The effects of increased mechanization on time consumption in small-scale firewood processing

Abstract

Firewood, which is mainly processed by the consumer, is still an important source of energy for heating houses in industrialised countries. Possibilities to compare the mechanization's impact on efficiency of firewood processing are limited, due to variations between working conditions in previous studies. Therefore, the objective was to compare time consumption for two small-scale firewood processing systems with different levels of mechanisation under identical conditions. The systems were tested on two classes of wood: one with a homogeneous and medium-sized diameter of logs and one with a mixture of small and largediameter-logs. Differences in time consumption were analysed for correlations with physical workloads, deviations to routine operations, operator influences and operator perceptions. Twelve operators (60-79 years old) were studied and they showed large variation in time consumption. However, the within-operator time consumption patterns were consistent. In other words, operators all responded similarly to the different combinations of systems and wood classes, but at different absolute levels. The time required to process a unit volume of wood was 25-33% lower when the more highly mechanised system was used, and the time required was 13-22% lower for the homogeneous wood class. Physical work load, deviations and perceptions of the work varied between operators, but were weakly correlated with time consumption. The results' implications for analyses of investments in equipment for firewood-processing for self-sufficiency purposes are discussed.

Applicability of International Harvesting Equipment Productivity Studies in Maine, USA: A Literature Review

“…Lindroos [44] investigated the differences between operators in terms of their effect on time consumption. The result of this study was that there were no significant interactions between operator and machine or wood class.…”

“…His conclusion is that in order to justify the normalization or correction of data the total unexplained variation must be significant. This once more suggests using the approach of Lindroos [44] and Brown et al [36] to leave the analysis of individual performance and analyze data of multiple experienced operators on the population level.…”

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

“…Hence, a particular activity can be performed several times with different settings, since the piece of work is not affected. Furthermore, a simulation approach eliminates variations in results due to uncontrollable factors, such as operator effects (Lindroos, 2008) and fluctuations in weather conditions. Rare work elements (non-cyclic) can also be excluded from the simulation model (Eliasson, 1999) as well as delays (Spinelli & Visser, 2008) of different kinds.…”

Relationships between observed and perceived deviations from normative work procedures

“…In total, 12 operators were randomly assigned to treatment orders and work days and were asked not to discuss the study with each other. Experimental settings relevant for the current paper are presented here, but more comprehensive details and productivity results are presented in Lindroos (2008).…”

“…In usability research terms the methodology used is similar to human error identification, but is more comprehensive in its error uptake since it also includes machine malfunctions. The relationship between deviations and final productivity (m 3 of processed wood) is described in Lindroos (2008).…”