• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.103-107
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• 2016

This study aims to select the most appropriate poplar clones for planting on short rotation coppice poplar plantations in a riparian area. The research investigated biomass production, nitrogen and carbon absorption with 2-year-old poplar (Populus spp.) clones including P. euramericana clone Eco28, P. deltoides hybrid clone 97-18, and P. alba ${\times}$ P. glandulosa hybrid clone 72-30. The average number of stems per stump was five and P. euramericana clone Eco28 had the greatest average number of live stems per stump with 5.9. The average stem diameter was 23.2 mm, and P. deltoides hybrid clone 97-18 achieved the largest average diameter with 25.4 mm. The average annual above-ground biomass production of Populus deltoides hybrid clone 97-18 was 16.1 ton/ha/year, followed by P. alba ${\times}$ P. glandulosa hybrid clone 72-30 and P. euramericana clone Eco28, 12.3 and 5.4 ton/ha/year, respectively. The average annual nitrogen uptake of poplar clones was 46.5 kg/ha/year. P. alba ${\times}$ P. glandulosa hybrid clone 72-30 had the highest average, 63.1 kg/ha/year. The average of annual carbon absorption was estimated 5.3 ton/ha/year and Populus deltoides hybrid clone 97-18 showed the best results with 7.7 ton/ha/year. Based on the results given above, P. deltoides hybrid aspen clone 97-18 is considered as the most suitable poplar clones for wood biomass production on riparian areas.

• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.9-15
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• 1976

Financial rotations of Pinus koraiensis stands are calculated and compared on the basis of five basic financial maturity concepts. The rotations given by the forest rent and average annual gross revenue models are in excess of sixty years by adopting zero interest rates of capital and forest lands. IRR model also neglects land value and highly sensitive to the changes of fixed and regeneration costs. The Faustmann doctrine recommands rotation ages of 23-39 years depend upon applied interest rates and site indices, and seems to be most adequate for determining financial maturity. It is however the situation in Korea that economic conditions are changing rapidly, and thus a model which does not require many exogenous variables in calculation process is preferable. The Duerr's solution has a basic simplicity and logic which is appealing from both a theoritical and practical viewpoint, and most adaptable to the Korean situation, even though the model completly neglects the opportunity cost for forest land. There is a tendency to reduce rotation length with the increase of site quality, but the difference is negligible.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.562-573
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• 2019

In a cable yarding system, a small-scale tower yarder attached to a farm tractor wasdeveloped and used for small-diameter tree harvesting operations. Based on this design, improvement of traction performance was required for medium- and large-diameter tree harvesting operations. In this study, the mechanical transmission employed for the tower yarder was modified into ahydro-mechanical transmission system. Maximum traction forces, including tractor engine speed and hydraulic power pressure, were investigated, and comparisons were made between the mechanical and hydro-mechanical transmission systems. Six tractor engine speeds (1,200, 1,400, 1,600, 1,800, 2,000, and 2,200) and three levels of power transmission mechanism pressure (4.9, 6.9, and 8.8 MPa) were investigated in the two different transmission systems. Results showed a maximum traction force of 15,146.6 N at an engine rotation speed of 757 rpm in the current mechanical transmission system, and 36,140.0 N at anengine rotation speed of 1,575 rpm in the modified hydro-mechanical transmission system. The maximum traction forces for the hydro-mechanical transmission were 2.4 times greater than those of the mechanical transmission, and may therefore be applicable to medium and large-diameter tree harvesting operations. Thus,as a modified version of the conventional transmission system, the new hydro-mechanical transmission system may be cost-effective for use in large-scale cable yarding operations. In the future, however, it will be necessary to investigate problems that may arise from field application tests.

• Journal of Korean Society of Forest Science
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• v.77 no.4
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• pp.389-400
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• 1988

The recent trend in multiple-use land management planning is using Model I and Model II formulations designed for timber activity scheduling problems. Numerous models hate been developed, with MUSYC(Johnson and Jones, 1979) being the first to incorporate both model structures. Currently the most popular computer program using both Model I and Model II is FORPLAN(Johnson and others, 1986). A Model I formulation requires fewer rows and provides more direct information on what happens to an acre from rotation to rotation. In some problems, Model II provides a much more compact problem matrix with much fewer columns and only a moderate increase in row number. In this paper we examined and evaluated their usefulness in comprehensive multiresource forest management planning.

• Journal of the Korean Wood Science and Technology
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• v.35 no.3
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• pp.10-21
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• 2007

It is necessary to study about moment performance of glulam-dowel connections which had been applied rotation. To analyze and predict the moment performance, angled to grain load was replaced with parallel to grain load and perpendicular to grain load. The dowel bending strength and dowel bearing strength were tested. And tensile strength test for connections of two different end distances was performed. Specimens of rotation test were composed with different drift pin numbers and drift pin arrangement. Connection deformation was occurred by plastic behavior of drift pin after yield when tensile load applied at connection. And the absorbing drift pin deflection by end distance continued the connection deformation. When rotation applied at connection that 2 drift pins were arranged parallel to grain (b2h), it showed similar performance with tensile perpendicular to grain. And connection that 2 drift pins were arranged perpendicular to grain (b2v) showed similar performance with tensile parallel to grain. Connection capacity that 4 drift pins were arranged rectangular (b4) showed 1.7 times as strong as connection that 2 drift pins were arranged parallel to grain (b2h). These results agreed predicted values and it is available that rotation replaced with tensile load.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.51-59
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• 2010

This study was conducted to analyze the type and priority order of forest functions that is suitable in assessing a private forest. A questionnaire survey of experts group and forest officers from the city and county office was conducted and the appropriateness of forest functions type and priority order of function were assessed. Based on the survey conducted, they mostly agreed that it is necessary to change the name of forest functions and integrate the forest functions. Four classifications of forest functions were presented: resources rotation, water yield, living environment, and forest conservation. As the variety of organizations and geographical areas determine which forest functions are the priority, it is necessary to determine which function will become the priority order according to geographical areas, instead of simply dividing the forest functions into national and publicly owned forest when assessing the forest functions of private forests across the nation.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.497-501
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• 2000

Twelve-year-old rootstocks of sycamore and sweetgum were coppiced at monthly intervals for one year. Sprout growth was measured three and five years after cutting. After three years, average dry weight of the sprouts cut in May, June and July was lower by 36% for sycamore and by 24% for sweetgum than those cut during the other months of the year. However, these differences were reduced to be 23% and 14%, respectively, after five years.

• Journal of Broadcast Engineering
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• v.21 no.4
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• pp.562-568
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• 2016

In this paper, we focus on recognition of speed-limit signs among a few types of traffic signs because speed-limit sign is closely related to safe driving of drivers. Although histogram of oriented gradient (HOG) and local binary patterns (LBP) are representative features for object recognition, these features have a weakness with respect to rotation, in that it does not consider the rotation of the target object when generating patterns. Therefore, this paper propose the fast rotation-invariant binary patterns (FRIBP) algorithm to generate a binary pattern that is robust against rotation. The proposed FRIBP algorithm deletes an unused layer of the histogram, and eliminates the shift and comparison operations in order to quickly extract the desired feature. The proposed FRIBP algorithm is successfully applied to German Traffic Sign Recognition Benchmark (GTSRB) datasets, and the results show that the recognition capabilities of the proposed method are similar to those of other methods. Moreover, its recognition speed is considerably enhanced than related works as approximately 0.47second for 12,630 test data.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.305-309
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• 2006

This paper presents and illustrates the application of a growth and yield model that supports both forest and mill side volume and value estimates. Traditional forest stand growth and yield models represent the forest landowner view of yield and economics. Predicted yields are estimates of what one would expect from a procurement cruise, and current stumpage prices are applied to investigate optimum management strategies. Optimum management regimes and rotation ages obtained from the forest side view are unlikely to be economically optimal when viewed from the mill side. The actual distribution of recoverable manufactured product and its value are highly dependent on mill technologies and configurations. Overcoming this limitation of growth and yield computer models necessitates the ability to predict and price the expected manufactured distribution of lumber, lineal meters of veneer, and tonnes of air dried pulp fiber yield. With these embedded models, users of the yield simulator can evaluate the economics of possible/feasible management regimes from both the forest and mill business sides. The simulator is a forest side model that has been modified to produce estimates of manufactured product yields by embedding models for 1) pulpwood chip size class distribution and pulp yield for any kappa number (Schultz and Matney, 2002), 2) a lumber yield and pricing model based on the Best Opening Face model developed by the USDA Forest Service Forest Products Laboratory (Lewis, 1985a and Lewis, 1985b), and 3) a lineal meter veneer model derived from peeler block tests. While the model is strictly applicable to planted loblolly pine (Pinus taeda L.) on cutover site-prepared land in the United States (US) Gulf South, the model and computer program are adaptable to any region and forest type.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.443-452
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• 2006

This study was conducted to investigate the site and growth characteristics of Mackia amurensis stand in natural forest of Mt. Joongwang, Pyongchang-Gun, Gangwon-Do, Korea. The 28 sample plots ($30m{\times}30m$) were established to examine the vegetation and site characteristics for M. amurensis stand. Stem analysis was performed on two sample trees for each of the 5 plots situated at intervals of 100 m by altitude. M. amurensis trees were mainly distributed at the ridge and the slope facing north, with altitudes ranging from 790 to 1,170 m. The M. amurensis grew at relatively deep A-layer of soil with high moisture but infertile. Dominant species with M. amurensis were Quercus mongolica, Fraxinus rhynchophylla, Acer pseudo-sieboldianum, A. pictum subsp. mono, Ulmus davidiana var., japonica, Tilia amurensis, and Populus davidiana. TWINSPAN classified four communities in Mt. Joongwang area; M. amurensis-P. davidiana community (xeric type), M. amurensis-U. davidiana var. japonica community (xeric type), M. amurensis-T. amurensis community (moist type), and M. amurensis-Styrax obassia community (moist type). According to the community type, trees per ha were more abundant in the area of the moist types than the xeric types. Height growth of M. amurensis increased with increasing ages until 10 years, and then decreased thereafter, especially at altitude of 1,020m. M. amurensis showed rapid early growth of height and volume, indicating possible high biomass production under enough light. Growth of M. amurensis increased greatly at about 40 years if released from severe competitions. The rotation age of natural M. amurensis stand was expected for above 50 years.