Time consumption analysis of the mechanized cut-to-length harvesting system

Nurminen, Tuomo; Korpunen, Heikki; Uusitalo, Jori

doi:10.14214/sf.346

Cited by 276 publications

(353 citation statements)

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“…In thinning forwarding of 1 type of sawlog assortments decreased the productivity by 20-25 % in comparison to forwarding of mixed loads of 2 types of assortments simultaneously. The productivity of pulpwood forwarding increased by 15-19 % in comparison to mixed loads of pulpwood and sawlogs [7]. …”

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confidence: 96%

Comparison of productivity of standard and accumulating forwarder grapple in thinning

Petaja

Kaleja

Zimelis

et al. 2018

Engineering for Rural Development

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Abstract. The aim of the study is to evaluate the impact of the accumulating grapple on forwarding productivity in thinning in comparison to the standard grapple and to evaluate potential areas of application of accumulating grapples. Trials were conducted in 3 coniferous stands on nutrient-poor mineral soil with the total area of 15.2 ha. Two work methods are compared in the study -forwarding with a John Deere 1110D ECO III forwarder, equipped either with an accumulating grapple (first method) or a standard grapple (second method). According to the study results the use of the standard grapple results in slight increase of productivity (2.3 % per load and 1.4 % per m 3 of logs). The difference is not significant, however additional trials are recommended to compare both grapples in more fertile forest stands with a larger number of assortments and extracted volumes, also in regenerative felling. According to the study results the prime forwarding cost is 9.4 EUR m -³, if the standard grapple is used and 9.5 EUR m -³, if the accumulating grapple is used. The difference is not significant. No significant difference is found between the methods also in terms of damages to the remaining trees.Keywords: forwarding, accumulating grapple, productivity, thinning. IntroductionProductivity and cost of forwarding, as well as damages to remaining trees are affected by several factors. Productivity of forwarding is influenced by the types and number of assortments, dimensions of extracted trees, extracted volume, forwarding distance and the machine utilized in the operation. The size and shape of grapple is one of the factors affecting the productivity [1]. Theoretically productivity can be improved by use of grapples, which can load different types of assortments per crane cycle, just like accumulating felling heads can handle several stems simultaneously. According to the results of a study carried out in Canada, productivity of a forwarder ranges from 7.9 to 17.0 m 3 per productive work hour [2]. In trials conducted in Sweden in 2014, focusing on productivity and fuel consumption, the standard grapple was equipped with an additional grip. It was found that additional grips do not affect fuel consumption during forwarding. Productivity in this trial increased by 5-8 %, when the accumulating grapple was used. The productivity was mainly influenced by the operator skills and their ability to use the advantages of the accumulating grapple [3].One of the most important factors influencing productivity of forwarding is the size of the assortment bundle gripped per working cycle. In the study conducted in Sweden the gripped assortment bundle is larger by 15 %, when the standard grapple is used. Assuming that the grip can load 0.2 m³ of logs per crane cycle, it is estimated that the accumulating grapple theoretically can load 0.38 m 3 of logs per crane cycle. Studies so far approve that use of the accumulating grapple increases productivity of forwarding by 1 %, which is considerably less than theoretical improvement of the forw...

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confidence: 96%

Comparison of productivity of standard and accumulating forwarder grapple in thinning

Petaja

Kaleja

Zimelis

et al. 2018

Engineering for Rural Development

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“…In the case of the small forwarder, the operation examined involved hauling whole trees for energy purpose in the aftermath of mechanized felling for thinning (Laitila et al 2007). Conversely, in the case of the medium sized forwarder, the operation of interest was the hauling of pulpwood during thinning (Nurminen et al 2006). These two publications were analyzed carefully to obtain accurate descriptions of parameters relating to the machine and the environment, such as the grapple area or the mean pile size in the loading phase.…”

Section: Methodsmentioning

confidence: 99%

“…Even productivity models based on relatively small data sets may include several independent variables (e.g. Nurminen et al 2006). However, forwarders are constantly being used with new assortments and in new working environments, so it can be challenging to accurately predict forwarder productivity in advance (cf.…”

Section: Literature Reviewmentioning

confidence: 99%

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Application of a primarily deductive framework describing time consumption for hauling of logs to road-side

Sängstuvall¹,

Lämås²,

Nordfjell³

2012

Ann Oper Res

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Forest management planning decisions are often based on the forest owner's goals, which typically focus on economic criteria. Logging operation work productivity functions are used when costing forest operations. These functions affect the conclusions drawn during forest management analyses because different logging environments give rise to different harvesting costs. When evaluating new combinations of machines and environments, there is generally a shortage of field data on productivity that can be examined in advance. We applied a previously published deductive framework describing time consumption in forwarding to known environments, in which field studies on forwarding have been conducted and for which extensive data are available. We then adapted the deductive framework to better reproduce the results obtained in the time studies. The deductive framework accurately reproduced the observed forwarding productivities; on average, the adaptation process improved the accuracy of this reproduction. However, it may also have reduced the accuracy of individual predictions. We conclude that the deductive framework can be used as a basis for constructing work productivity functions for forest management analyses, and can serve as a foundation when constructing new productivity functions based on time study results to use when pricing forwarding.

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“…Generally, the crane work is the most time-consuming work element (Kellogg and Bettinger 1994;Nurminen et al 2006;Manner et al 2016b). Though, relative time consumption distribution between the work elements depends on extraction distance, assortment-specific log concentrations (expressed e.g.…”

Section: Introductionmentioning

confidence: 99%

Forwarder crane’s boom tip control system and beginner-level operators

Manner¹,

Gelin²,

Mörk³

et al. 2017

Silva Fenn.

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Highlights• Boom tip control (BTC) allows the operator to control boom tip movements directly, instead of controlling each movement separately to achieve the desired boom tip movement.• BTC eased boom control, so beginner-level operators using BTC achieved higher productivity than beginner-level operators using a conventional (reference) system. • There were no significant differences in the slopes of learning curves between the systems. AbstractThe forwarder loads processed wood and transports it to a landing. Productivity of forwarding could be improved by increasing driving speed, but difficult forest terrain limits this. According to current literature, crane work is the most time-consuming work element of forwarding, so improving crane work productivity is essential for improving forwarding productivity. One way to do this is through automation of recurrent boom movement patterns, or alternatively automation can be used to ease crane work. When using conventional boom control (CBC), the operator manually controls each of the independent boom joint movements and combines them to achieve a desired boom tip movement, but boom tip control (BTC) allows the operator to control boom tip movements directly. The objective of the present study was to examine whether BTC facilitates crane work and affects the slopes of learning curves for beginner-level forwarder operators. The study was carried out using a standardised test routine to evaluate effects of two fixed factors, system (levels: CBC, BTC) and point of time (four levels), on five dependent variables. Four of the five dependent variables measured ease of boom control and the fifth measured crane work productivity. The results showed that there were no significant differences in the slopes of learning curves between the systems but the BTC did increase crane work productivity and made boom control easier.

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Time consumption analysis of the mechanized cut-to-length harvesting system

Cited by 276 publications

References 15 publications

Comparison of productivity of standard and accumulating forwarder grapple in thinning

Comparison of productivity of standard and accumulating forwarder grapple in thinning

Application of a primarily deductive framework describing time consumption for hauling of logs to road-side

Forwarder crane’s boom tip control system and beginner-level operators

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