Poplar Logs Research Articles

Production and technical performance of scrimber composite manufactured from industrial low-value wood for structural applications

Development of scrimber composites and other engineered wood products from low-value wood and wood waste provides an effective opportunity to preserve natural resources, minimize waste, and innovate the production of higher-performance, environment-friendly construction materials. In this study, peeler cores, which are the center of poplar logs remaining after the peeling process in the veneer production, were utilized to develop scrimber composites. This study investigated the effects of different resins, including phenol-formaldehyde (PF) and urea formaldehyde (UF), as well as hydrothermal treatments at various temperatures (60 °C and 130 °C), on the physical and mechanical properties of the scrimber composites. Chemical changes in wood components and morphological changes in wood cell walls resulting from hydrothermal treatment were analyzed using Fourier transform infrared spectroscopy and scanning electron microscopy. To clarify how resin type and hydrothermal treatment affect structural performance, several physical and mechanical properties of scrimber composites, including thickness swelling, water absorption, internal bond strength, bending modulus of elasticity, and modulus of rupture, were measured. The test results revealed that hydrothermally treated wood scrims at 130 °C, when bonded with PF resin, produced scrimber composites with superior structural performance.

Producing structural grade hardwood lumber as a raw material for cross-laminated timber: Yield and economic analysis

The economic feasibility of producing structural-grade hardwood lumber (SGHL) that qualifies as a raw material for structurally rated cross-laminated timber (CLT) was examined. 126 yellow poplar logs from diameters 12 to 15 inches were selected and divided into test and control samples. A log yield study was then conducted of the yield and revenue generated when producing lumber graded with National Hardwood Lumber Association (NHLA) rules, SGHL rules, and a mix of both rules (NHLA and SGHL-graded lumber). Producing mix-grade lumber added approximately 27% more revenue than producing NHLA-grade lumber on average if sawmills adopt a cant sawing method. Mix-grade lumber production resulted in 32% of the total volume produced as SGHL and the remaining 68% as NHLA lumber. As a result, 2 Common and lower-grade lumber board footage was reduced to only 29% in test samples and remained converted into SGHL compared to more than 85% of 2 Common and lower-grade lumber boards for control samples. 95% of the SGHL produced as mixed-graded lumber with NHLA-grade lumber met the specifications required to produce structural CLT, and the remaining 5% can be utilized to produce non-structural grade CLTs if they meet the minimum requirement of the materials for CLT production.

Interception of live Phratora laticollis (Suffrian) (Coleoptera: Chrysomelidae) on poplar logs imported from Belgium and Germany

Logs of Populus nigra L., frequently exported from Belgium and Germany are frequently being intercepted with a beetle Phratora laticollis (Suffrian) (Coleoptera, Chrysomelidae, Chrysomelinae), which is a pest of poplar trees in their native range. Such interceptions of exotic pests pose biosecurity risk to India, and hence these intercepted shipments require to be fumigated with methyl bromide @ 48 g/ m3 for 24 hr at the normal atmospheric pressure. The treated shipments also need to be re-inspected prior to release to ensure that these are free of live infestation. Its non-compliances need to be notified to the trading partners on each interception as per the guidelines in the ISPM-13. Significance of such interception in plant biosecurity is discussed herein.

Interception of Hololepta plana (Sulzer) (Coleoptera, Histeridae) a rare beetle on poplar logs imported from Belgium

Interception of Hololepta plana (Sulzer) (Coleoptera, Histeridae) a rare beetle on poplar logs imported from Belgium

Natural Drying and Chemical Characteristics of Hybrid Poplar Firewood Produced from Agricultural Bioenergy Buffers in Southern Québec, Canada

Implementing bioenergy buffers on farmland using fast-growing tree species could reduce firewood harvest pressure in woodlots and increase forest connectivity, while improving carbon sequestration, phytoremediation, stream habitats, soil stabilization and hydrological regulation. The objective of the study was to evaluate the natural drying and chemical characteristics of hybrid poplar firewood produced from bioenergy buffers, and to compare these characteristics with those of native species harvested in adjacent woodlots. In Trial A, 110 cm-long unsplit logs (a feedstock for biomass furnaces) were produced to evaluate the effect of log diameter class on firewood quality. In this trial, hybrid poplar firewood characteristics were also compared with Populus tremuloides, Acer rubrum and Fraxinus americana. In Trial B, the effect of hybrid poplar genotype and cover treatment was evaluated on the moisture content of short split logs (40 cm long). Firewood of satisfactory quality was produced on a yearly cycle for short split logs, and on a biannual cycle for long unsplit logs. Covering short split log cords with metal sheeting lowered the final moisture content (from 20.7% to 17.3%) and reduced its variability, while genotype did not significantly affect final moisture content. In Trial A, larger-diameter logs from hybrid poplar had lower element concentrations, but slightly higher moisture content after two years. A two-fold variation in N concentration was observed between diameter classes, suggesting that burning larger poplar logs would minimize atmospheric N pollution. Heating value, carbon and calcium concentrations increased following the seasoning of hybrid poplar firewood. After the first seasoning year outdoors, hybrid poplar had the highest moisture content (33.1%) compared to native species (24.1–29.5%). However, after the second seasoning year in an unheated warehouse, the opposite was observed (14.3% for hybrid poplar vs. 15.0–21.5% for native species). Heating value, carbon and nitrogen concentrations were similar between tree species, while high phosphorus and base cation concentrations characterized hybrid poplar, suggesting higher ash production. Poplar bioenergy buffers could provide a complementary source of firewood for heating in the fall and in the spring, when the heat demand is lower than during cold winter months.

To split or not to split: Feasibility of pre-storage splitting of large poplar (Populus spp. L.) fuelwood logs

Contrary to firewood, and despite the availability of dedicated equipment splitting of logwood is not yet a common practice in fuelwood supply. This study investigated the impact of a pre-storage splitting treatment on moisture content alteration, dry matter loss and volumetric energy density. Further, economic and environmental implications of splitting were investigated. Splitting increased the drying rates of large poplar logs 2–3 times and enabled to reach a 15.3% lower final moisture content compared to intact logs at similar dry matter loss rates (9.2% vs. 7.8%). Final volumetric energy density of split logs was 27.2% higher than for intact logs. Splitting increased the profit from poplar fuelwood and decreased respective supply cost. Further, 26.3% less truck trips were required for woodchips produced from split logs. Pre-storage splitting is highly recommended for large logs of slowly drying species like poplar, to, firstly, reach low moisture content levels at all, and secondly, reach them in less time. This treatment has the potential to become an integral part of sustainable and responsible utilization of our fuelwood resources, as less material is required to supply the same amount of energy. At the same time, less truck trips are required to transport it, which is clearly beneficial from an environmental viewpoint.

Relationships between transpiration, water loss, and air conditions during physiological drying

ABSTRACTTree transpiration can cause a rapid decrease in the moisture of tree trunk after felling. In this study, the physiological drying of poplar logs was examined as a result of transpiration. Experiments were conducted on poplar trees with and without canopies and where the water supply from the roots was blocked. The effect of transpiration on the drying process and the relationships between transpiration, water loss, and air conditions were investigated. Statistical analysis of the data showed that the moisture content (MC) decreased significantly as a result of physiological drying at a rate of 5.65% MC/day within 3 days, 3.85% MC/day within 5 days, and 2.30 MC/day within 9 days. The transpiration rate of the trees was positively correlated with the moisture loss. Leaf transpiration of control trees and those where access to water was blocked was strongly and similarly affected by air conditions, although the water-blocked treatment resulted in a significantly lower transpiration rate. The transpiration rate and stomatal conductance increased as relative humidity increased and as vapor pressure deficit decreased. When transpiration-mediated water loss occurred, the temperature difference between the air and leaf surface was approximately 1–3°C. The results indicate that transpiration is the main driving force that reduces water during physiological drying, and the main factors that influence this process are the air conditions.

Precision dating of Cook’s Mill, a Civil War era structure in West Virginia

Dendroarchaeology can provide critical understanding of a structure built during key historic periods, such as the American Civil War (1861–1865), when historical documentation is likely to be sparse or incomplete. Cook’s Mill is located in Greenville, West Virginia and extensive information derived from deeds, court records, wills, and oral history places the present mill’s original construction in 1857. The American Civil War began shortly after its construction and military conflict in the area led to the burning of several key structures, one of which was an unknown mill in Greenville (formerly Centerville). Written history suggests the mill is original and survived the American Civil War, however we used dendroarchaeology to confirm its precise date of construction. We collected 46 samples from the mill and 6 cross sections from a nearby exhumed bridge for dendrochronological dating. The mill was constructed with white oak (Quercus alba) and tulip poplar (Liriodendron tulipifera) logs and the bridge samples were white oak. We visually and statistically crossdated 32 white oak samples from the mill and bridge by comparing them to a local chronology developed for this study and two regional oak chronologies from the International Tree-Ring Data Bank. Based on terminal ring attributes and cutting date years we were able to provide a suggested construction date of the spring or early summer of 1868. This date suggests Cook’s Mill was the mill burned during military conflict in the area and that the current structure was subsequently rebuilt following the conclusion of the war.

A Methodology for Experimental Research of the Freezing Process of Logs

Abstract This paper describes a methodology for experimental research of the change in the temperature and humidity of the air processing medium and also in the temperature at 4 points of the longitudinal section of logs during freezing. The suggested methodology is used to research the change in the mentioned parameters of poplar logs with diameters of 240 mm, lengths of 480 mm and moisture content above the hygroscopic range during 50 h of freezing in a freezer at a temperature of about -30 °C. The automatic measurement and recording of the parameters is carried out with the help of Data Logger type HygrologNT3 produced by the Swiss firm ROTRONIC. The precise instrumentation allowed, for the first time ever, the measuring of the impact the latent heat released by the free water on the log had on the warming up of the wood during water crystallization in the logs.

Structural Analysis of Forest Product Businesses in Gumushane Province

In total, 95% of all business enterprises established in Turkey are micro-scale, and this figure increases to 98.6% in the forest products industry. Micro-scale enterprises are important in terms of production, employment, and overcoming economic imbalances among regions. The forest products industry, which includes three subdivisions within the manufacturing sector, occupies an important place in the overall Turkish manufacturing sector. Thus, this study examined the structural characteristics of forest product enterprises in Gumushane Province. The research involved in-person interviews with personnel at 47 enterprises. The data revealed that the sawmill division was especially important with respect to the use of local poplar logs. The sawmill and furniture divisions accounted for 28% of all enterprises and 26% of all employees in the manufacturing sector in Gumushane. We found that 57% of enterprises had difficulty in finding working capital and 55% of enterprises experienced shortages of labour. The average contribution of each forest products business to employment (2.55) was more than that of other manufacturers in Gumushane (2.27). The forest product businesses in Gumushane resemble other micro-scale enterprises located in other regions of Turkey in terms of their structural properties

Laser vibrometry as a diagnostic tool for detecting wood-boring beetle larvae

Wood-boring insect pests, such as the invasive Asian longhorned beetle (ALB, Anoplophora glabripennis), are difficult to detect because larvae mine inside deciduous trees, logs or wood packing material. Currently, only visual survey methods are used, which are mostly unable to detect the presence of wood-boring insects. Bioacoustic detection, however, exploits sounds and vibrations produced by larvae during feeding and other movements inside the wood. Bioacoustic detection methods require mounting of the sensors, which can be complicated, time consuming and may even damage the surface of the tested material. Laser vibrometry avoids all these problems as vibrations produced by the larvae are detected via the laser beam. We used a portable digital laser vibrometer to detect the activity of mining ALB larvae within poplar logs. Three types of pulses were recorded: the broadband pulses lasting 1–2 ms were the most frequent, with frequency maxima between 8 and 13 kHz. Less frequent were the low and the high frequency pulses, covering frequency bands between 4 and 7, and 9 and 20 kHz, respectively. The signal-to-noise ratio across the whole frequency range (0–22 kHz) of the laser vibrometer was around 35 dB. We show that laser vibrometry can be successfully employed as a non-destructive diagnostic tool for detecting infestations by the wood-boring beetles.

Chipping machines: disc and drum energy requirements

Air pollution and fossil fuel reserves exhaustion are increasing the importance of the biomass-derived products, in particular wood, as source of clean and renewable energy for the production of electricity or steam. In order to improve the global efficiency and the entire production chain, we have to evaluate the energetic aspects linked to the process of transformation, handling and transport of these materials. This paper reports results on a comparison between two chippers of similar size using different cutting technology: disc and drum tool respectively. During trials, fuel consumption, PTO torque and speed, processing time and weight of processed material were recorded. Power demand, fuel consumption, specific energy and productivity were computed. The machine was fed with four different feedstock types (chestnut logs, poplar logs, poplar branches, poplar sawmill residues). 15 repetitions for each combination of feedstock-tool were carried out. The results of this study show that the disc tool requires, depending on the processed material, from 12 to 18% less fuel per unit of material processed than the drum tool, and consequently, from 12 to 16% less specific energy. In particular, the highest difference between tools was found in branches processing whereas the smallest was in poplar logs. Furthermore the results of the investigation indicate, that, in testing conditions, the productivity of drum tool is higher (8%) than disc tool.

Forecasting air-drying rates of small Douglas-fir and hybrid poplar stacked logs in Oregon, USA

Managing moisture in woody biomass can lead to significant economic advantages in the woody biomass energy business. In this study, two prediction models were developed to estimate moisture content for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and hybrid poplar (Populus spp.) woody biomass in the form of small stacked logs. Experimental data were collected in Oregon over a 12-month period at two locations each for Douglas-fir and hybrid poplar. These data were used to develop linear mixed-effects multiple regression models for predicting the change in moisture content for each species separately. The major factors considered in this study for predicting woody biomass moisture-content change were cumulative precipitation, cumulative reference evapotranspiration (ET0), and biomass piece size. Use of the model was demonstrated for four of the nine climate zones in Oregon: two in which air-drying data were collected, and two in which these were not collected. Considerable differences in predicted drying times were observed, depending on the climate zone and on the season in which air-drying began.

Performance of a small-scale chipper for professional rural contractors

The study determined the productivity, fuel consumption and product quality obtained with a new tractor-powered drum chipper, designed to reduce the gap between industrial chippers and small-scale chippers. The machine was tested with poplar logs and beech slabs, considered as representative of the raw material commonly used for energy wood production. After accounting for accessory work and delays, productivity of green chips ranged between 4 and 6 tons per scheduled machine hour, which was very good for a tractor-powered unit. Specific fuel consumption of oven-dry chips varied between 2.5 and 3.0 L per ton, or 0.6 L per m3. These figures compared favourably with those obtained from previous studies of both smaller and bigger chippers. Chip quality was very good. Samples contained no oversize particles, qualifying for use in small-scale plants. The average size of beech chips was significantly larger than for poplar chips, possibly due to the higher strength of beech wood.

Acoustic Testing and Sorting of Chinese Poplar Logs for Structural LVL Products

The purpose of this study was to investigate the feasibility of using resonance-based acoustic technologies for sorting Chinese poplar logs for laminated veneer lumber (LVL) products. Representative poplar logs were sampled. Each log was first tested for acoustic velocity and then peeled into veneer. Each veneer sheet was subsequently dried and measured with a production-line veneer tester. LVL beams were made, and their stiffness was non-destructively measured by both time-of-flight (TOF) acoustic method and free-beam vibration methods. Based on the LVL dynamic modulus of elasticity (MOE) values, logs were sorted into several grades with known grade outturns. The results showed that there was a strong correlation between resonance-based acoustic velocities of logs and dynamic MOE of veneer and LVL. Thus, it is feasible to predict the stiffness of LVL products based on log resonance-based acoustic velocity measured. The resonance-based acoustic measurement is easy to use and reliable, which can help increase the grade outturn and in turn value recovery of Chinese poplar logs. It was estimated that the log grade outturns were approximately 31.1% for LVL grade 1, 38.6% for LVL grade 2, and 26.1% for LVL grade 3.

Study of Chemical Modification by Impregnation of Fresh Poplar Log and by Hot-Press Drying Process

In this work, fresh poplar logs were chemically impregnated with a pulse-dipping machine. The impregnated timbers were compressed and dried by use of a multilayer hot-press drying kiln. With a compression rate of 28.67%, such an approach not only enhanced the density and mechanical properties of the treated wood, but also influenced the set recovery from the compressive deformation. Extra urea was added into the modifier to optimize the effect of the set recovery; however the result was a slight decrease in the mechanical properties. The positions of the X-ray diffraction (XRD) peaks did not change, which indicated that the structure of the cellulose was not noticeably affected by this treatment. The Fourier transform infrared spectroscopy (FT-IR) analysis showed that the intensity amide (N–C=O) absorption peak increased significantly due to the chemical impregnation. Scanning electron microscopy (SEM) showed that the high strain in the hot-press process drastically reduced the volume of void spaces in the specimens and deformed the cell lumens.

Research on Compression and Bending Resistance Characteristics of Logs

The testing experiments to healthy poplar and larch logs samplings were conducted by using hydraulic machine. The relationships among compression and bending strength, modulus of elasticity in compression and bending were studied in the two logs samplings. The results indicated that, in the both species, the compression strength had certain linear correlation with bending strength, and so did the modulus of elasticity in compression and bending. Meanwhile there were remarkable linear correlations with the compression strength and the modulus of elasticity in compression as well as the bending strength and the modulus of elasticity in bending.

Variation in diameter of central columns of discoloration in six hybrid poplar clones

The percentage of stem diameter discolored in the center of hybrid poplar logs varied by clones. For the six clones studies, discoloration columns ranged in percentage of total stem diameter from 85.0 to 55.8.

Association of Gonatorrhodiella highlei with Nectria Species

DURING 1947, Gonatorrhodiella Highlei A.L.Sm., a member of the Fungi Imperfecti only once recorded in Great Britain before1, was observed forming yellowish felts of conidiophores on the bark surfaces of stored beech and poplar logs at the Royal Botanic Garden, Edinburgh.

Poria Andersonii and Polyporus Glomeratus, Two Distinct Heart-Rotting Fungi

Pure-culture studies of wood-rotting fungi, which are conducted as an aid in distinguishing macroscopically similar rots and determining their relative importance, frequently also clarify the taxonomic relationships of the species involved. Such is the case with Poria Andersonii (Ellis & Ev.) Neuman and Polyporus glomeratus Peck, two species frequently isolated in a decay study, which to date have not been clearly separated by mycologists and pathologists. Peck (10) in 1873 described P. glomeratus and it has since been recognized by most mycologists as a well-defined species of Polyporus. Unfortunately the taxonomic position of P. Andersonii has not been so well established. In 1890 Ellis and Everhart (5) described Mucronoporus Andersoni as a resupinate polypore fruiting under the bark of an oak log. Only a fragment of the type specimen is still in existence in The New York Botanical Garden and it appears to be as originally described. This fungus has since been confused with P. glomeratus. In fact Ellis and Everhart themselves were in part responsible for this confusion because they issued exsiccati sets in which they included a resupinate form of P. glomeratus, from maple, under the name M. Andersoni. In 1894 Underwood (11) described a fungus similar to M. Andersoni on the under side of poplar logs in Indiana as Polyporus (Poria) xanthosporus. Murrill (7) in 1916 described a new genus Xanthoporia based on Ellis and Everhart's Mucronoporus Andersoni. Neuman (8) listed the Ellis and Everhart species as Poria Andersonii and gave Poria xanththospora as a synonym. Lloyd at first separated P. glomeratus from P. xanthospora, as he classified his