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Productivity and Cost of Post-Tornado Salvage Logging in Upper Coastal Plain of South Carolina, USA

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Salvage harvesting is common in the US South following natural disasters such as tornadoes and hurricanes; nevertheless, few studies have evaluated the productivity and costs of these harvests because of their geographic dispersion and the short interval between natural disasters and salvage harvesting. An Enhanced Fujita Scale 3 (EF3) tornado with winds in excess of 250 km per hour struck Aiken County, South Carolina in April of 2020, uprooting trees and severing other stems above breast height. The goal of this study was to estimate the productivity and cost of salvage harvesting in loblolly pine (Pinus taeda L.) stands following severe tornado damage. Salvage harvests were conducted with a rubber-tired drive-to-tree feller-buncher, grapple skidder, tracked loader, and chipper. All stems were chipped and used to produce energy; no roundwood was produced from the harvests. Elemental time-and-motion studies were conducted in three pulpwood-sized stands (<30 cm large-end diameter) and three sawtimber-sized stands (≥30 cm large-end diameter). Hourly harvesting costs were estimated using the machine rate method and per-ton costs were estimated using a modified version of the Auburn Harvesting Analyzer. Skidding productivity was low in each harvest unit, but especially so in the three pulpwood-sized stands because of stem breakage and low weight per stem. Harvesting costs averaged $29.78 and $19.97 (USD) per tonne (onboard truck) in the pulpwood- and sawtimber-sized stands, respectively. High salvage harvesting costs mean that landowners can expect significantly reduced stumpage prices from these harvests; nonetheless, landowners do benefit from reduced reforestation costs. Harvesting promptly after a tornado can reduce harvesting costs and increase timber value recovery.

Logging Crew Attributes by Region in the Southeast USA

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Urbanization, shrinking markets, and reduced forestry investment may affect harvesting efficiency in regions of the US South. To monitor these conditions, logging businesses have been tracked by surveys conducted by universities and trade associations. This project used a sampling approach coordinated with FIA utilization studies to sample logging crews based on a harvesting location. The approach was used to develop relationships among firm attributes and site attributes in six southeastern states (AL, GA, FL, NC, SC, and VA) from 2011 to 2018. The data included harvest attributes (location, harvest size and stand type) and logging firm attributes (production, crew labor, crew number, the number of machines by type, and machine age). For crew capital value, an equation was developed for this study using machine number and average machine age. The data from logging crews on 419 harvests were analyzed by region, harvest size, and stand type. Mean values for crew labor ranged from 3.1 to 7.1 workers. The average capital value per crew ranged from $220,000 to $524,000 per crew in the Coastal Plain with a narrower range in the Piedmont. In the Coastal Plain, higher productivity was detected for larger harvests and pine versus hardwood and mixed stands; however, in the Piedmont those trends were less obvious. Ratio of feller-bunchers, skidders and loaders were mostly 1:1:1 or 1:2:1 with 41% and 24% of samples, respectively. There were notable trends among Coastal Plain loggers regarding capital value and productivity with evidence supported by a production function. The differences in Piedmont (e.g., ownership size, market access, terrain, population density, etc.) may combine to limit daily production and labor productivity.

Evaluation of Morphometric Terrain Parameters and Their Influence on Determining Optimal Density of Primary Forest Road Network

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Planning forest truck roads network involves a lot of factors that directly affect their density and length. Depending on the purpose of the forest truck road network, this number is higher or lower. Our opinion was that these factors should be divided into invariable and variable. Common parameters, regardless of the purpose of the roads, are morphometric parameters because they can limit the length and density of the network of forest truck roads due to their variety of forms. For this reason, this paper deals exclusively with the morphometric characteristics of the terrain and their influence on the density of the network of forest truck roads. The DEM of the terrain was processed with GIS software based on the seven most important influencing factors. By standardizing the criteria, the obtained maps were reclassified, and then each of the seven selected parameters was weighted with the coefficients obtained by the AHP method.

In this way, a map of the suitability of the terrain for the construction and addition to the existing network of forest truck roads was obtained. The terrain is divided into 4 categories of suitability. Zero lines were drawn with GIS tools for road design. During the creation of the optimal road network, it was tested with absolute and relative openness.

As a final result, each of 26 Forest Economic Areas (FEA) was assigned to one of 4 categories of terrain suitability for the construction and density of the forest truck road network. For each category of terrain convenience, the optimal absolute and relative openness is shown. Based on this work, we suggest that the use of morphometric parameters should be considered as the first step of forest road planning in other regions.

Evaluation of Light Falling Weight Deflectometer for In Situ Measurement of Secondary Deformation Modulus of Various Forest Road Pavements

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Roads in forests are necessary for proper forest management and active protection of the natural environment. They facilitate tourism and recreation and have a very important function in firefighting. The cost of building roads in forest areas is considerable, even when relatively cheap materials such as aggregates of natural or anthropogenic origin are used. Therefore, any road investment must be well prepared and executed. Bearing capacity and compaction are among the most important and frequently used geotechnical parameters in road construction. The aim of this study was to determine the possibility of predicting the value of the secondary deformation modulus E2 (obtained from measurements with a static plate load test – PLT) based on measurements with a light falling weight deflectometer (LFWD) Zorn, type ZFG 3000 GPS with a drop weight of 10 kg. The regression analysis included 245 results of bearing capacity measurements carried out on 46 forest road sections with various road pavements. Different regression models were tested: linear, logarithmic, polynomial, exponential and power models, excluding polynomials of fourth and higher degree. Prediction of E2 (PLT) values from dynamic deformation modulus Evd (LFWD) values is possible. However, the reported unsatisfactory strength of the relationship between the two parameters is associated with a high risk of error (r=0.73, R2=0.54, Se=80.37 MN·m-2). Neither the use of more complex non-linear regression models nor the use of multiple regression by introducing an additional estimator in the form of the s/v ratio significantly improved the estimation results. The quality of the prediction of E2 values is not constant. It varies depending on the type of forest road pavements, the use of geosynthetic pavement reinforcements and the type of road subgrade. The study also found that the quality of E2 prediction can be improved by limiting the range of tested Evd values upwards. It is advisable to continue this type of research, as the results obtained could be the basis for developing national standards for the application of LFWD to control the bearing capacity and compaction of forest road surfaces in the future.

Tree Felling with a Drill Cone

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Motor-manual timber felling is one of the most dangerous operations in the forest and cannot be completely replaced by fully mechanized timber harvesting by a harvester when dealing with large and deciduous trees. Shifting the center of gravity of tree ready to be felled beyond its tipping line using conventional felling wedges is dangerous because the forest worker is directly behind the stem and under the tree crown until just before the tree falls. The worker can be hit by the trunk itself, but also by falling parts of the crown. In a preliminary study for the development of a new type of felling head, felling with a drill cone that can open the felling cut with the help of an applied torque was investigated. A drill cone does not require any special cutting technique, no counter forces to the tree, works without impulses, it is self-retaining and can be unscrewed again.

In order to determine the torque required for felling the tree as a function of the tree parameters, the mathematical equation framework was established and practical experiments were used to determine the friction parameters and verify the calculations. The torque of the drill cone is used to bend the intact fibers of the hinge, shift the center of gravity of the tree in the direction of fall, and to overcome the friction of the drill cone on the felling cut. The effects of forward or backward leaning trees on the required torque can also be quantified. It has been shown that the efficiency of a drill cone is low, but this is compensated for by the high internal torque to lift ratio. The maximum measured input torque for felling trees with a felling diameter up to 55 centimeter was 100 Nm.

Growth and timber quality of European larch planted in areas reclaimed after coal mining in central Poland

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Understanding the impact of reclamation measures on the quality of timber produced in post-mining areas is crucial for the proper establishment of future forest cultures on such sites. We studied European larch trees (Larix decidua Mill.) grown since 1981 on the external dump of a brown coal mine in Bełchatów (Central Poland). In particular, the effects of stand admixture and the intensity of mineral fertilization, applied in the initial phase of tree growth, on the increments and quality of larch wood were evaluated. Total tree height and stem diameter of 4-meter sections were measured. Qualitative timber classification took into account the share of wood defects, which excluded the timber from a higher quality-dimensional class. Larch trees grown in a monoculture had a better quality of wood compared to larch grown mixed with other species. Fertilization, applied in the initial afforestation period, had only a limited effect on the growth of larch trees. Curvature and knots determined timber quality most significantly. While knots had a decisive importance in larch growing in the monoculture stands, curvature determined wood quality in the admixed larch stands.

Influence of Stump-Root System of Trees on Rut Formation During Forwarder Operation on Peat Soils

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To explain the soil deformation processes under the influence of logging machines, average values of various indicators are often used. One of these indicators is the rut depth formed during tractor passages. The average values do not fully describe the consequences of passages on the skidding trails, for example, the rut depth varies along the track. This variability includes both random and regular components. The stump-root systems of trees located on the skidding trail and along its border act as a factor that introduces a pattern. To determine the degree of influence of stumps on 8 sections of skidding trails with the length of 25 and 50 m, located on peat soils (the average mass fraction of water is 82.3%), the rut depth was measured at intervals of 0.5 m and the locations of stumps were noted. The resulting arrays of vertical marks represent the microprofiles of the experimental sections. Measurements were taken after 2 harvester passages and 2 forwarder passages. The stumps were divided into two groups: located inside the tractor track and outside it. Statistical processing of the data showed a wide spread of the rut dimensions in each array. Average values at the sections (standard deviations) in cm were: 21.6(17.7); 30.6(21.6); 37.7(22.7); 46(20.3); 36.4(15.0); 36(15.4); 30.6(21.0); 34(21.0). The autocorrelation functions, constructed for the series of values, showed surges with moderate correlation coefficients on the lags where stumps were noted. An increase in stumps per a length unit of the skidding trail shows an increase in the number of such surges. A decrease in the rut dimensions, in relation to the places where the influence of the roots was absent, averaged: in points 0.5 m away from the stump – 44% (22.6); 1 m away – 32% (20.4); 1.5 m away – 22% (14.2). The spatial influence factor of the roots explains 21% of the variability of the rut dimensions along the skidding trail. The factor of the stump location relative to the track is 19%. The combined influence of these factors is 25%. Further identification of regularities in the rut formation processes is associated both with the continuation of studies of the root system influence, but with the inclusion of factors of the stump size and variety, and with the study of the variability of the soil physical properties along the skidding trails, analysing how this is found in the microprofile structure.

Evaluation of Different Modes for Yarding Windthrown Timber with a Double-Hitch Carriage

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Yarding whole trees is the most efficient way of extracting timber in steep terrain and allows reaping the combined benefits of mechanization and biomass recovery. In downhill yarding, however, whole-tree extraction is associated with a greater risk of loosening rocks or debris by the incoming loads as they bounce around along the extraction corridor. That may also cause damage to the cables and anchors by corresponding shock loads, ultimately endangering the yarder and its crew. To avoid these risks, »double-hitch carriages« can be employed. They combine a conventional motorized dropline carriage with a secondary carriage (»trailer«), equipped with a further, independent dropline winch. Thus, loads can be attached at two points and transported fully suspended above the ground in a horizontal position.

Operation of these carriages may not be limited to the »horizontal« mode: the main carriage could also be operated without trailer (»single« mode), or separate loads may be attached to the two droplines (»double« mode), but their impact on the efficiency and economy of yarding operations is yet unknown. Therefore, the present study investigated how these modes affect the productivity and cost of downhill whole tree yarding. To this end, a classic time and motion study was conducted during a salvage logging operation in Northern Italy under a strictly controlled experimental design.

Average productivity (18.2±7.2 to 24.5±15.4 m³ PSH0-1 merchantable volume per productive system hour excluding delays) and extraction cost (18 to 20 Euro m-³) did not differ significantly between treatments, while load composition and time consumption by task did. More (2.2±0.5) pieces per load were yarded under the »double«, than under the »single« (1.4±0.5) and »horizontal« (1.1±0.3) treatments. Inhaul speed (3.1±0.6 m s-1) was significantly higher under the »horizontal« treatment, which compensated for increased loading time derived from attaching the load at least at one point outside the corridor. Unloading took significantly longer under the »double« treatment, as loads had to be dropped successively due to the confined conditions on the landing. Though slowest (2.5±0.9 m s-1) during inhaul, the »single« treatment exhibited none of the other treatments disadvantages and larger loads could be accumulated due to partial suspension. From an economic viewpoint, the »horizontal« mode may only be warranted over yarding distances substantially beyond average. On shorter ones, it must be justified by other reasons, such as minimizing product contamination, soil disturbance or excessive strain to the skyline when the terrain profile impedes sufficient ground clearance.

Evaluating the Impact of Meteorological Data Sources on Moisture Prediction Accuracy of Eucalyptus Nitens Log Pile Natural Drying Models

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Drying forest biomass at roadside can reduce transport costs and greenhouse gas emissions by reducing its weight and increasing its net calorific value. Drying models are required for forest supply chain analysis to determine optimum storage times considering storage costs and returns. The study purpose was to evaluate the impact of the source of meteorological data on the goodness of fit and practical application of Eucalyptus nitens log pile drying models. The study was conducted in Long Reach, NE Tasmania, Australia from the 6th of February to 6th of August 2020. Four data sources were compared: the nearest meteorological station, interpolated meteorological data, a portable weather station, and digital temperature/RH sensors. Predicted moisture content (MC) values from the only previously published E. nitens log pile drying model were also evaluated using the current study data sources as inputs.

Log pile MC changes were determined from weight changes measured by placing the study logs on a steel frame bolted to load cells at each corner. As the study was based on debarked logs, dry matter losses were assumed to be negligible. Initial MC of the logs was determined by extracting samples using an electric drill and drying them until constant weight was achieved.

Initial log pile drying rates were high with several daily MC  losses >2%. Portable weather station data produced the best goodness of fit drying model. The second-best goodness of fit model was based on meteorological station data. From a user acceptability perspective (highest proportion of results within ±5% of measured values), the best model was based on temperature/RH sensor data. Goodness of fit measures for the temperature/RH sensor data model were poorer than for the other data sources, but still acceptable. The published E. nitens log drying model had the poorest results for goodness of fit and user acceptability.

In conclusion, portable weather stations are best suited to research trials due to the expense of placing a weather station at each log pile. Drying models based on data from the nearest meteorological station or temperature/RH sensors are best suited for practical applications, such as forest supply chain analysis. Additional benefits could accrue from a forest estate-wide network of low cost temperature/RH sensors potentially supplying data to forest supply chain analysis as well as fire prediction and tree growth models.

Relationship Between Some Structural Elements of Macedonian Pine (Pinus peuce Gris.) in Different Elevations in National Park Pelister in North Macedonia

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The influence of elevation on the forest development and also on more structural elements is evident. The aim of this paper is to research the impact of elevation on the relationship between diameter at breast height (DBH), tree height (H), crown length (L) and stem volume (V). In the area of the Pelister National Park in North Macedonia, 22 experimental plots (EPs) were established in the even-age Pinus peuce Gris. stands with an average age of 90 years. The EPs were of a circular form and covered an area of 500 m2 each; 6 of them were established at 1150 meter above sea level (m asl), 7 at 1350 m asl and 9 at 1550 m asl. DBH, tree height, and crown length of 481 trees were measured in all EPs. The DBHH model was prepared in accordance with Prodan, as well as nonlinear (polynomial) regression for the relation between DBH and L and nonlinear (power) regression for the relation between DBH and V. The stem volume was calculated with a formula by Parishko for Pinus peuce Gris. The quadratic mean of DBH, average Loray height, average crown ratio, and the density of the stands were also calculated. The relationship between DBH and H, L, and V was examined with Pearson correlation and root mean square deviation (RMSE). The differences between averages of H, L, and V from the EPs were tested with analysis of variance (ANOVA) with an elevation class (1150, 1350 and 1550 m asl) as single factor. The density of stands was 490, 429 and 409 trees per ha on 1150 m, 1350 m and 1550 m asl, respectively. The average DBH was 39.8 cm, 46.5 cm and 45.5 cm, and Loray height was 23.9 m, 24.1 m and 22.6 m at 1150 m, 1350 m and 1550 m asl, respectively. Crown ratio (CR) pointed out different results on the different elevations, with the average value of 40.5%, 43.7%, and 39.3% at 1150 m, 1350 m, and 1550 m asl, respectively. Differences between average structural elements at different elevations can be confirmed with ANOVA with a significance of p<0.05 and F of 3.4 for H, the significance of p<0.05 and F 3.2 for L data and p<0.05 and F of 9.7 for the value of V. In that way, the regression model for H is higher at a lower elevation, the tree has a longer crown length at lower elevation and also has a bigger volume at lower elevation. From the results, it can be concluded that the elevation has an influence on the relationship between DBH on the one hand and H, L and V as structural elements on the other hand. It can be said that at higher elevation trees have a smaller average height, DBH, and volume and have longer crown length than trees at lower elevation.

County Transportation Officials’ Perceptions of Timber Transportation Economic Importance, Infrastructure Impact, and Weight Limits in Georgia, USA

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Log truck gross vehicle weight (GVW) limits in the US state of Georgia are among the lowest of any timber-producing state in the US and are far below GVW limits in countries such as Australia, Canada, Finland, and Sweden. In the state of Georgia, log trucks travel on county and state roads between harvest sites and forest industry mills. Most county roads were not constructed to support heavy trucks and so log trucks may damage these roads, even at the low GVW limits allowed in Georgia. Local governments sometimes enact timber harvesting ordinances to constrain timber transportation and often oppose efforts to increase GVW limits. The purpose of this study was to document local transportation officials’ perceptions of timber harvesting and transportation and to measure their support or opposition to alternative log truck weights and configurations. A telephone survey of county transportation superintendents or their equivalent was conducted in Georgia during the summer of 2020. Forty-three county officials responded to the survey, yielding a response rate of 43%. Ninety-eight percent of respondents reported that timber harvesting was important to their local economy, and 86% agreed that local governments were cooperative with log truck owners. County officials were concerned about damage from overweight log trucks and mud on public roads. The average preferred GVW and tandem axle weight limits were approximately 10% lower than the existing limits. County officials opposed six- and seven-axle 45,359 kg (100,000 lbs) GVW configurations but did support allowing log trucks to operate on interstate highways at current state weight limits. Findings suggest that logging businesses and mills should focus on improving compliance with weight laws, improving the condition of log trucks, and maintaining or improving relationships with the public and local government officials.

Forecasting Future Procurement Potential of Swedish Forest Biomass Using Forest Inventory Data

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In the last 20 years the use of forest biomass for energy production and sawlog and pulpwood production has increased by 68%, 11% and 31% in Sweden. As Sweden is trying to achieve net zero greenhouse gas emissions by 2045, the high demand for biomass can also be expected in future. Therefore, a method to project the amount of spatially available biomass assortments for industries was developed. Available amounts of different forest assortments were estimated and visualised in a web-based tool using forest inventory data and nationwide projection analyses of available biomass for 2035–2039. In this interval, the greatest amount of available biomass and roundwood will be in Northern Sweden. Results also indicate that already existing harvesting intensity is very high compared to the available biomass in the future. The industry can expect noticeably more available biomass in the coming 100 year period. With increased competition between large pulp mills and biorefineries, the supply areas can exceed 200 km to satisfy raw material demand. The long distance and high volume supply chain requirements will demand further improvement in transportation solution nationally and cross-border in the Baltic Sea Region.


Web of Science Impact factor (2021): 2.542
Five-years impact factor: 2.443

Quartile: Q2 - Forestry

Subject area

Agricultural and Biological Sciences