Current issue: 53(2)

Under compilation: 53(3)

Impact factor 1.683
5-year impact factor 1.950
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'terrain classification'.

Category: Article

article id 4890, category Article
Rihko Haarlaa. (1973). Maaston vaikutuksesta metsäteiden rakennukseen. Silva Fennica vol. 7 no. 4 article id 4890. https://doi.org/10.14214/sf.a14728
English title: Effect of terrain on forest road construction.

As a subproblem in the joint Nordic Terrain-Machine Project the requirements set by forest road construction on the terrain classifications were studied during the summer 1973 in ten operations, in which either a bulldozer or an excavator method was used.

The most important terrain factors of the ground factors affecting the construction time of the road base were the so-called depth index and the moisture content of the soil, and in addition to these the amount of stumps as a ground roughness factor. These variables explained, however, only a rather minor part of the wide variation in the construction output of the practical operations.

The PDF includes a summary in English.

  • Haarlaa, ORCID ID:E-mail:
article id 4843, category Article
Unto Silvennoinen, Rihko Haarlaa. (1971). Metsätraktoreiden liikkuvuus lumessa. Silva Fennica vol. 5 no. 2 article id 4843. https://doi.org/10.14214/sf.a14645
English title: The mobility of logging tractors on snow.

The mobility of logging tractors was tested in the winter 1969 on difficult snow conditions to gather information for planning of logging operations and for logging machinery design. The tractors tested were Clark Ranger 666, Timberjack C, Valmet Terra, Ford Brunett 5000, Fiskars 510, BM-Volvo SM 660, BM Volvo SM 661, Ford Country 6, MF-Robur I and BM-Boxer T-350.

According to the results, there is a preference of tracked vehicles in difficult snow conditions compared to wheeled tractors. Ford Country with long and bearing full-tracks proved to have the best mobility. On downhill grades it was found significant differences between three-quarter-track-tractors and skidders, although the performance on level ground and uphill grades was relatively similar. The tracked vehicles can easier move on the packed snow layer and reach a higher speed.

The driving speed does not increase significantly until the density of snow has entirely changed through getting wet. Wet top layer of snow affects positively on driving, because it increases packing of the snow. Increasing density of the snow improves especially the mobility of broad-tired wheeled tractors. To be able to predict the driving speed of a tractor in winter working conditions one must know the depth of the snow layer and the density of the snow and the grade of the slope. In addition, the passages on the same route and the packing of the snow must be regarded.

The PDF includes a summary in English.

  • Silvennoinen, ORCID ID:E-mail:
  • Haarlaa, ORCID ID:E-mail:
article id 7598, category Article
T. Eriksson, G. Nilsson, G. Skråmo. (1978). The Inter-Nordic project of terrain and machines 1972-1975. Acta Forestalia Fennica no. 164 article id 7598. https://doi.org/10.14214/aff.7598

The paper is the final report of the Inter-Nordic Terrain-machine Project (1972–1975). It deals with the requirements for a terrain classification for forestry, its factors and classes, and presents a terrain classification.

The mechanization of hauling, which took place in the field of forestry in the 1950's, added to the need for a terrain classification. Different terrain classifications based on different terrain factors have been developed in many countries. In the meeting of IUFRO Section 32 held in Montreal in 1964, it was found that a general system was needed for measuring and describing those terrain conditions having a significant influence on forest operations. The requirements for such a classification system are given in the paper. Because some of the requirements are contradictory, the classification must be a compromise. The most important factors from the forestry point of view are presented in the article.

The terrain classification presented in this report consists of two stages. The first stage is a primary terrain classification, in which terrain factors are measured or described objectively. The second is a secondary descriptive classification. Only factors essential to the activity in question are taken into account. After this, in a secondary functional stage, the requirements of the employer of the system, e.g., working method, machines etc., are also taken into account.

The PDF includes a summary in Finnish.

  • Eriksson, ORCID ID:E-mail:
  • Nilsson, ORCID ID:E-mail:
  • Skråmo, ORCID ID:E-mail:

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