• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.598-606
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• 2015

This study analyzed the characteristics of the disaster occurrence and disaster-prone zones on the 85 forest roads in the Jeollabuk-do area by referring to their forest environment factors. The on-site survey reveal the types of forest road disasters as follows: erosions of cutting slopes 54.1%, erosions of the filling slope 35.3%, collapses of cutting slopes with filling slope 9.4%, and erosions of road surface 1.1%. Disasters most frequently occurred in the vertical location (the hillside) and the horizontal location (the slope), and the forest factors affecting the road disasters were degree of cutting slopes in $31^{\circ}{\sim}40^{\circ}$, degree of filling slopes in $21^{\circ}{\sim}30^{\circ}$, and the soil texture of SiL. The most significant factors on the most frequent occurrence of forest road disasters were forest type of coniferous, slope aspect northeast, forest age of plantation and felling area, and rainfall in 1601~1700. An analysis of the occurrence of the forest road disasters in the Jeollabuk-do area showed a positive correlative relationship with the following factors of the forest environment within a 1% error: degree of cutting slope in $31^{\circ}{\sim}40^{\circ}$, annual accumulation rainfall in 1601~1700. and showed a positive correlative relationship with the following factors of the forest environment within a 5% error: horizontal location of valley, forest type of coniferous, length of slope more than 20 m, forest age of plantation and felling area, soil texture of SiL.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.229-238
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• 2013

This study was conducted to analyze on the operational cost of logging operations in the whole-tree logging operation system by tower-yarder and swing-yarder, and in the cut-to-length logging operation system by excavator with grapple in order to spread efficient logging operation technique and to establish the logging operation system. In the results of the analysis of operation cost, in case of the whole-tree logging operation system, the operation cost was 2,099 won/$m^3$ in felling by chain saw, 28,286 won/$m^3$ in yarding by tower-yarder, 18,265 won/$m^3$ in yarding by swing-yarder, 18,939 won/$m^3$ in bucking by excavator with grapple and chain saw, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle. In case of the cut-to-length logging operation system, the operation cost was 10,160 won/$m^3$ in felling and bucking by chain saw, 7,567 won/$m^3$ in cut-to-length extraction by excavator with grapple, 6,982 won/$m^3$ in branches and leaves extraction by excavator with grapple, 3,040 won/$m^3$ in the operation road construction by excavator with grapple, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle.

• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.8-16
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• 2003

The Phyllostachys pubescens planted in the Nambu forest Experiment was used for this study. The growth ages of the P. pubescens were 1, 2 and 3 years, respectively. The experiment was carried out every month in between June of 2001 and May of 2002. The p. pubescens were divided into upper, middle and lower parts according to the growing points. The static modulus of elascity($MOE_d$) and dynamic modulus of elascity($MOE_d$) were investigated for the physical and mechanical properties of the P. pubescens. The density, MOEs and $MOE_d$according to the growing points were highest in the upper part of the P. pubescens. Generally, density and MOEs and $MOE_d$ of the P pubescens for 3 years grows larger every month. However, moisture content, MOEs and $MOE_d$ of the P. pubescens for 1, 2 years had nothing to do with growth ages and felling time. In the case of the relationships between average MOEs and $MOE_d$ the correlation coefficient was 0.88 in between June of 2001 and May of 2002. Also, $MOE_d$ showed about 18.5% higher than MOEs. Generally, the equally expressed in research that was known that $MOE_d$ of wood is higher than MOEs of wood. Therefore, the $MOE_d$ using a resonance frequency mode is useful as a nondestructive evaluation(NDE) method for predicting the MOE of the P. pubescens.

• Journal of Korean Society of Forest Science
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• v.6 no.1
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• pp.37-42
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• 1967

This experiment was carried out to study the peeling effect affecting to the natural seasoning by the treatments such as complete peeling, outer bark peeling (attached inner bark) and non peeling for the logs felled in summer and winter season in the stand of about 40 years old pitch pine, located in Kwangyang College Forest, Chollanam-do, Korea. According to the results this study may be concluded as followings. 1. Although the complete peeled logs are seasoned rapidly as compared with the outer barked and non peeled logs but they are more developed seasonal checking. 2. As to the drying effects of the logs felled in summer season, the difference between complete peeled and outer barked or non peeled logs are recognized. Whereas, the difference between outer barked and non peeled logs was not recognized. 3. As to the drying effects of the test logs felled in winter season the difference between complete peeled and outer barked logs were not shown, whereas, the difference between complete peeled or outer barked, and non peeled logs was significantly recognized. Accordingly it is considered that the drying effect of outer barked logs is same with those of complete peeled logs. 4. In this experiment it is expected that the complete peeled logs of summer season felling, and complete peeled or outer barked logs of winter season felling were attained equilibrium moisture contents within four months.

• Journal of agriculture & life science
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• v.43 no.2
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• pp.9-15
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• 2009

The objectives of this study was to obtain the basic information for reasonable management of soil ecosystem damaged by pine wilt disease. Soil temperature and moisture content were $15.3{^{\circ}C}$ and 11.5% at whole-cut site, $14.4{^{\circ}C}$ and 13.5% at partial-cut site, and $13.7{^{\circ}C}$ and 14.8% at control site, respectively. The content of soil organic matter throughout the study period ranged from 2.11 to 2.64% at whole-cut site, 2.26 to 3.33% at partial-cut site, and 2.27 to 3.10% at control. Soil respiration rates showed seasonal fluctuations increasing in summer, which showed positive correlations between soil respiration and soil temperature. Average soil respiration were 0.24, 0.36 and $0.32gCO_{2}/m^{2}/hr$ at whole-cut site, partial-cut site, and control, respectively. $Q_{10}$ values ranged from 2.39 to 2.68 at Pinus densiflora stands damaged by pine wilt disease. Annual soil respiration rate at whole-cut site, partial-cut site and control were 8.1, 15.6 and $14.6tCO_{2}/ha/yr$, respectively.

• Tunnel and Underground Space
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• v.19 no.1
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• pp.43-51
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• 2009

In order to analyze collapse behavior of structure containing irregular and large displacement, many numerical analyses have been conducted. In this study, using a new method, Applied Element Method (AEM) for collapse analysis of structures, collapse behavior of model RC structures Is simulated. From these simulations results, displacement of X-direction (or horizontal) and displacement of Y-direction (or vertical) is similar to that of mode) RC structures. It is confirmed that collapse behavior of structures using AEN is reliable accurately simulated with that of model RC structures.

• Journal of the Korea Furniture Society
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• v.23 no.1
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• pp.95-102
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• 2012

The objective of this study was to conduct the species identification and tree-ring dating of Lotus Pedestal of the Amitabha Statue at Ssangbong-Temple in Hwasun. The six wood blocks used for the Lotus Pedestal were hard pines (Pinus spp.; diploxilon) except one piece which was ginkgo (Ginkgo biloba L.). The lotus leaves surrounding the pedestal body were also made of ginkgo. Tree-ring patterns of 3 blocks were synchronized and a 133 years chronology was made. The chronology was crossdated well with the master chronology of Japanese red pine in South Korea. It dated back to A. D. 1551~1683, i.e. the last ring dated A. D. 1683. Through the estimation of the number of sapwood rings removed during carving, the felling year was calculated A. D. $1704{\pm}10$. The calligraphic writing on the Pedestal indicated that this statue was made in A. D. 1694. Therefore, the accuracy of the tree-ring dating has been proven.

• Journal of architectural history
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• v.12 no.3
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• pp.87-100
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• 2003

This study is on the construction of government office of Dongnaebu through researching the construction reports and historical documents in 19century. Especially it focuses on the local construction system and operation for the government office. Main contents of the study are 1) Scope and process of construction, 2) Architectural administration and official notes, 3) Organization of participants and the feature, 4) Felling trees and transport, 5) Monetary of construction The results are summarized as follows. 1) Repair office customary were the courtesy new provincial man. Government building were inspected and repaired periodically. 2) Administrative system of construction have been operated. There are official notes which are about application, permition and order, concerned works such as logging at the bongsan, means of transport, paying wages and progressing works. 3) Organization of construction was made up of an officer and sangnee to supervise and supply. 4) Due to financial difficulty, local government reserved and appropriated funds with moneylending for building office.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.419-425
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• 2020

There are many accident risks in logging operation of forestry such as struck by felled trees and caught in, under, or between felled trees. These accidents are primarily occurred by not keeping a safe distance between workers. According to the forestry safety instruction, workers are not supposed to go into the safety zone which is a circle with a radius of more 2 times the height of felling tree. However, this rule does not keep because of poor safety consciousness, poor sight and extreme noise of logging operation machines. This problem causes many major accidents every year. To solve this problem, we made forestry safety helmets based on IoT technology. These helmets have functions to make a visual and an acoustic alarm signal when reach the distance between workers within 20 meters. We developed the algorithm to operate the helmet's functions and conducted tests to check the functions. As a result of tests, we assured the normal system operating conditions.

• Journal of Forest and Environmental Science
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• v.34 no.2
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• pp.119-125
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• 2018

The tropical forests in developing countries are faced with the problem of illegal exploitation of trees. However, dearth of empirical means of expressing the dimensions, structure, quality and quantity of a removed tree has imped conviction of offenders. This study aimed at developing a model that can effectively estimate individual tree basal area (BA) from stump diameter (Ds) for Tectona grandis stands in Omo Forest Reserve, Nigeria, for timber valuation in case of illegal felling. Thirty-six $25m{\times}25m$ temporary sample plots (TSPs) were laid randomly in six age strata; 26, 23, 22, 16, 14, and 12 years specifically. BA, Ds and diameter at breast height were measured in all living T. grandis trees within the 36 TSPs. Least square method was used to convert the counted stumps into harvested stem cross-sectional areas. Six basal area models were fitted and evaluated. The BA-Ds relationship was best described by power model which gave least values of Root mean square error (0.0048), prediction error sum of squares (0.0325) and Akaike information criterion (-15391) with a high adjusted coefficient of determination (0.921). This study revealed that basal area estimation was realistic even when the only information available was stump diameter. The power model was validated using independent data obtained from additional plots and was found to be appropriate for estimating the basal area of Tectona grandis stands in Omo Forest Reserve, Nigeria.