Distance driven and driving speed when forwarding during final felling in Central Sweden

Berg, Simon; Ersson, Back Tomas; Manner, Jussi

doi:10.17221/23/2019-jfs

Cited by 12 publications

(16 citation statements)

References 19 publications

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“…We found that productivity and TTD were strongly correlated. These results are consistent with many published studies, such as Matthews et al, [48], Kumazawa et al, [49], and Berg et al, [50]. These studies posited that the driving unloading speed increases with an increase in driving distance.…”

Section: Discussionsupporting

confidence: 93%

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Performance Analysis of Log Extraction by a Small Shovel Operation in Steep Forests of South Korea

Lee

Han

2019

Forests

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In South Korea, logs for low-value products, such as pulpwood and fuelwood, are primarily extracted from harvest sites and transported to roadside or landing areas using small shovels. Previous studies on log extraction, however, have focused on cable yarding operations with the goal of improving productivity on steep slopes and inaccessible sites, leaving small-shovel operations relatively unexamined. Therefore, the main objectives were to determine small-shovel extraction productivity and costs and to evaluate the impact of related variables on productivity. In addition, we developed a model to estimate productivity under various site conditions. The study took place in 30 case study areas; each area has trees with stems at a diameter at breast height ranging from 18 to 32 cm and a steep slope (greater than 15%). The areas ranged from 241 to 1129 trees per hectare, with conifer, deciduous, and mixed stands. Small-shovel drives ranged from 36 to 72 m per extraction cycle from stump to landing. The results indicated that the mean extraction productivity of small-shovel operations ranged between 2.44 to 9.85 m 3 per scheduled machine hour (including all delays). At the forest level, the estimated average stump-to-forest road log production costs were US $4.37 to 17.66/m 3 . Small-shovel productivity was significantly correlated with stem size (diameter at breast height and tree volume) and total travelled distance (TTD). However, a Pearson's correlation analysis indicated that stand density and slope did not have a significant effect on productivity. Our findings provide insights into how stem size and TTD influence small shovel performance and the predictive ability of productivity. Further, this information may be a valuable asset to forest planners and managers.

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Section: Discussionsupporting

confidence: 93%

“…In addition, extraction productivity may be influenced by the number of logs [46,50]. This pattern could be explained by the fact that productivity increases with a decrease in the number of load stops and driven distances.…”

Section: Discussionmentioning

confidence: 99%

Performance Analysis of Log Extraction by a Small Shovel Operation in Steep Forests of South Korea

Lee

Han

2019

Forests

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“…Speed is suggested to increase during stress to maintain high productivity, e.g. during long distances (Berg et al 2019). High productivity demands in rough terrain may therefore cause high postural loads and may be something to consider when setting productivity norms, so the operational productivity goals are balanced to the operators' risk for occupational health problems.…”

Section: Discussionmentioning

confidence: 99%

Seated postural loads caused by shock-type whole-body vibration when driving over obstacles

Stenlund

Lundström

Lindroos

et al. 2020

International Journal of Forest Engineering

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Operators of mobile machines within forestry work long hours in seated postures while being exposed to whole-body vibration (WBV) that is associated with pain in the lower back and neck. Still, little is known about the contribution from postural loads. In this study postural loads and shock-type WBV exposure on drivers operating a forwarder during terrain-like conditions was measured and quantified using inertial measurement units (IMUs). Five male drivers drove a forwarder repeatedly over standardized steel obstacles using a predefined speed and posture followed by driving over natural obstacles along a terrain course using a self-selected speed and posture. IMUs were affixed along the spine, on the back of the head of the driver and on the seat to detect orientation, velocity, and acceleration. The result shows that the methodology for measuring WBV and postural load with IMUs is feasible. Postural loads, expressed as range of motions (ROMs), when driving over a single standardized obstacle at a speed of 3.3 km/h were up to 21°in the neck segments. Increasing vehicle speed and size of obstacles increased postural loads. The terrain course resulted in higher ROMs in all body segments compared to a standardized obstacle, a difference in sideway seat acceleration but no differences regarding angular velocities of the head. Mechanical shocks at the seat were prevalent but the action limit value was exceeded only for one driver. Postural loads remained small during all conditions indicating that the spine can remain stable during exposure to shock-type WBV of this nature.

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“…However, no systematic rule-based filtering was used to remove outliers (cf. Berg et al 2019). In general, beyond specifying which boom-control system was used, the data-gathering did not require any special arrangements or changes to working practices.…”

Section: Randomized Follow-upmentioning

confidence: 99%

Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset

Manner¹,

Mörk²,

Englund³

2019

Silva Fenn.

Self Cite

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Highlights• Boom-tip control saves time compared to the conventional system. • This study introduced a field-study design enabling establishment of causal relationships during ordinary forwarding operations. • Although the study design requires some extra arrangements, it efficiently combines the representativeness of conventional follow-up datasets with establishment of causal relationships that traditionally have been possible only through observational time studies or standardized experiments. AbstractCrane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deere's version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (p ≤ 0.05). The corresponding saving when using IBC for unloading work was 7.9% (p ≤ 0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments. Silva Fennica vol. 53 no. 2 article id 10161 · Manner et al. · Comparing forwarder boom-control systems based …

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Distance driven and driving speed when forwarding during final felling in Central Sweden

Cited by 12 publications

References 19 publications

Performance Analysis of Log Extraction by a Small Shovel Operation in Steep Forests of South Korea

Performance Analysis of Log Extraction by a Small Shovel Operation in Steep Forests of South Korea

Seated postural loads caused by shock-type whole-body vibration when driving over obstacles

Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset

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