Publikasjoner
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1994
Sammendrag
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Forfattere
Tord K. RindalSammendrag
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Forfattere
Halvor SolheimSammendrag
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Forfattere
Øystein Dale J. StammSammendrag
The goal of the project was to collect technical data for selective harvesting operations. The main emphasis was on areas which had not earlier been studied, and in which there were a lack in knowledge. Gross operational statistics from 6 harvesters and 3 forwarders were collected throughout a period of 50 working days. This material is used as a reference representing ordinary harvesting operations. A model study of a forest estate in the Gardermoen area practicing selective harvesting was made. The main goal of the study was to see how much longer it took to administrate the selective harvesting compared to the reference material. A comparison between the motor-manual and the mechanized working methods was also made. Studies of gross operational statistics at Gardermoen showed that the portion of total working time used for planning increased from 2 % to 10 % for harvesters in the reference material and selective harvesting operations, respectively. The equivalent numbers for forwarders was 2 % and 4 %. The main reasons for the differences between harvesters and forwarders is that operational planning is normally done by the harvester operator. The differences in the portion of time required for planning were small between mechanized and motor-manual working methods in single-tree selection and small clear-cuts (1-2 daa). On the other hand, harvesters used 6 times the proportion of time for planning of group selection ( 1 daa) than that of motor-manual cutters. From the reference material and the sampled gross operational statistics from the Gardermoen study, we have worked out a system for estimating time consumption for moving forestry machines. A practical consequence of selective harvesting may be the division of harvested volume into smaller operational units and, therefore, more frequent moves between operational units.Moving forestry equipment by means of car transport: Y = 0.85 (X/32.5) Y = Time consumption in hours X = Moving distance in kilometres Moving forestry equipment by itselves along roads: Y = 0.41 (X/10.6) Y = Time consumption in hours X = Moving distance in kilometres In the Sessvollmoen area a study of harvester production in a pine shelterwood was made. The production of a two-grip harvester for cutting in a pine shelterwood can be described with the following function: Y= 14.819 8948 * (X*X) 0.356 * T Y = Production in m3 ob. per effective hour (E0) X = Average tree size (m3 ob.) T = Number of trees harvested per daa The production for mechanized cutting of windthrown trees will be reduced by 60-70 % compared with ordinary clear-cutting. Knowledge from other experiments shows that the frequency of wind thrown trees can be a considerable problem in shelterwoods. In the Rakkestad area we saw how the production of a forwarder varied with different levels of volume removal. The time consumption for forwarding in selection harvesting can be described as Y = ((0.0124*Rb0.0131*Lb0.017*Rt0.021*Lt)/Lv) 2.72 - 0.0166 * Ut Y = minutes per m3ob (E0) Rb = Return distance on base or strip road (m) Lb = Driving distance on the base or strip road while loaded (m) Rt = Return distance in the terrain (m) Lt = Driving distance in the terrain while loaded (m) Lv = Volume per load (m3 ob.) Ut = Volume removal in m3/daa (ob.)
Forfattere
Øystein Johnsen Ola Gram Dæhlen Gunnar Haug B.S. Grønstand Anne Tove RognstadSammendrag
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Forfattere
Richard Horntvedt Bernt-Håvard ØyenSammendrag
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Forfattere
Dan AamlidSammendrag
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Forfattere
Kjell AndreassenSammendrag
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Forfattere
Bjørn TveiteSammendrag
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Forfattere
Halvor SolheimSammendrag
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