The visual grading system for Scots pine logs in relation to the quality of sideboards produced

• Presorting logs in the sawmill's log yard is one of the strategies used by the Swedish sawmilling industry in order to maximize profits. Almost 96 percent of Swedish sawmills perform the presorting of logs according to their dimension, most commonly by the top diameter. Only a very small number of sawmills use log grade information as a sorting criterion. However, the grade information at individual log level, together with the estimated volume, is always used for the calculation of log payment. The quality assessment of the log is done on a visual basis, i.e., the measurer grades the log on what he/she sees on the outside of the log. This judging should correspond to the expected quality of the Centerboards produced after sawing. Current studies have only related the centerboards' quality to the log quality grade arrived at by visual inspection. In view of the economic importance of the sideboards in the lumber yield and in the entire functioning of a sawmill, a real need for information on the recovery of sideboards in relation to log and centerboard quality is now arising and becoming a key issue. In this study, with the help of the entire Swedish Pine Stem Bank material, the relationship between the sideboard's quality and the log's quality and the relationship between the quality of sideboards and of centerboards were studied. Results show that sideboard quality cannot be predicted from the visual quality assessment of the logs. Nevertheless, fairly good correlation exists between sideboard quality and the quality of the corresponding centerboards. A financial analysis focusing on the relationship between the commercial values of the sawlogs and the corresponding lumber output for the Swedish Pine Stem Bank material is also included in this study. The study shows that the actual Swedish log pricing system should be improved because the commercial values of the logs are not in accord with the real values of the lumber produced.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Annan maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Other Mechanical Engineering (hsv//eng)

Nyckelord

Träteknik

Wood Technology

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