Browsing by Author "Terblanche, Marius"

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    Unlocking the potential of harvester on-board-computer data in the South African forestry value chain
    (Stellenbosch : Stellenbosch University, 2019-12) Terblanche, Marius; Ackerman, P. A.; Ackerman, Simon; Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science.
    ENGLISH ABSTRACT: The South African forest industry is in a state of change from motor-manual to fully mechanised harvesting systems. This is predominately driven by health and safety concerns related to motor-manual harvesting systems, and the need to enhance systems productivity and product quality.Through the use of technologically advanced harvesting machinery with on-board computing systems, and standardised and compatible data collection software, all mechanised processing operations are able to produce real-time (time-stamped) data related to almost every action or function of the machine. The software referred to above is the Standard for Forest Communication (StanForD) first developed by Skogforsk in 1987, as a standard for managing the information flow from the forest machines through the value chain.Although most machines in South Africa are compatible with the StanForD systems, the usefulness of the concept remains under-utilised due to limited understanding of the interface between harvester heads and the computing systems. This includes validating the integrity and accuracy of the data emanating from the system, and that is firmly embedded in quality assurance and computer calibration. The objective of this study is to propose and develop an applicable bark deduction method for Pinuspatula in the Mpumalanga Highveld region of South Africa for more precise log volume calculations. This was accomplished by modelling historical P. patulabark thickness data from the Mpumalanga Highveld region to obtain bark thickness estimates for the two methods of bark deduction to be assessed that are available on the Ponsse Opti OBC system. Three trials were run: T1 (status quo no bark deduction function), T2 (length-based [LB] bark deduction method) and T3 (diameter-class length-based [DLB] bark deduction method). The two bark deduction methods were implemented successfully, and the harvester`s under bark (UB) diameter measurements compared well with manual measured UB diameter measurements which was derived through the novel application of photogrammetry technology. Results showed that if no bark deduction method is used the harvester over-estimates stem volume by 13.7% and 14.6% for each of two respective bark deduction methods. Furthermore, by the nature of P. patula bark being extremely thick at the base of the tree stem, means this over-estimation is even greater for butt logs. The harvester over-iv estimated the log volume of the first plywood log cut by 20.8% for T1, where through the implementation of a bark deduction method the volume estimation was improved to an under-estimation of only 1.6% and 0.2% for T2 and T3 respectively. The results of this study show that by not implementing bark deduction methods the harvester`s log volume estimations are grossly over-estimated and the usefulness of theharvester`s data for value chain management is lost.