Characteristics and Significance of a Harvester Operators’ Working Technique in Thinnings

Ovaskainen, Heikki; Uusitalo, Jori; Väätäinen, Kari

doi:10.1080/14942119.2004.10702498

Cited by 79 publications

(81 citation statements)

References 3 publications

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“…If the same machine is operated by another operator, results may differ. Differences could be explained by human factors (driver's motoric skills, work planning and decision-making process) during the operation (Ovaskainen et al 2004). Purfürst (2009) concluded that under favorable conditions and in easy terrain the effect of the operator on the overall performance amounts to 37%.…”

Section: Discussionmentioning

confidence: 99%

Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings

Erber¹,

Holzleitner²,

Kastner³

et al. 2016

Silva Fenn.

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Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings Erber G., Holzleitner F., Kastner M., Stampfer K. (2016). Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings. Silva Fennica vol. 50 no. 1 article id 1428. 17p. Highlights• Harvesting with the accumulating energy wood head EF28 was studied under small tree dimension (8 dm³) in hardwood thinnings.• Reasonable productivity was achieved.• Maximum achieved cutting diameter in hornbeam stand was 23 cm and 15% lower than in softwood stands.• Head has potential under such conditions. AbstractEarly thinnings are laborious and costly. Thus forest companies are searching for cost and time efficient ways to carry out this task. The study's purpose was to determine the productivity of the EF28 accumulating energy wood harvesting head in harvesting small-diameter hornbeam (Carpinus betulus L.) undergrowth trees and evaluate the effect of its multi-tree handling (MTH) capacity on time consumption. The harvester was a wheeled, three-axle Komatsu 911. A time study of 7.1 hours on 19 plots, with a total area of 0.76 ha was conducted. On average, the harvested tree volume was 8 dm³ and the stand density was 2666 trees/ha. The productivity was modelled with MTH conduction, mean diameter at breast height and the number of trees handled per cycle as independent variables. On average, MTH took 27% longer per cycle, increased extracted volume per cycle by 33% and consequently increased productivity with 5.0%. In 71.9% of the cycles more than one tree was handled and if so, dimensions were smaller than in single-tree handling (5.8 cm vs. 12.0 cm). Maximum felling diameter of 23 cm was about 15% smaller than in softwood (according to the manufacturer's specifications) and the driver didn't exploit the EF28's theoretical potential in terms of trees handled per cycle. It can be concluded that the head could significantly improve productivity in small-diameter wood procurement.

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Section: Discussionmentioning

confidence: 99%

Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings

Erber¹,

Holzleitner²,

Kastner³

et al. 2016

Silva Fenn.

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show abstract

“…If this had been considered in the model, TMRW Sel and TMFF Sel,Corr would have had a somewhat poorer performance, relative to both TSRW Sel , 2m2FF Corr and CFF Corr (Table III). In real-life forest operations, the operator often handles obstructing trees by reversing the machine along the strip road to gain access to a certain tree (Ovaskainen et al, 2004;Lindroos et al, 2008). In our model, the algorithms presented in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Bergström et al, 2007;Iwarsson Wide & Belbo, 2009) and harvester and forwarder working patterns (e.g. Gullberg, 1997;Ovaskainen et al, 2004;Ovaskainen et al, 2006;Ovaskainen, 2008). Functions describing new machine systems with boom-tip mounted, area-based felling devices and new working techniques were also implemented.…”

Section: Approach and Scenario Definitionsmentioning

confidence: 99%

Simulation of harvester productivity in selective and boom-corridor thinning of young forests

Sängstuvall¹,

Bergström²,

Lämås³

et al. 2012

Scandinavian Journal of Forest Research

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Forest management practices may change in the future, due to increases in the extraction of forest fuel in first thinnings. Simulation models can be used to aid in developing new harvesting systems. We used such an approach to assess the productivity of innovative systems in various thinnings of young stands with wide ranges of mean breast height diameter (1.5 -15.6 cm), stems per hectare (1 000 -19 100) and mean height (2.3 -14.6 m).The results show that selective multiple-tree-handling increases productivity by 20 -46% compared to single-tree-handling. If the trees are cut in boom-corridors (narrow 10 m strips between strip roads), productivity increases up to 41%, compared to selective multiple-tree-handling. Moreover, if the trees are felled using area-based felling systems, productivity increases by 33 -199 %, compared to selective multiple-treehandling. For any given harvesting intensity , the increases in productivity were highest in the densest stands with small trees.The results were used to derive time consumption functions. Comparisons with time study results suggest that our simulation model successfully mimicked productivity in real-life forest operations, hence the model and derived functions should be useful for cost calculations and evaluating forest management scenarios in diverse stands.

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“…[29,31]). Numerous earlier forest work studies have been carried out to analyze the effect of the harvester operator on performance, and many studies have emphasized that there is a significant correlation between the work experience and skills of an operator and his/her productivity in forest machine work (e.g., [68][69][70][71][72][73][74][75]). For instance, Purfürst and Erler [74] have found out that together, the stem volume and the operator explain 84% of the total overall variation in cutting productivity, and the operator alone explains 37% of the variance.…”

Section: Evaluation Of Datasets and Approachesmentioning

confidence: 99%

“…Hence, on the basis of the results of this study, it can be concluded that a big leap has not necessarily been taken in the development of forest machine technology during the last ten years. Nevertheless, when comparing the results of different forest work studies, attention must be paid to the effect of the operator and his/her skills on his/her work performance in cutting operations [68][69][70][71][72][73][74][75]. As the influence of the harvester operator on the cutting productivity in windthrown areas is significant [29,31], it is very important that the skills of operators are superior for the purpose of cutting windfalls safety and effectively.…”

Section: Evaluation Of the Main Findingsmentioning

confidence: 99%

Evaluation of Salvage Logging Productivity and Costs in Windthrown Norway Spruce-Dominated Forests

Kärhä

Anttonen

Poikela

et al. 2018

Forests

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Different abiotic and biotic disturbances are expected to become more common in the future due to a warming climate. Globally, post-disturbance salvage logging is becoming more predominant to recover economic value from timber in disturbed forests. This study collected comparative time-study data and analyzed the productivity of cutting for windfalls in clear cuttings and determined the cutting costs of windfalls. Furthermore, the logging (i.e., cutting and forwarding) costs of wind-damaged trees and those of undamaged standing Norway spruce (Picea abies (L.) Karst.) trees in clear cuts were calculated in Finland. The results revealed that the cutting productivity of windfalls was 19-33% lower than that of undamaged stems. The cutting costs of windthrown stems with a volume of 0.3-1.5 m 3 were 35-64% higher and the logging costs of windfalls were 10-30% higher than those of undamaged standing stems. The study provided new understanding regarding the productivity and costs of salvage logging operations under Finnish conditions. Even if the logging of windfalls is expensive and laborious, salvage logging operations are important for forest stands and their health to minimize post-disaster damage outbreaks in coniferous forests, such as the damage caused by bark beetles-mainly Ips typographus L.

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Characteristics and Significance of a Harvester Operators’ Working Technique in Thinnings

Cited by 79 publications

References 3 publications

Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings

Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings

Simulation of harvester productivity in selective and boom-corridor thinning of young forests

Evaluation of Salvage Logging Productivity and Costs in Windthrown Norway Spruce-Dominated Forests

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