Vibration Levels of Used Chainsaws Landekić, Matija; Bačić, Marin; Pandur, Zdravko ...
Forests,
02/2020, Letnik:
11, Številka:
2
Journal Article
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Although professional chainsaws have come a long way regarding technical and ergonomic development since first introduced into forestry, they still remain a high-risk tool that can cause serious ...health problems. In this research, three types of used professional chainsaws were observed regarding harmful vibrations they emit and possible connection to years in use, chainsaw type, characteristics and level of vibrations. Measurements were performed in accordance with the recommendations of ISO 5349:2001. For the measurements, a measuring chain consisting of a triaxial accelerometer manufactured by Bruel & Kjaer and a vibrometer of the same manufacturer Type 4447. To evaluate the emitted vibrations, a daily exposure value A(8) was used. Exposure durations to predefined working operations were identical for every used chainsaw to enable the possibility of equal comparability. Obtained results indicate that the daily vibration exposure A(8) is not affected by the years in use of the chainsaw. Results also show that the power and chainsaw type have an influence on daily vibration exposure. The recommendation for the praxis is to use even lighter and smaller chainsaw wherever is possible.
In order to solve the problem of complicated processes, low efficiency and high cost of economic tree trunks girdling, inspired by cam mechanism this study developed a new type of automatic half-ring ...girdling device, which can automatically complete a series of operations, including the tree trunk profile scanning, girdling trajectory calculating and automatic bark cutting. A pair of laser rangefinders and guide screws were symmetrically arranged on a half-ring rotating rail, which could rotate around the tree trunk, and two chainsaws assembled above the guide screws were controlled to move radially. The laptop was used as upper computer, and a 4-axis motion control card was used as the lower computer, which constituted the control system of precise movement. The programs of the tree trunk profile scanning, the xylem profile curve fitting and the chainsaw centre trajectory calculation were designed in LabVIEW. The scanning tests and girdling experiments were carried out on the different sections of the tree trunks in the laboratory. The feasibility of the automatic girdling device for economic tree trunks was verified with one complete and automatic girdling operation finished by this device, which took 150 seconds, and the error range of automatic girdling was within ±2mm. This device improves the automation degree of girdling operation and provides a support for the development of economic forestry.
•Herbaceous response was measured after cutting and burning in juniper woodland.•Herb cover was measured in interspaces, around tree stumps, and under felled trees.•Sites burned in winter recovered ...best and were dominated by native perennials.•Invasive annuals replaced native perennials when sites were burned in fall or spring.•Maintaining site resilience and resistance is key to conserving the sagebrush steppe.
Decreased fire activity has been recognized as a main cause of expansion and infilling of North American woodlands. Piñon-juniper (Pinus-Juniperus) woodlands in the western United States have expanded in area 2–10-fold since the late 1800s. Woodland control measures using chainsaws, heavy equipment and prescribed fire are used to restore big sagebrush (Artemisia tridentata Nutt.) steppe plant communities and reduce woody fuel loading. Immediate objectives in the initial control of piñon-juniper are; (1) recovery of perennial herbaceous species to restore site composition, structure and processes (resilience) and resist invasion and dominance by invasive annual grasses (resistance) and (2) reducing woody fuel accumulations. Spanning a 7year period (2006–2012), we compared herbaceous recovery following cutting and prescribed fire on three sites in mid and late succession western juniper (Juniperus occidentalis spp. occidentalis Hook.) woodlands in southeast Oregon. Treatments were untreated controls, partial cutting followed by fall broadcast burning (SEP), clear-cut and leave (CUT), and clear-cut and burn in winter (JAN), and spring (APR). Cover of herbaceous species was measured in three zones; interspace, litter mats around tree stumps (stump), and beneath felled trees. In interspace zones of all treatments, comprising between 51% and 63% of site areas, perennial bunchgrasses dominated two sites and co-dominated with invasive annual grasses at one site after treatment. Burning in the JAN treatments, when fuel moisture and relative humidity were high and temperatures cooler, reduced disturbance severity in stump and felled tree zones, which maintained perennial herbaceous understories and prevented or limited the presence of invasive annuals. Burning felled juniper in SEP and APR treatments resulted in moderate to high fire severity in stump and felled tree zones. At two sites, these fires consumed all fuel up to the 1000-h fuel class, largely eliminated herbaceous perennials, and created islands within treatments that enhanced annual grass invasion and dominance. To maintain or boost site resilience and resistance following control of late successional woodlands, reducing piñon-juniper fuels by burning in winter provides managers with a low-impact option for conserving sagebrush steppe.
Portable chainsaws for cutting wood, like other handheld machines, are commonly used for mechanical work. Portable combustion chainsaws are still used in many countries, including Poland, as basic ...wood harvesting machines and in agriculture. The use of portable chainsaws, however, poses a high risk of injury, especially with the phenomenon of kickback. Important European documents (e.g., 2006/42/EC) qualify these machines as a specific group, and assessing them for compliance with the essential applicable requirements (before placing them on the market) can be done with the participation of a third party (notified body). In Poland, only employees with appropriate training are allowed to work with chainsaws for professional wood harvesting. This paper presents the results of an analysis of the hazards posed by portable combustion chainsaws. A practical assessment was conducted of the effectiveness of the most relevant technical solutions used to protect operators from injury. Reference is made to tests on chainsaws that were carried out as part of scientific research (described in previous publications) and as part of research commissioned by market surveillance authorities operating in Poland. The presented research results show that the risk of injury caused by the use of chainsaws is influenced not only by the design features of the machines but also by their proper use, including the selection of equipment appropriate to the working conditions (e.g., wood type and properties, use of chainsaws for professional or non-professional work).
In the conditions of Slovakia, forest harvesting is largely carried out by hand-held chainsaws. Working with a chainsaw is one of the most demanding tasks in forestry, both in terms of demands on the ...operator and compliance with technological and work discipline. The aim of this work is the analysis of selected anthropometric dimensions of the upper limbs of the adult male population and their comparison with parameters and approaches in the design of hand-held controls for manual chainsaws. The research was conducted on a sample of 1629 men aged 18 to 25, in whom six anthropometric dimensions related to the upper limbs were measured, which are important for the sizing of the controls on the chainsaw handles. The results of the anthropometric analysis were compared with the recommended values for the design of hand-held chainsaws. Based on the results obtained, we identified some parameters of the front and rear handles that would need to be resized. Most of the recommended dimensions are in a convenient range. However, to take into account user comfort, we suggest, in some cases, increasing their minimum recommended values.
The aim of this research is to measure the energy consumption and compare the cutting performance of three types of battery-powered chainsaws (Stihl MSA 200, Stihl MSA 220, and Stihl MSA 300). Tested ...chainsaws were powered by two different battery packs (Stihl AP 300 S and Stihl AP 500 S) with different energy capacity and output current when cutting two wooden beams, European beech (Fagus sylvatica L.) and black locust (Robinia pseudoacacia L.) with different densities and moisture content. Energy consumption was measured using a multimeter built-in battery charger housing, and consumed energy was noted in watt-hours. Each individual cut was recorded with an action camera at 60 frames per second, and the duration of the cuts recorded in centiseconds was observed on the obtained recordings. Results show significant differences in energy consumption and cutting duration between individual chainsaw/battery combinations. Energy consumption ranged from 2.45 to 4.50 Wh per cut for beech (Stihl MSA300E_AP500S and Stihl MSA220_AP300S, respectively) and from 3.10 to 5.00 Wh per cut for black locust (Stihl MSA300M_AP500S and Stihl MSA220_AP500S, respectively). Duration of the cut ranged from 3.48 to 9.24 s per cut for beech (Stihl MSA300M/H_AP500S and Stihl MSA220_AP300S, respectively) and from 3.74 to 9.35 s per cut for the black locust (Stihl MSA300M_AP500S and Stihl MSA220_AP300S, respectively). In general, it can be concluded that more powerful chainsaw/battery combinations (Stihl MSA300_AP500S) consumed less energy per cut and had better cutting performance (shorter cut). In that regard, more powerful chainsaws had greater cutting efficiency, i.e., more cuts on one charge (battery) but shorter cutting time on one charge. The effect of tree species (fresh-sawed beech/air-dried black locust) on energy consumption and cutting performance is absent on the most powerful chainsaw/battery combinations. Today, lithium-ion batteries still have 70 times less energy density than petrol. However, if there is a significant increase in the energy density of the batteries in the coming times, battery chainsaws will most certainly displace petrol chainsaws from use in the future.
In Italy, the use of chainsaws for field operations such as Felling (FE), Delimbing (DE), and Bucking (BU) is widespread due to the topography, the medium–small size of farms, and the predominant ...presence of broad-leaved forests managed through coppicing. However, this has led to an increase in injuries and illnesses due to exposure to physical factors (e.g., noise, dust, and vibrations) and chemical agents (e.g., various volatile compounds). Occupational health and safety legislation in Italy has undergone several phases, including the approval of U.T. 81/2008. The present study aims to evaluate the noise generated by chainsaws and the concentration of pollutants (CO, VOC, and C6H6) present in chainsaw exhaust gases during interventions in a chestnut coppice in relation to the limits set by current legislation. The analysis of the noise generated by chainsaws during chestnut cutting operations showed that it exceeded the legal noise limits during all chainsaw activities, with peak levels of about 110 dB. The detected noise could cause important critical issues in relation to the health and safety of specialized operators. Furthermore, the correlation between the specific work (FE, DE, and BU) and the ratio between maximum and average values of CO and VOC emissions was evaluated. Notably, comparable levels of maximum VOC emissions were observed during the FE and BU phases. However, the average emission values during these phases exhibited significant differences, suggesting higher VOC production when the engine was running but not actively engaged in cutting. The highest emissions were recorded during the FE phase (CO = 135 ppm, VOC = 17.28 ppm, and C6H6 = 2.13 ppm).
•Chinese privet was removed from heavily infested riparian forests in 2005.•Pollinators were sampled in removal, infested, and un-infested plots five years later.•Removal plots had more species and ...more individuals than infested plots.•Pollinator communities in removal plots were similar to un-infested plots.•Removing privet results in long term conservation of these insect groups.
Chinese privet (Ligustrum sinense) is an invasive shrub of the Southeastern U.S. that forms dense stands and limits biodiversity. It was removed from heavily infested riparian forests of the Georgia Piedmont in 2005 by mulching machine or chainsaw felling and subsequent herbicide application. Abundance and species richness of bees and butterflies were sampled using pan traps on removal plots, heavily invaded control plots, and reference plots in 2012, approximately five years after complete removal of privet. Removal plots had nearly three times as many species as control plots and were similar to reference plots in numbers of species. Traps on removal plots captured four times more individuals than those on control plots and similar numbers to reference plots. Bee and butterfly abundance and richness were positively correlated with non-privet plant cover, diversity, and evenness and negatively correlated with privet shrub cover. Removing Chinese privet from riparian forests had a beneficial effect on insect pollinator communities five years after removal and is a relatively simple method of improving pollinator habitat. These findings provide justification for allocating resources for invasive shrub species removal to support long term conservation of these important insect groups and the ecological services they provide.
PURPOSE: Forest residues are becoming an increasingly important bioenergy feedstock. This study evaluates the environmental impacts associated with the production of fuel chips from eucalypt logging ...residues in Portugal, in order to identify the supply chains and machinery that bring the best environmental performance. Besides, the stages and operations with the largest environmental impact are identified. METHODS: Life cycle assessment methodology is used starting with forest management up to delivery of chips to power plant. Three different configurations for logging residue processing were simulated as follows: roadside chipping of loose residues, terminal chipping of loose residues, and terminal chipping of bundled residues. In addition, the use of different equipment for tree felling and extraction of logging residue was considered. The default impact assessment methodology was the CML. In a sensitivity analysis, calculations were performed using characterization factors recommended by the International Reference Life Cycle Data System (ILCD). Different allocation criteria were tested for partitioning the environmental burdens between wood and forest residues produced during the stage of forest management. RESULTS AND DISCUSSION: Roadside chipping of loose residues seems to have less impacts regardless of the equipment used in tree felling and residue forwarding. However, for photochemical oxidant formation, this is not the case when trees are felled with a chainsaw when the CML methodology is applied. For the systems with terminal chipping, the better option will depend both on type of machinery used and distances traveled between the forest site and the power plant. The forest management stage has a relevant contribution to all the supply chains analyzed. Chipping and bundling have also important impacts, as well as forwarding when this operation is accomplished with a modified farm tractor. Moreover, transports have a significant impact when loose residues are chipped in a terminal. CONCLUSIONS: The choice of the allocation method between wood and residues affects significantly the absolute results, but it is irrelevant when the objective is to select the best supply chain configuration. The results obtained are valid for the input data considered, which rely on average values representative of the current most typical practices in Portugal. However, this methodology can also be applied as a decision supporting tool to select the supply chain with the best environmental performance on a case by case basis, using site-specific data.
The development of technology and the means of labour in the technological
process of forest harvesting in FBiH mainly depends on the factors related to
the specific manner of forest management. The ...dominant share of mixed tall
forests with natural regeneration, the selective manner of management and
rather difficult natural conditions have resulted in the application of the
cut-to-length method and to a lesser extent, the tree-length and
semi-tree-length methods. On the basis of expert classification of the
development phases in forest harvesting, it can be noted that wood assortment
production in FBiH is currently partially mechanised. With the aim of
defining measures for increasing productivity, lowering the costs and a
greater humanisation of work, there has been an analysis of the current state
of the means of work in all three phases of forest harvesting. The analysis
included the following parameters: number of means in different phases, the
type, the average age, ownership and technical planned obsolescence. All the
data were collected through a survey which included all stakeholders
(cantonal forest companies and private contractors). The results showed a
satisfactory state only when chainsaws are concerned, i.e. the rather cheap
tools. Other equipment (adapted tractors, skidders, trucks, etc.) has largely
reached planned obsolescence. Their old age results in a low level of
utilisation, i.e. an insufficient amount of working hours per year which
eventually leads to a decrease in productivity and increase in expenses.
Based on the data, it can be concluded that it is necessary to begin the
process of new mechanisation procurement and the replacement of existing,
time-worn and technologically obsolete machines with new ones. At the same
time, it is clear that, in the conditions of low availability of investment
capital and cheap labour force, this has to be a gradual process. In relation
with this, the process should start in the most expensive phase - timber
extraction, i.e. the phase in which the economic efficiency is
unquestionable.
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