Current issue: 53(3)

Under compilation: 53(4)

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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles containing the keyword 'processor'.

Category: Research article

article id 227, category Research article
Ola Lindroos. (2008). The effects of increased mechanization on time consumption in small-scale firewood processing. Silva Fennica vol. 42 no. 5 article id 227. https://doi.org/10.14214/sf.227
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 large-diameter-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.
  • Lindroos, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@srh.slu.se (email)

Category: Article

article id 5304, category Article
Jimin Tan. (1987). A method to evaluate productivity of logging machines. Silva Fennica vol. 21 no. 1 article id 5304. https://doi.org/10.14214/sf.a15461

This study deals with the evaluation of logging machines. The analyses were based on the results of a productivity study with special reference to a PIKA 35 processor, a delimber-bucker, working in Kyröskoski forest area in Finland. Factors affecting the productivity of the machine were surveyed. Mathematical models for determining the productivity were developed and their practical applications to the particular problem under study was demonstrated.

The PDF includes an abstract in Finnish.

  • Tan, ORCID ID:E-mail:
article id 5179, category Article
Pertti Harstela, Antti Maukkonen. (1983). Tavanomainen ja kuormainprosessori varttuneissa harvennusmetsiköissä. Silva Fennica vol. 17 no. 2 article id 5179. https://doi.org/10.14214/sf.a15095
English title: A conventional and grapple loader processor in second and third thinnings. A simulator experiment.

Using literature and a simulator experiment, an ordinary processor and a grapple loader processor were compared in conditions corresponding to thinning later than the first commercial thinning. Visual bucking only was employed in the simulator experiment. The strip road spacing was 30 m and there was no preliminary skidding of the trees. The simulator experiment confirmed the view reached in the literature that work productivity of the grappler loader processor is 20–40 % greater than that of an ordinary processor provided that the stem size is under 0.2–0.4 m3.

The PDF includes a summary in English.

  • Harstela, ORCID ID:E-mail:
  • Maukkonen, ORCID ID:E-mail:
article id 4874, category Article
Matti Kärkkäinen. (1973). Runkojen järeys puunkorjuun monitoimikoneiden ajanmenekin ennustamisessa. Silva Fennica vol. 7 no. 1 article id 4874. https://doi.org/10.14214/sf.a14704
English title: The size of stems in estimating the time consumption of processors.

The problem considered in this paper is how to analyse the usefulness of some average volume values of stems in predicting the average time consumption of some processors. In this connection, the usual arithmetic mean, the arithmetic mean weighted with volume and the geometric mean were used. The functions describing the dependence of time consumption per tree on the volume of the tree were obtained from previous studies, as were the stand properties.

The results were obtained with the aid of computer simulation techniques and the deterministic model described above. According to the results, the usual arithmetic mean is very applicable for predicting the time consumption. The geometric mean is nearly as good, or in some cases even better. However, as a rule its computation is much more tedious than that of the arithmetic average volume for the purpose.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:

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