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Jämförelser mellan metoder för fastvolymbestämning av stockar

Björklund, Lars and Hesselman, Jonas and Lundgren, Christina and Nylinder, Mats (2009). Jämförelser mellan metoder för fastvolymbestämning av stockar. Uppsala: (S) > Dept. of Forest Products, Sveriges lantbruksuniversitet. Rapport (SLU, Institutionen för skogens produkter) ; 15
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Abstract

In 2008 a new method for automatic measurement of solid volume under bark (m3sub) of sawlogs was introduced in southern Sweden. In this method the diameters at 10 cm intervals are used, thus producing a section-wise volume (m3sub-sw). The scanners used are programmed to leave out bumps and indents when diameters are calculated. The objective of the study was to compare this method with two other methods used on the Swedish wood market; a) volume based on top and butt end diameters (m3sub-tb) and b) volume based on top end diameters and conversion factors to solid volume (m3sub-cf). The conversion factors are arranged as a matrix based on diameter and length of the logs. Volume m3sub-tb is the most widely used method for measuring m3sub in Sweden. M3sub-cf is partly used for payment but more widely for planning purposes, for example when the logs are priced as a cylinder volume based on top end diameter.

The study was performed on spruce (Picea abies). The three different volume estimates as well as the diameters obtained from the log scanners were evaluated on 435 manually measured control logs from five different mills. For an additional 180 000 automatically measured logs from four of the sawmills the m3sub-sw and m3sub-cf volume estimates were compared.

The results showed only minor differences between the methods. The volume m3sub-sw was, for the 180 000 logs, 0.6 % greater than the volume m3sub-cf. The analysis of the matrix for conversion factors showed that, if the matrix was to be revised, this should be done as slightly increased factors for small diameter logs and for big diameter logs. However, it was concluded that it would mean less implications for the wood market if the section-wise volume could be reduced to make this volume equal to m3sub-tb and m3sub-cf. This to achieve that all three methods, given a sufficient number of representative logs, would give the same volume

Authors/Creators:Björklund, Lars and Hesselman, Jonas and Lundgren, Christina and Nylinder, Mats
Title:Jämförelser mellan metoder för fastvolymbestämning av stockar
Series/Journal:Rapport (SLU, Institutionen för skogens produkter) (1654-1383)
Year of publishing :2009
Depositing date:7 September 2017
Number:15
Number of Pages:54
Place of Publication:Uppsala
Publisher:Department of Forest Products, Swedish University of Agricultural Sciences
ISSN:1654-1383
Language:Swedish
Publication Type:Report
Article category:Other scientific
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
K Forestry > K50 Processing of forest products
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:forest mensuration, wood, Picea abies, sawlogs, timber trees, bark, timber structure, measuring instruments, measurement
Keywords:Virkesmätning, mätramar, automatisk, sågtimmer, volym-mätning, sektionsmätning, topprotmätning, toppformtalsmatris
URN:NBN:urn:nbn:se:slu:epsilon-e-4337
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-4337
ID Code:14080
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Products
Deposited By: SLUpub Connector
Deposited On:07 Sep 2017 12:41
Metadata Last Modified:07 Sep 2017 12:41

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