A productivity study and system evaluation was carried out on a tree-length operation working in ... more A productivity study and system evaluation was carried out on a tree-length operation working in a second thinning of loblolly pine near Greenville, North Carolina. The average tree volume was 8.1 ft 3 and the average dbh was 8.4 in. The machines studied in the system were the Tigercat 720B feller-buncher, the Tigercat 630 skidder, and the tracked loader Tigercat 245. The goal was to reduce the standing timber from 225 trees/ac down to 92. Standard time-study methodology and multivariance statistical analyses were used to capture and evaluate the data. The key productivity parameters identified for the feller-buncher was piece volume and number of trees in the bunch, and for the skidder extraction distance, average piece volume and number of bunches picked up to make a turn. The ability of the loader to process increasing number of trees as average tree volume decreased, and the increased difficulty of delimbing the larger trees resulted in no significant variance for average piece size. Productivity functions were developed for the feller-buncher and the skidder. The system evaluation discusses the productivity balance between the machines for the given range of piece size as well as potential operational improvements based on in-field observations. South. J.
Every state in the Southeast US has developed a set of Best Management Practices (BMPs) to protec... more Every state in the Southeast US has developed a set of Best Management Practices (BMPs) to protect water quality during silvicultural activities. These BMPs are either voluntary or quasi-regulatory in the Southeast, though water quality protection is mandatory under the Clean Water Act. Although the Southern Group of State Foresters (SGSF) has adopted a Silvicultural BMP Implementation Monitoring Protocol, each
Understanding how stand and terrain parameters impact the productivity of harvesting machines is ... more Understanding how stand and terrain parameters impact the productivity of harvesting machines is important for determining their optimum use. Productivity studies in forest operations are often carried out on new equipment, or on equipment being used in new conditions. Such information is normally presented as a productivity or efficiency function; that is, a regression equation that best represents the data. Most studies establish that piece size is the dominant predictor that impacts overall productivity. A common concept, know as the 'piece-size law', is that productivity increases at a decreasing rate with increasing piece size. What is not well understood is the upper limit to this piece-size law. That is, as the trees get 'too' large, the machine starts to struggle and we can expect a decrease in productivity. Four different mechanised felling machines were studied in New Zealand radiata pine plantations. Using more complex non-linear equations it was possible to identify an 'optimum' piece-size for maximum productivity, whereby this 'sweet-spot' piece size for all machines is considerably smaller than their maximum. Unexpectedly, productivity tended to decrease gradually, not drop off suddenly beyond the optimum. Using more complex statistical functions when correlating piece size to productivity will help identifying the 'sweet-spot'.
In most countries biomass recovery from existing timber harvesting operations is recognised as an... more In most countries biomass recovery from existing timber harvesting operations is recognised as an important component of any bio-energy program. At present, there are very few biomass recovery operations in New Zealand, despite the very large amount of residue generated by large-scale harvesting operations in plantation forests. Much of this residue is readily available post-harvest at landings, with a major concern being the contamination. Currently, residue constitutes a problem for both processing as well as the subsequent planting. A research project has commenced to help assess what an optimal residue recovery system may be. The paper considers what strategy could be employed to successfully integrate biomass recovery into NZ logging operations, with the integration of biomass recovery into the harvesting operation being key. Based on both international literature as well as extensive field visits three favourable options are established. Productivity and cost estimates are provided: with both the post-harvest residue recovery from the landing using a tub grinder, as well as using off-road trucks to transport the residues to a secondary landing for comminution estimated at 34 NZ$/ton. Whereas the post-harvest option provides for easier logistics, the concurrent recovery option will yield both greater quantity as well as quality biomass. Using a bundler to accumulate slash, and then comminute at the power plant is expected to increase the cost to 44 NZ$/ton. Finally, limitation and future research considerations are also discussed.
Mechanised cut-to-length (CTL) harvesting is commonly deployed in eucalypt plantations and is bas... more Mechanised cut-to-length (CTL) harvesting is commonly deployed in eucalypt plantations and is based on the application of specialised machinery for felling, delimbing, debarking and crosscutting trees directly at the stump site. Debarked logs are then moved to the roadside with dedicated forwarders for loading onto transportation vehicles. This study determined the cost of stump-site debarking, which was calculated between 1.7 and 6.7 V m À3 , depending mainly on tree size. Avoiding stump-site debarking would allow reducing the overall stump-to-road harvesting cost between 11 and 17%, while making bark biomass available for energy or biochemical conversion. The figures obtained from this study are specifically valid for European pulpwood plantations and winter harvest conditions, but the underlying principles may hold a general significance. Further studies should determine the cost of off-site debarking, and the effects of bark removal on soil fertility. journal homepa ge: www .e lsev ie r.com/locate/issn/153 75110 b i o s y s t e m s e n g i n e e r i n g 1 1 0 ( 2 0 1 1 ) 4 4 3 e4 4 9
... Christine Hodges and Rien Visser Master's Student and Assistant Professor, Department of... more ... Christine Hodges and Rien Visser Master's Student and Assistant Professor, Department of Forestry, Virginia Tech, Blacksburg VA 24061 Email [email protected] ... Results of these requirements are given in Table 2. KY, SC, and LA haven't set any requirements within SMZs of ...
A productivity study and system evaluation was carried out on a tree-length operation working in ... more A productivity study and system evaluation was carried out on a tree-length operation working in a second thinning of loblolly pine near Greenville, North Carolina. The average tree volume was 8.1 ft 3 and the average dbh was 8.4 in. The machines studied in the system were the Tigercat 720B feller-buncher, the Tigercat 630 skidder, and the tracked loader Tigercat 245. The goal was to reduce the standing timber from 225 trees/ac down to 92. Standard time-study methodology and multivariance statistical analyses were used to capture and evaluate the data. The key productivity parameters identified for the feller-buncher was piece volume and number of trees in the bunch, and for the skidder extraction distance, average piece volume and number of bunches picked up to make a turn. The ability of the loader to process increasing number of trees as average tree volume decreased, and the increased difficulty of delimbing the larger trees resulted in no significant variance for average piece size. Productivity functions were developed for the feller-buncher and the skidder. The system evaluation discusses the productivity balance between the machines for the given range of piece size as well as potential operational improvements based on in-field observations. South. J.
Every state in the Southeast US has developed a set of Best Management Practices (BMPs) to protec... more Every state in the Southeast US has developed a set of Best Management Practices (BMPs) to protect water quality during silvicultural activities. These BMPs are either voluntary or quasi-regulatory in the Southeast, though water quality protection is mandatory under the Clean Water Act. Although the Southern Group of State Foresters (SGSF) has adopted a Silvicultural BMP Implementation Monitoring Protocol, each
Understanding how stand and terrain parameters impact the productivity of harvesting machines is ... more Understanding how stand and terrain parameters impact the productivity of harvesting machines is important for determining their optimum use. Productivity studies in forest operations are often carried out on new equipment, or on equipment being used in new conditions. Such information is normally presented as a productivity or efficiency function; that is, a regression equation that best represents the data. Most studies establish that piece size is the dominant predictor that impacts overall productivity. A common concept, know as the 'piece-size law', is that productivity increases at a decreasing rate with increasing piece size. What is not well understood is the upper limit to this piece-size law. That is, as the trees get 'too' large, the machine starts to struggle and we can expect a decrease in productivity. Four different mechanised felling machines were studied in New Zealand radiata pine plantations. Using more complex non-linear equations it was possible to identify an 'optimum' piece-size for maximum productivity, whereby this 'sweet-spot' piece size for all machines is considerably smaller than their maximum. Unexpectedly, productivity tended to decrease gradually, not drop off suddenly beyond the optimum. Using more complex statistical functions when correlating piece size to productivity will help identifying the 'sweet-spot'.
In most countries biomass recovery from existing timber harvesting operations is recognised as an... more In most countries biomass recovery from existing timber harvesting operations is recognised as an important component of any bio-energy program. At present, there are very few biomass recovery operations in New Zealand, despite the very large amount of residue generated by large-scale harvesting operations in plantation forests. Much of this residue is readily available post-harvest at landings, with a major concern being the contamination. Currently, residue constitutes a problem for both processing as well as the subsequent planting. A research project has commenced to help assess what an optimal residue recovery system may be. The paper considers what strategy could be employed to successfully integrate biomass recovery into NZ logging operations, with the integration of biomass recovery into the harvesting operation being key. Based on both international literature as well as extensive field visits three favourable options are established. Productivity and cost estimates are provided: with both the post-harvest residue recovery from the landing using a tub grinder, as well as using off-road trucks to transport the residues to a secondary landing for comminution estimated at 34 NZ$/ton. Whereas the post-harvest option provides for easier logistics, the concurrent recovery option will yield both greater quantity as well as quality biomass. Using a bundler to accumulate slash, and then comminute at the power plant is expected to increase the cost to 44 NZ$/ton. Finally, limitation and future research considerations are also discussed.
Mechanised cut-to-length (CTL) harvesting is commonly deployed in eucalypt plantations and is bas... more Mechanised cut-to-length (CTL) harvesting is commonly deployed in eucalypt plantations and is based on the application of specialised machinery for felling, delimbing, debarking and crosscutting trees directly at the stump site. Debarked logs are then moved to the roadside with dedicated forwarders for loading onto transportation vehicles. This study determined the cost of stump-site debarking, which was calculated between 1.7 and 6.7 V m À3 , depending mainly on tree size. Avoiding stump-site debarking would allow reducing the overall stump-to-road harvesting cost between 11 and 17%, while making bark biomass available for energy or biochemical conversion. The figures obtained from this study are specifically valid for European pulpwood plantations and winter harvest conditions, but the underlying principles may hold a general significance. Further studies should determine the cost of off-site debarking, and the effects of bark removal on soil fertility. journal homepa ge: www .e lsev ie r.com/locate/issn/153 75110 b i o s y s t e m s e n g i n e e r i n g 1 1 0 ( 2 0 1 1 ) 4 4 3 e4 4 9
... Christine Hodges and Rien Visser Master's Student and Assistant Professor, Department of... more ... Christine Hodges and Rien Visser Master's Student and Assistant Professor, Department of Forestry, Virginia Tech, Blacksburg VA 24061 Email [email protected] ... Results of these requirements are given in Table 2. KY, SC, and LA haven't set any requirements within SMZs of ...
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