Sequencing of harvester work during standard cuttings and in areas with windbreaks

Abstract

(2014). Sequencing of harvester work during standard cuttings and in areas with windbreaks. Silva Fennica vol. 48 no. 4 article id 1159. 16 p. Highlights• In standard cutting stands and thinning areas with windbreaks there occurred three-activity operational cycles. In mature stands with windbreaks the occurrence of stable sequences supplemented with five-activity cycles was noted. Consequently, the operational time in post-disaster thinning stands should be increased by 55% whereas in mature stands it should be 30% longer in comparison with standard stands. AbstractThe aim of the study was to characterize repetitive cycles of harvester operation. The study was conducted in thinning, mature and post-disaster pine stands. The sequences of the activities characteristic of harvester operation were described as time series. In order to detect the cyclic variable structure of the analysed time series, the methodology of the single spectrum Fourier analysis was applied. In standard stands, post-disaster late-thinning stands and mature stands, the existence of stable operational cycles with the length of three activities was discovered while in post-disaster mature stands additional five-activity operational phases were noted. Described in this way, the lengths of the operational cycles of harvesters working in post-disaster areas were higher by about 55% and 30% respectively, as compared to standard thinning and mature stands.

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

“…In the study by Szewczyk et al [35], in the mature post-disaster stands, the share of moving time averaged 19% of the total effective time, and it was higher by almost 100% than in normal stands of undamaged standing trees. The share of moving time was, on average, 18% of the total effective time consumption in the clear-cutting stands of windfalls in this study.…”

“…For instance, Szewczyk et al [35] reported that the duration of a harvester operation cycle in stands with windbreaks is 28% longer in mature stands in comparison with normal forest stands. Kim et al [79] studied the effect of downed trees on harvesting productivity in beetle-killed stands.…”

The accuracy of measurements in a time study of harvester operations

“…For such data, a cyclicality of its occurrence can be determined, which was used in the study presented here. Having obtained a time series with the use of a moving average (equal weights), the single-band Fourier analysis was employed to detect a variable cyclical structure of the time series under investigation (Szewczyk et al 2014). With regard to the snap-back timing PSION calculation method, the duration of a work cycle was determined for regular, five-activity cycles.…”

“…Simultaneously, the DOD LS 430W video camera (DODTech, ON, Canada) mounted in the operator's cabin recorded the same work cycles. The duration of different activities in the work cycle was recorded to the nearest second (PSION method) or 0.1 s. (VIDEO method) and then classified according to the International Union of Forest Research Organisations (IUFRO) standards regarding forest work study nomenclature (Björheden 1991;IUFRO 1995;Szewczyk et al 2014) (Table 2). …”

“…A time study is the most common manner of measuring work time at worksites in forestry. Accurate measurements of work times are particularly important in complex, variable production processes, which are typical of timber harvesting and extraction (Palmroth 2011;Szewczyk 2011a;Szewczyk and Stańczykiewicz 2012;Szewczyk et al 2014).…”