Faculty of AgriSciences

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The Faculty of AgriSciences at Stellenbosch University (SU) is held in high esteem at national and international levels for the quality of its training and research and also as consultant in the agricultural and forestry industry.

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Browsing Faculty of AgriSciences by Author "Ackerman, Pierre Alexander"

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    An investigation into the shorthaul transport of pulpwood in South Africa
    (Stellenbosch : Stellenbosch University, 2001-12) Ackerman, Pierre Alexander; Pulkki, R. E.; Stellenbosch University. Faculty of Faculty of Agrisciences. Dept. of Forest and Wood Science.
    ENGLISH ABSTRACT: Ackerman PA. 2001. An Investigation into the Shorthaul Transport of Pulpwood in South Africa. M.Sc. in Forestry thesis. University of Stellenbosch. 178 pp Shorthaul transport also known as secondary intermediate transport (SIT), a unique feature of pulpwood transport in South Africa, is an additional transport phase within traditional secondary transport. SIT originates at a roadside landing or depot and terminates at another depot, rail siding or merchandising area (not the final destination). The reason for the addition of SIT into the transport chain is identified as the steady decline of forest road conditions to the extent that highway vehicles are unable to reach roadside landings, necessitating the use of intermediate storage sites, from where the timber is once again loaded and transported to final destination. An industry survey established that the decline of forest road conditions are related to excessively high road densities, insufficient funding for road maintenance/upgrading and the lack of understanding by landowners of the importance of maintaining forest road infrastructure. Total funding, by pulpwood companies on roads have shown an increase of R18.55 million from 1997 to 2000, however, subsequent surveys have indicated, that despite this increase in funding, the forest road conditions continue deteriorating. Of the total annual pulpwood intake of 9.39 million tonnes for 1998, 3.7 million tonnes are subject to SIT. Of this 3.7 million tonnes, 2.5 million tonnes are transported from stump to depot and 1.2 million tonnes are transported from landing to depot. The survey identified the agricultural tractor and semi-trailer as the most favoured transport system between stump or landing and depot, responsible for transporting 2.22 million tonnes annually. For 1998, manual loading and three wheel log loaders accounted for the loading of 0.6 and 2.1 million tonnes respectively of the 3.7 million tonnes subject to SIT. This survey information, assisted by newly developed terminology, was used to develop transport scenarios for the economic analysis of total cost of the different transport phases. A network analysis model and pixel-based geographic information system (GIS) were combined to analyse the various transport scenarios within three study areas in the KwaZulu/Natal Midlands, employing SIT on poor, high-density road networks. The simple pixel-based GIS contained information on the forest road network, surface cover and slopes. The results of the economic analysis highlighted the need for the reduction of road network density and for the improvement of the remaining network. This would eliminate the need for extended primary transport and allow the use of highway vehicles transporting from the compartment roadside to and past plantation exits. Results show an average annual cost penalty to the industry, by maintaining SIT, to be R43.25 million or R8.24/m3 . By not employing SIT the industry will potentially save R4.60 for every tonne of the 9.4 million tonnes consumed by the pulpwood processing plants during 1998. Key words: Network analysis. Pixel-based GIS. Timber transport. Secondary transport. Secondary intermediate transport. Secondary terminal transport. Extended primary transport. Primary transport. Dirichlet tessellations. Shorthaul. Note: Throughout this document a full stop (.) is used as a decimal separator.
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    Supply chain management to integrate strategic, tactical and operational planning of wood procurement in the Eastern Cape
    (Stellenbosch : Stellenbosch University, 2015-12) Ackerman, Pierre Alexander; Pulkki, R. E.; Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science.
    ENGLISH ABSTRACT: This study quantifies and models potential monetary gains and improved resource utilisation of a typical forest to mill softwood sawlog supply chain in South Africa through incremental improvements of the various stages of the wood procurement process, given road, silvicultural and management costs. The findings are based on the outcomes of four studies: fibre losses during the timber harvesting phase; establishing a primary transport wander ratio, travel speeds and operations efficiencies; predicting secondary transport travel speeds along with a study of current and potential efficiencies in softwood sawlog transport; and finally a supply chain management case study. Fibre loss analysed losses occurring in motor-manual and mechanised felling systems, in tree volume above and below 1 m3 , and merchandising at either roadside landing or centralised merchandising yard. Fibre volume losses were categorised according to stump wood, felling and crosscut saw kerfs, log trimming allowance, wood left in field, and excessive trimming and removal of utilisable wood. Total losses ranged from 6.7% and 9.9% of total utilisable volume with stumps generally felled 7 cm higher than necessary. Based on the volume of wood not recovered, the revenue lost was R393 million in board products and R166 million in roundwood supply from plantations annually. The second study found a wander ratio of 1:1.2. In terms of predicting travel speeds of primary transport, gross power rating (kW), payload size (m3 ), extraction distance (m) and slope (%) variables were included. Skidder payloads were found to be approximately 50% of potential design loads. Truck travel speed predictor variables included Visual Condition Index (VCI), road width, average gradient, percentage of maximum load and truck maximum power. Applying multivariate analysis the predictor variables were reduced to road width and percentage maximum load, and a multiple linear regression equation was produced with an adjusted r2 of 0.52. Analysis found that overloading of trucks was a common occurrence. The Case Study required the current forest road network to be repeatedly refined through road decommissioning and selected upgrades over which the timber resource is subsequently flowed to the processing plant. Based on sequentially improved truck speeds, skidder efficiency and fibre use the Net Present Value (NPV) of the various projects, production costs and available timber resource use were quantified. The supply chain was analysed by investigating the effect downstream efficiency improvements have on financial returns over one rotation. NPV results ranged from approximately R40 million to R300 million. The scenario associated with the highest NPV used the most improved road network, highest possible transport speed, and motor-manual felling, cable skidder extraction, merchandising yard and optimal skidder and transport performance. The lowest NPV yielding scenario is associated with an abridged road network, low secondary transport speed, cable skidder extraction, mechanised felling, roadside merchandising, and normal skidder and transport performance. Examination of the individual factors found that road network; secondary transport speeds and performance had a significant effect. Harvest system had no significant effect. A limitation of this study was that only the forest to mill supply chain was analysed. Extending the supply chain to the mill and onto the final customer the benefits to the entire chain are expected to increase further. This gap in knowledge is a likely follow-up study.
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    Supply chain management to integrate strategic, tactical and operational planning of wood procurement in the Eastern Cape
    (Stellenbosch : Stellenbosch University, 2015-12) Ackerman, Pierre Alexander; Pulkki, E.; Stellenbosch University. Faculty of AgriSciences. Dept. of Forest of Wood Science.
    ENGLISH ABSTRACT: study quantifies and models potential monetary gains and improved resource utilisation of a typical forest to mill softwood sawlog supply chain in South Africa through incremental improvements of the various stages of the wood procurement process, given road, silvicultural and management costs. The findings are based on the outcomes of four studies: fibre losses during the timber harvesting phase; establishing a primary transport wander ratio, travel speeds and operations efficiencies; predicting secondary transport travel speeds along with a study of current and potential efficiencies in softwood sawlog transport; and finally a supply chain management case study. Fibre loss analysed losses occurring in motor-manual and mechanised felling systems, in tree volume above and below 1 m3, and merchandising at either roadside landing or centralised merchandising yard. Fibre volume losses were categorised according to stump wood, felling and crosscut saw kerfs, log trimming allowance, wood left in field, and excessive trimming and removal of utilisable wood. Total losses ranged from 6.7% and 9.9% of total utilisable volume with stumps generally felled 7 cm higher than necessary. Based on the volume of wood not recovered, the revenue lost was R393 million in board products and R166 million in roundwood supply from plantations annually. The second study found a wander ratio of 1:1.2. In terms of predicting travel speeds of primary transport, gross power rating (kW), payload size (m3), extraction distance (m) and slope (%) variables were included. Skidder payloads were found to be approximately 50% of potential design loads. Truck travel speed predictor variables included Visual Condition Index (VCI), road width, average gradient, percentage of maximum load and truck maximum power. Applying multivariate analysis the predictor variables were reduced to road width and percentage maximum load, and a multiple linear regression equation was produced with an adjusted r2 of 0.52. Analysis found that overloading of trucks was a common occurrence. The Case Study required the current forest road network to be repeatedly refined through road decommissioning and selected upgrades over which the timber resource is subsequently flowed to the processing plant. Based on sequentially improved truck speeds, skidder efficiency and fibre use the Net Present Value (NPV) of the various projects, production costs and available timber resource use were quantified. The supply chain was analysed by investigating the effect downstream efficiency improvements have on financial returns over one rotation. NPV results ranged from approximately R40 million to R300 million. The scenario associated with the highest NPV used the most improved road network, highest possible transport speed, and motor-manual felling, cable skidder extraction, merchandising yard and optimal skidder and transport performance. The lowest NPV yielding scenario is associated with an abridged road network, low secondary transport speed, cable skidder extraction, mechanised felling, roadside merchandising, and normal skidder and transport performance. Examination of the individual factors found that road network; secondary transport speeds and performance had a significant effect. Harvest system had no significant effect. A limitation of this study was that only the forest to mill supply chain was analysed. Extending the supply chain to the mill and onto the final customer the benefits to the entire chain are expected to increase further. This gap in knowledge is a likely follow-up study.