Economic value of optical and X-ray CT scanning in bucking of Scots pine

In the Nordic countries, trees are typically bucked into logs using harvesters that measure only a two-dimensional diameter profile of the stem. Because the value of a log can vary significantly depending on its shape and internal defects, bucking decisions can in principle be improved by optical scanning of the three-dimensional stem shape, and detection of knots and other features inside the stem by X-ray computed tomography (CT). The objective of this study was to quantify how much the value recovery at a sawmill could be increased, if bucking decisions took advantage of additional measurement data and a sawing simulator to estimate log values. A simulation study on 1582 Scots pine stems was performed to compare bucking based on a two-dimensional diameter profile with bucking that maximises log value based on either optical scanning alone, or both optical and CT scanning. For log positioning, both the traditional ?horns-down? position, and value-maximising rotation based on CT scanning were considered. The results show that bucking based on optical scanning alone can potentially increase the value of sawn timber by up to 5%, and CT scanning before bucking provides little additional value for a sawmill using a CT scanner to optimise log rotation.

Automated summary

The study aimed to quantify the impact of optical scanning and CT scanning on increasing the value of sawn timber, with results showing that optical scanning can potentially increase the value of sawn timber by up to 5%, while CT scanning provides little additional value in optimizing log rotation.