High-quality Logs Research Articles

EVALUATION OF WOOD QUALITY OF PINUS MONTEZUMAE LAMB. IN A DISTURBED FOREST USING NON-DESTRUCTIVE ACOUSTIC METHODS

The objective of this study was to evaluate the modulus of elasticity and wood quality for structural use in standing trees of Pinus montezumae Lamb. in a natural forest. An acoustic method was used, measuring the ultrasonic flight time for one cross-sectional and two longitudinal sections in 70 trees. Significant differences were found between the two longitudinal moduli of elasticity, and the P. montezumae trees in the study area show potential for structural use according to the modulus of elasticity. It is concluded that for sustainable management, wood of medium quality would be obtained in the same proportion for the first two sections of the tree stems, while high-quality logs would be obtained in the second longitudinal section (2–4 m).

The relationship between branch scar attributes and knot features in birch (Betula pendula and B. pubescens)

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.

Optimizing Bucking Decisions in Korean Red Pine: A Dynamic Programming Approach to Timber Profitability

Poor bucking decisions in forest stands can result in underestimating the profitability of timber sales. This study focuses on Pinus densiflora, commonly known as a red pine in Korea, which has often been underutilized as pulp and chips, leading to reduced profit margins. This study aimed to improve bucking decisions for red pine by analyzing the potential values in different log types and the profitability of manufacturing lumber products compared to pulp chips. A log sawing simulation model was developed using dynamic programming. This study optimized sawing patterns and estimated net profits for varying log sizes within the lumber market in Korea. The findings reveal that manufacturing lumber products from 3.6 m and 2.7 m logs can yield net profits 861% and 723% higher, respectively, than producing pulp chips from 1.8 m logs. Notably, sawing 3.6 m logs resulted in an average net profit 24% higher than from 2.7 m logs. These results advocate for more strategic bucking decisions based on potential timber sale profits and the end-uses of logs, especially in trees with large diameters at breast height (DBH), which can produce high-quality logs and should be bucked into long sawlogs whenever possible. Additionally, the study emphasizes the importance of practicing timber cruise to appraise the stumpage value of forest stands more accurately, moving beyond mere volume estimation to include tree type and expected volume. By implementing these practices, timber sale profits and the overall value of forest stands in Korea can be significantly enhanced. This approach not only benefits the economic aspect of forestry but also encourages sustainable and efficient resource management.

An economic analysis of management practices to mitigate butt rot and deer browse of planted western redcedar

We consider the economic feasibility of silviculture investments to reduce butt rot (through stump removal) and ungulate browse damage (stand establishment strategies), which are the most serious impacts to planted western redcedar (Thuja plicata Donn ex D. Don) stands in coastal British Columbia, Canada. We find mixed support for these investments, even if carbon sequestration benefits are included. We do find butt rot causes significant material damage to volumes, but such damage tends to occur well into the future of the stand diminishing the negative impact on stand value. As such, given the high costs of stump removal, and despite losses of high-quality logs, we find little support for stump removal except under very low discount rates (2%). Deer browse impacts are found to occur in the early stages of stand development, and projected stands should sufficiently recover volumes and value by harvest age. However, under positive carbon prices, because deer browse mitigation measures have an immediate impact on biomass accumulation in the early stages of stand development, we find some conditions for which low-cost deer browse mitigation options might be economically supported on forestlands. Finally, we found that increased planting of seedlings is likely a low-cost, financially attractive option under a broad set of conditions, even on sites without risk to damage, meaning a possible no-regrets strategy to mitigate damages from either deer browse or decay. The benefits of planting highlight the feasibility of using tree breeding to increase growth, resistance to deer, decay, and drought. The methods developed in the paper to evaluate the impact of both root rot and ungulate browsing could be applied to other ecosystems elsewhere.

Mixed Castanea sativa plantations including arboreal companion species enhance chestnut growth and high-quality timber production

ContextChestnut (Castanea sativa Mill.) is an important tree species for its timber, which is widely used for multiple purposes, including the veneer industry. The species has an interesting productive potential in Chile and requires specific management strategies to produce valuable, high-quality logs. Although mixed plantations including companion species usually enhance timber quality of several trees, the performance of chestnut under different associations is not well known. AimsThe objective of this study was to assess growth, survival, health, and timber quality of chestnut trees in several plantation types, including monoculture and mixtures with other companion trees and/or shrub. MethodsGrowth and survival measurements were taken periodically in pure chestnut and mixed plantations established in southern Chile for a 20-year period after planting. The mixed plantations tested were: a main forest species mixture (Castanea sativa Mill., Quercus rubra L., Quercus robur L. and Prunus avium L.); three mixtures including main forest species plus one arboreal companion species (Alnus glutinosa L., Gevuina avellana Mol. or Embothrium coccineum J.R. Forst. & G. Forst.); one including main forest species plus one shrub nurse species (Fabiana imbricata Ruiz & Pav.); and three mixtures including one of the arboreal companion species and the shrub. Timber quality variables were assessed at age 20, and health status was recorded at ages 7 and 20 in all plantations. Growth variables were analyzed using linear mixed models to assess plantation effect over time. Kaplan-Meier survival analysis and Log Rank Test were used to compare chestnut tree survival among plantation types. Quality timber variables were analyzed with a χ2 test. ResultsChestnut trees associated with arboreal main species (P. avium, Q. rubra, Q. robur) (Mix1) showed the best performance, with 10.1 % and 8.3 % higher height than average values of the other mixtures and the monoculture, respectively, and 19.1 % and 12.8 % higher diameter growth than across plantation types and monoculture average values, respectively. Mix1 had the highest average volume per tree (0.34 m−3), at least 30 % higher than the average volume of pure and other mixed plantations. This mixture including only main species also exhibited the highest percentage of trees with high trunk length values of all plantation types. No pest or diseases were recorded on chestnut trees, and survival was high in all plantation types. ConclusionThe impact of mixed plantations on growth and timber quality was evidenced at age 20. In particular, the association including arboreal companion species enhanced chestnut tree performance.

Predicting sonic and density logs from drilling parameters using temporal convolutional networks

Sonic and bulk density logs are crucial inputs for many subsurface tasks including formation identification, completion design, and porosity estimation. Economic and operational concerns restrict the acquisition of these logs, meaning the overburden and sometimes entire wells are completely unlogged. In contrast, parameters that monitor drilling operations, such as weight on bit and torque, are recorded for every borehole. Previous studies have applied supervised machine learning approaches to predict these missing logs from the drilling parameters. While the results are promising, they often do not investigate the importance of different features and the corresponding practical implications. Here, we explored the feasibility of predicting compressional slowness and bulk density logs using various combinations of formation markers, gamma-ray logs, and drilling data recorded at the rig. Our tests utilized a temporal convolutional network to allow the model to learn from sequences of input features. Bayesian-based hyperparameter tuning found the optimum set of parameters for each experiment before producing the final log predictions. Finally, a permutation feature importance analysis revealed which input variables contributed most to the outputs. Although drilling parameters contain some insight into the mechanical rock properties, we found that they cannot produce the high-quality log predictions required for many tasks. Supplementing the drilling parameters with a gamma-ray log and formation data produces good-quality log predictions, with the additional inputs helping to constrain the model outputs.

Модернизация валочно-сучкорезно-раскряжевочного механизма лесного харвестера

There is an annual increase in the number of modern forestry machines at logging enterprises both in Russia and in foreign countries. At the same time, the fleet of forestry machines is becoming more diverse and multifunctional, and their manufacturers, competing for market outlets, find themselves interested in constant upgrading of existing and development of new design and technological solutions. The research is aimed at finding a new engineering solution that will allow along with harvesting high-quality logs to perform their partial debarking without a significant reduction in the processing speed. The effective result is achieved by the fact that the proposed new method of processing tree trunks provides the possibility of timber barking in strips, i.e. removing the bark from a fallen tree along its entire length, as well as bast removal (partially or completely). The method involves, as in the traditional model of harvesting (processing) head functioning, crosscutting of the trunk by the sawing mechanism and delimbing by delimbing knives. This leads to accelerated natural drying of wood during its storage in the warehouses and significantly increases the floatability of thin coniferous logs during their further timber floating. The implementation of the proposed option of harvesting debarked timber at the logging site and the working body of harvesters (processors) to carry out such harvesting will increase the share of logging waste at the logging site. The design of the new harvesting (processing) head does not require significant financial expenses for its upgrading. The design of the new harvester head allows the logs to be barked in strips along the entire length. Additional drive of working mechanisms is not required. This will enable the implementation of rough debarking with minimal financial costs already at the stage of logging operations and increase the efficiency of logging and timber processing enterprises.

Operational Testing of a Solid Fuel Boiler with Different Fuels

In the course of our investigations, we burned high-quality logs as well as wood briquettes in a conventional, manually fed mixed-fired boiler, under different operating parameters. Based on the evaluation of the measurement results, there is a significant difference in terms of recoverable energy and carbon monoxide emissions for the two fuels burned in the same device at different air supply parameters. Studies have shown that a constantly changing position of the draft control door has an adverse effect on carbon monoxide emissions as well as the energy produced. In the case of a constant draft door setting, the preset values that can be considered ideal for energy yield and CO emissions were determined for the two fuel types. The obtained results were compared with the requirements according to the MSZ EN 303-5 standard.

Material Flow Analysis to Evaluate Supply Chain Evolution and Management: An Example Focused on Maritime Pine in the Landes de Gascogne Forest, France

The Landes de Gascogne forest, located in southwestern France, spans nearly 10,000 km2 and consists largely of maritime pine (Pinus pinaster). This forest in unique to Europe because it is almost entirely created and managed by man for specific industries. On the basis of a material flow analysis, we assessed the upstream supply chain of maritime pine from 2013 to 2019, using a cradle-to-gate approach. The assessment is based on data provided by Alliance Forêts Bois, an important stakeholder of the region and leader in the production of forest resources in France. For various reasons, the harvest totals decreased 10% in the last years. We identified a clear orientation to specific industries—in 2019, 45% was used as pulpwood. This is due to the overall design of the current territory, species of tree, and market values of the pulp and paper industry. The current design provides a limited supply of old growth trees, which produce high-quality logs for construction-based products, and are also more resistant to climate variability. A future shift or balance in raw material flows could be a crucial step in protecting the long-term economic viability of the region. This article aims to contribute to new attempts in providing comprehensive views of stocks and flows in the French forest-wood supply chain.

Intention-aware log automation

Log automation is a technique that helps developers write high-quality log code. When software systems fail, log code can ease the failure diagnosis process and reduce system recovery time. Existing log automation tools can be roughly classified into two groups: feature- and pattern-based tools. These existing tools define log placement rules by either extracting syntax features or summarizing code patterns, but they are hard to understand the source codes intention. In this paper, we design and implement SmartLog, which can create log statements based on deep understanding of log intention. To achieve this, we propose a log intention description model to describe the intention of log statements. SmartLog then explores the intentions of existing logs and mines log rules from those intentions. We evaluated SmartLog on six mature open-source projects. Compared with two state-of-the-art projects, i.e., Errlog and LogAdvisor, SmartLog improved the accuracy of log placement by 43% and 16% respectively. SmartLog could cover 49 out of 86 real-world patches aimed to add logs, while the state-of-the-art works could cover 10 and 22 patches, respectively.

Pure and mixed plantations of Persian walnut (Juglans regia L.) for high quality timber production in Chile, South America

AbstractAimsPersian walnut (Juglans regia L.), an interesting forest species for the veneering industry, requires adequate management to produce valuable high-quality logs. Since species associations and management level can improve stand productivity, the novelty of this work was to assess Persian walnut performance in different planting mixtures and in pure plantations conditioned to management intensity.MethodsGrowth, straightness and survival measurements were taken annually for 7 years after planting pure and mixed plantations under two contrasting management scenarios. Diseases were recorded at Age 7 in all plantations. Under each management intensity, besides the monoculture, three mixtures were tested: a mixture of only main forest species, main forest species plus one arboreal companion species, Black alder (Alnus glutinosa L.) and main species plus the shrub Russian olive (Elaeagnus angustifolia L.) as nurse species. A test of interaction between plantation type and management scenario was conducted using repeated growth data.Important FindingsThe interaction was significant, indicating the presence of different mechanisms underlying plantation effects under high and low management level. Compared with pure plantations, Persian walnut associated with the nurse shrub exhibited 78% higher height and 53% higher diameter growth in plantations under low management. Health benefits (lower presence of walnut blight than in the monoculture) and better straightness were also found in the association including the shrub when the management intensity was not high. These beneficial effects in the presence of Russian olive were not present under high management intensity (irrigation, fertilization, tutoring and frequent pruning). Site-specific designs for Persian walnut plantations would depend on the foreseen management intensity.

VOLUME TEGAKAN Acacia mangium PADA UJI PEROLEHAN GENETIK DENGAN KERAPATAN TEGAKAN TINGGI

High initial stand density is commonly practiced in forest plantations subjected to produce high quality logs through successive thinnings. In this study, genetically improved seed of Acacia mangium was verified in genetic gain trial using high initial stand density. The trial was established in Jonggol, West Java and laid out in randomized complete block design with high initial stand density of 2500 trees/ha or in spacing of 2 x 2 m. The improved seeds tested in the trial were collected from four seedling seed orchards (SSOs). As a control, unimproved seeds from seed production area (SPA) were also planted together in the trial. The assessment of stand volume productivity was periodically conducted at two, three and four years of age. The results of study showed that the improved seeds from the four SSOs out performed the unimproved one. However, the significant difference among the seed sources was initially found at the four years of age. The average stand volumes of improved seed were 58.56m3/ha, 94.87m3/ha and 163.8m3/ha for two, three, and four years of age, respectively. The superiority of improved seed over the unimproved one ranged from 23%-36% (two years), 6%-30% (three years) and 2%-22% (four years). The four SSOs showed different behaviours in response to high stand density. Improved seed from SSOs with higher selection intensity was likely to be more tolerant to high stand density.

Relation between forest stand diversity and anticipated log quality in managed Central European forests

ABSTRACTThis study examined the influence of tree species and structural diversity on the production of high-quality logs. The data were from the regional forest inventory of the University Forest Enterprise, Czech Republic, performed from 2009 to 2011 on 1188 sample plots. For every sample plot, we quantified 38 diversity indicators. The plots were divided into four age groups (young, middle-aged, old and uneven-aged stands). The anticipated proportion of high-quality logs was determined using local assortment tables. For each age group, the impact of species and structural diversity indicators on the volumetric proportion of high-quality logs was assessed using backwards multiple regression. The relationship between diversity measures and log quality changed with stand age. In old stands, horizontal structure had a more profound effect on the proportion of high-quality logs. In young stands, species diversity and vertical structure were more influential. In middle-aged stands, the impact of stand diversity on log quality was most complex. In uneven-aged stands, vertical structure was the diversity component most affecting the proportion of high-quality logs. Overall, the proportion of best quality logs increased with the increasing stand diversity in all age classes, suggesting that timber production and stand diversity are not contradictory management goals.EDITED BY Sheila Ward

The coppice-with-standards silvicultural system as applied to Eucalyptus plantations — a review

We review the management of Eucalyptus species under a coppice-with-standards (CWS) silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because: there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipurpose species. We discuss (1) short rotation Eucalyptus coppice management for energy and pulping and (2) Eucalyptus seedling management for solid wood products. We review the literature and discuss experiences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environment of the standard trees (heavy competition up to the first harvest, free growth afterwards) coupled with long rotations (>20 years) results in high quality logs for solid wood products. Early pruning should be applied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.

Improving tree selection for partial cutting through joint probability modelling of tree vigor and quality

Tree classification systems are generally designed to predict the supply of high-quality logs for the wood processing industries and to mark defective trees for removal with the aim of improving both the vigor and quality of future stands. Although these two objectives are generally inversely related, their joint consideration could enable the development of robust criteria for improved tree selection in partial cuttings of northern hardwood stands by targeting low-vigor (LV) trees of high quality (HQ). In this study, we used a copula approach to model the joint probability distribution of trees characterized by both vigor and quality, which accounts for the statistical dependence between the different classes of both classification systems. The relationships between the probability of occurrence of a tree in each joint category and tree diameter at breast height (DBH) were quite similar among the three studied species: yellow birch (Betula alleghaniensis Britt.), sugar maple (Acer saccharum Marsh.), and American beech (Fagus grandifolia Ehrh.). In particular, the probability of occurrence of LV–HQ trees was characterized by a parabolic curve with a maximum value attained at the mid-DBH range, whereas that of LV and low-quality (LQ) trees increased with increasing DBH. This suggests that instead of harvesting large and mostly LV–LQ trees, partial cutting should target smaller LV–HQ trees, so that the volume of harvested HQ trees would increase without compromising the silvicultural objective of improving the vigor of future stands.

Spacing affects stem form, early growth and branching in young whitewood (Endospermum medullosum) plantations in Vanuatu

SUMMARY This paper investigates the early growth response, branching and stem quality of Endospermum medullosum (whitewood) at different spacings. Whitewood plantings were established at stockings of 400–833 trees per hectare and early growth, tree stem quality and branching were quantified up to age 3 years. Growth, number of live branches and branch size were negatively correlated with stocking. The stocking of trees of acceptable quality had high spatial variation. Initial spacing in whitewood plantations can be used to manipulate branch size, crown rise and stem size; all of which are important for development of pruning and thinning regimes to produce high quality logs. If unimproved whitewood stock is used, to ensure that there are 300 stems per hectare of acceptable quality to produce sawlogs, more than 600 trees per hectare should be established at planting.

Effect of wide spacing on tree growth, branch and sapwood properties of young Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in south-western Germany

The influence of stand density on Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] is conceptually understood, but for wide spacings not well quantified, particularly in Europe. This study used 41 trees from 7 different locations in south-western Germany to compare important tree- and branch-level attributes across three different densities, namely 100, 200, and 1,200 stems ha−1. In general, there were only a few tree and branch attributes that were significantly different between the 100 and 200 ha−1 densities. Crown projection area and diameter of the thickest branches were the most important differences between the 100 and 200 ha−1 densities. The most obvious and significant differences in this study were between 100 and 1,200 ha−1 densities, where nearly every examined tree and branch attributes were statistically significant. However, relative sapwood area, the number of branches, branch angle, and the occurrence of spike knots were insensitive to stand density. Although the two lowest stand densities in this study represent rather extremely wide spacings, these results still have important implications for the development of effective thinning regimes for Douglas-fir in south-western Germany. Important management recommendations from this study include thinned stands should be maintained to at least 200 stems ha−1 to maintain high log quality and stand stability. Furthermore, even at stand densities exceeding more than 1,200 trees ha−1 planted trees, artificial pruning may even be necessary to produce high quality logs.

Adaptive versus fixed policies for economic or ecological objectives in forest management

In the context of forest management, a fixed harvesting policy consists in trying to convert stands of trees to a chosen state at fixed intervals, regardless of the stand state and of the state of the market. In an adaptive policy, instead, the post-harvest state and the timing of the harvest depend on the stand and market states at the time of the decision. The objective of this study was to determine the practical gain from the theoretically superior adaptive policies. To this end, we compared optimal fixed and adaptive policies obtained with identical models and assumptions, and with data from the Douglas-fir/western-hemlock forests in the Pacific Northwest of the United States. In maximizing economic returns from harvests over an infinite time horizon, the net present value was 17 percent higher with an adaptive than with a fixed policy. It was 22 percent higher when the objective was to maximize annual harvest. The adaptive policy was even more superior with undiscounted, non-economic objectives, such as the area of spotted owl habitat (+37 percent gain), or the area of late-seral forest (+51 percent), but less so in maximizing the stock of high quality logs (+6 percent). The adaptive formulation also lent itself readily to multi-objective management.

Frost damage on the terminal shoot as a risk factor of fork incidence on common beech (Fagus sylvatica L.)

Forking is a frequent flaw in beech which can adversely affect the formation of high quality logs. Even though the hypothesis that late frosts increase forking is widely accepted by forest managers, it remains to be proved and quantified experimentally. Damage caused by a late frost on 15 May 1995 to young beech trees in an experimental site at Lyons-La-Forêt (France) and the consequences on the development of forking were analysed. The beech trees were 17 years old with heights between 1.5 and 9 m. Of all the plantation densities tested only the lowest density (625/ha) showed various and severe frost damage. Three levels of immediate damage to the growing terminal shoot were observed, with increasing intensity from: (1) no trace of frost damage, (2) reddened leaves and (3) frost-nipped shoots. The intensity of visible damage to the terminal shoot appeared to be very dependent on the height of the plant which justified our original experimental approach, based on an evaluation of the damage for each individual. Almost all of the beech trees less than 4 m high suffered frost damage and all those taller than 7 m were unaffected. Three-year-old forks due to frost which occured in May 1995 were recorded at the end of 1997 using an objective definition based on dendrometric and age criteria. The worst frost damage resulted in a significant increase in the risk of fork emergence (71.7% of the plants were forked). With a risk related to forking in the presence of frost-nipped shoots equal to 2.15 and a fraction of the attributed risk of 0.36 it was concluded that the late frost observed played a significant role in the degradation of the shape of the beech affected by frost and the overall quality of the stand.

Population growth impairment of aliphatic alcohols to Tetrahymena.

The toxicity of a series of 120 aliphatic alcohols was evaluated using the Tetrahymena pyriformis population growth impairment assay. For tertiary propargylic alcohols; primary, secondary, and tertiary homopropargylic alcohols; allylic alcohols; and saturated alcohols, a statistically robust structure-activity model was developed for toxicity data [log (IGC(50) (-1))] using the 1-octanol/water partition coefficient (log K(ow)) as the lone descriptor [log (IGC(50))(-1) = 0.74 (log K(ow)) - 1.73; n = 97; r(2) (adj.) = 0.933; r(2) (pred.) = 0.932; s = 0.298; F = 1328; Pr > F = 0.0001]. Analysis of data for the primary propargylic alcohols yielded a separate, high-quality log K(ow)-dependent quantitative structure-activity relationship (QSAR) [log (IGC(50))(-1) = 0.65 (log K(ow)) - 1.22; n = 10; r(2) (adj.) = 0.969; r(2) (pred.) = 0.964; s = 0.222; F = 254; Pr > F = 0.0001]. A comparison of the observed toxicity and that predicted by the first QSAR showed that the primary propargylic alcohols with log K(ow) values < 2.00 exhibited enhanced toxicity and that this increased toxicity was inversely related to hydrophobicity. In sharp contrast, analysis of the data for the secondary propargylic alcohols exhibited little relationship with log K(ow) (r(2) = 0.339). Although the initial QSAR can be used to model the toxicity of any aliphatic alcohol for the T. pyriformis population growth impairment end point, the estimated potency would be underestimated for primary propargylic alcohols with log K(ow) values < 2.00. Moreover, estimates of toxic potency of secondary propargylic alcohols based on this QSAR should be viewed with limited confidence. The findings for beta-unsaturated alcohols in Tetrahymena were sharply different from that reported for fathead minnow acute mortality; this difference in toxicity is a result of a difference in the protocol used rather than in metabolism.