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Jansson, Lisa (2009) Sorterar skotaren bort det timmer som skördaren har tillrett? Other thesis, SLU.

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The efficiency of the harvesters work is more often reviewed, than the work of the forwarders. In a local Stora Enso office the differences between the harvesters reported volume of timber, and the actual volume delivered to the industry had been noticed. Therefore, the decision was made to do a review on the forwarders work. The review was conducted together with a worker from Vmf Qbera, who is working daily with wood measurement, in order to get a valid evaluation of the logs. Eight sites were included in the survey, and on each site 50 logs were marked. Approximately one third of the marked logs were pulpwood, and the remaining logs marked were timber. The sites had been harvested by three different entrepreneurs. At every site between 46 and 49 of the marked logs were found. There can be different reasons to why not all the logs were found. One likely reason is that the marked logs had been used as coasters for the piles, or that the numbers had been erased by weather and wind. There is also a possibility that the missing logs had been left on the site. Possible source of error can be that the forwarder operators paid the marked logs some extra attention. They claimed afterwards that that was not the case. The marked logs were evaluated from what was visible. The possibility therefore exists that the logs contained hidden errors, which could have been detected by the forwarder operator. The forwarder operator would in that case have done the right thing, but it would have been noticed as wrong in the review. The total amount of timber, compared to the wood measurement workers evaluation was 95 %. This amount can only be more than 100 % if a lot of pulpwood is placed in the timber-pile. The three different entrepreneurs in the review are also very equal when it comes to the amount of extracted timber, compared to the wood measurement workers evaluation. The complete result for how much timber that is actually put in the pulpwood is 1,6 %. Beyond that, 3,6 % of the marked volume was not found. Some of the lost logs have probably been put in the wrong piles, but it can not be proven. It is an acceptable outcome which implies, that the cause from which less timber is delivered to the industry, is not the fault of the forwarder operators. The reason for why less timber is delivered to the industry can depend on multiple causes. One reason can be the way the harvester lay the logs out during the harvesting operation. This substantially affects the work of the forwarder. Therefore, a similar review of the harvesters work would be interesting to conduct. One of the entrepreneurs differs when it comes to a comparison between how much pulpwood has been put in the timber. This entrepreneur has a proportion of 7 4 % pulpwood put in the timber while the other two has a proportion below 1 %. The entrepreneur with the high proportion is probably too tolerant in their evaluation of timber. Stora Enso accepts a proportion of refused logs of 2,5 %. This implies that the two entrepreneurs that have a proportion below 1 % are too harsh in their evaluation of timber. In theory, they should be able to increase their timber proportion and still have an acceptable proportion of refused logs. One of the entrepreneurs was marking logs with colour which would imply an easier way to work, for the forwarder operator. No clear differences between the entrepreneur using colour marking, and the other not using it could be seen. But in order to be able to prove that this is really the case, a more comprising review with more sites has to be conducted.

Item Type: Thesis (Other)
Keywords: Timmersortering, skoteruppföljning, timmerfortfall
Subject (faculty): Faculty of Veterinary Medicine and Animal Science > School for Forest Engineers
Divisions: SLU > Faculty of Forest Sciences
Depositing User: Gina Parkatti
Date Deposited: 23 Mar 2009
Last Modified: 18 Aug 2015 10:13
URI: http://ex-epsilon.slu.se/id/eprint/3196

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