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Zethraeus, Fredrik (2007) Inventering av röjningsobjekt från helikopter. Other thesis, SLU.

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In time with HolmenSkog district Egenskog Norrköping´s decreasing mountain of cleaning, the office started to look around for new alternative cleaning strategies to lower the costs connected with cleaning. One option was to make the inventory strategy more effective and after a phonecall with the head of the district, Jonnie Friberg, the planning started to try inventory in pictures taken from a helicopter. The pictures was at last taken from a digtal camera and the vegetationheight was mesured with a laser. The gear was supplied from Kallax Flyg AB, Luleå. In the trial 15 stands was selected depended on age and different mixtures between pine (Pinus sylvestris), spruce (Picea abies) and birch (Betula pubescense and Betula pendula). Eatch pictures was about 300 – 400 m2 and was divided in to nine equal squares with the aerial discription in m2. The vegetationheight was mesured in profiles. The result showed that no systematic deflection was found if the total number of stems was <6000 st/ha. To get the standard error (SE) from the pictures to be comparable with the traditional method used for inventery, we needed 6-10 pictures for each stand depending on the area. The SE for vegetationheight was between 0,1 to 0,8 m and for the traditional method 0,1 to 1,2 m. In the pictures three of the nine squares was counted, and it was an acceptable accuracy. So in this studie the costs for the helicopter method was 110 SEK ha-1, and for the traditional method 155 SEK ha-1.

Item Type: Thesis (Other)
Keywords: Röjning, inventering, helikopter, bildtolkning, laser, digitalt
Subject (faculty): Faculty of Forest Sciences > Southern Swedish Forest Research Centre
Divisions: SLU > Faculty of Forest Sciences
Depositing User: Fredrik Zethraeus
Date Deposited: 13 Jun 2007
Last Modified: 18 Aug 2015 09:51
URI: http://ex-epsilon.slu.se/id/eprint/1726

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