Quality of sawmilling output predictions according to the size of the lot - The size matters!

Lors de l'évaluation de modèles d'apprentissage automatique supervisé, on considère généralement le rendement de prédiction moyen obtenu sur les tests individuels comme mesure de choix. Toutefois, lorsque le modèle est destiné à prédire quels produits du bois seront obtenus lors du sciage de certains billots, c'est généralement la performance pour un lot complet qui importe. Dans cet article, nous montrons l'impact de cette nuance en termes d'évaluation du modèle. En fait, la qualité d'une prédiction (globale) s'améliore considérablement lorsque l'on augmente la taille des lots, ce qui offre un solide soutien à l'utilisation de ces modèles en pratique.When comparing supervised learning models, one generally considers the average prediction performance obtained over individual test samples. However, when using machine learning to predict which lumber products will be obtained when sawing logs, it is usually the performance over the entire lot that matters. In this paper, we show the impact of this by evaluating a model performance for various batch sizes. The quality of a (global) prediction improves tremendously when batch size increases, which offers a strong support for the use of such models in practice

제재 시뮬레이션을 통한 소나무 원목의 제재 수익성 분석

학위논문 (석사)-- 서울대학교 대학원 농업생명과학대학 산림과학부, 2017. 8. 정주상.This study conducted a profitability analysis on sawing Pinus densiflora logs by comparing the profitability of lumber and pulp-chip productions. In order to estimate the maximum value recovery from log sawing, a log sawing simulation model was developed based on dynamic programming algorithm proposed by Reinders and Hendriks (1989). Through the log sawing simulation, Pinus densiflora logs in lengths of 3.6 m and 2.7 m were optimally sawn for maximized lumber value in regards with the dimensions and prices of lumber products in Korea. On the other hand, 1.8 m Pinus densiflora logs were applied for pulp-chip production considering the current timber harvesting and log allocation in Korea. Net profits generated from the two productions were estimated using the data obtained from the actual sawmills and pulp-chip manufacture facilities. According to the result, sawing Pinus densiflora logs for 3.6 m and 2.7 m lumber products generated 861% and 723% higher net profits, respectively than pulp-chip production with 1.8 m logs. Between the two lumber productions, the average net profit generated from sawing 3.6 m logs was 24% higher than sawing 2.7 m logs. In addition to the comparative analysis on sawing profitability, the sawing potential of short (1.8 m) Pinus densiflora logs was also evaluated for wooden cutting board and wooden tray manufacture using the log sawing simulation model. The lumber for wooden cutting board manufacture could be sawn from the log with 18 cm of diameter and the lumber for wooden tray manufacture from the log with 22 cm of diameter. The results of this study reconfirm that sawlog harvesting would lead to higher timber sale profits and support the bucking decisions in terms of value recovery and increased stumpage value of Pinus densiflora stands in Korea. Additionally, the study also suggests that thorough considerations of various end-uses of harvested timber would increase the timber sale profits.I. INTRODUCTION 1 II. OBEJCTIVES 4 III. LITERATURE REVIEW 5 IV. RESEARCH FRAMEWORK 9 V. MATERIALS AND METHODS 10 1. A log sawing simulation model 10 1) Model assumptions 10 2) Structure of the model 12 3) Mathematical algorithm 13 2. Comparative analysis on sawing and chipping profitability of Pinus densiflora 17 1) Sawing profitability of Pinus densiflora 17 (1) Process of profitability analysis using the log sawing simulation model 17 (2) Data collection 19 (3) Profitability analysis 22 2) Profitability analysis on pulp-chip production with Pinus densiflora 23 (1) Process of profitability analysis on pulp-chip production 23 (2) Data collection 24 (3) Profitability analysis 25 3. Analysis on sawing potential of short Pinus densiflora logs for wood product manufacture 27 1) Research process 27 2) Data collection 28 (1) Log type 28 (2) Production process 28 3) Analysis on sawing potential 29 (1) Log sawing simulation 29 (2) Estimation of lumber production 29 VI. RESULTS AND DISCUSSION 30 1. Optimal sawing pattern for 3.6m Pinus densiflora logs 30 2. Optimal sawing pattern for 2.7m Pinus densiflora logs 32 3. Lumber yield and recovery rate of sawing 3.6m and 2.7m Pinus densiflora logs 34 4. Pulp-chip yield from chipping 1.8m Pinus densiflora logs 36 5. Net profit comparison between lumber and pulp-chip production 37 6. Production estimation of lumber for wooden cutting board. 40 7. Production estimation of lumber for wooden tray 41 VII. CONCLUSION 42Maste

Development of a 3D log processing optimization system for small-scale sawmills to maximize profits and yields from central appalachian hardwoods

The current status of log sawing practices in small hardwood sawmills across West Virginia was investigated and the effects of log sawing practices on lumber recovery evaluated. A total of 230 logs two species, red oak (Quercus rubra) and yellow-poplar (Liriodendron tulipifera), were measured in five typical hardwood sawmills in the state. Log characteristics such as length, diameter, sweep, taper, and ellipticality were measured. Additionally, the characteristics of sawing equipment such as headrig type, headrig kerf width, and sawing thickness variation were recorded. A general linear model (GLM) was developed using Statistical Analysis System (SAS) to analyze the relationship between lumber recovery and the characteristics of logs and sawing equipment for small sawmills in West Virginia. The results showed that the factors of log grade, log diameter, species, log sweep, log length, different sawmills, the interaction between log species and grade, and the interaction between log species and log length had significant impacts on volume recovery. Log grade, log species and headrig type had significant effects on value recovery.;Hardwood lumber production includes a sequence of interrelated operations. Methods to optimize the entire lumber production process and increase lumber recovery are important issues for forest products manufacturers. Therefore, a 3D log sawing optimization system was developed to perform 3D log generation, opening face determination, headrig log sawing simulation, cant resawing, and lumber grading. External log characteristics such as length, largeend and small-end diameters, diameters at each foot, and external defects were collected from five local sawmills in central Appalachia. The positions and shapes of internal log defects were predicted using a model developed by the USDA Forest Service. 3D modeling techniques were applied to reconstruct a 3D virtual log that included internal defects. Heuristic and dynamic programming algorithms were developed to determine the opening face and grade sawing optimization. The National Hardwood Lumber Association (NHLA) grading rules were computerized and incorporated into the system to perform lumber grading. Preliminary results have shown that hardwood sawmills have the potential to increase lumber value by determining the optimal opening face and optimizing the sawing patterns. Our study showed that without flitch edging and trimming, the average lumber value recovery in the sawmills could be increased by 10.01 percent using a heuristic algorithm or 14.21 percent using a dynamic programming algorithm, respectively. An optimal 3D visualization system was developed for edging and trimming of rough lumber in central Appalachian. Exhaustive search procedures and a dynamic programming algorithm were employed to achieve the optimal edging and trimming solution, respectively.;An optimal procedure was also developed to grade hardwood lumber based on the National Hardwood Lumber Association (NHLA) grading rules. The system was validated through comparisons of the total lumber value generated by the system as compared to values obtained at six local sawmills. A total of 360 boards were measured for specific characteristics including board dimensions, defects, shapes, wane and the results of edging and trimming for each board. Results indicated that lumber value and surface measure from six sawmills could be increased on average by 19.97 percent and 6.2 percent, respectively, by comparing the optimal edging and trimming system with real sawmill operations.;A combined optimal edging and trimming algorithm was embedded as a component in the 3D log sawing optimization system. Multiple sawing methods are allowed in the combined system, including live sawing, cant sawing, grade sawing, and multi-thickness sawing. The system was tested using field data collected at local sawmills in the central Appalachian region. Results showed that significant gains in lumber value recovery can be achieved by using the 3D log sawing system as compared to current sawmill practices. By combining primary log sawing and flitch edging and trimming in a system, better solutions were obtained than when using the model that only considered primary log sawing. The resulting computer optimization system can assist hardwood sawmill managers and production personnel in efficiently utilizing raw materials and increasing their overall competitiveness in the forest products market

The Effect of Log Rotation On Value Recovery In Chip And Saw Sawmills

Advances in three-dimensional scanning techniques and computer optimization permit real time solution and implementation of optimal log rotation before it is fed into the chipper heads. A random sample of 834 S-P-F logs from the interior of British Columbia were examined using simulation to determine the effects of log rotation strategies on value recovery for a small log Chip and Saw. Both log sweep and cross-sectional eccentricity are shown to cause significant reductions in value recovery. Eight rotation placements from 0° to 315° were studied to determine if a single rotational placement could be found that performs best. On average, the "horns up" position (0° rotation) was found to significantly outperform all others in maximizing value recovery. The ability to rotate each log into the optimal position produced significant benefits. The benefits were more highly related to the degree of cross-sectional eccentricity present in the log rather than the degree of sweep present in the log

Development of A 3D Log Sawing Optimization System for Small Sawmills in Central Appalachia, US

A 3D log sawing optimization system was developed to perform log generation, opening face determination, sawing simulation, and lumber grading using 3D modeling techniques. Heuristic and dynamic programming algorithms were used to determine opening face and grade sawing optimization. Positions and shapes of internal log defects were predicted using a model developed by the USDA Forest Service. Lumber grading procedures were based on National Hardwood Lumber Association rules. The system was validated through comparisons with sawmill lumber values. External characteristics of logs, including length, large-end and small-end diameters, diameters at each foot, and defects were collected from five local sawmills in central Appalachia. Results indicated that hardwood sawmills have the potential to increase lumber value through optimal opening face and sawing optimizations. With these optimizations, average lumber value recovery could be increased by 10.01% using the heuristic algorithm or 14.21% using the dynamic programming algorithm. Lumber grade was improved significantly by using the optimal algorithms. For example, recovery of select or higher grade lumber increased 16-30%. This optimization system would help small sawmill operators improve their processing performance and improve industry competitiveness

The Growth, Yield, and Financial Performance of Isolated Eastern White Pine (Pinus strobus L.) Reserve Trees

The ability of eastern white pine (Pinus strobus L.) to persist as emergent trees makes this species well suited to silvicultural systems in which they are retained as isolated reserves after a regeneration harvest. While such systems are implemented throughout the Acadian spruce-fir region of Maine, little is known about the growth response and financial performance of eastern white pine following complete release from competition. In this study, 77 trees from 8 sites throughout the Acadian spruce-fir region were sampled tree and crown measurements, and increment cores were extracted at breast height, as well as from the top of the valuable first 16 foot log. Volume growth was examined prior to and following release, and overall response to release was favorable. A subsample of 9 trees climbed to measure basal diameter and vertical location of each branch to develop allometric leaf area equations and to examine influence of site productivity and age on growth efficiency. Leaf area-volume increment relationships were modeled with a nonlinear power function with a random effect for site, and employed to forecast future growth. A sawmill simulator was used to estimate postrelease standing tree values and financial analysis was performed to assess performance of completely released trees for an unpruned and a hypothetical pruned scenario. Unpruned trees, on average exhibited peak net present value 52 years post-release. Pruned trees declined in net present value following release, due to high initial values. The net benefit of pruning reached its maximum 30 years after pruning, and stayed positive for 101 years, suggesting that pruning is a viable practice for eastern white pine that will be released and retained as reserve trees. The retention of eastern white pine reserve trees appears to be both biologically and financially sound, but forest managers should be careful to select vigorous younger trees as reserves to maximize financial performance

Growth ring pattern consideration in computer sawing simulation

The Best Opening Face (BOF) log breakdown model was modified to keep track of growth ring angle and growth ring density in boards. The model was used to determine the effects of producing rectangular rather than square pencil stock. While an increase in volume did result, there was also a decrease in pencil stock quality regarding ring angle due to the lack of choice left in orienting these pencil stock when producing slats. The results were expressed as the percentage of change that occurred in both volume and value recovery between rectangular and square sawing. Overall, when considering both pencil stock prices and ring angle factors, there was an increase in value of 0.64% when sawing rectangles instead of squares. However, a high standard deviation of 1.97% was linked to that average. No trends were found as a function of log diameter, but the total value increased slightly with an increase in log length and taper rate. From a pencil stock seller's viewpoint, only pencil stock prices needed to be considered. Due primarily to an increase in volume recovery, there was an average value increase of 6.85% when sawing rectangles instead of squares. Once again, an increasing trend was observed as a function of log length and taper rate. From a pencil slats producer's viewpoint, a per board foot approach was taken. An average decrease in value of 6.51% per board foot resulted when rectangles were sawn instead of squares. In addition, the distribution of pencil stock in the three ring angle classes varied dramatically between rectangular and square sawing. Results were sensitive to relative prices given to pencil slats as a function of ring angle

Improving Structural Lumber Quality in a Sample of Picea Mariana Logs Sawn According to the Knots

This paper examines the effect of knots on the strength recovery of black spruce lumber. A model was developed and used to simulate sawing and grading of boards from knotty logs. Since a log internal defect scanner was unavailable, the internal knot morphology was modeled from external measurements. A standard cant and flitch sawing pattern was used in the simulations and rotated about the log axis. for each 30° of log rotation, the theoretical lumber grades were obtained based on knot sizes and positions within the boards. A best and worst sawing rotation angle based on the potential lumber grade yield was retained for each of 54 logs simulated Half of the logs were sawn into 2 X 4 nominal lumber according to the best rotation angle and the other half according to the worst rotation angle. The resulting pieces of lumber were first visually graded according to the knots and then according to all defects, followed by dynamic MOE testing and finally tested to destruction using a third-point standard bending procedure. The results demonstrate that there was little difference in visual grades between the "best" and "worst" groups and that knots played a minimal role in grade determination of the boards. However, there was significant difference in terms of MOE values, where the group of "best" boards showed an overall 15% increase over the "worst" boards. This result significantly impacts the potential MSR yield of the sample pieces of lumber. Bending tests showed a lurther 25% difference in average MOR between the two groups. These results suggest that there is potential for black spruce to yield higher strength lumber when knots are considered during breakdown. Further refinements should include a model that determines quality in terms of knot position within the board section rather than one that determines quality in terms of potential visual grades

Évaluation du volume et des pertes de qualité causées par les principaux défauts des tiges d'épinette blanche et de pin gris

Les objectifs de ce travail sont donc, dans un premier temps, de mieux comprendre les effets de l’espacement initial sur les caractéristiques des arbres de pin gris et d’épinette blanche ainsi que sur les propriétés mécaniques de leur bois. Il sera également possible de développer un facteur de correction du volume des sciages obtenus en fonction des déformations naturelles présentes sur les tiges pour ces deux essences, et ce, dans le but d’estimer de manière plus précise le volume de sciage disponible à partir des données d’inventaires forestiers. Dans un deuxième temps, le travail consiste à modéliser la présence des nœuds et à percevoir leurs impacts sur le rendement en sciage à l’aide d’Optitek, un logiciel de simulation du procédé du sciage. Pour réaliser cette étape, un certain nombre de billes ont été traitées dans un CT Scanner et un nouveau logiciel a été mis au point afin d’extraire l’information désirée des images tomodensitométriques (CT) pour ensuite la rendre compatible au logiciel Optitek. Le but de cette étape est d’être en mesure d’effectuer des simulations du procédé de débitage en tenant compte de la dimension et de l’emplacement des nœuds de façon à maximiser la valeur de chaque bille. Les arbres proviennent d’une plantation d’épinette blanche (Picea glauca (Moench) Voss) et de pin gris (Pinus banksiana Lamb.) de type Nelder (1962). Ce type de plantation se caractérise par une forme circulaire qui fait en sorte que la densité de peuplement diminue graduellement du centre vers la périphérie du cercle. Ce site a permis l’étude de deux essences différentes ayant grandi dans des conditions de croissance similaires. Premièrement, les résultats démontrent que les caractéristiques des arbres sont fortement influencées par la densité de peuplement. En effet, le DHP, la hauteur totale, le défilement, la longueur et la largeur de la cime vivante, le diamètre des cinq plus grosses branches mortes et vivantes ont généralement augmenté avec l’accroissement de la distance entre les arbres, autant chez le pin gris que chez l’épinette blanche. L’optimisation du débitage primaire en fonction de l’emplacement spatial réel des nœuds internes dans les arbres a généré un volume de sciage significativement plus élevé et de plus grande valeur que les simulations du débitage uniquement basées sur la géométrie des tiges. En effet, la prise en compte de la distribution des nœuds lors des simulations du sciage a permis d’augmenter le nombre de pièces de qualité No.2 & meilleur produites de 15% pour l’épinette blanche et de 40% pour le pin gris. L’augmentation de la valeur des sciages associée à la connaissance de la distribution interne des nœuds a varié de 9,5% à 15,1% pour l’épinette blanche et de 15,2% à 23,0% pour le pin gris. Encore une fois, l’augmentation du rendement en valeur a été plus forte chez le pin gris que chez l’épinette blanche en raison de la présence de nœuds de plus fortes dimensions qui augmentent le potentiel d’optimisation.The first objective of this work is to characterize the properties of jack pine and white spruce and develop a lumber volume correction factor due to stem shape for both species. The purpose of this section is to more precisely predict lumber volume from forest inventory data. The second objective is to model the presence of knots and evaluate their impact on lumber yield using Optitek, a sawing simulation software. To achieve this goal, a new software had to be developed in order to extract CT image information and make it compatible with the Optitek software. Hence, the second objective is simulate lumber sawing while taking into account the knot dimension and location. The trees come from a Nelder (1962) type plantation of white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb.). This type of plantation is characterized by a circular shape which makes the stand density vary from the center to the periphery of the circle. This site makes possible the study of two different species growing in similar conditions. Several field data were analyzed such as diameter at breast height (DBH), curvature, taper, total tree length, live crown size. First, the results show that tree characteristics are strongly influenced by the stand density. Indeed, DBH, total height, taper, length and width of the live crown, diameter of the five largest branches dead and alive generally increased with greater distance between the trees, both for jack pine and white spruce. The results obtained with the simulation using the knot information gave a lumber sawing volume and value significantly higher. Both jack pine and white spruce have produced more No.2 & better pieces when knots have been considered in the sawing simulations (15% for white spruce and 40% for jack pine). As for lumber value, the increase varied from 9.5% to 15.1% for white spruce and 15.2% to 23.0% for jack pine. Again, the larger jack pine knot size could explain this greater potential for improvement