Search Results (28)

To address the imbalance between the “ecological advantage” and “economic benefit” of wooden structure buildings, this study examines two structural construction methods utilizing inexpensive and readily available small-diameter round timber as the primary material. It demonstrates the advantages of these two structural systems in terms of material consumption, life cycle carbon emissions, and economic efficiency. Through the research methods and processes of “Preliminary analysis–Proposing the construction system–The feasibility analysis of structural technology–Efficiency assessment”, the sustainable wood structure technical system suitable for the development of China is explored. The main conclusions are as follows: (1) Employing the preliminary analysis method, this paper examines and analyzes construction cases that primarily utilize small-diameter round timber as the main material. It delineates specific construction types based on the characteristics of small-diameter round timber. Additionally, it technically reconstructs the methodology for utilizing small-diameter round timber. (2) Two lattice structural systems are proposed, leveraging the mechanical properties and fundamental morphological characteristics of inexpensive and readily available small-diameter round timber of fast-growing Northeast larch. The technical feasibility of these two small-diameter log structure systems is validated through simulation analysis of their spatial threshold suitability. (3) This study conducted a comprehensive comparison between the two small-diameter round timber structural systems and the conventional grain-parallel glued laminated timber (Cross-Laminated Timber) frame structural systems. The analysis was performed from three perspectives. As the primary structural material, grain-parallel glued laminated timber frame structural systems exhibits significant advantages in terms of timber utilization per unit area of the structural system. From a life cycle carbon emission analysis perspective, compared to grain-parallel glued laminated timber frame structures, small-diameter round timber structures can achieve carbon emission reductions ranging from 79.19% to 97.74%. Additionally, the unit area cost of small-diameter round timber structures is reduced by 21.02% to 40.42% relative to grain-parallel glued laminated timber frame structures. Consequently, it can be concluded that small-diameter round timber structural systems possess technical feasibility and construction advantages for small and medium-sized buildings, offering practical value in optimizing technical systems to meet the objective needs of ecological construction. Full article

In the years 2022 to 2023, the harvesting of medium-sized round wood by the State Forests Service in Poland was estimated at between 22.2 and 23.6 million solid cubic meters per year. This is a significant amount of timber to be transported by road. It is a challenge for both transport companies and round wood buyers. The high variability of wood density depending on the species in combination with its moisture content is a significant issue in logistics operations. This study focuses on the influence of the absolute moisture content on selected parameters of wood deliveries, taking into account the differences in the seasons. The total weight of a transport set (GVW) and empty set (Tare) and the weight of the load (Net) were determined on the basis of weighing the transports on stationary scales at the recipient. The moisture content of each wood load was determined using the dryer-weigher method for sawdust taken from the cutting of several logs from the delivery. This study analyzed a total of 13,602 transports of ten tree species and two wood assortments of pulpwood (S2a) and industrial wood (S2ap) in four seasons in the years 2020–2022. Pine was the dominant species in 5352 deliveries, and spruce was the dominant species in 3161. In terms of seasons, 3983 transports were recorded in the summer, 3650 were recorded in the spring, and 3492 were recorded in the autumn. The lowest number of 2475 was in winter. The mean volume of delivered wood (from 13,602 transports) was 28.18 m³, with a range of results from 19.00 to 51.29 m³ and SD = 2.40. The mean weight of the shipment was 24.95 Mg, with SD = 3.36. The range was from 13.92 Mg to 38.20 Mg. The mean absolute moisture content (AMC) of all wood loads (regardless of species and quality) was 42.91%. The results varied significantly (SD = 6.41). The minimum value was 15.64%, and the maximum value was 66.79%. The absolute moisture content of round wood is related to the season, species and assortment of transported wood. Loads of hardwood have lower average solid cubic meter values than softwood. Full article

Hardwood has a variety of applications and can be used for low-value products, such as firewood, or for high-value applications, achieving significantly higher prices. Therefore, assessing the quality of raw material is essential for allocating the wood to the most suitable end use. The aim of this study was to explore the use of the photogrammetry technique to determine dimensional characteristics and perform remote visual grading of round oak timber stored at a log yard. The results of the visual classification were then compared with non-destructive acoustic measurements to assess their level of agreement. Based on the point cloud obtained from photogrammetry, logs were classified into three quality groups according to the European standard for round timber grading. The diameter measurements of the logs obtained through the photogrammetry survey were comparable to those taken manually, with an average difference of 0.46 cm and a mean absolute error of 2.1 cm compared to field measurements. However, the log lengths measured from the 3D survey were, on average, 5 cm shorter than those obtained using a measuring tape. The visual classification performed on the 3D reconstruction was based on the evaluation of log size, knots, buckles, and sweep, resulting in 39%, 27%, and 24% of the pieces being grouped into the high-, medium-, and low-quality classes, respectively. Acoustic measurements, performed using both resonance and time-of-flight (ToF) methods, were highly correlated with each other and successfully distinguished the three quality classes only when sweep was excluded from the classification criteria. When curvature was also considered as a parameter for log grading, acoustic velocity only differentiated the lowest quality class from the other two. Full article

Machine traffic during timber harvesting operations induces soil compaction, which is particularly evident in the formation of ruts. Visual inspection of rut formation is labor-intensive and limits the volume of data that can be collected. This study aims to contribute to the limited knowledge base regarding the extent of soil physical disturbance caused by machine traffic on steep slopes and to evaluate the utility of LiDAR and UAV photogrammetry techniques. The selected traffic trails included single-pass uphill, single-pass downhill, three-pass round trip, and five-pass round trip trails, with an average slope of 70.7%. Traditional methods were employed to measure rut depth using a pin board and to assess soil bulk density (BD) and soil porosity (SP) from soil samples. The results revealed that the average rut depth was 19.3 cm, while the deepest ruts were observed after a single pass (uphill: 20.0 cm; downhill: 22.7 cm), where BD and SP showed the most significant changes. This study provides a rare quantitative evaluation of the applicability of remote sensing methods in forestry by comparing surface height data collected via a pin board with that derived from a Mobile LiDAR System (MLS) and UAV photogrammetry using structure-from-motion (SfM). When compared to pin board measurements, the MLS data showed an R² value of 0.74 and an RMSE of 4.25 cm, whereas the SfM data had an R² value of 0.62 and an RMSE of 5.27 cm. For rut depth estimation, SfM (16.0 cm) significantly underestimated values compared to the pin board (19.3 cm) and MLS (19.9 cm). These findings not only highlight the potential and limitations of remote sensing methods for assessing soil disturbance in steep forest environments but also contribute to addressing the knowledge gaps surrounding the effects of soil compaction in steep terrain. Full article

The extraction of timber is expensive, energy intensive, and potentially damaging to the forest soil. Machine development aims to mitigate risks for environmental impact and decrease energy consumption while maintaining or increasing cost efficiency. The development of rubber-tracked forwarders has gained renewed interest, not least due to climate change leading to unreliable weather in combination with low tolerance for soil damage. The increased cost of rubber tracks compared to wheels is believed to be compensated by higher driving speed enabled by semi-active suspension. Thus, the aim of this study was to theoretically investigate how the productivity and cost efficiency of rubber-tracked forwarders are affected by variations in driving speed and machine costs. The calculations were made with fixed stand parameters, to evaluate performance in well-defined working conditions, and with parameters from 2500 final felling stands in central Sweden, to evaluate performance in varied working conditions. Scenarios were compared to a baseline corresponding to mid-sized wheeled forwarders. The results show higher productivity with the increased driving speed enabled by rubber tracks and suspension at all extraction distances, with larger differences at long extraction distances. Assuming a 15% higher machine price for the rubber-tracked forwarder and a variable cost increase proportional to speed increase, extraction costs break even with the baseline at 400 m and 700 m extraction distance for moderate and fast driving speed, respectively. Furthermore, a rubber-tracked forwarder is likely to enable access to a larger part of the harvest area during longer seasons. For the studied set of stands, the year-round accessible volumes are estimated to increase from 9% to 92% with a rubber-tracked forwarder. With rubber tracks instead of wheels, good accessibility has the potential to be combined with low soil impact and cost efficiency in a favourable way for both industry and ecosystem. Full article

The accurate estimation of bark thickness is important for foresters for several reasons. It is crucial for timber volume estimation and can help improve the quality of forestry records, and bark has a growing commercial importance as a high-value bioresource. The problem is that models such as the Czech Cubic Tables (CCT) polynomial model are frequently unique. Furthermore, the official method requires rounding down the midspan over-bark diameter (DOB) to the nearest centimetre to estimate the double bark thickness (DBT) and merchantable timber volume. Therefore, we verified the significance of the effects of rounding down the midspan DOB on DBT using a dataset of 438 recently harvested Norway spruce (Picea abies L. Karst.) logs from the Central Bohemian region. The correlation analysis showed that for measured data without rounding down the diameters, the variability of the DBT was able to explain only 8% of the DOB variability. As for the rounded-down data, the coefficient of determination was slightly higher, reaching 9%. The paired-samples T-tests showed a significant difference between the DBT as calculated directly from measured data and that from the rounded-down over-bark diameters (p < 0.05). The polynomial and linear models underestimated the DBT (2.24 and 1.75 mm on average, respectively) on measured data. In contrast, for data from the rounded-down DOB, the models overestimated the DBT (2.70 or 3.18 mm on average, respectively). Full article

Deforestation is a common threat to the environment that has a substantial impact on the forest’s distribution across territorial boundaries. It is simply defined as the loss of forest cover, which most commonly occurs as a result of deforestation for various reasons. Pakistan is among those countries which have a very high deforestation rate. This paper analyzes the various socioeconomic factors which cause deforestation in northern Pakistan and the existing economic incentive tools for reducing deforestation. Data collected from 602 respondents were analyzed using descriptive statistics and a logistic regression model, while the Likert scale was used to determine the mean socioeconomic factor score encouraging deforestation and the economic incentives used to reduce deforestation. Gender distributions showed that the majority (65.9%) of the respondents were male while 34.1% were female. On family size, the majority of the respondents (66.8%) had a family size of 5–8. On age, between 21–25 years (46.0%) recorded the highest number. The average age of the respondents was 24 years. Educationally, 13.8% had a master’s education, 11.1% a bachelor’s education, 4.3% no formal education, 5.6% a higher education level, meaning master’s or PhD students, 56.1% had a primary education, and 9.0% had a secondary education. On occupation, the majority (50.4%) of the respondents were involved in farming as their main occupation. On income, the major income recorded a mean of 25,000 net, while the minor income recorded a mean of 15,500 net. Setting the forest ablaze, increasing farming activities, low level of literacy, increasing timber mafia, growing population, and poverty were the socioeconomic factors found. The economic incentives listed were for forest crop subsidies, an enhanced system of taxes on exploited forest products, the acquisition of well-monitored hunting licenses, alternative job opportunities, credit provision, and a limited ban on round log exports. The results of the logit regression established that rewarding socioeconomic factors were statistically significant variables at (p < 0.05). Conclusively, if adequately controlled and applied, economic incentives can be an important instrument for reducing deforestation. Therefore, deforestation activities cannot be entirely eradicated but they can be reduced to the barest minimum by properly enforcing forest policies in terms of efficient forest policing. The goals of this study are to help with the implementation of appropriate policies and decision-making in forest management, as well as to provide a foundation for future scenario analysis of deforestation potential or to investigate potential environmental and human implications. Full article

Pruning is an important technique in culturing good knot-free timber. However, to make more accurate pruning plans, it is necessary to consider the growing status of trees and set reasonable pruning intensities based on this. In a seven-year-old Pinus massoniana Lamb. plantation, we carried out pruning twice with a time interval of two years. The treatments included one unpruned treatment (CK) and five pruned treatments (from P1 to P5, representing the live branch height being kept at 68%, 55%, 60%, 55% and 45% of the tree height). CK, P1 and P2 were conducted in the first pruning in March 2019, and the remaining treatments were conducted in the second pruning in January 2021. The growth investigations were carried out in March 2019, December 2019, December 2020 and December 2021. Another investigation was carried out only for the measurement of live branch heights and crown widths in January 2021 just after the second pruning. The results showed that pruning resulted in a 15.08% to 60.62% increase in diameter growth and an 10.28% to 29.87% increase in volume growth. The stem form was also improved. Significant differences were recorded in live branch heights after green pruning but gradually recovered to the same level in two years by branch senescence. Pruning also resulted in a faster extension of the crown width with an enlarged growing space by the removal of green branches. We highlighted that trees with different growth statuses responded differently to pruning intensities: trees of weak growth statuses grew better under a light pruning intensity, while those with a strong growth status grew better under a severe pruning intensity. Overall, for the seven-year-old young mason pine plantation, keeping four rounds of branches in trees with diameters of less than 8 cm and keeping three rounds of branches in trees with diameters of more than 8 cm were appropriate measures. Full article

Bamboo scrimber is a sustainable engineered material that overcomes natural round bamboo’s various weaknesses. This study compared the bamboo scrimber’s mechanical (strength, stiffness, and ductility) to timber. The results showed that scrimber’s physical and mechanical properties are comparable, even superior, to wood, especially in compression. Scrimber has a higher density than timber. Its drier equilibrium moisture content indicates that scrimber is more hydrophobic than timbers. The maximum crushing strength (σ_c//), compressive stress perpendicular-to-fiber at the proportional limit (σ_cp⊥) and that at the 0.04” deformation (σ_c0.04⊥), shear strength (τ_//), longitudinal compressive modulus of elasticity (Ec_//), lateral compressive modulus of elasticity (E_c⊥), and modulus of rigidity (G) of scrimber are higher than those of timbers. Both scrimber’s and timber’s flexural properties (modulus of rupture (σ_b) and flexural modulus of elasticity (E_b)) are comparable. On the contrary, the tensile strength parallel-to-fiber (σ_t//) of scrimber is weaker than that of timber. Scrimber is high ductility (μ > 6) when subjected to compression perpendicular-to-fiber, medium ductility (4 < μ ≤ 6) when subjected to compression parallel-to-fiber, and low ductility (brittle) when subjected to bending, shear, or tensile parallel-to-fiber. The higher ductility of scrimber may give an alarm and more time before failure than timbers. Timbers have brittle to lower ductility when receiving each kind of loading scheme. The ratio of shear modulus to strength (G/τ) and compression modulus to strength parallel-to-fiber (E_C∥/σ_C∥) strongly correlates with the ductility ratio. However, the ratio of the flexural modulus of elasticity to the modulus of rupture (E_b/σ_b) and the ratio of the modulus Young to compression stress perpendicular-to-fiber (E_c⊥/σ_cp⊥) do not strongly correlate to the ductility value. Full article

There is a growing interest in low-tech technologies, drawing on the tradition of building with organic and unprocessed materials. One such technology is straw bale constructions. This paper presents an example of a timber-frame building in which straw bales were used as wall filling. The building is located in northern Poland and is a small, year-round single-family dwelling. Based on the available literature and experimental studies, it can be concluded that straw bale technology carries several potential threats related to the selected technology, quality of workmanship, and climatic conditions. The article describes the measurements of the air tightness of the building, the heat transfer coefficient U and the analysis of the humidity of straw walls. The study results confirm the risks related to the low air tightness of the building and the risk of water vapour condensation in the external partitions. Full article

Considering the current rate of expansion of the lumber processing industry in the world, the current annual allowable cut of one million cubic meters of round logs is considered to be insufficient to satisfy the increasing demand of timber industries. One major area that has been highlighted in the forest policy is the introduction of lesser-used species to widen the natural resource base of the forest and to address the imbalance between supply and demand for the resources. As a contribution to addressing this problem, oil palm lumber, a lesser-used species, was subjected to different moisture content variations to determine its behavior with respect to discoloration. Specimens of oil palm trunks were extracted at Norpalm Oil Mill in the Western Region of Ghana. Oil palm lumber specimens were conditioned in a kiln to a moisture content of 15%, 20%, 25%, 30%, 40%, and 50%. The results obtained covered discoloration and mold. The effect of the extractives on the discoloration of oil palm lumber was also investigated by means of immersing some samples of oil palm lumber into sea water and tap water for 48 h. Although Dursban 4E is a widely used preservative in the timber industry, oil palm lumber specimens of 40 mm thick immersed in Dursban 4E for 48 h and conditioned in a kiln to a moisture content of 30% were discolored from week 2. However, oil palm lumber specimens of 40 mm thick that were immersed in tap water for 48 h, and thereafter immersed in Dursban 4E for another 48 h, then kiln dried to a moisture content of 15%, 20%, 25%, and 30%, did not show any discoloration from week 2 to week 18. It was discovered that in the utilization of oil palm lumber, it should be immersed in tap water for 48 h before any chemical treatment is given, and thereafter kiln dried. From the general results, the species proved to be good substitute for some of the ‘noble’ species that are going extinct from the forests of Ghana. Full article

Forest mechanisation plays an important role in increasing labour productivity and reducing production costs. Chainsaws are the most commonly used tool used for tree felling and can have both positive and negative environmental impacts on the forest ecosystem. Impacts that should be analysed considering all implemented inputs and outputs related to the involved technology. This work aims at evaluating the operational and environmental performance of a medium-sized chainsaw during a second thinning carried out on Calabrian Pine high forests. The trees, located at an altitude of 1100 m a.s.l, had an average diameter at the breast height of 30.6 cm and a height of 18 m for a density of 950 trees ha⁻¹. The terrain roughness presents obstacles on less than 1/3 of the surface while the slope was between I and II classes (0–40%). A work time study on the felling operation was conducted considering a full-tree system. Thirty operational cycles were registered: observed time was separated into working time, which included main and complementary working times, calculated as average gross productivity, inclusive of all delays up to the maximum event duration of 15 min. The life cycle assessment (LCA) approach was adopted for environmental performance. As a functional unit, 1 m³ of round wood was chosen. The inventory data, relating to the background processes, were collected from Agribalyse 3.0.1., while data from the foreground, such as materials and fuel consumption, were directly collected. Environmental impact data were processed using OpenLCA software and the ReCiPe 2016 method at the midpoint level. Team productivity was equal to 10.30 trees h⁻¹, corresponding to a volume of timber of 11.2 m³ h⁻¹. Considering a working day of 8 h, productivity was equal to 41 trees d⁻¹ worker⁻¹ for a volume of timber of 44.8 m³ d⁻¹ worker⁻¹. The performed LCA showed that emissions related to the stage of use represented a major hotspot in “Global warming” (2.169 kg CO₂ eq.), “Ozone Formation–Human Health” (0.038 kg No_x eq.), “Fine particulate matter formation” (0.001774 kg PM 2.5 eq.) and “Terrestrial ecotoxicity” categories (4.234 kg 1,4-DCB). In conclusion, the analysed site showed a suitable level of internal organization, but more regular management of the chainsaw is required. The environmental impact is affected by the energy systems in the use phase but is needed to deepen the knowledge of all aspects involved from upstream processes for certain materials to manufacture components. Full article

Timber construction is considered a main strategy towards a more sustainable built environment. Industrialized manufacturing methods have advanced the realization of multi-storey timber buildings generating enthusiasm about their implementation in urban areas, and the expectation of their further completion. These are still pilot projects, so there is a lack of specific literature and guidelines, including common understanding, standard procedures and holistic considerations. This paper aims to assess the current situation of design and construction processes of timber buildings in Austria, highlighting barriers and opportunities and formulating recommendations for its further adoption. The methodology used is based on an extended literature review and a qualitative analysis from expert interviews. Different disciplines were involved to approach the topic holistically. Interviews were recorded, transcribed and inductive coded within several iterative rounds. Excerpts were organized into codes, sub-codes and categories to identify and classify themes and patterns and build the case. The findings are structured into the categories of Acquisition, Design and Production and Assembly, and further identified as Barriers and Opportunities. Upon the analysis of results, a selective range of recommendations are formulated and summarized in a catalogue, serving as a guide for further research and actions to widespread the adoption of timber. Full article

Proper measurements are extremely significant for the forest owner, the harvesting company, the hauler, the final buyer, and the wood processing company. The accuracy of round wood volume determination is of fundamental importance in planning and accounting for individual processes related to the wood trade. It is the basis for determining the maximum quantity in single load of wood that allows for using the permissible total gross vehicle weight. The determination of wood load in cubic meters does not allow unequivocally determining its weight, which often leads to overloading of vehicles. This paper presents a comparison of the photo-optical method for determining the volume of wood to be transported with the real measurement and determination of the weight of a load and the total gross vehicle weight (GVW) with the simultaneous application of conversion factors determining the weight of the load from the volume of wood. The measurement included 23 broadleaf round wood piles (193.73 m³) and 14 coniferous round wood piles (149.23 m³). The measurement error for broadleaf wood piles ranges from −47.67% to 63.16%, and from −43.31% to 24.72% for coniferous wood piles. Determination of the volume of a broadleaf wood pile using the iFOVEA method had an average error of 1.34%, while the Timbeter method had an average error of −1.83%. In the coniferous wood pile measurement, the error is −12.82% and 2.41%, respectively. Verification of the volume of the large-sized wood indicated on the delivery note (reference value) on the log sorting line (by laser scanning) showed larger volumes by 0.10 m³ to 2.54 m³, giving a percentage error of 0.35% and 8.62%, respectively. As a consequence of the application of such methods for determining the weight of wood loads, the transport truck sets are often significantly overloaded, which has a significant impact on the accelerated degradation of roads and safety in traffic and timber transportation. Full article

Glulam beams are increasingly used in the construction industry because of their high strength and the possibility of using round timber with smaller cross-sections. The load-bearing capacity of beams is strongly related to the quality of the outer layers and, in the case of wood, especially the tension zones. For these reasons, this study decided to replace the outer lamella with tensile plywood. The produced beams were subjected to static bending strength and modulus of elasticity evaluation. It was shown that the best static bending strength values were obtained for beams containing plywood in the tension layer. However, the change in structure in the tension zone of beams made of glued laminated timber results not only in an increase in the load capacity of elements produced in this way but also in a decrease in the range/range of the obtained results of bending strength. This way of modifying the construction of glued laminated beams allows a more rational use of available pine timber. Full article