15,293 SNPs. However, a low-density SNP panel might not be economically and technically advantageous compared to the current high-density multi-species Eucalyptus EUCHIP60k. Our results support a positive outlook to implement GS to accelerate Eucalyptus benthamii breeding for adaptation to frost-prone regions. [ABSTRACT FROM AUTHOR]

Nutrient return to soil by applying forest industry residues help ameliorate soil nutrient exhaustion and promote forest management sustainability. This study evaluated the effects of forest industry residue application on soil attributes, on forest floor amounts, and on growth and nutrition of Pinus taeda L. (loblolly pine). Six rates (0, 14, 25, 49, and 60 T ha−1) of residue (boiler ash and cellulose sludge mixture) were applied to P. taeda stands on a low fertility soil. Seven years after application, trees were harvested for wood volume, wood biomass, canopy mass, and nutrient composition. Wood density was determined along the trunk length. Soil samples from 0–10 to 10–20 cm depths were collected for evaluating chemical attributes. Although residue application only resulted in small increases in soil Ca and P availability, high yield enhancements were observed with no compromise to wood density. Maximum growth response was obtained with the 49 T ha−1 residue application. This rate enhanced trunk volume from 117 to 250 m3 ha−1, total biomass from 76 to 127 T ha−1, and total C from 34.5 to 57.2 T ha−1. Residue application decreased Mn content in all biomass compartments, and values above 193.5 (needles) and 26.2 mg kg−1 (bark) defined low annual growth increases. Residue application also decreased Al, Fe, S, B, Ca, and P concentrations in branches or needles. Forest floor was enhanced by residue amendment, which increased C sequestration by 7 T/ha. Forest sustainability practices can be enhanced by applications of industrial residues while improving tree yield and nutrition. [ABSTRACT FROM AUTHOR]

Trade-offs between high stand productivity and good wood quality exist for chestnut coppices and related wood-based products. The main objective of this study was to determine the most suitable duration (in years) of cutting cycles that maximizes stand productivity and preserve wood quality of chestnut coppices in a Mediterranean setting. To this aim, a stand-level growth model was developed to verify if wood quality of chestnut coppices at different stand ages varies when the rotation period is modified. Wood quality and stand productivity were analysed, using a chronosequence approach, in coppice stands in Southern Italy characterized by four cutting cycles (15, 25, 30, and 50 years). Results implied that the culmination of the mean annual increment occurs at 28 years, while the current annual increment culminates 10 years earlier. The MOEd values revealed a negative correlation with shoot age; however, a cutting cycle between 25 and 30 years might represent the best compromise for balancing stand productivity and wood quality. Results are discussed in the context of adaptive forest management. [ABSTRACT FROM AUTHOR]

The aim of this study was to conduct single- and multi-trait genome wide association studies (GWAS) and identify quantitative trait loci (QTLs) for the expression of phenotypic traits in Eucalyptus grandis. We evaluated an open-pollinated breeding population with 1772 genotypes composed of 25 different families established using a randomized complete block design. We performed single-trait GWAS using the fixed and random model circulating probability unification (FarmCPU) and multi-trait GWAS for genetically correlated phenotypic traits using the multi-trait mixed model (MTMM). Then, gene annotation was identified through the Phytozome database. The FarmCPU model identified 43 and 38 QTLs that are significantly associated with growth and wood quality traits, respectively. Similarly, 40 pleiotropic QTLs were discovered using the MTMM model. Gene ontology for single-trait analysis identified loci responsible for regulating several important biological processes in different tissues and at different stages of maturation. On the other hand, the multi-trait model identified loci associated with gibberellin signaling, which regulates several aspects of plant growth and development, as well as loci related to the reinforcement of cell wall composition. Our study demonstrates the complex nature of E. grandis quantitative traits and provides new evidence of loci not described before which are associated with the expression of important phenotypic traits. [ABSTRACT FROM AUTHOR]

The aim of this study is to estimate the physical properties, absorbed energy, impact bending strength, and Monnin hardness of clonal Eucalyptus wood (E. grandis, E. camaldulensis) from the region Maâmora (North-West of Morocco). The physical properties, impact bending strength, and Monnin hardness were evaluated on standard samples according to the French norms AFNOR. The obtained results show that the wood of two Eucalyptus clones is classified in the category of medium density, nervous, and normal quality wood. The E. camaldulensis wood has high average values of volumetric, tangential, radial, and longitudinal shrinkage, which are 17.440; 10.731; 6.957; and 0.373% compared to E. grandis wood, which are 14.851; 9.383; 5.718; and 0.366%, respectively. The mean values of absorbed energy and impact bending strength are great for the radial direction compared to the tangential direction for both E. camaldulensis and E. grandis wood. Moreover, the E. camaldulensis wood exhibits high values for absorbed energy, impact bending strength, and Monnin hardness than that of E. grandis wood. The correlation analyses appeared that the shrinkages (volumetric, radial, tangential), impact bending strength, and Monnin hardness have a significantly positive correlation with the oven-dry density of E. grandis and E. camaldulensis wood. The good knowledge of clonal Eucalyptus wood shrinkage may help us to take suitable procedures to reduce their influence (such as collapses) during drying this wood type. Furthermore, knowing its physical and mechanical properties is necessary to reveal the possibility of their use in construction, carpentry, and other works. [ABSTRACT FROM AUTHOR]

The quality control of wood products is often only checked at the end of the production process so that countermeasures can only be taken with a time delay in the event of fluctuations in product quality. This often leads to unnecessary and cost-intensive rejects. Furthermore, since quality control often requires additional procedural steps to be performed by a skilled worker, testing is time-consuming and costly. While traditional machine learning (ML) methods based on supervised learning have been used in the field with some success, the limited availability of labeled data is the major hurdle for further improving model performance. In the present study, the potential of enhancing the performance of the ML methods random forest (RF) and support vector machines (SVM) for quality classification by using semi-supervised learning (SSL) was investigated. Labeled and unlabeled data were provided by Swiss Wood Solutions AG, which produces densified wood for high-value wood products such as musical instruments. The developed approach includes labeling of the unlabeled data using SSL, training and 10k cross-validation of the ML algorithms RF and SVM, and determining the generalization ability using the hold-out test set. Based on the evaluation indices such as accuracy, F1-score, recall, false-positive-rate and confusion matrices, it was shown that SSL could enhance the prediction performance of the quality classification of ML models compared to the conventional supervised learning method. Despite having a small dataset, the work paves the way for future applications of SSL for wood quality assessment. [ABSTRACT FROM AUTHOR]

Lignin is essential for the characteristics and quality of timber. Nitrogen has significant effects on lignin contents in plants. Nitrogen has been found to affect wood quality in plantations and lignin content in plants. Caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) is an important methyltransferase in lignin biosynthesis. However, the classification of woody plant CCoAOMT gene family members and the regulation mechanism of nitrogen are not clear. Bioinformatics methods were used to predict the members, classification, and transcriptional distribution of the CCoAOMT gene family in Populus trichocarpa. The results showed that there were five PtCCoAOMTs identified, and they could be divided into three sub-groups according to their structural and phylogenetic features. The results of tissue expression specificity analysis showed that: PtCCoAOMT1 was highly expressed in roots and internodes; PtCCoAOMT2 was highly expressed in roots, nodes, and internodes, PtCCoAOMT3 was highly expressed in stems; PtCCoAOMT4 was highly expressed in young leaves, and, PtCCoAOMT5 was highly expressed in roots. Different forms and concentrations of nitrogen had varying effects on the expression patterns of genes in different plant tissue types. The results of real-time PCR showed that the expression levels of PtCCoAOMT1 and PtCCoAOMT2 in stems increased significantly under different forms of nitrogen. PtCCoAOMT3 and PtCCoAOMT4 were induced by nitrate nitrogen in upper stems and lower leaves, respectively. PtCCoAOMT4 and PtCCoAOMT5 were induced by different concentrations of nitrate nitrogen in lower stems and roots, respectively. These results could provide valuable information for revealing the differences between functions and expression patterns of the various CCoAOMT gene family members under different forms and concentrations of exogenous nitrogen in poplar. [ABSTRACT FROM AUTHOR]

Branches are as essential for tree growth as knots are detrimental from the wood quality point of view. To bridge the gap between tree growth and the quality toward end-use, this study aims to establish a relationship between internal and external diameters of Douglas-fir whorl branches. The data comprised 102 trees of a wide age range (30–80 years old) from nine study sites in Southwest Germany. External branch measurements were performed in the field following an established protocol. Logs were scanned on a MiCROTEC CT.LOG, and knots were detected by applying an automated algorithm. Obvious detection artefacts by the CT algorithm were excluded to reveal the relationship between inner-outer branch diameters as clear as possible. Results showed a significant mean difference of 13.8 (± 10.0) mm between the methods (external diameter being larger), with a model indicating an offset of 9.75 mm and angular shift of 0.53 (RMSE = 7.12 mm; R2 = 0.57) between the methods. Separate calculations of sound and dead datasets did not reveal a statistically significant difference. By linking the internal knot structure to external branch measurements, the findings of this study constitute a first step toward the incorporation of CT data into growth models, providing a meaningful prediction of the maximum internal knot diameter at an early stage in the wood supply chain. [ABSTRACT FROM AUTHOR]

Branches are not only of vital importance to tree physiology and growth but are also one of the most influential features in wood quality. To improve the availability of data throughout the forest-to-industry production, information on internal quality (e.g. knots) of both felled and standing trees in the forest would be desirable. This study presents models for predicting the internal knot diameter of Douglas-fir logs based on characteristics measured in the field. The data were composed of 87 trees (aged from 32 to 78 years), collected from six trial sites in southwest Germany, and cut into 4–5 m logs on-site. The internal knot diameter was obtained by applying a knot detection algorithm to the CT images of the logs. Applying the Random Forest (RF) technique, two models were developed: (1) MBD: to predict the branch diameter (BD) at different radial positions within the stem, and (2) MBDmax: to predict the maximum internal branch diameter (BDmax). Both models presented a good performance, predicting BD with an RMSE of 4.26 mm (R2 = 0.84) and BDmax with an RMSE of 5.65 mm (R2 = 0.78). In this context, the innovative combination of CT technology and RF modelling technique showed promising potential to be used in future investigations, as it provided a good performance while being flexible in terms of input data structure and also allowing the inclusion of otherwise underexplored databases. This study showed a possibility to predict the internal diameter of branches from field measurements, introducing an advance towards connecting forest and sawmill. [ABSTRACT FROM AUTHOR]

Purpose: Soil physical-chemical characteristics are key factors to intraspecific variability in plant functional traits. However, little is known about how wood and leaf traits can interact to ensure similar tree growth and wood quality in sites with different edaphoclimatic conditions. Here, we investigated the effect of soil on the wood features, leaf traits, and plant growth in Eucalyptus urophylla and E. urophylla x grandis trees. Methods: We evaluated the wood features, leaf traits and tree growth in 20 six-year-old trees from the same clone of each species. We applied linear models to verify the variability in these characteristics for both clones in two trial sites. Results: Wood with larger vessels in a lower density, higher potential hydraulic conductivity, taller and wider rays, a higher fraction of vessels and parenchyma cells and a lower fraction of fibers were observed in trees from the trial site with higher availability of water and nutrients. Moreover, the trees had lower specific leaf area and higher leaf dry matter content in this trial site. Conclusion: Our results show that trees studied have similar wood features that ensure safety and relative efficiency in water transport. In addition, we found different leaf traits strategies to optimize carbon uptake, thus maintaining similar productivity and wood quality in sites with different soil conditions. [ABSTRACT FROM AUTHOR]

Wood decomposition is faster in open habitats than closed-canopy forests, with the mechanisms unclear. When allowing access, termites outcompete fungi during wood decomposition. If increasing canopy density shifts the dominance from termites to fungi, decomposition rates will fall. We conducted wood decomposition experiments in 148 plots of two regenerating forest sites (Site A vs. B) in subtropical China with tree species diversity and composition (for example, specific leaf area) manipulated. Branches of seven species with varying quality were deployed and measured for wood mass-loss rates and decomposer abundance at two time steps (that is, after 1 year and 2 years). We also monitored understory microclimate and predatory ant diversity in 40 plots of Site A. We found that higher canopy density drove the shift of dominance from termites to fungi via facilitating predatory ants and wetter–cooler microclimate. Furthermore, termites promoted decomposition after 1 year especially for the species with highest wood quality, but fungi slowed decomposition after 2 years especially for two species with lower quality. Notably, canopy density negatively correlated with wood mass-loss rates in closed-canopy Site A but not so in more open Site B. Tree diversity and community-weighted mean specific leaf area increased canopy density but did not affect abundance nor decomposition. Our study highlights the importance of canopy density for retarding fine wood decomposition in closed-canopy regenerating forests, probably via shifting the dominance from more (that is, termites) to less efficient decomposer (that is, fungi). Future cross-regional studies are necessary to test the generality of canopy density effect on wood decomposition and the related mechanisms. [ABSTRACT FROM AUTHOR]

Pine plantations are an important wood source in Brazil, with Pinus taeda being most frequently planted. Most pinewood is directed to the paper and pulp industry, but there is an increasing demand for wood for solid end-uses, requiring large stems from longer rotations which can be obtained using P. taeda as the canopy in two-aged stands. We evaluated radial growth and wood density at different stem heights of P. taeda in the highlands of Southern Brazil over a production period of 36 years and subjected to shelterwood harvest. Cross-sectional disks were obtained from 15 trees in different stem heights; 10 were used for growth analyses and 5 for growth and density analyses. We used disk images and X-ray techniques for growth and density analyses, respectively. Samples were analyzed for ring (width and density), earlywood, and latewood (width, density, and proportion). Ring width varied between 0.4 and 1.7 cm, with the widest rings in the first years (3–5 years.) of growth. Ring density increased with age, with higher densities on the lower stem portions. Mature wood started to be formed from the 16th ring onwards. Shelterwood harvest affected both ring width and density, but the effects on ring width lasted for at least 5 years, while the effects on wood density were short-lasting. Mature P. taeda trees increased their size after the shelterwood harvest without compromising their wood density. Longer production periods of P. taeda as retained trees in the canopy of two-aged stands provide high-quality wood for structural purposes. [ABSTRACT FROM AUTHOR]

Trees are vital resources to human ecology. Many trees, wooden logs and timbers lose their quality when they degrade due to fungal decay and insect attacks. In this work, stress wave method and radiography technique are the Nondestructive Evaluation (NDE) tools employed to check the presence of the defects in an Artocarpus heterophyllus wooden log. The influence of these defects, especially, the fungal decay on wood quality is studied by introducing an artificial defect and the resulting properties obtained are evaluated using stochastic approaches. A theoretical model for the distribution of the wood properties is proposed using Radon transform and the results are compared with the path analysis of the stress wave velocities in random cross-sections of the wood. Additionally, the variability of the properties for different grain angles is calculated using Hankinson equation. Further, the results are analyzed statistically using Weibull distribution and effect size to inspect the quality and invasiveness of the defects, respectively. Results show that a reasonable prediction of the properties can be made from the analytical formulation and the Weibull modulus can be used to quantify the wood quality. Finally, the values of Weibull modulus and effect size are compared and validated for the two NDE techniques. [ABSTRACT FROM AUTHOR]

There is a growing interest in improving wood properties through clonal selection. However, traditional methods for determining wood properties are difficult to implement at the scale required for large-scale selection programs. In this study, we used rapid phenotyping methods (i.e., drill resistance (DR) and stress wave velocity (SWV)) for assessing wood quality in a 3-year-old clonal trial containing 125 clonal poplar hybrids. These hybrids belong to interspecific crosses of Populus deltoides [D], P. trichocarpa [T], P. nigra [N], and P. maximowiczii [M]. We estimated clonal variation and correlations among DR, SWV, basic density (BD), and dynamic modulus of elasticity (MOEd). Clonal repeatabilities were moderate for all traits, but were higher for BD and DR (i.e., R2 = 0.45 and 0.46, respectively) than for SWV and MOEd (i.e., R2 = 0.30 and 0.35, respectively). Clonal mean phenotypic correlations were high between BD and DR (rc = 0.84) and between SWV and MOEd (0.87), and the clonal correlations (rg) were 0.90 and 0.96, respectively. Overall, there was a weak relation between BD and MOEd (rc = 0.23 and rg = 0.29, respectively). Results support the use of DR and SWV as tools for the selection of poplar clones oriented to improve solid wood properties. [ABSTRACT FROM AUTHOR]

The biodiversity–ecosystem function relationship is a central topic in ecology. Fungi are the dominant decomposers of organic plant material in terrestrial ecosystems and display tremendous species diversity. However, little is known about the fungal diversity–decomposition relationship. We evaluated fungal community assemblies and substrate quality in different stages of wood decay to assess the relationships between fungal species richness and weight loss of wood substrate under laboratory conditions. Wood-inhabiting fungal communities in the early and late stages of pine log decomposition were used as a model. Colonisation with certain species prior to inoculation with other species resulted in four-fold differences in fungal species richness and up to tenfold differences in the rate of wood substrate decomposition in both early- and late-decaying fungal communities. Differences in wood substrate quality had a significant impact on species richness and weight loss of wood and the relationships between the two, which were negative or neutral. Late communities showed significantly negative species richness–decay relationships in wood at all decay stages, whereas negative relationships in early communities were significant only in the intermediate decay stage. Our results suggest that changes in fungal communities and wood quality during wood decomposition affect the fungal diversity–decomposition relationship. [ABSTRACT FROM AUTHOR]

Trees accumulate biomass by sequestrating atmospheric carbon and allocate it to different tree components. A biomass component ratio is the ratio of biomass in a tree component to total tree biomass. Modeling the ratios for Zelkova serrata, an important native reforestation tree species in Taiwan, helps in understanding its biomass allocation strategy to design effective silvicultural treatments. In this study, we applied Component Ratio Method (CRM) to relate biomass component ratios of main stem, large branch, twig, and foliage to tree attributes of Z. serrata from a 9-year-old plantation. Nonlinear and linear CRM models were fitted with Seemingly Unrelated Regression to account for model correlations. Linear CRM models with dbh as the predictor had the best fit with model correlations as high as 80%. About 46% and 40% of total tree biomass was allocated to main stem and large branch, respectively. However, main stem biomass decreased by 1.9% with every 1-cm increase in dbh, but large branch biomass increased by 2.2% instead. Results suggest that dominant Z. serrata trees tend to branch and fork, while smaller trees invest in larger main stem. An early pruning treatment should focus on dominant trees to maintain crown ratio and ensure wood quality. [ABSTRACT FROM AUTHOR]

Picea mongolica, a native species with excellent industrial wood quality and strong sand-fixing capacity, may be utilized in construction of urban green spaces in arid areas in China. However, now the sustainability of the ecosystems where this species grows is at serious risk due to a lack of natural regeneration. In this study, we developed an efficient regeneration system and comprehensively analyzed various factors affecting somatic embryogenesis (SE) using zygotic embryos as explants. We identified the optimal plant growth regulators (PGRs) performance and the best donor trees (k81) for the generation of somatic embryos (SEMs). Additionally, we confirmed that the positive developmental window of SEMs initiation was at the end of July to early August, which is when zygotic embryos was at the late embryogeny. In this time period, specific transcripts associated with the regulation of epigenetic modifications, plant hormone-related genes, and embryonic development-related transcription factors play important roles for early SEMs initiation. These results may provide a valuable resource for vegetative propagation of Picea mongolica. Our results may help to establish a reliable protocol for plantlet regeneration, which may facilitate urban greening applications and industrialization in arid areas. [ABSTRACT FROM AUTHOR]

Several studies have highlighted the importance of the chemical composition of Eucalyptus woods in the generation of thermal energy and charcoal production. However, the influence of wood chemical constituents on the pyrolysis mass balance is still not sufficiently clear. This paper brings new insights about the influence of extractives and guaiacyl (G) to syringyl (S) ratio of lignin macromolecule in the carbon, hydrogen, and oxygen balances of the pyrolysis process. Thus, the aim of this research was to investigate the effect of the wood quality of genotypes of Eucalyptus on the carbonization mass balances. Ultimate analysis, structural chemical constituents, and lignin composition analyses were carried out in 14 clonal materials of Eucalyptus spp. at 81 months of age. After pyrolysis, the ultimate analysis of charcoal and the carbonization mass balance was also investigated. The findings show a positive relationship between the percentages of carbon and hydrogen retained in the charcoal with the lignin content and its composition. E. camaldulensis (clone 1025) and E. grandis hybrids (clone 1039) presented better wood quality for charcoal production, due to the results of gravimetric yield (35.7%), retained carbon (59.6%), and retained hydrogen (20.2%) after pyrolysis. In addition, these genetic materials stood out for the high values of lignin (32.0%), extractives soluble in acetone (2.4%), and mass of guaiacyl per kg of dry wood (27.2 g kg-1) associated with the low S/G ratio (2.5). The extractives content and lignin composition must be simultaneously analyzed to improve the Eucalyptus clones classification for charcoal production. [ABSTRACT FROM AUTHOR]

This study aims to produce and characterize wood-based composites (WPC) by in situ polymerization with poly(vinyl acetate) into juvenile and mature woods from a pine specie. Vacuum-pressure method was used to impregnate the wood with a vinyl acetate monomer and benzoyl peroxide (1.5 wt%) was used as initiator. The studied WPC were characterized for treatment parameters (weight percentage gain and specific gravity), as well as chemical (by infrared spectroscopy), thermal (by thermogravimetric analysis) and mechanical (by flexure and hardness tests) features. The in situ polymerization yielded improved mechanical properties and increased thermal stabilities, which were attributed to the impregnated poly(vinyl acetate) (especially on the wood surface) as suggested by treatment parameters and infrared spectra. The presented wood treatment may be a key strategy to improve pinewood properties, especially from juvenile wood, which may overcome the properties of the pristine mature wood. [ABSTRACT FROM AUTHOR]

Identifying high-grade valuable wood resources by the visible individual traits of trees is a challenge for foresters and a requirement for sustainable resource management. The aim of this study was to identify the most relevant phenotypic descriptors of the acoustic quality of Norway spruce standing timber. Two highly valuable Norway spruce (Picea abies) stands located in the Romanian Carpathians were selected for this purpose. A total of 27 tree, bole, bark, and crown variables and nine variables related to wood structure were statistically checked against the velocities of stress waves measured on standing trees at breast height, and the derived parameters: the radiation, the impedance, and the moduli of elasticity in L and R directions. Principal component analysis was used for exploratory data analysis as well as mixed linear models were involved in explaining these acoustics. There were consistent variations in the measured acoustics from tree to tree, according to the age and social class. Wood acoustical parameters measured in the R direction are better predicted by tree phenotype than the acoustical parameters measured in the L direction. Bark thickness and branch width were the best predictors, while tree ring features were less predictive. At a given age, trees with high velocity had thinner and reddisher bark, thinner branches, and a narrower crown. Trees with high velocity anisotropy had narrower branches and wider sapwood. Furthermore, the phenotypic traits used had a poor explanatory power of the radiation ratio. In conclusion, spruce standing trees from the studied area bring forward certain outside features that enable us the multitrait identification of highly valuable wood for string instruments. [ABSTRACT FROM AUTHOR]

There are many studies describing the physical and anatomical properties of eucalypt wood, but studies comparing the performance of diploid and polyploid clones in terms of wood anatomy and wood quality are scarce. In this context, this study aimed to compare the performances of Eucalyptus diploid and polyploid clones with the same genetic origin by analyzing the physical and anatomical properties of the wood to extend the information on wood quality for pulp and paper production. Woods samples from eucalypt hybrids (E. grandis x E. urophylla) from experimental plantations of Suzano S.A. were used. Moisture content, basic density and fiber size were determined. The data related to these variables were tested by analysis of variance. Moisture content in polyploids was 4% higher than in diploids. The mean basic density in diploid clones was 13% higher than in polyploid clones, although there was no significant difference between one of the evaluated clones. The mean fiber length in polyploid clones was 18% higher than in diploid clones. No significant differences were found in the wood quality indexes for cellulosic pulp production. Synthetic polyploid clones of eucalypt presented lower basic density and fibers with higher length and wall thickness when compared to diploids, indicating the potential use of polyploids in eucalypt pulp and paper production. [ABSTRACT FROM AUTHOR]

Hardness has been considered an important indicator of wood quality and presents a high correlation with density, and, as far as the authors know, there is no specific methodology to evaluate the hardness of charcoal. In this context, it is necessary to develop a reliable and efficient methodology to classify charcoal mechanical properties. Therefore, the aim of this study was to establish multivariate models to estimate dynamic hardness and density of wood and charcoal based on near-infrared spectra. For this, nine wood specimens were examined and pyrolyzed at 300, 450, 600 and 750 °C. The density of wood and charcoal was determined according to standard NBR 11941 (2003) and hydrostatic method, respectively. Dynamic hardness of wood and charcoal was determined by an automated portable hardness tester. Materials submitted to thermal treatment have different spectral signatures compared to those obtained by the wood. Charcoals produced at temperatures of 450, 600 and 750 °C exhibit similar behaviour, with low absorbance compared to wood and thermally treated material at 300 °C, indicating homogenization of charcoal caused by pyrolysis temperature. NIR spectroscopy was able to estimate density and dynamic hardness of wood and charcoal. Charcoal produced at 450 °C obtained a model with highest coefficient of determination and smaller errors. The results show the potential of NIR technology for fast and reliable estimation of physical and mechanical properties of charcoal based on spectra recorded on charcoal and even from wood before pyrolysis. [ABSTRACT FROM AUTHOR]

Eucalyptus bosistoana is an important durable hardwood species selected by New Zealand Dryland Forest Initiative (NZDFI) for their adaptability to diverse environments and good quality wood. There is no report on in vitro methods for callus induction and plantlet micropropagation of this species, although these methods could assist further genetic improvement of plants. In this study, different combinations of α-naphthalene acetic acid (NAA) and benzyl adenine (BA) at concentrations ranging from 0.5 to 2 mg L−1 were investigated for callus induction, shoot regeneration, shoot elongation and root formation. High frequency of callus induction was obtained when cotyledon explants were cultured on MS (Murashige and Skoog medium 1962) with 1.0 mg L−1 NAA and 1.5 mg L−1 BA. For shoot regeneration from callus, MS medium with 0.5 mg L−1 NAA and 1.5 mg L−1 BA was an effective medium. Shoot elongation was observed on MS medium supplemented with 0.5 mg L−1 NAA, 1.0 mg L−1 BA and 1.0 mg L−1 GA3. High frequency of adventitious root formation in micro-cuttings of E. bosistoana was observed on half-strength MS medium with 0.5 to 1.0 mg L−1 NAA. Finally, pre-acclimatization of the micropropagated plantlets led to 100% survival under glasshouse conditions. [ABSTRACT FROM AUTHOR]

Wood density is one of the most important physical properties of the wood, used in improvement programs for wood quality of major timber species. Traditional core sampling of standing trees has been widely used to assess wood density profiles at high spatial resolution by X-ray microdensitometry methods, but alternative methods to predict wood properties quality are also needed. Near-infrared (NIR) spectroscopy, a non-destructive technique, is being increasingly used for wood property assessment and has already been demonstrated to be able to predict wood density. However, the estimation of wood density profiles by NIR has not yet been extensively studied, and improved models using spectra information (NIR) and X-ray data need to be developed. To this end, partial least square regression (PLS-R) models for predicting wood density were developed at a 1.4 mm spatial resolution on Pinus pinaster wood cores, with an improved spatial synchronization along the tangential and radial directions of the strip, between X-ray data and NIR spectra. The validation of the best model showed a high coefficient of determination (0.95), low error (0.026) and no outlier. Compression wood samples were not detected as outliers and were correctly predicted by the model. However, pith spectra were detected as outliers and its predicted values were overestimated by 33% due to unusual spectra suggesting a diverse chemical composition. The results suggest that NIR-PLS models obtained can be used for screening maritime pine wood density profiles along the radii at 1.4 mm spatial resolution. [ABSTRACT FROM AUTHOR]

Main conclusion: EgPHI-1 is a member of PHI-1/EXO/EXL protein family. Its overexpression in tobacco resulted in changes in biomass partitioning, xylem fiber length, secondary cell wall thickening and composition, and lignification. Here, we report the functional characterization of a PHOSPHATE-INDUCED PROTEIN 1 homologue showing differential expression in xylem cells from Eucalyptus species of contrasting phenotypes for wood quality and growth traits. Our results indicated that this gene is a member of the PHI-1/EXO/EXL family. Analysis of the promoter cis-acting regulatory elements and expression responses to different treatments revealed that the Eucalyptus globulus PHI-1 (EgPHI-1) is transcriptionally regulated by auxin, cytokinin, wounding and drought. EgPHI-1 overexpression in transgenic tobacco changed the partitioning of biomass, favoring its allocation to shoots in detriment of roots. The stem of the transgenic plants showed longer xylem fibers and reduced cellulose content, while the leaf xylem had enhanced secondary cell wall thickness. UV microspectrophotometry of individual cell wall layers of fibers and vessels has shown that the transgenic plants exhibit differences in the lignification of S2 layer in both cell types. Taken together, the results suggest that EgPHI-1 mediates the elongation of secondary xylem fibers, secondary cell wall thickening and composition, and lignification, making it an attractive target for biotechnological applications in forestry and biofuel crops. [ABSTRACT FROM AUTHOR]

Genomic selection (GS) can substantially reduce breeding cycle times in forest trees compared to traditional breeding cycles. Practical implementation of GS in tree breeding requires an assessment of significant drivers of genetic gains over time, which may differ among species and breeding objectives. We present results of a GS study of growth and wood quality traits in an operational Eucalyptus grandis breeding program in South Africa. The training population consisted of 1575 full and half-sib individuals, genotyped with the Eucalyptus (EUChip60K) SNP chip resulting in 15,040 informative SNP markers. The accuracy of the GS models ranged from 0.47 (diameter) to 0.67 (fibre width). We compared a 4-year GS breeding cycle equivalent to half of a traditional 8-year E. grandis breeding cycle and obtained GS efficiencies ranging from 1.20 (wood density) to 1.62 (fibre length). Simulated over 17 years, the ratio of the accumulated genetic gains between three GS cycles and two traditional breeding cycles ranged from 1.53 (diameter) to 3.35 (wood density). To realise these genetic gains per unit time in E. grandis breeding, we show that significant adjustments have to be made to integrate GS into operational breeding steps. [ABSTRACT FROM AUTHOR]

The study of the potential of a plant population makes the selection of a breeding program more efficient, allowing satisfactory genetic gains and identifying the potential of this population, among others, for advances in generations. The genetic potential of Eucalyptus benthamii is still poorly studied. This species has relevant characteristics for increasing productivity, frost tolerance and, mainly, the quality of wood, with an emphasis on cellulose production. The goal of this study was to evaluate the potential of a sample of Eucalyptus individuals for suitability of use, based on technological characteristics and wood growth through uni, bi, and multivariate techniques. The genetic material sampled comes from a test of progenies of E. benthamii, 4 years old from the company CMPC Celulose Riograndense. The sample consisted of 75 individuals of E. benthamii and three individuals of three other species that were used as controls (E. saligna, E. grandis and E. dunnii), totaling 87 individuals, chosen by industrial criteria. The population of E. benthamii under study has good potential to be explored through selective techniques in view of the witnesses used, considering the descriptive statistics, the association of characteristics and analysis of factors. Also, enabling the selection of superior materials within this sampling. [ABSTRACT FROM AUTHOR]

Afforested farmland is a phenomenon of Central Europe. In this study, we evaluate the radial growth of Norway spruce [Picea abies (L.) Karst.] and European larch (Larix decidua Mill.) in forest stands established on abandoned agricultural land compared to forest stands on standard forest soils. As the quality of wood from such sites is often challenged, we also focused on wood quality of those species. The following characteristics of wood were evaluated: wood density, bending strength, impact bending strength, modulus of elasticity and radial growth in relation to climatic factors. The radial growth of both tree species showed higher radial increment to tree age of 19–23 years on former agricultural land compared to forest land. Norway spruce growing on forest land was significantly (p < 0.05) more sensitive to climatic factors than on agricultural land (7 significant moths vs. 3 months), while there were low differences in larch. Spruce produced wood with significantly higher density on agricultural land (399 kg m−3), while larch had higher density on forest land (583 kg m−3). In other characteristics, significant differences were found only in the case of larch. Higher values were detected for impact bending strength (4.5 J cm−2) and bending strength (87 MPa) on forest land. The detected differences between wood characteristic were not important for industrial purposes and final usage of the wood. Therefore, afforested agricultural lands provide wood of similar quality and also showed higher resistance in relation to climatic change compared to permanent forest lands. [ABSTRACT FROM AUTHOR]

As a multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medicinal use. However, it remains unclear to what extent geographical gradients in growth and wood quality are shaped by the environment. We used data of 197 trees from 22 natural populations to assess geographic variation patterns in radial growth and wood density, and their correlations with environmental factors. Significant differences in mean annual DBH and wood basic density were observed among the 22 populations (p < 0.05). Based on mean annual DBH and wood basic density, the 22 populations were classified into three groups by hierarchical cluster analysis. Within its natural distribution, soil nutrients are more closely associated with DBH growth than are temperature and precipitation. However, correlations between wood density versus altitude and annual precipitation were found (p < 0.01). Trend surface analysis revealed that mean annual DBH growth and wood density displayed an increasing trend from north-west to south-east across its natural distribution. Our study provides valuable insights into the geographical patterns in growth and wood quality of C. paliurus, and an opportunity to improve tree growth and wood quality through phenotypic selection and selecting suitable sites for planting. [ABSTRACT FROM AUTHOR]

One of the characteristics of great relevance in the wood quality in Spanish coniferous forests due to growth conditions is the presence of corewood. This wood area presents properties and characteristics inferior to those in outerwood, which are more appropriate for certain uses. In plantations with short rotations, the percentage of juvenile timber is higher, and the profitability of the wood can be affected due to its unsuitability for high added value applications, such as structural. This work focuses on determining whether the use of models of current annual increase in height can provide suitable estimations of the year or transition zone between corewood and outerwood. This knowledge will contribute to analyze the expected yield of quality wood. The material studied is from Pinus sylvestris L. (Scots pine) and Pinus nigra Arnold subsp. nigra (black pine) pure stands. Densitometry results showed that the corewood–outerwood transition year could not be predicted by tree height functions. [ABSTRACT FROM AUTHOR]