• The Journal of the Petrological Society of Korea
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• v.8 no.3
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• pp.131-148
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• 1999

Characteristics and complex structures in the northwest Nevada, U.S.A. are de-veloped due to relative tectonic movement of major tectonostratigraphic terranes. Theresearch area is composed of autochthonous rocks of both Early Triassic Koipato Group and Middle Triassic Star Peak Group, which is located in the Humboldt Range, northwest Nevada, U.S.A. The present research is focused on deformation history, related fabric development, and state of regional paleostress during the Jurassic to Late Cretaceous. The Triassic autochthonous rocks in the Humboldt Range, Nevada, U.S.A. display polyphase deformation due to E- to ESE-directed tectonic transport of the Fencemaker allochthon over autochthonous rocks of the Humboldt Range. Structures involving the Mesozoic foreland deformation are development of intense foliation, different styles of folds, minor thrusts, transposed layering, and strong mylonitization. These tectonic structures are mostly developed along the western flank of the Humboldt Range, and are reported as the first deformation of the Mesozoic foreland in the Humboldt Range, Nevada, U.S.A. Regional principal stress(${\sigma}_1$) is interpreted to be E to ESE between the Jurassic and Early Cretaceous on the basis of orientations of strongly developed $D_1$ structures. The deformation during the Middle to Late Cretaceous, is characterized by development of consistent N- to NNE-trending metamorphic quartz veins, and shear zones parallel to pre-existing $D_1$ foliation. Orientations of metamorphic quartz veins as well as other kinematic indicators are N to NNE and are interpreted as those of regional principal stress(${\sigma}_1$) during the Late Cretaceous. The sense of shear applied in the Humbololt Range is dextral and is caused by reactivation of early-formed $D_1$ structures. These results reflect counterclockwise rotation of regional principal paleostress in the Humboldt Range from the Jurassic to Late cretaceous. Finally, development of both shear band cleavage and S/C mylonitic fabrics indicates that the shear zones in the Humboldt Range reflect involvement of enhanced non-coaxial flow during bulk shortening in mylonitic formation.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.632-639
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• 2015

Working in the forest would require a wide range of skills and experience for specific tasks which involve with a high level of risks to worker's safety. However, there has been a concern on the current standard wage system for forest workers because it does not effectively reflect the characteristics of typical working conditions in the forest. In addition, the current standard wages for forestry workers was estimated based on the construction industry's wage system. Therefore, the purpose of this study is to assess a current wage system through the mail survey method and to develop a new wage system for forest worker which effectively reflects skill sets and experience required for successful completion of the work in the forest. We mailed the survey questionnaire consisting of 19 questions to 659 forest workers and received 188 responses resulting in a 28.5% response rate. The results showed that the current average optimal wages of forest worker, special worker and feller were 97,680won/day, 127,559won/day and 152,403won/day, respectively though there were variations depending on the regions. In developing the new standard wage system, this study suggest the current work types(worker, special worker and feller) could be divided into 5 work types (forest-environment workers, forest operations in beginner, forest operations in intermediate, forest operations in advanced and forest equipment operator) reflecting specialty of forest operation thereby stabilizing the new wage system for forest workers.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.87-97
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• 2014

This study was conducted to provide field-based harvesting study information which can be used to select an optimal cable system for certain work conditions on steep grounds (> $20^{\circ}$ ground slope) in Korea. To accomplish this study objectives, we evaluated three cable yarding systems (RME-300T tower-yarder, Chuncheon tower-yarder, FARMI tractor winch) working in typical work conditions for their yarding productivity and operational efficiency. Those yarders are commonly used for removing logs or trees on steep grounds in Korea. Under the same work conditions (average DBH of tree to be cut, 20 cm; yarding distance, 60 m; lateral yarding distance, 10 m; and machine utilization rate, 70%), the average productivities were $33.04m^3$/day, $38.47m^3$/day, and $14.17m^3$/day for RME-300T, Chuncheon tower-yarder, and FARMI, respectively. Our standardized cost comparison study also showed that the yarding cost was highest at $37,835won/m^3$ with FARMI, followed by RME-300T at $25,105won/m^3$ for the same work conditions. We found the lowest yarding cost with the Chuncheon tower-yarder at $20,520won/m^3$ which was resulted primarily from high yarding productivity at the yarding distance (60 m). Our analysis suggested that a small machine such as FARMI could be a low-cost yarding machine option for a cable yarding job with a short yarding distance (40 m or less). The Chuncheon tower-yarder is well suited for a mid-range yarding distance job in Korea, ranged between 40 to 140 m. If yarding distance were longer than 140 m, the RME-300T tower yarder appears to be most cost-effective.