The Analysis of Coniferous Logs Top Diameter Measurement Accuracy using Harvester and 3D Systems

Abstract

High productivity and more value-added production are the main strategies of the Latvian sawmills as sawing the appropriate products from each log have always been actual for each sawmill. The requirements of sawn timber specification have been used for the preparation of the round wood specification, where top diameters, maximum diameters, and length parameters have been determined. These parameters have been studied in a harvesting task where, for each top diameter group, the appropriate length dimensions were identified. Log recovery was organized by adjusting the cuts to each log according to sawn timber specifications. Therefore, almost all larger sawmills in Latvia are presorting the logs by the top diameter values divided into groups, often resulting in rejection or size reduction when the parameters measured by the sawmill’s 3D systems do not agree to the specifications. The goal of this study was to evaluate the effect of a harvester calibration system on the accuracy of coniferous logs' top diameter measurements (under bark) by measuring the diameters in short intervals using electronic 3D systems.