Estimation of Tracheid Morphological Characteristics of Green Pinus Taeda L. Radial Strips by Near Infrared Spectroscopy

The application of near infrared (NIR) spectroscopy to the green wood of radial samples (simulated increment cores) and the development of calibrations for the prediction of several tracheid morphological characteristics are described. Twenty Pinus taeda L. (loblolly pine) radial samples were characterized in terms of coarseness, perimeter, radial and tangential diameter, specific surface, and wall thickness. NIR spectra were obtained in 10-mm steps from the radial-longitudinal and transverse face of each sample and were used to generate calibrations for each property. NIR spectra were collected from all samples when the wood was green (moisture content ranged from approximately 100 to 154%), and when dried to approximately 7% moisture content. The relationships between measured and NIR-estimates for green wood were strong for coarseness, specific surface, and wall thickness, with coefficients of determination (R2) ranging from 0.89 to 0.73. Differences between calibrations developed using radial-longitudinal and transverse face NIR spectra were generally small. Dry wood calibrations demonstrated strong relationships for all parameters apart from perimeter and radial diameter; R2 ranged from 0.59 to 0.91. Calibrations were tested on an independent set; relationships for coarseness, specific surface, and wall thickness were strong. Good calibrations can be obtained for some tracheid morphological characteristics using NIR spectra collected from the surface of green P. taeda wood

EVALUATING LOG STIFFNESS USING ACOUSTIC VELOCITY FOR MANUFACTURING STRUCTURAL ORIENTED STRAND BOARD

Oriented strand board (OSB) is an engineered panel product formed by layering strands of resinated wood in specific orientations into a mat, then pressing the mat at a high temperature to form a panel of desired strength and stiffness. OSB manufacturing facilities utilize small diameter logs from thinning operations and waste from harvesting. Considerable variation exists in the wood properties of the raw material and ideally the OSB industry would take advantage of such variation, however, it lacks the technology required to rapidly assess log quality on-site. Non-destructive evaluation (NDE) techniques based-on acoustics have the potential to rapidly segregate logs in the field, however the influence of acoustic-based log segregation on OSB panel properties is unknown. The aims of this project were to determine if log quality affects panel properties and if acoustic NDE technology is a satisfactory tool for determining log stiffness prior to entering the manufacturing process. It was found that low velocity (stiffness) logs produced panels with low stiffness while high and medium velocity (stiffness) logs produced panels with similar properties. The Director HM 200 was a satisfactory tool for determining log stiffness. Further studies are required to determine how to incorporate NDE tools into the manufacturing process

Determination of Important Pulp Properties of Hybrid Poplar by Near Infrared Spectroscopy

Hybrid poplars are widely grown in the northwestern United States for manufacturing short fiber market pulp. Improvement of whole-tree basic density and pulp yield, important variables in the economics of pulp production, is an objective of tree breeding programs; but the number of trees analyzed is limited by expensive analytical methods. Near infrared (NIR) spectroscopy provides a rapid alternative, and in this study we investigate its ability to estimate poplar pulpwood properties. Whole-tree cellulose content and pulp yield calibrations, based on 3- and 6-year-old clones, were generally strong, while relationships were weaker for basic density. Breast height cores from 6-year-old clones gave a strong core cellulose content calibration. Cellulose content and pulp yield calibrations based on NIR spectra from milled increment cores and whole-tree data gave strong relationships for 6-year-old clones, indicating that the prediction of these properties, on a whole-tree basis, using breast height increment cores may be possible

Radial variation in cell morphology of melia azedarach planted in northern vietnam

The radial variation in cell morphology of ten-year-old Melia azedarach trees planted in northern Vietnam was experimentally investigated. The earlywood fiber lumen diameter and latewood fiber lumen diameter were almost unchanged from pith to 6th ring before significantly decreasing and remaining constant from 7th ring outwards. In contrast, fiber cell wall thickness in both earlywood and latewood increased from pith to 7th ring before becoming stable towards the bark. The maturation age of earlywood vessel lumen diameter estimated by segmented regression analysis indicated that wood of the Melia azedarach could be classified into core wood and outer wood, and the boundary between core and outer wood may be located at 7th ring from pith. This should be taken into account in wood processing using M. azedarach grown in northern Vietnam

Rapid Assessment of Southern Pine Decayed by G. Trabeum by Near Infrared Spectra Collected from the Radial Surface

The use of near infrared (NIR) spectroscopy for predicting levels of degradation in southern pine (Pinus spp.) by Gloeophyllum trabeum for periods over 1-8 da was investigated. NIR spectra collected from the center of the radial face of each sample after laboratory soil block decay tests were used to develop calibrations. Calibrations were developed for mass loss, compression strength, and exposure period using data measured from prior methods and untreated and mathematically treated (multiplicative scatter correction and first and second derivative) NIR spectra from various ranges of wavelengths by partial least squares regression. Strong relationships were derived from the calibrations with the strongest R2 values of 0.97 (exposure period), 0.94 (compression strength), and 0.91 (mass loss). Calibrations for exposure period showed the strongest statistics for predicting wood decay of the validation test set (R2 = 0.92; RPDp [ratio of the standard deviation of the measured data to the standard error of prediction] = 3.95 [first derivative, 1100-2250 nm]), while predictions for mass loss of the decayed samples resulted in R2 = 0.86 and an RPDp = 3.17 (multiplicative scatter correction, 1100-2500 nm), and the strongest compression strength prediction resulted in R2 = 0.76 and an RPDp = 2.50 (second derivative, 1100-2500 nm). These results suggest that NIR spectroscopy can adequately predict wood decay from spectra collected from the radial face of southern pine

FIBER QUALITY PREDICTION USING NIR SPECTRAL DATA: TREE-BASED ENSEMBLE LEARNING VS DEEP NEURAL NETWORKS

The growing applications of near infrared (NIR) spectroscopy in wood quality control and monitoring necessitates focusing on data-driven methods to develop predictive models. Despite the advancements in analyzing NIR spectral data, literature on wood science and engineering has mainly uti- lizedthe classic model development methods, such as principal component analysis (PCA) regression or partial least squares (PLS) regression, with relatively limited studies conducted on evaluating machine learning (ML) models, and specifically, artificial neural networks (ANNs). This couldpotentially limit the performance of predictive models, specifically for some wood properties, such as tracheid width that are both time-consuming tomeasure and challenging to predict using spectral data. This study aims to enhance the prediction accuracy for tracheid width using deep neural networks and tree-based ensemble learning algorithms on a dataset consisting of 2018 samples and 692 features (NIR spectra wavelengths). Accord- ingly, NIR spectra were fed into multilayer perceptron (MLP), 1 dimensional-convolutional neural net- works (1D-CNNs), random forest, TreeNet gradient-boosting, extreme gradient-boosting (XGBoost), and light gradient-boosting machine (LGBM). It was of interest to study the performance of the models with and without applying PCA to assess how effective they would perform when analyzing NIR spectra with- out employing dimensionality reduction on data. It was shown that gradient-boosting machines outper- formed the ANNs regardless of the number of features (data dimension). Allthe models performed better without PCA. It is concluded that tree-based gradient-boosting machines could be effectively used for wood characterization utilizing a medium-sized NIR spectral dataset

Effects of Vegetation Management on Wood Properties and Plant Water Relations of Four Conifer Species in the Pacific Northwest of the USA

In plantation forests, competition from unwanted vegetation may reduce survival and negatively impact tree growth. The goal of this study was to examine the influence of vegetation management treatments on plant water relations and wood properties. Control trees (no treatment) were compared to trees subjected to post-planting competing vegetation control for five consecutive years after planting. Four conifer species (Douglas-fir, western hemlock, western redcedar, and grand fir) were studied on two different sites in western Oregon, USA. Carbon isotope (C-13) analysis was used to study intrinsic water use efficiency (iWUE) and X-ray densitometry was used to measure specific gravity, ring width, and latewood percent. We found a significant interaction between vegetation management treatment and wood ring (growing season) in iWUE for Douglas-fir. There was little effect of vegetation management treatment on ring specific gravity for all species. Only western redcedar growing at a central Coast Range site showed increased ring specific gravity under sustained competing vegetation control. When growing under conditions of sustained control of competing vegetation, western redcedar at a central Coast Range site had a significant increase in earlywood specific gravity, while Douglas-fir at a Cascade Foothills site had a significant decrease in latewood specific gravity. Western redcedar and grand fir had a significant interaction-effect on its latewood percentage, with treatment trees having a higher latewood percentage than control trees after ring 8. Further, Douglas-fir and western hemlock had a significant increase in ring, earlywood, and latewood area with treatment, and grand fir had a significant interaction-effect of treatment x ring for ring, earlywood, and latewood area. This study indicates that, for conifer trees growing under sustained vegetation control, growth gains could be achieved without compromising wood properties. However, if harvested at a target diameter, these trees will have a larger proportion of low quality corewood compared to trees from conventionally managed stands

Contents lists available at ScienceDirect Forest Ecology and Management

journal homepage: www.elsevier.com/locate/foreco Effect of early age woody and herbaceous competition control on wood propertie

Effect of mid-rotation fertilization on stiffness and strength of loblolly pine wood

Trees sampled from a loblolly pine mid-rotation fertilization trial were used in this study. The study was laid out in a randomized complete block design with four levels of nitrogen fertilizer as treatments: control (000N), 112 (112N), 224 (224N), and 336 (336N) kg/ha of nitrogen, with each treatment replicated in 4 blocks. Two trees were destructively sampled from each plot giving a total of 32 trees. Bolts 0.6 m in length were collected from each tree (3 bolts per tree); with the midpoint of each bolt at heights of 2.4, 7.3 and 12.2 m from the base of the tree (each bolt represented the midpoint of standard 4.9 m saw logs). Static bending samples with dimensions 25 by 25 by 406 mm (radial, tangential and longitudinal dimensions respectively) were cut from the bolts that included the 25 mm of wood produced immediately following fertilization. Data on modulus of elasticity (MOE, stiffness) and modulus of rupture (MOR, strength) were collected from clear static bending samples. Based on the analysis of variance, no significant treatment effect was observed on MOE and MOR. However, MOE and MOR decreased in wood produced immediately after fertilization for trees which received the highest level of fertilization (336N). A decreasing trend in MOE and MOR with height was also present.Keywords: Loblolly pine, Fertilization, Strength, Stiffnes

Growth and wood properties of genetically improved loblolly pine: propagation type comparison and genetic parameters

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5 mm in diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core density, latewood and earlywood density, and latewood percent) were measured for each tree sampled in the study. Overall, growth properties were better for full-sib seedling than for clonal lines, whereas wood density was higher for clonal lines than full-sib and open-pollinated seedlings. However, there were clonal lines with better growth and higher wood density. Clonal repeatability of both growth and wood properties across sampled sites and genetic correlations between growth and wood traits were determined, with higher repeatability observed for wood traits compared with growth traits. Significant genetic correlations were observed for tree height and wood properties, whereas weak correlations were observed for diameter and wood properties