Pinus saw timber tree optimisation in South Africa: a comparison of mechanised tree optimisation (harvester/processor) versus current manual methods

Abstract

Both Cut to Length (CTL) and Full Tree/Tree Length (FT/TL) ground-based systems are used to harvest pine in South Africa. The fully mechanised CTL system is the most recently introduced system in South Africa. One of the reasons for the limited use of CTL harvesting systems in South Africa is the perceived inability of the harvesting head to accurately optimise tree lengths when the logs produced are high-value saw timber logs that have multiple specifications and lengths. The study showed that tree diameter, branch characteristics, and other defects such as forked trees had no significant effect on the ability of the harvester or processor to optimise tree lengths as accurately as currently used manual methods for both value and fibre recovery. The accuracy of the log lengths produced by the harvester was not influenced by the diameter of the trees.