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10 pages, 1155 KiB

Open AccessArticle

Productivity and Cost of Retention Harvesting Operation in Conifer Plantations

by Toshiyuki Tsushima, Ichiro Watanabe, Nobuhiro Akashi and Kenichi Ozaki

Forests 2023, 14(2), 324; https://doi.org/10.3390/f14020324 - 6 Feb 2023

Cited by 3 | Viewed by 1735

Abstract

Retention forestry is a harvesting system that intentionally retains important forest structures at harvest time. We examined the effect of dispersed retention on the productivity and cost of harvesting operations in a large-scale field experiment in conifer plantations in Hokkaido, Japan. For dispersed [...] Read more.

Retention forestry is a harvesting system that intentionally retains important forest structures at harvest time. We examined the effect of dispersed retention on the productivity and cost of harvesting operations in a large-scale field experiment in conifer plantations in Hokkaido, Japan. For dispersed retention, we retained broad-leaved trees in three levels (10, 50, or 100 trees/ha). We used daily operator reports and investigated time consumption (h/m³) of felling and pre-hauling operations and the total cost to roadside. Compared with clearcutting, mean felling time was 7% and 17% longer, and mean pre-hauling time was 20% and 19% longer in 50 and 100 retained trees/ha, respectively. The other operations were not affected by tree retention because they were conducted at pre-existed strip roads or landings where no trees were retained. Increased time consumption caused an increased cost of felling and pre-hauling. Compared with clearcutting, the combined cost of felling and pre-hauling was 14% and 18% higher in 50 and 100 retained trees/ha, respectively. However, the total cost to roadside increased only by 3% compared with clearcutting because these two operations in total occupied 19% of the overall cost, and the cost of the other operations was not affected by tree retention. This suggests that the impact of tree retention on the total cost was small and that the harvesting system used in the present study can reduce cost increment due to tree retention unless trees are not retained on strip roads. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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16 pages, 3682 KiB

Open AccessArticle

What Is the Current Ergonomic Condition of Chainsaws in Non-Professional Use? A Case Study to Determine Vibrations and Noises in Small-Scale Agroforestry Farms

by Salvatore F. Papandrea, Maria F. Cataldo, Giuseppe Zimbalatti, Stefano Grigolato and Andrea R. Proto

Forests 2022, 13(11), 1876; https://doi.org/10.3390/f13111876 - 9 Nov 2022

Cited by 5 | Viewed by 1804

Abstract

Agroforestry or agricultural forestry is an important resource for the exploitation of wood resources commonly based on a low level of mechanization and integrating agriculture crops land-management. Agroforestry areas consist often of buffer strip forest along the farms’ boundaries or on small forest [...] Read more.

Agroforestry or agricultural forestry is an important resource for the exploitation of wood resources commonly based on a low level of mechanization and integrating agriculture crops land-management. Agroforestry areas consist often of buffer strip forest along the farms’ boundaries or on small forest stands within the same farms. Felling is commonly based on the use of chainsaws which are used occasionally, and are often aged models and with little maintenance done on them. In this context, the present study analyzes the vibration and noise generated by chainsaws in the specific contest of the agroforestry farms. The aim is to verify the hand-arm vibrations and noise level, which self-employed agroforest operators are exposed with the occasional use of aged and rarely maintained chainsaws. The main results show that vibration exposures are significantly affected by the model and condition of use of the chainsaw and at lower level, but still significant, by the wood and the position of the handle. Regarding noise levels, the chainsaw model and condition of use also has significant effects. In summary, this study highlights that the importance of the condition of use of the chainsaw has an important effect on the vibrations and noise exposition and that these, although limited due to the limited daily use by operators, must be carefully taken into consideration, and provide for containment actions through adequate information and training. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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23 pages, 2434 KiB

Open AccessArticle

A Unique Grubbing Head Prototype for Environmentally Friendly and Sustainable Stump Removal

by Luboš Staněk, Ladislav Zvěřina, Radomír Ulrich and Eva Abramuszkinová Pavlíková

Forests 2022, 13(9), 1515; https://doi.org/10.3390/f13091515 - 19 Sep 2022

Cited by 2 | Viewed by 1565

Abstract

Stumps left behind after the felling of trees represent an important source of renewable energy that could be used for fuel mixtures as a sustainable solution. The subject of this research was to determine the influence of tree species, stump diameter size, and [...] Read more.

Stumps left behind after the felling of trees represent an important source of renewable energy that could be used for fuel mixtures as a sustainable solution. The subject of this research was to determine the influence of tree species, stump diameter size, and subsoil on the time required for stump processing. Evaluated parameters included the mean time for one stump’s processing; the stump processing time based on the stump diameter; different soil types and tree species; and the tree species type (coniferous, broadleaved). The research was conducted in the territory of the Czech Republic in 2020/2021. There were 287 stumps and 6 tree species in total. The stumps were uprooted using a new prototype of grubbing head, developed at Mendel University in Brno, attached as an adapter on the boom of a JCB JS 220 LC excavator with a tracked undercarriage and was controlled remotely from an excavator cab. Research results confirmed that the processing time of one stump depends on the stump diameter (GLM), and the time needed for the processing of one stump increased with an increase in stump diameter in all experimental sites. An equation was suggested to predict the time needed to work on one stump. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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26 pages, 2877 KiB

Open AccessFeature PaperArticle

Productivity and Fuel Consumption in Skidding Roundwood on Flat Terrains by a Zetor Farm Tractor in Group Shelterwood Cutting of Mixed Oak Forests

by Stelian Alexandru Borz and Victor-Bogdan Mititelu

Forests 2022, 13(8), 1294; https://doi.org/10.3390/f13081294 - 15 Aug 2022

Cited by 4 | Viewed by 1870

Abstract

Productivity assessment studies are essential in forest operations, mainly because their results enable operational planning and rate setting, the development of equitable payment systems, the assessment of environmental performance, the assessment of improvements brought by technology development, and the optimization of larger forest-based [...] Read more.

Productivity assessment studies are essential in forest operations, mainly because their results enable operational planning and rate setting, the development of equitable payment systems, the assessment of environmental performance, the assessment of improvements brought by technology development, and the optimization of larger forest-based systems. This study examines productive performance and fuel consumption in farm-tractor based skidding operations implemented in flat terrain oak harvesting by developing detailed statistics and predictive models on skidding performance. Two felling areas were selected to monitor the operations, and detailed statistics and predictive models were developed at two resolutions by an end-to-end assessment. Based on 56 observed work cycles, and for average values of the number of logs, payload volume, winching distance and extraction distance of 4.96, 1.81 m³, 14.43 m, 177.3 m, respectively, the net efficiency and productivity rates of skidding operations were estimated at 0.125 h/m³ and 8.03 m³/h, respectively. At the resolution of piece-by-piece winching, winching time depended only on the winching distance. At the resolution of overall skidding operations, the skidding time depended on the number of logs in a payload and average winching and extraction distances. The same predictors were relevant in explaining the fuel consumption in skidding operations, which accounted for 3.72 L/h or 0.46 L/m³, while there was a variation in fuel consumption induced by the type of operation. Both efficiency and productivity were found to be highly sensitive to the operational distances, as the main factors affecting them. Nevertheless, significant improvements in efficiency, productivity, and fuel consumption may be achieved when dealing with fewer logs per turn and higher volumes per piece, since the models indicated no effects brought in fuel and time consumption by the log size, and the technical limits of the used winched reached 8.5 tons. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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15 pages, 2347 KiB

Open AccessArticle

The Predictive Accuracy of Modulus of Elasticity (MOE) in the Wood of Standing Trees and Logs

by Salvatore F. Papandrea, Maria F. Cataldo, Bruno Bernardi, Giuseppe Zimbalatti and Andrea R. Proto

Forests 2022, 13(8), 1273; https://doi.org/10.3390/f13081273 - 11 Aug 2022

Cited by 6 | Viewed by 2123

Abstract

The characterization of poplar wood assumes a strategic position to increase the competitiveness of the entire forest wood supply chain. From this aspect, the identification of wood quality represents a primary objective for researchers and private landowners. The quality of wood can be [...] Read more.

The characterization of poplar wood assumes a strategic position to increase the competitiveness of the entire forest wood supply chain. From this aspect, the identification of wood quality represents a primary objective for researchers and private landowners. The quality of wood can be defined via traditional visual methods based on the experience of technicians or using traditional tools, such as incremental drills and sound hammers. The traditional properties of these traits, based only on visual characteristics, can outline a classification based on the macroscopic properties of wood with the aim of defining the volume of recoverable wood. However, this approach does not provide a good indicator of the physical or mechanical properties of wood. Mechanical tests of wood require the felling of trees with the correlated preparation of the specimens. A different solution to determine wood quality is based on the application of non-destructive technology (NDT). In this context, the aim of the present study was to determine the predictive accuracy of non-destructive analysis of the MOEd in standing trees and logs of a 22-year-old poplar clone and to examine the relationship with MOEs in sawn specimens. This relationship was also studied at three different stem heights. We non-destructively measured poplar trees and green logs using TreeSonic and Resonance Log Grader and compared the results with those obtained via a destructive method using a universal testing machine. The results showed that for clone I-214 poplar trees, the dynamic elastic moduli of standing trees and logs were validly correlated with the static elastic modulus. These results suggest that it is possible to evaluate the mechanical properties of poplar wood directly from standing trees using non-destructive techniques (NDT) and that this tool can be easily used to presort material in the forest. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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14 pages, 32118 KiB

Open AccessArticle

Research on Static Stability of Firefighting Adapter

by Jaroslav Matej, Richard Hnilica and Michaela Hnilicová

Forests 2022, 13(8), 1180; https://doi.org/10.3390/f13081180 - 26 Jul 2022

Viewed by 1422

Abstract

The article is focused on the static stability of a vehicle with a 2000-liter water tank behind the rear axle. The purpose of the research is to evaluate the influence of the tank on stability. The vehicle is composed of a forestry skidder, [...] Read more.

The article is focused on the static stability of a vehicle with a 2000-liter water tank behind the rear axle. The purpose of the research is to evaluate the influence of the tank on stability. The vehicle is composed of a forestry skidder, a water tank, and equipment. To equilibrate the tank a ballast weight of 500 kg in front of the skidder is used. The influence of various combinations of the full water tank, half-filled water tank, and ballast weight is evaluated. The stability is determined as the distances of vectors of a stability triangle and a gravity vector, that is placed in a center of gravity of the whole vehicle. A Python programming language is used to implement the solution. The results are displayed in form of heatmaps. For the analyses, a slope angle of

18^{\circ}

is used. The results show that the longitudinal stability is decreased and lateral stability is increased. The tank also makes the vehicle unstable in some positions. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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21 pages, 5428 KiB

Open AccessArticle

Assessment and Sustainability of Logging Operations in Calabrian Pine High Forests

by Bruno Bernardi, Giorgio Macrì, Giacomo Falcone, Teodora Stillitano, Souraya Benalia and Anna Irene De Luca

Forests 2022, 13(3), 403; https://doi.org/10.3390/f13030403 - 2 Mar 2022

Cited by 5 | Viewed by 2789

Abstract

Forest mechanisation plays an important role in increasing labour productivity and reducing production costs. This work aims at evaluating various logging scenarios in Calabrian pine high forests, considering technical, economic and environmental aspects. The cut-to-length system was adopted and structured as follows: felling [...] Read more.

Forest mechanisation plays an important role in increasing labour productivity and reducing production costs. This work aims at evaluating various logging scenarios in Calabrian pine high forests, considering technical, economic and environmental aspects. The cut-to-length system was adopted and structured as follows: felling and processing operations were carried out using a medium-sized chainsaw while extraction of the processed material was carried out using three different vehicles for timber extraction: (i) by cable skidder, (ii) by grapple skidder and (iii) by a forwarder. The methodology was based on productivity analysis and production cost analysis, while for environmental performance, the life cycle assessment (LCA) approach was adopted. The selected functional unit (FU) was referred to as 1 h of logging operations. However, to assess the resulting usefulness, further analyses were performed using an alternative FU consisting of 1 m³ of round wood. The study’s outcomes show the complexity in achieving an optimal balance between productivity, economic aspects and sustainable management in forest operations. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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17 pages, 2343 KiB

Open AccessArticle

Economic Assessment and Management of Agroforestry Productivity from the Perspective of Sustainable Land Use in the South of the Russian Plain

by Evgenia A. Korneeva

Forests 2022, 13(2), 172; https://doi.org/10.3390/f13020172 - 23 Jan 2022

Cited by 9 | Viewed by 3409

Abstract

Recent international climate documents emphasize the great importance of the afforestation of agricultural land having a positive impact on CO₂ levels, not only by absorbing carbon by trees, but also by replacing fossil fuels with biomass. In Russia, until recently, the importance [...] Read more.

Recent international climate documents emphasize the great importance of the afforestation of agricultural land having a positive impact on CO₂ levels, not only by absorbing carbon by trees, but also by replacing fossil fuels with biomass. In Russia, until recently, the importance of forest plantations in the production of wood was underestimated, which created the problem of its accounting and effective management. When justifying modern protective afforestation programs, ambiguity in the estimates of tree productivity of plantings is one of the reasons for significant uncertainty regarding their impact on the energy security of the country. The purpose of this study was to undertake an economic assessment and assess the regularities of the dynamics of tree productivity of protective forest plantations on the flat terrain and slopes of the forest-steppe zone in the south of the Russian Plain for the effective management of agroforestry taking into account environmental aspects. At the level of the simulation unit—the protective forest cover of the agricultural territory—the main forest reclamation strategies were modeled from the perspective of sustainable land use, depending on the type of relief, the level of forest protection of land and the erosive state of soils. These models comprehensively analyzed the wood productivity of the main forest-forming species, which differ in functionality and service life. It is established that the productivity of 1 ha of forest stands in the forest-steppe is 320–400 m³ of wood, and the commercial effect of its harvesting is EUR 14675–EUR 56567. The specific (per 1 ha of land use) wood productivity of trees on flat terrain increases with the growth of forest protection of the site (due to the reduction of inter-band space) by 1.2–1.8 times. On the slopes, with an increase in their steepness, the specific effect of harvesting wood also increases by almost twofold. On steep slopes with highly eroded soils, the efficiency of forest reclamation decreases by 23%–24% due to a decrease in the width of forest stands and the inclusion of a hydraulic element in their systems. The use of long-lasting forest-forming species for all forest reclamation strategies is more profitable than the use of fast-growing species—the value of the specific average annual (discounted) income per 1 ha of the agroforest landscape is, respectively, EUR 427–EUR 970 and EUR 166–EUR 545. The study will confirm the need to finance forest reclamation measures not only to ensure sustainable rural development, but also Russia’s qualitative transition to a low-carbon economy. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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18 pages, 2248 KiB

Open AccessArticle

Damage to Residual Trees in Thinning of Broadleaf Stand by Mechanised Harvesting System

by Branko Ursić, Dinko Vusić, Ivica Papa, Tomislav Poršinsky, Željko Zečić and Andreja Đuka

Forests 2022, 13(1), 51; https://doi.org/10.3390/f13010051 - 3 Jan 2022

Cited by 7 | Viewed by 2230

Abstract

This research was conducted to determine the cause, intensity and location of damage (stem, butt end, root collar, root) and the extent of damage to standing trees during felling and processing by an harvester and timber extraction by a forwarder (cut-to-length system). The [...] Read more.

This research was conducted to determine the cause, intensity and location of damage (stem, butt end, root collar, root) and the extent of damage to standing trees during felling and processing by an harvester and timber extraction by a forwarder (cut-to-length system). The research was conducted in the central part of the Republic of Croatia in the Management Unit (MU) “Bjelovarska Bilogora” during the thinning of Subcompartment 14b, area of 18.28 ha, in the stand of hornbeam (Carpino betuli—Quercetum roboris fagetosum Rauš 1975), age 70, and of Subcompartment 14c, area of 9.07 ha, in a stand of common beech (Carici pilosae—Fagetum Oberdorfer 1957) aged 79 years. The thinning intensity was 12.13% in Subcompartment 14b and 13.72% in Subcompartment 14c. Field measurements were carried out on sample plots—the first time in 2017 to determine the intensity and characteristics of the damage to standing trees with regard to the cause of the damage (harvester or forwarder), and the second time in 2018 to determine the overall intensity and features of the damage to standing trees after finishing harvesting operations. For all trees remaining in the stand after the harvesting operations, the following were determined: tree species, diameter at breast height (DBH), the position of the tree in the stand depending on the forest traffic infrastructure, and—if damaged—cause of damage, type of damage, the position of damage on the tree, and dimensions of damage. The intensity of the damage was expressed by the ratio of damaged and undamaged trees, with a detailed analysis of bark damage (squeezed-bark damage and peeled-bark injuries). The results of the research indicate the highest prevalence of peeled-bark injuries. In relation to the total number of standing trees, trees with peeled-bark injuries were more represented in Subcompartment 14c (39%) than in Subcompartment 14b (33%). In Subcompartment 14b, the harvester and the forwarder damaged an equal number of trees, while in Subcompartment 14c, the harvester damaged 59% of the damaged trees. In both subcompartments, an average of 83% of (peeled bark) injuries were up to 1.3 m above the ground. In both subcompartments, the most common (67%) were injuries up to 100 cm² in size, for which many authors claim the tree can heal by itself. Given the increasing use of harvester-forwarder systems in deciduous stands and research results that indicate possible damage to standing trees, it is necessary to pay attention to all phases of planning and execution of timber harvesting operations, thus minimising negative effects. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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15 pages, 2739 KiB

Open AccessArticle

Changes in Soil’s Chemical and Biochemical Properties Induced by Road Geometry in the Hyrcanian Temperate Forests

by Saeid Rahbarisisakht, Mohammad Hadi Moayeri, Elyas Hayati, Seyed Mohammad Moein Sadeghi, Sebastian Kepfer-Rojas, Mohammad Hadi Pahlavani, Inger Kappel Schmidt and Stelian Alexandru Borz

Forests 2021, 12(12), 1805; https://doi.org/10.3390/f12121805 - 18 Dec 2021

Cited by 12 | Viewed by 2869

Abstract

Forest roads play an important role in providing access to forest resources. However, they can significantly impact the adjacent soil and vegetation. This study aimed to evaluate the effects of road geometry (RG) on the chemical and biochemical properties of adjacent soils to [...] Read more.

Forest roads play an important role in providing access to forest resources. However, they can significantly impact the adjacent soil and vegetation. This study aimed to evaluate the effects of road geometry (RG) on the chemical and biochemical properties of adjacent soils to assist in environmentally friendly forest road planning in mountainous areas. Litter layer, canopy cover, soil organic carbon (SOC) stock, total nitrogen (TN), the activity of dehydrogenase (DHA), and urease (UA) enzymes at a 0–20 cm soil depth were measured by sampling at various distances from the road edge to 100 m into the forest interior. The measurements were done for three road geometries (RG), namely straight, curved, and bent roads, to ensure data heterogeneity and to reflect the main geometric features of the forest roads. Analysis of variance (ANOVA) showed that the effects of RG on the measured variables were statistically significant. Spearman’s correlation test clearly showed a strong positive correlation between environmental conditions, SOC, TN, DHA, and UA for given RGs. Based on piecewise linear regression analysis, the down slope direction of the straight and the inside direction of bent roads accounted for the lowest and highest ranges of ecological effects, respectively. The results of this study contribute to our understanding of the environmental effects brought about by road geometry, which can be important for forest road managers when applying the best management practices. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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11 pages, 1793 KiB

Open AccessArticle

Using a Simple Model to Determine the Best Management Regimes for Plantations at the Stand Level: A Case Study of Moshao Forest Farm in the Red-Soil Hilly Region of Southern China

by Jianjia Zhu, Erfu Dai, Du Zheng and Silong Wang

Forests 2021, 12(10), 1358; https://doi.org/10.3390/f12101358 - 6 Oct 2021

Cited by 2 | Viewed by 1726

Abstract

Plantations in Southern China are experiencing several major problems concerning even-aged forest structures and dwindling ecosystem services under traditional forest management. The objective of this study was to determine the best management regimes (BMRs) for sustainable forest management using the Moshao forest farm [...] Read more.

Plantations in Southern China are experiencing several major problems concerning even-aged forest structures and dwindling ecosystem services under traditional forest management. The objective of this study was to determine the best management regimes (BMRs) for sustainable forest management using the Moshao forest farm as a case study. We constructed a framework for BMR modeling characterized by highly scheduled timber production (STP), low fluctuations in periodically scheduled timber harvest levels (FPS), and age class structure (ACS) at the end of the planning horizon. A paired analysis was conducted between the three indicators to identify suitable management planning for long-term timber production. Our results suggest that STP, FPS, and ACS are correlated, enabling the control of these forest performance indicators by setting various harvesting intensities in a planning horizon. We found that management regimes (MRS) with cutting area percentages from 20% to 40% and a cutting period of 10 years combined with small-area clear-cutting (≤5 ha) are optimal (MR6–MR10) for the Moshao forest farm in Southern China. In particular, MR with a cutting area percentage of 35% is the best option (MR9). These findings suggest that an applicable MR is designed by identifying the optimal harvesting intensity. The current local harvesting intensity can be properly increased to balance between timber production and ecological impacts on plantations. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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13 pages, 2162 KiB

Open AccessArticle

Injury Patterns among Forestry Workers in Croatia

by Matija Landekić, Ivan Martinić, David Mijoč, Matija Bakarić and Mario Šporčić

Forests 2021, 12(10), 1356; https://doi.org/10.3390/f12101356 - 6 Oct 2021

Cited by 14 | Viewed by 2573

Abstract

Timber harvesting, especially motor-manual felling, in Croatia, as in many other countries, is one of the most hazardous economic activities. Consequently, the aim of this paper is to analyse and compare the latest trends and risk factors related to the incidence of work-induced [...] Read more.

Timber harvesting, especially motor-manual felling, in Croatia, as in many other countries, is one of the most hazardous economic activities. Consequently, the aim of this paper is to analyse and compare the latest trends and risk factors related to the incidence of work-induced injuries in structural organization units of national forest enterprise. A combined approach of literature review and assembled secondary data was applied to gather data on workplace accidents over the years 2014–2020. Work-induced injuries data were drawn from the records of the national enterprise Croatian Forests Ltd. which manages state forests (76% of total forest area). A total of 1626 work-induced injuries were processed and entered into the database. Data analysis was conducted using statistical and descriptive methods. Research results have proven a significant difference in the injury rate over the years 2014–2020 in the Croatian forest enterprise. During the analysed period the highest number of workplace accidents (51.35% of all recorded workplace accidents) occurred during the forest harvesting phase, i.e., during motor-manual felling. Trends in the incidence of work-induced injuries in the observed period do not show any significant improvement. The key findings have pointed out that forest administrations which practice even-aged forest management have 25% or more injuries than forest administrations which practice selective forest management. Related to the average rate of change by forest administration, the largest annual increase or decrease of the selected safety indicators is recorded for smallest forest administrations. Related to total number of injuries, the smallest forest administrations have the least injuries and show statistically significant difference compared to large forest administrations. When comparing the number of injuries per 1000 employees, medium sized forest administrations have the highest value of indicator and show statistical significance. Discussion and conclusion of the paper emphasizes the need for systematic research in the field of ergonomy, safety and health of forest workers in Croatian forestry sector. Additionally, the development and inclusion of proactive safety culture is recognized as a mechanism that can further reduce work injuries and improve occupational safety which should have a significant role in the process of certification of forest management according to the FSC standard. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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15 pages, 4527 KiB

Open AccessArticle

Models for the Evaluation of Productivity and Costs of Mechanized Felling on Poplar Short Rotation Coppice in Italy

by Giulio Sperandio, Andrea Acampora, Angelo Del Giudice and Vincenzo Civitarese

Forests 2021, 12(7), 954; https://doi.org/10.3390/f12070954 - 19 Jul 2021

Cited by 11 | Viewed by 2135

Abstract

The forest biomass, as a renewable energy source, can significantly contribute to the progressive replacement of fossil fuels in energy production, with a positive final balance in terms of greenhouse gas emissions. One of the different sources of woody biomass supply is represented [...] Read more.

The forest biomass, as a renewable energy source, can significantly contribute to the progressive replacement of fossil fuels in energy production, with a positive final balance in terms of greenhouse gas emissions. One of the different sources of woody biomass supply is represented by short rotation coppices (SRC) plantations, currently present in various European countries for a total of about fifty thousand hectares. In Italy, part of the SRC surface has been converted into other more profitable crops, both the low levels reached by the woodchips market price and the scarce availability of specific public incentives. In this study, the authors expose the results of the models for evaluating work time, productivity, and costs of the felling operation on SRC poplar plantations with 8- and 11-year-old trees. The aim is to evaluate the economic sustainability in the use of advanced mechanization on these plantations. The machine was a crawler excavator equipped with a shear head. In the 11-year-old plantation, the productivity estimation model returned a range of 1.09–18.93 Mg h⁻¹ (average 5.56 ± 3.88 SD) when the weight variation of the trees was 20–491 kgw (average 100.41 ± 87.48 SD). In the 8-year-old poplar, the range was 1.02–11.60 Mg h⁻¹ (average 3.80 ± 1.71 SD), for weight variation of 17–137 kgw (average 50.57 ± 18.82 SD). The consequent variation in unit cost was EUR 2.82–51.63 Mg⁻¹ and EUR 4.05–49.65 Mg⁻¹, corresponding to EUR 1252.17–3463.78 ha⁻¹ and EUR 922.49–2545.11 ha⁻¹ for 11- and 8-year-old trees, respectively. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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20 pages, 2234 KiB

Open AccessArticle

Enhancing Working Posture Comparability in Forest Operations by the Use of Similarity Metrics

by Stelian Alexandru Borz, Eugen Iordache and Marina Viorela Marcu

Forests 2021, 12(7), 926; https://doi.org/10.3390/f12070926 - 15 Jul 2021

Cited by 7 | Viewed by 2197

Abstract

Forest operations are well known in exposing their workers to many risk factors, and they often require ergonomic interventions for improvement. In this regard, evaluation of biomechanical exposure has gained a lot of interest due to the concerning scientific results repeatedly showing the [...] Read more.

Forest operations are well known in exposing their workers to many risk factors, and they often require ergonomic interventions for improvement. In this regard, evaluation of biomechanical exposure has gained a lot of interest due to the concerning scientific results repeatedly showing the association between poor working postures and the development of work-related musculoskeletal disorders. Due to its simplicity, easy understanding, cost affordability, and the capability to evaluate the whole body, the OWAS method has been commonly used in postural evaluation of forestry work, being able to map the experimental observations in a final action category, in the form of a postural risk index (PRI), which helps designing or taking actions for ergonomic improvement. However, postural comparability is both relevant and important when, for instance, one tries to improve a work method or to introduce a new technology. Unfortunately, the PRI metric holds a rather low capability to characterize the changes brought by such factors in terms of postural dissimilarity or similarity, making it difficult to accurately follow the changes. For this reason, we introduce in the postural analysis, test and discuss herein two commonly used similarity metrics as specific to plant sociology and other ecology-related sciences, namely the Sørensen’s quotient of similarity (hereafter QS) and the Canberra metric (hereafter CM); their selection was based on their mathematical capabilities of dealing with data at two resolutions, namely species and individuals. Three case studies were setup to show the differences between QS, CM, and PRI and their usefulness for postural analysis while, for a better understanding, the results were described and discussed by analogy to the living world. As the technology of automating data collection and processing for postural analysis is in progress, the utility of similarity metrics in postural assessment and comparison could be further expanded so as to map a given work sequence in the time domain against best-fit postural profiles. The main conclusion of this study is that the PRI is useful for action-taking while the similarity metrics are useful for pairwise postural change evaluations and comparison. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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8 pages, 723 KiB

Open AccessArticle

Comparison of Physical and Mechanical Properties of Beech and Walnut Wood from Iran and Georgian Beech

by Mohammad Najafian Ashrafi, Hooman Shaabani Asrami, Zeynolabedin Vosoughi Rudgar, Mohammad Ghorbanian Far, Ali Heidari, Esmail Rastbod, Hamed Jafarzadeh, Mohammad Salehi, Ehsan Bari and Javier Ribera

Forests 2021, 12(6), 801; https://doi.org/10.3390/f12060801 - 18 Jun 2021

Cited by 10 | Viewed by 3808

Abstract

Beech (Fagus orientalis Lipsky) forests in Iran are one of the most important sources of the hardwood species used for lumber, furniture, and interior object design due to its hardness, wear resistance, strength, and excellent bending capabilities. Furthermore, Iran is third most [...] Read more.

Beech (Fagus orientalis Lipsky) forests in Iran are one of the most important sources of the hardwood species used for lumber, furniture, and interior object design due to its hardness, wear resistance, strength, and excellent bending capabilities. Furthermore, Iran is third most important country for walnut wood production after China and United States. Therefore, in this study, we compared specific mechanical properties between beech wood obtained from Sangdeh (Iran) and Georgia and four different kinds of walnut woods in Iran. Physical and mechanical tests were performed according to ISO 3129 (2012) and ASTM (D143-14) standards. The moisture content of all samples was 12% during mechanical tests. The mean dry density of Sangdeh and Georgian beech obtained was 0.61 and 0.65 g/cm³, respectively, while the mean dry density of Noor, Shahrekord, Mashhad, and Mako walnut woods measured 0.62, 0.59, 0.62, and 0.57 g/cm³, respectively. The results showed significant differences among the properties of the Sangdeh and Georgian species and the four different walnut tree woods. Overall, the obtained strengths of Georgian timber were higher than that of the Iranian beech, which was attributed to the higher density of Georgian timber. Furthermore, due to the higher density of the walnut species in the Noor and Mashhad regions, the measured mechanical strengths of these trees were higher than those of other walnut species. The obtained results provide relevant information to determinate the future applications of each wood source. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

15 pages, 2027 KiB

Open AccessArticle

Evaluation of Salvage Logging Productivity and Costs in the Sensitive Forests of Bulgaria

by Stanimir Stoilov, Andrea R. Proto, Georgi Angelov, Salvatore F. Papandrea and Stelian Alexandru Borz

Forests 2021, 12(3), 309; https://doi.org/10.3390/f12030309 - 7 Mar 2021

Cited by 18 | Viewed by 2749

Abstract

Steep terrain harvesting can only be implemented by a limited set of operational alternatives; therefore, it is important to be efficient in such conditions, in order to avoid incurring high costs. Harvesting abiotically-disturbed forests (salvage harvests caused by wet snow), which is becoming [...] Read more.

Steep terrain harvesting can only be implemented by a limited set of operational alternatives; therefore, it is important to be efficient in such conditions, in order to avoid incurring high costs. Harvesting abiotically-disturbed forests (salvage harvests caused by wet snow), which is becoming common these days, can significantly impact the operational efficiency of extraction operations. This study was implemented in order to evaluate the performance of truck-mounted uphill cable yarding operations in salvage logging deployed in coniferous stands. A time study was used to estimate the productivity and yarding costs, and predictive models were developed in order to relate the time consumption and productivity to the relevant operational factors, including the degree of wood damage. The average operational conditions were characterized by an extraction distance of 101 m and a lateral yarding distance of 18 m, resulting in a productivity rate of 20.1 m³ h⁻¹. In response to different kind of delays, the productivity rate decreased to 12.8 m³ h⁻¹. Under the prevailing conditions, lateral yarding accounted for 32% of the gross work cycle time, and for 50% of the delay-free work cycle time of the machine. Decreasing the lateral yarding distance and increasing the payload volume to the maximum capacity of the machine would eventually lead to a yarding productivity of close to 30 m³ per SMH (scheduled machine hour). The calculation of the gross costs of uphill yarding showed that the labor costs (35.7%) were slightly higher than the fixed costs (32.9%), and twice as high compared to the variable costs (17.7%). The remote control of the carriage, mechanical slack-pulling mechanisms, and radio-controlled chokers are just some of the improvements that would have led to increments in operational efficiency. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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19 pages, 4264 KiB

Open AccessArticle

Processing Small-Sized Trees at Landing by a Double-Grip Machine: A Case Study on Productivity, Cardiovascular Workload and Exposure to Noise

by Monica Cecilia Zurita Vintimilla, Sarahi Nicole Castro Pérez and Stelian Alexandru Borz

Forests 2021, 12(2), 213; https://doi.org/10.3390/f12020213 - 12 Feb 2021

Cited by 3 | Viewed by 1978

Abstract

To be characterized as sustainable, forest operations need to be studied and validated from many points of view, including their productivity, ergonomics and costs. In most of these areas, performance enhancement was found to be sustained by the development and use of mechanization, [...] Read more.

To be characterized as sustainable, forest operations need to be studied and validated from many points of view, including their productivity, ergonomics and costs. In most of these areas, performance enhancement was found to be sustained by the development and use of mechanization, including that of landing operations done to process small-sized trees. For these, an affordable and sustainable alternative could be that of using double-grip processors. However, there is a lack of information characterizing their capability and performance, which was one of the main reasons for carrying on this study. Observational data were collected over four operational days for a HYPRO 775 double-grip processor to estimate the productivity, exposure to noise and cardio-vascular workload in processing small-sized trees at landing. Miniaturized dataloggers and video recording were used to document close to 28 h spent at the workplace and 15 h of operation, respectively. A time study was used to estimate the productive performance and the commonly used metrics were computed to evaluate the exposure to noise and cardio-vascular workload. A delay-free work cycle was framed around a processed tree and it took, on average, ca. 45 s. Based on 901 processed trees (average height of ca. 12 m and average breast height diameter of ca. 12 cm), the net productivity rate was estimated at ca. 65 trees per hour (ca. 224 logs of 2.4 m produced per hour). While the cardiovascular activity indicated light work, exposure to noise seems to be a concerning problem to be addressed in the future, given the figures found (A-weighted sound pressure level higher than 85 dB(A) and the sound pressure level normalized for a nominal day of 92.79 dB(A)). This becomes even more important as this study found a machine utilization rate of ca. 60%, therefore an extension of productive time could increase the exposure to noise. We conclude that double-grip processors represent a valuable technical alternative in processing small-sized trees at landing if supplementary precautions would be taken against exposure to noise. These may rest very well in the awareness and behavior of the operators as well as in wearing protective equipment. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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22 pages, 17941 KiB

Open AccessArticle

Comparison of Selected Terramechanical Test Procedures and Cartographic Indices to Predict Rutting Caused by Machine Traffic during a Cut-to-Length Thinning Operation

by Marian Schönauer, Stephan Hoffmann, Joachim Maack, Martin Jansen and Dirk Jaeger

Forests 2021, 12(2), 113; https://doi.org/10.3390/f12020113 - 20 Jan 2021

Cited by 12 | Viewed by 2858

Abstract

Timber harvesting operations using heavy forest machinery frequently results in severe soil compaction and displacement, threatening sustainable forest management. An accurate prediction of trafficability, considering actual operating conditions, minimizes these impacts and can be facilitated by various predictive tools. Within this study, we [...] Read more.

Timber harvesting operations using heavy forest machinery frequently results in severe soil compaction and displacement, threatening sustainable forest management. An accurate prediction of trafficability, considering actual operating conditions, minimizes these impacts and can be facilitated by various predictive tools. Within this study, we validated the accuracy of four terramechanical parameters, including Cone Index (MPa, Penetrologger), penetration depth (cm, Penetrologger), cone penetration (cm blow⁻¹, dual-mass dynamic cone penetrometer) and shear strength (kPa, vane meter), and additionally two cartographic indices (topographic wetness index and depth-to-water). Measurements applying the four terramechanical approaches were performed at 47 transects along newly assigned machine operating trails in two broadleaved dominated mixed stands. After the CTL thinning operation was completed, measurement results and cartographic indices were correlated against rut depth. Under the rather dry soil conditions (29 ± 9 vol%), total rut depth ranged between 2.2 and 11.6 cm, and was clearly predicted by rut depth after a single pass of the harvester, which was used for further validations. The results indicated the easy-to-measure penetration depth as the most accurate approach to predict rut depth, considering coefficients of correlation (r_P = 0.44). Moreover, cone penetration (r_P = 0.34) provided reliable results. Surprisingly, no response between rut depth and Cone Index was observed, although it is commonly used to assess trafficability. The relatively low moisture conditions probably inhibited a correlation between rutting and moisture content. Consistently, cartographic indices could not be used to predict rutting. Rut depth after the harvester pass was a reliable predictor for total rut depth after 2–5 passes (r_P = 0.50). Rarely used parameters, such as cone penetration or shear strength, outcompeted the highly reputed Cone Index, emphasizing further investigations of applied tools. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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18 pages, 3404 KiB

Open AccessArticle

Integrating Offline Object Tracking, Signal Processing, and Artificial Intelligence to Classify Relevant Events in Sawmilling Operations

by Stelian Alexandru Borz and Marius Păun

Forests 2020, 11(12), 1333; https://doi.org/10.3390/f11121333 - 15 Dec 2020

Cited by 13 | Viewed by 2409

Abstract

Sawmilling operations are typically one of the most important cells of the wood supply chain as they take the log assortments as inputs to which they add value by processing lumber and other semi-finite products. For this kind of operations, and especially for [...] Read more.

Sawmilling operations are typically one of the most important cells of the wood supply chain as they take the log assortments as inputs to which they add value by processing lumber and other semi-finite products. For this kind of operations, and especially for those developed at a small scale, long-term monitoring data is a prerequisite to make decisions, to increase the operational efficiency and to enable the precision of operations. In many cases, however, collection and handling of such data is limited to a set of options which may come at high costs. In this study, a low-cost solution integrating offline object tracking, signal processing and artificial intelligence was tested to evaluate its capability to correctly classify in the time domain the events specific to the monitoring of wood sawmilling operations. Discrete scalar signals produced from media files by tracking functionalities of the Kinovea^® software (13,000 frames) were used to derive a differential signal, then a filtering-to-the-root procedure was applied to them. Both, the raw and filtered signals were used as inputs in the training of an artificial neural network at two levels of operational detail: fully and essentially documented data. While the addition of the derived signal made sense because it improved the outcomes of classification (recall of 92–97%) filtered signals were found to add less contribution to the classification accuracy. The use of essentially documented data has improved substantially the classification outcomes and it could be an excellent solution in monitoring applications requiring a basic level of detail. The tested system could represent a good and cheap solution to monitor sawmilling facilities aiming to develop our understanding on their technical efficiency. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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Review

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17 pages, 22952 KiB

Open AccessReview

A Literature Review on Cable Extraction Practices of South Korea: 1990–2020

by Eunjai Lee, Yunsung Choi, Minjae Cho, Koohyun Cho, Jaeheun Oh, Sangkyun Han and Sangjun Im

Forests 2021, 12(7), 908; https://doi.org/10.3390/f12070908 - 12 Jul 2021

Cited by 5 | Viewed by 3518

Abstract

Cable yarding technology remains the most effective operation in steep terrain harvesting systems; however, it has limitations and challenges. Using cable yarders (tractor-, truck-, and excavator-based) to extract tree lengths and whole trees has been common since the late 20th century in South [...] Read more.

Cable yarding technology remains the most effective operation in steep terrain harvesting systems; however, it has limitations and challenges. Using cable yarders (tractor-, truck-, and excavator-based) to extract tree lengths and whole trees has been common since the late 20th century in South Korea, and cable yarding operations were developed in the late 1800s in the United States and Europe. Machine potential and limitations must be understood to ensure the widespread use of technology, strong cooperation, and optimal selection of machinery size. We reviewed the literature on tower yarder performances from 1990–2021 to determine the alteration of yarders and its productivity pattern and obtained 23 papers; <2 publications per year discussed the determination of cable yarding productivity. We selected independent variables (e.g., silvicultural treatment, harvesting method, and cycle log volume) for cable yarding that would likely affect productivity. Data were analyzed to compare productivities under silvicultural treatment, the harvesting method, and yarding direction and identify the interaction mechanical power (i.e., lifting capacity and machine power), yarding distance, and slope. Cable yarder productivity rates generally depended on the silvicultural treatment, harvesting method, and yarding direction, particularly in clear-cut, tree-length, and uphill yarding operation activities. The lifting capacity, machine power, and slope had no significant correlation with yarders’ productivity, particularly in thinning operations, whereas, in clear-cut productivity, it was influenced by these variables. The results contribute to improving operation activities for cable yarding systems and towards future research directions. Full article

(This article belongs to the Special Issue Mechanization, Wood Production and Environmental Sustainability in Forest Operations)

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