• The Korean Journal of Quaternary Research
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• v.24 no.1
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• pp.25-33
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• 2010

Holocene vegetation and climate changes were assumed on the basis of pollen records from Wonpyeong Trench II-3 of the Osong archaeological site, Cheongju, Chungbuk Province, Korea. An organic matter beared in coarse sediments appeared to be low throughout the succession. Although an occurrence of pollen grains is not high, some dominant and principal taxa may indicate vegetation changes response to climate changes in central inland area of the Korean Peninsula. The age determination can be estimated with indirect way by comparing with previous age-controlled pollen studies. It is assumed that the former last glacial conifer forests had been changed into open mixed conifers and deciduous broadleaved forest during the early Holocene period. Warmer and more humid climate conditions, during the mid-Holocene, might have allowed the hardwoods including deciduous- and evergreen-broadleaved trees, and warm-preferring pine tree to flourish. Subsequently, the former forests were replaced by mixed of conifer and deciduous broadleaved forest owing to deterioration of climate conditions during the late Holocene. Human activity is also detected by agricultural indicators, such as buckwheat and large pollen grains comparable to corn, in upper most pollen profile. During this time, the forests in studied area were primarily affected by human disturbance rather than natural environment.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.496-503
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• 2021

Pinus densiflora is an essential tree species native to the Republic of Korea (ROK) and covers most of the total natural forest areas in the ROK. This study was conducted to understand the site characteristics and stand structure of P. densiflora forests distributed at sites where P. densiflora covered over 50% of the stand basal area during the 7th National Forest Inventory (NFI) period from 2016 to 2020. P. densiflora dominated 3,665 circular sample plots (400 m²). P. densiflora forests predominated at elevations less than 600 m above sea level (a.s.l). However, most P. densiflora forests were distributed at the slopes facing south and west over 800 m a.s.l. At altitudes below 800 m, they were distributed at all slopes but dominated at the southern and western slopes. P. densiflora grew mainly in the soils of sandy loam, loam, or silt loam with relative infertility. Dominant tree species distributed with P. densiflora were Quercus mongolica, Q. variabilis, Q. serrata, Prunus serrulata var. pubescens and Castanea crenata by the descending order. P. densiflora, P. thunbergii, and P. rigida were grown in large DBH classes, Quercus species and Fraxinus rhynchophylla in middle DBH classes, while Juniperus rigida and Styrax japonicus in small DBH classes. Dominant tree species distributed mainly at the lower layer of P. densiflora stands were Rhododendron mucronulatum, Q. serrata, Lindera obtusiloba, Fraxinus sieboldiana, Toxicodendron trichocarpum and Rhododendron schlippenbachii by the descending order.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.100-107
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• 2022

Quercus mongolica is an important deciduous tree species in the Republic of Korea; it covers most of the total natural deciduous forest area in the country. In this study, the site characteristics and stand structure of Q. mongolica forests were investigated at sites where Q. mongolica occupied >50% of the total basal area during the 7th National Forest Inventory period (2016-2020). The total number of circular sample plots (400 m²) of Q. mongolica forests was 1,421. These forests were mainly dominant at >800 m above sea level (a.s.l). However, they were also distributed on north-facing slopes at <600 m a.s.l. and gradually on southern slopes with ascending altitudes. Quercus mongolica forests were distributed in silt loam, loam, or sandy loam soils with relatively high fertility. Dominant species distributed with Q. mongolica included Pinus densiflora, Quercus variabilis, Acer pseudosieboldianum, Fraxinus rhynchophylla, and Quercus serrata. Pinus densiflora and Q. variabilis grew in large DBH classes, Q. serrata grew in middle DBH classes, and A. pseudosieboldianum and F. rhynchophylla grew in small DBH classes. The dominant species distributed at the lower layer of Q. mongolica forests were Sasa borealis, Lindera obtusiloba, Rhododendron mucronulatum, Rhododendron schlippenbachii, Q. mongolica, and Fraxinus sieboldiana.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.1
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• pp.76-87
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• 2019

The purpose of this study was to evaluate the performance of and to derive future maintenance-management measures of the constructed alternative habitat for the Kaloula borealis at the University of Seoul, examining the period between 2015-2017. The research was constructed in 2014 and in a $191m^2$ area. The performance evaluation was divided into maintaining the habitat of the target species, maintaining the population and reproduction rates of the target species, maintaining the habitat of the wild species, the resilience of natural ecosystems, and the harmony with the surrounding environment. In terms of maintaining the habitat of the target species, soil collected from the existing habitat of the Kaloula borealis and was the depth was increased to 30cm in the alternative habitat. An artificial water supply was required every year during the supporting the spawning and hatching of other amphibians along with the Kaloula borealis. The sources of water of the alternative habitat were both rain and tap water, as it cannot be maintained naturally. Additionally, the Kaloula borealis thrived because it inhabited the research site and the average temperature was $26.2^{\circ}C$ from April-June, which is when the Kaloula borealis spawns. In terms of maintaining the population and reproduction rates of the Kaloula borealis, they were evaluated to have stable rates of reproduction. In terms of maintaining the habitat of the wild species, studies on vegetation and the structure of the characteristics of prey or predators will be needed. Also, alien species, such as Humulus japonicus and Bidens frondosa needed to be removed to maintain the wetland ecosystem of the wild species. In the assessment of the resilience of the natural ecosystems, the mud was monitored, noting the changes in the depth of water, with steps taken to reduce the leakage of water. The mud collected from the Haneul Pond wetland, which is located around the research site was piled up. Also, partial mowing management and the inducement of a natural vegetation colony was required for vegetation management. It was also necessary to create porous spaces, such as old trees and tree branches to create a habitat with hiding places and feeding and spawning places for small organisms. In terms of the harmony with the surrounding environment, the following threat factors needed to be managed: amphibian roadkill by vehicles and pedestrians and artificial draining due to nearby user access. Based on the monitoring results, alternative habitat management measures presented the promoting various waterside structures, in which amphibians can spawn and hide in, managing the water environment consistently, managing the vegetation, focused on the habitat of the wild species, and managing the surrounding environment for the habitat. The creation of an alternative habitat should be managed through monitoring, reflecting the characteristics of the changes in the site. Also continuing efforts are also needed to improve the habitat of the target species.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.427-433
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• 2015

This study was conducted to provide a method of establishing two-storied forests by the adjustment of stand structures in natural deciduous forests of Pyeongchang area. Three permanent sampling plots of 0.09 ha were established in study site and some tree variables were measured in each sampling plot before the treatment of two-storied system. Stand attributes and stand structures before treatment were estimated based on the data measured in sampling plots. The results indicate that the current stand status is different from typical stand structures of two-storied forests. A simulation technique was applied to predict stand attributes and stand structures after the treatment of two-storied system. Results suggest that significant time is required to accomplish target stand structures even after applying the treatment of two-storied system. Number of trees in the upper canopy class after treatment was predicted to be 170 trees/ha, which adequately meets the target of two-storied forests. It was predicted, however, that the lower canopy class trees has much less trees compared with the typical stand structures of two-storied forests. This problem could be solved with ingrowth of infant trees over time or by under-planting of tolerant species. It is confirmed that the target growing stock volumes of the upper canopy class should be approximately $150m^3/ha$ considering stand status after treatment. It is predicted that twenty years of conversion period is required to accomplish this goal. The changes in stand structures over time should be assessed based on stand inventory carried out every five years, and additional treatments for inducing two-storied forests should be applied if necessary.

• Journal of Korean Society of Forest Science
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• v.108 no.2
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• pp.189-199
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• 2019

The forest management paradigm has recently shifted from focusing on commercial production to focusing on ecosystem management. Accordingly, a natural seedling regeneration method that has a naturally high affinity has attracted much attention in recent years. The aim of this study was to determine the relationship among various environmental factors, lower stratum vegetation, and seedling regeneration in Pinus densiflora forests. The survey site comprised 50 sectors divided using the line transect method, and the survey data were divided into those from wet habitat (19 sites) and dry habitat (31 sites), depending on the soil humidity, and were analyzed separately to show the close relationship between soil humidity and natural seedling regeneration. As a result, the dry habitat exhibited high seedling density (157,419 trees/ha), with the main species being Quercus serrata, Zanthoxylum piperitum, Smilax china, and Pueraria lobata, while wet habitat exhibited low seedling density (57,895 trees/ha), with the main species being Stephanandra incisa, Castanea crenata, Lespedeza maximowiczii, Lysimachia barystachys, Aralia elata, and Styrax japonicus. The height and root-collar diameter under wet conditions exhibited faster growth than those under dry conditions. Height growth by the root-collar diameter in dry habitat increased faster than that in wet habitat. It was also confirmed that seedling regeneration in wet habitat exhibited a rapid growth pattern 5 years after germination. These results suggest that the seedlings begin to grow more rapidly after a period of suppression by competition with surrounding plants. Considering an ecosystem or ecological management approach, specific practices, such as bush control and vine clearing in wet habitats, should be more intensively conducted, especially at the beginning of the management operations.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.26-47
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• 2009

This study examined dwelling site from among the sites of the Neolithic age found in the Asan Bay(牙山灣) area, and the temporal-spatial location and meaning of the dwelling site (settlement). The majority of the settlements in the area are of a square style but some coexist with rectangular-style settlements, which is noteworthy. The dwelling sites of the Neolithic age found in Asan Bay area are mostly located in a ridge of hilly areas, divided into gentle, low areas (20~50 meters above sea level) and relatively high areas (50~80 meters above the sea level). Although location strongly corresponded to the residents' subsistence and the technical levels within the culture, it likely was greatly affected by natural environment where they lived, as well. In examining radiocarbon dating results and the excavated artifacts, the settlements found in Asan Bay were determined to belong to the period II(3,500~3,000 B.C.) stated in the Relative Chronological table of Dwelling sites in the Neolithic age, written by the author. Said Dwelling sites are proven to have a close relationship with those found on the coast of Gyeonggi Province(京畿道) and in the Geum River(錦江) valley. This is deemed to be the result of expansion and interchange between Gyeonggi Province(京畿道) group and Geum River(錦江) valley group, who constituted the large settlements. Additionally, the Daecheon-ri type dwelling sites in the Geum River valley were verified to be the result of exchange, and spread to the Asan Bay area in the same era. Two forms of Dwelling sites coexisted dynamically in the Asan Bay area around 3,500 B.C. Such a phenomenon resulted primarily from the expansion of the dwelling site due to the introduction of primitive agriculture, as well as environmental (temperature), biological and social changes at those times.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.3-13
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• 2010

The Tsushima leopard cat, Prionailurus bengalensis euptilurus, a small felid, inhabits only the Tsushima Islands in Japan. Previous studies of the Tsushima leopard cat revealed that natural factors; including sex, reproductive activity, season, and prey distribution and abundance affect leopard cat home range variation and habitat use. In this study, we focused on clarifying how anthropogenic factors influenced home range variation and habitat use of a male Tsushima leopard cat living near a suburban area in January, March, May and September 2005 using radio-tracking. The home range size (100% MCP) of this cat was $0.78\;{\pm}\;0.26\;km^2$ (mean ${\pm}$ SD, n = 4 tracking sessions) across the whole study period. However, the cat did not use all parts of its home range uniformly; rather it used some habitat types selectively. The cat avoided agriculture areas and residential areas in all of the tracking-sessions. On the other hand, the cat showed a weak preference for artificial structures and a strong preference for baiting sites in January and March, while it avoided them in May, and no baiting site was included in its home range in September. These results suggest that anthropogenic factors influenced the ranging patterns and habitat use of the leopard cat living near a suburban area. Artificial structures might provided good resting spaces for the cat in bad weather. When the density of its main prey was low in the winter, the cat tended to rely on artificial prey and had a small home range size.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.2
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• pp.203-212
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• 2001

During the growing season from June to August, 2000, the soil NO and $N_2$O fluxes were measured to elucidate characteristics of soil nitrogen emissions from different types of intensively managed agricultural soils at outskirts of Kunsan City, located in the western inland of Korea, Flux measurements were made using a closed chamber technique at two different agricultural fields; one was made from upland field, and the other from rice paddy field. The flux data from upland field were collected for both the green onion and soybean field. Concentrations of NO and $N_2$O inside a flux chamber ar 15 minute sampling interval were measured to determine their soil emissions. Either polyethylene syringes of teflon air bags were used for gas samples of $N_2$O and NO. The analysis of NO and $N_2$O was made using a chemiluminesence NO analyzer and GC-ECD, respectively no later than few hours after sample collection at laboratory. The gas fluxes were varied more than one standard deviation around their means. Relatively high soil gas emissions occurred in the aftermoon for both NO and $N_2$O. A sub-peak for $N_2$O emission was observed in the morning period, but not in the case of NO. NO emissions from rice paddy field were much less than those from upland site. It seems that water layer over the rice paddy field prevents gases from escaping from the soil surface covered with were during the irrigation and acts as a sink of these gases. The NO fluxes resulted from these field experiments were compared to those from grass soil and they were found to be much higher. Diurnal and daily variations of NO and $N_2$O emission were discussed and correlated with the effects of nitrogen fertilizer application on the increase of the level of soil nitrogen availability.

• Journal of the Korean Professional Engineers Association
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• v.15 no.4
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• pp.12-24
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• 1982

East Parts of Bangladesh have been benifited by low cost energy generated by domestic natural gas but West parts where energy generated by imported fuel. Bangladesh Government authority has very much concerned to transmit the low cost electricity to the West from the East for past several years. To solve such concerns, cross-country 230kv double circuits Power transmission line was proposed, however there was a big obstacle for the realization of this line to cross the Jamuna river which has 12 km long width with a deep muddy river bed. A consultant engineering firm named Merz-Mclellan anyway finalized this plan and a world-wide bid was announced on June 31, 1979. Due to the expected difficulty to construct the towers on sea like area, only three construction groups have participated. including a Korean joint venture organization of Samsung-Korean Developement corporation-Kolon Electric Machinery company. After 3 months bid evaluation, contract was awarded to Korean Consosium and KEM Co was in charge of designing steel towers with anchor bolts and base plates beside to electrical engineering field. Then KEM Co have faced and over-comed many unenpected technical difficulties such as forced eccentricity joint on base plate, distorsion issue of 60mm thick plates welding, threading anchor bolts, tad heat treatment of some anchor bolts, disagreement from Consultant Engineer on multiplying factor of leg stresses for 45$^{\circ}$ wind and on reducing O.L.F for wind loads on cables for such 1220km long spans. After spending two years long period for designing and engineering towers, base plates, and anchor bolts, first shipment of tower was finally realized on Nov. 8, 1981 and on the other hand KDD has proceeded concrete caisson work on schedule at Jamuna river site and expected to complete tower erection and stringing of cables within this year of 1982 which was original completion target.