Three semi-mechanised and one mechanised system were examined, with the focus on tree size, form and bark adhesion.
The title of the research was “Acacia mearnsii debarking: Comparing the productivity and costs of different debarking machines and systems in the KwaZulu-Natal and Mpumalanga forestry regions of South Africa”, and the publication appeared as ICFR Bulletin 08/2011. The authors were A McEwan, J Eggers and M Ramantswana. The research examined systems containing a Demuth DDM 420 mobile ring debarker, Hyena MK3 debarking head, Hypro 765 tractor mounted debarker and a harvester (Hitachi excavator with a SP 591LX harvesting head).
The systems needed to be able to produce pulpwood logs, and the bark removed needed to be used by bark processing mills. The factors affecting machine productivity that were quantified were tree volume, form and bark adhesion to the stem. Productivity levels of the various machines were determined, and based on this, system costs were calculated. The Hyena debarking head was the most productive machine across all tree sizes studied, followed by the Demuth and harvester which had similar productivity levels, and the lowest productivity was from the Hypro. Cost comparisons included a system where manual debarking took place.
When the bark was utilised, the Demuth system had the lowest system costs in tree sizes of 0.1m3, while the manual system had the lowest cost in tree sizes of 0.15m3 and 0.2m3. When bark was discarded infield, the harvester had the lowest cost in tree sizes of 0.10m3, but once again the manual system had the lowest costs in tree sizes of 0.15m3 and 0.20m3.
Please access the bulletin for a more complete account of the research.
Source: http://www.icfr.ukzn.ac.za/collaboration/forest-engineering-southern-africa/fesa-publications/
The title of the research was “Acacia mearnsii debarking: Comparing the productivity and costs of different debarking machines and systems in the KwaZulu-Natal and Mpumalanga forestry regions of South Africa”, and the publication appeared as ICFR Bulletin 08/2011. The authors were A McEwan, J Eggers and M Ramantswana. The research examined systems containing a Demuth DDM 420 mobile ring debarker, Hyena MK3 debarking head, Hypro 765 tractor mounted debarker and a harvester (Hitachi excavator with a SP 591LX harvesting head).
The systems needed to be able to produce pulpwood logs, and the bark removed needed to be used by bark processing mills. The factors affecting machine productivity that were quantified were tree volume, form and bark adhesion to the stem. Productivity levels of the various machines were determined, and based on this, system costs were calculated. The Hyena debarking head was the most productive machine across all tree sizes studied, followed by the Demuth and harvester which had similar productivity levels, and the lowest productivity was from the Hypro. Cost comparisons included a system where manual debarking took place.
When the bark was utilised, the Demuth system had the lowest system costs in tree sizes of 0.1m3, while the manual system had the lowest cost in tree sizes of 0.15m3 and 0.2m3. When bark was discarded infield, the harvester had the lowest cost in tree sizes of 0.10m3, but once again the manual system had the lowest costs in tree sizes of 0.15m3 and 0.20m3.
Please access the bulletin for a more complete account of the research.
Source: http://www.icfr.ukzn.ac.za/collaboration/forest-engineering-southern-africa/fesa-publications/