Slope effect on costs and productivity of single-grip purpose-built and excavator based harvesters

Martin, Chad Jay (2016-12)

Thesis (MScFor)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: In this study a mechanised Eucalyptus pulpwood cut-to-length harvesting operation comprising felling, debarking, debranching and cross cutting of assortments, was observed using time studies to determine the effect of slope on harvester productivity and cost of wood production. Time studies and data analysis was done according to the South African Forestry time study standard and machine costs according to the South African Harvesting and Transport Costing Model. Two different types of harvesting machines were studied; an excavator based machine, Volvo EC210BF, and a purpose built levelling machine, TimberPro TL725B, both fitted with Maskiner SP 591 LX harvester heads. A single operator with significant experience and training on both machines was used throughout the duration of the study. The machines were observed harvesting on a range of slopes, from level to 50% in two separate work corridors with relatively similar trees in terms of individual tree volume and form. The species studied was a Eucalyptus grandis x camaldulensis clone. Continuous slope data, as opposed to slope categories, for each position at which the harvesters would position themselves to undertake harvesting and processing, was derived using large footprint LiDAR data of the area. The purpose built harvester was levelling enabled as opposed to the Volvo which was not. Apart from differences in mass, the Volvo was not modified for forestry work and the booms were on different sides of the particular machine. Cost calculations were carried out on each machine to determine which machine was more cost effective. The study design was a 2 x 2 factorial design with two treatments (machine type) against slope and individual tree volume as factors. The results indicate that the productivity of the excavator based machine decreased by 0.048m3.PMH-1 for every 1% increase in slope. The purpose built machine was not significantly affected by slope in this study and maintained an average productivity regardless of extreme slope. The purposed built machine was found to have a higher mean productivity (16.24 m3.PMH-1) than the excavator based machine (13.00 m3.PMH-1), but this extra productivity came at a price, as the excavator based machine was more economical per cubic metre. The mean harvest cost for the purpose built machine was found to be R122.67.m-3 whilst the excavator based machine achieved a mean cost of R94.46.m-3.

AFRIKAANSE OPSOMMING: In hierdie studie 'n gemeganiseerde Eucalyptus pulphout cut-to-lengte oes werking bestaande afkap, ontschorsing, debranching en kruis sny van ruimtes, is waargeneem met behulp van tyd studies aan die effek van helling op stroper produktiwiteit en koste van hout produksie te bepaal. Tyd studies en data-ontleding is gedoen volgens die Suid-Afrikaanse Bosboumaatskappy tyd studie standaard en masjien koste volgens die Suid-Afrikaanse oes en vervoer kosteringsmodel. Twee verskillende tipes snymasjiene bestudeer; 'n graaf gebaseer masjien, Volvo EC210BF, en 'n doelgeboude nivellering masjien, TimberPro TL725B, toegerus met Maskiner SP 591 LX stroper koppe. 'N Enkele operateur met 'n groot ervaring en opleiding op beide masjiene gebruik regdeur die duur van die studie. Die masjiene is waargeneem oes op 'n verskeidenheid van hange van vlak tot 50% in twee afsonderlike werk gange met 'n relatief soortgelyke bome in terme van individuele boom volume en vorm. Die spesie bestudeer was 'n Eucalyptus grandis x camaldulensis kloon. Deurlopende helling data, in teenstelling met helling kategorieë, vir elke posisie waarteen die stropers self sal posisioneer om die oes en verwerking onderneem, is afgelei met behulp van groot voetspoor LiDAR data van die gebied. Die doel gebou stroper is nivellering aktief, want in teenstelling met die Volvo wat nie was. Afgesien van verskille in massa, is die Volvo nie aangepas is vir bosbou werk en die valbome was op verskillende kante van die spesifieke masjien. Kosteberekeninge is uit op elke masjien om te bepaal watter masjien meer kostedoeltreffend was gedra. Die studie ontwerp was 'n 2 x 2 faktoriale ontwerp met twee behandelings (tipe masjien) teen helling en individuele volume boom as faktore. Die resultate dui daarop dat die produktiwiteit van die graaf gebaseer masjien het met 0.048m3.PMH-1 vir elke 1% -verhoging in helling. Die doel gebou masjien is nie beduidend beïnvloed deur helling in hierdie studie en 'n gemiddelde produktiwiteit ongeag uiterste helling gehandhaaf. Die voorgeneem gebou masjien is gevind dat 'n hoër gemiddelde produktiwiteit het (16.24 m3.PMH-1) as die graaf gebaseer masjien (13.00 m3.PMH-1), maar dit ekstra produktiwiteit het teen 'n prys, as die graaf gebaseer masjien meer was ekonomiese per kubieke meter. Die gemiddelde koste oes vir die doel gebou masjien gevind om R122.67.m-3 wees terwyl die graaf gebaseer masjien 'n gemiddelde koste van R94.46.m-3 behaal.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100446
This item appears in the following collections: