• Journal of Korean Society of Forest Science
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• v.94 no.1 s.158
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• pp.6-10
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• 2005

This study was conducted to understand the dynamics of naturally regenerated seedlings and saplings in 28years after selective cutting at natural Korean pine-broadleaved forests in Mt. Changbai. The number of naturally regenerated tree species was 16 species in 28 years after selective cutting. The appearance rate of naturally regenerated tree species was 56 percentage and the early-successional tree species of Acer ukurunduense, Acer mono, Acer pseudosieboldianum, Prunus padus var. pubescens, and Maackia amurensis were found in the first 10 years after selective cutting. The seedlings and saplings of shade-tolerant tree species of Pinus koraiensis, Acer mandshuricum, Ulmus laciniata were appeared and the appearance rate was higher than 75% after 15 years while it showed little changes from 19 years after selective cutting. The distribution density of seedlings and saplings of regenerated tree species in selective cutting area was 5,500~6,100 trees per hectare in the first 10 years, and it increased gradually along with the restoration of disturbed area and it could reach 7,500 trees per hectare after 15 years.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.143-151
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• 2016

Shoreline armoring is a globally used engineering strategy to prevent shoreline erosion along stream, lake and reservoir coastlines. Armoring alters the land-water interface and has the potential to affect shoreline vegetation by changing nearshore geomorphology, hydrology, sediment composition and water quality. We quantified the effects of the artificial disturbances and alternation of the land-water interface on the community structure and distribution of shoreline vegetation in a large reservoir, Uiam Reservoir, Korea. More than 60% of shorelines were disturbed by armoring with retaining wall of concrete block, riprap and gabion in the Uiam Reservoir. The results of detrended correspondence analysis showed that the vegetation structures of the shoreline modified by armoring changed from hydrophyte-dominated to hygrophyte-dominated ecosystems. The shoreline armoring caused the disruption of gradual continuity in the water-land interface and the biological invasion by alien plants. The changes in distribution area of shoreline vegetation showed that the area of hydrophytic vegetation decreased and that of hygrophytic vegetation increased from 2010 to 2013. In conclusion, the human disturbance such as armoring, road construction, recreation etc. could lead to terrestrialization, the loss of transverse continuity and biological invasion in the shoreline vegetation of the Reservoir Uiam. Our findings suggest that redesigning or removing shoreline armoring structures may benefit nearshore hydrophytic vegetation for the conservation of novel shoreline ecosystems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.4
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• pp.24-35
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• 2006

The vascular plants of the studied area was listed 384 taxa of 90 families, 234 genera, 331 species, 1 subspecies, 45 varieties and 7 forms. The flora of each reservoir, 285 taxa of 83 families, 190 genera, 247 species, 1 subspecies, 30 varieties, 7 forms in Osongjae, 117 taxa of 39 families, 87 genera, 100 species, 17 varieties in Ogongjae, 83 taxa of 30 families, 67 genera, 73 species, 8 varieties, 2 forms in Shinyongjae and 86 taxa of 33families, 70 genera, 75 species, 1 subspecies, 10 varieties in Eodujae. Based on the list of the rare plants by the Forest Research Institute, 3 taxa were recorded in the studied areas; Magnolia kobus (Preservation priority order : No. 187), Penthorum chinense (No. 144), Prunus yedoensis (No. 110) and based on the list of Korean endemic plants, 4 taxa were recorded; Populus tomentiglandulosa, Clematis trichotoma, Prunus yedoensis, Paulownia coreana. Specific plant species by floral region were total 15 taxa; Prunus yedoensis in class V, 2 taxa (Carex idzuroei, Magnolia kobus) in class IV, 2 taxa (Monochoria korsakowi, Poncirus trifoliata ) in class III, 10 taxa (Sagittaria aginashi, Salix glandulosa, Clematis brachyura, Nymphoides peltata, etc.) in class I. The naturalized plants in this site were 13 families, 29 genera, 43 species, 1 varieties, 44 taxa and naturalization rate was 11.5% and based on the list of an ecosystem disturbance plants, 3 taxa were recorded in the studied areas : Paspalum distichum, Solanum carolinense, Ambrosia artemisiifolia var. elatior. The hydrophytes was listed 31 taxa of 15 families, 20 genera, 29 species, 2 varieties and Eleocharis mamillata var. cyclocarpa, Penthorum chinense, Soirodela polyrhiza were recorded in Osongjae, Sagittaria aginashi, Eleocharis kuroguwai, Scirpus juncoides, Scirpus triqueter, Monochoria korsakowi, Monochoria vaginalis var. plantaginea were recorded in Ogongjae. Besides, Scirpus fluviatilis, Trapa pseudoincisa were recorded in Shinyongjae and Scirpus triangulatus, Nymphoides peltata, Myriophyllum verticillatum were recorded in Eodujae. This site is located in the urban area and ecosystem-disturbing wild animal and plant has been imported here, therefore ecosystem has been disturbed more and more. The wetland here rapidly has changed into upland, so it needs conservation measures through long-term monitoring.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.29-42
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• 2017

As the "Guidelines for GHG Environmental Assessment" was revised, it pointed out that the developers should evaluate GHG sequestration and storage of the developing site. However, the current guidelines only taking into account the quantitative reduction lost within the development site, and did not consider the qualitative decrease in the carbon sequestration capacity of forest edge produced by developments. In order to assess the quantitative and qualitative effects of vegetation carbon uptake, the CASA-NPP model and satellite image spatial-temporal fusion were used to estimate the annual net primary production in 2005 and 2015. The development projects between 2006 and 2014 were examined for evaluate quantitative changes in development site and qualitative changes in surroundings by development types. The RMSE value of the satellite image fusion results is less than 0.1 and approaches 0, and the correlation coefficient is more than 0.6, which shows relatively high prediction accuracy. The NPP estimation results range from 0 to $1335.53g\;C/m^2$ year before development and from 0 to $1333.77g\;C/m^2$ year after development. As a result of analyzing NPP reduction amount within the development area by type of forest development, the difference is not significant by type of development but it shows the lowest change in the sports facilities development. It was also found that the vegetation was most affected by the edge vegetation of industrial development. This suggests that the industrial development causes additional development in the surrounding area and indirectly influences the carbon sequestration function of edge vegetaion due to the increase of the edge and influx of disturbed species. The NPP calculation method and results presented in this study can be applied to quantitative and qualitative impact assessment of before and after development, and it can be applied to policies related to greenhouse gas in environmental impact assessment.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.339-350
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• 2009

This study was carried out to investigate distributional condition of rare plants and useful plant resources, and to verify distributional patterns of understory vegetation associated with the upper layer's vegetation structure. Total 59 families, 160 genera, 218 kinds of vascular plants were identified at the study site including 6 rare plants designated by Korea Forest Service (Lloydia triflora Bak., Trillium kamtschaticum Pall., Lilium distichum Nakai, Anemone koraiensis Nakai, Iris odaesanensis Y.N. Lee, Viola diamantica Nakai). Twenty three species of useful plant resources were also identified at the site; 8 of them showed clustered distributions and the others were prone to scatter. Actual vegetation of this study area consisted of one natural community dominated by Quercus mongolica Fisch. and three disturbed communities of Larix kaempferi (Lamb.) Carriere, Abies holophylla Max. and/or a herbaceous vegetation resulting from forest removal and strong wind of mountain top. This classification was strongly supported by cluster analysis based on the surveyed plot data. Distributional patterns of understory vegetation within forest stand were somewhat related to overstory vegetation structure, but showed a different tendency according to site condition, species composition, and competitive pressure among understory vegetation. Therefore, in order to protect the important understory components as forest genetic resources, forest treatments such as density control of overstory should be implanted based on understanding of impact on understory's dynamics and growing condition.

• Korean Journal of Plant Resources
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• v.25 no.5
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• pp.550-560
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• 2012

The aim of this study is to research spatial diffusion, a condition for spread of Ailanthus altissima, and conduct flora analysis to provide useful information for management of it. Three research spots where the community dominance value was found to be high and habitat was homogeneous according to a 2010 in-depth species study were selected, and census was conducted using a line-transect method. The diffusion area included 1,435 $m^2$ in Yangpyeong, 1,118 $m^2$ in Gimcheon and 760 $m^2$ in Sancheong, in order of increasing size, and a total of 510 trees were found to be randomly diffused in space. An average of 83.2% of Ailanthus altissima were found to be included in DBH classes I (1.0-3.4 cm) and II (3.5-6.4 cm), showing that young trees were dominant in Ailanthus altissima communities and there was an age diffusion pattern according to degree of disturbance in habitats. A total of 41 families 75 genera and 91 species of flora made up the list, and Therophytes were most widely found in all of the three areas. This shows that habitats in these areas have recently been disturbed. It was evaluated that elimination of roadside population and mountainous area population was necessary to prevent diffusion of Ailanthus altissima.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.117-126
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• 2021

Satellite magnetic observations reflect the magnetic properties of deep crust about the depth of Curie isotherm that is a boundary where the magnetic nature of the rocks is disappeared, showing long wavelength anomalies that are not easily detected in near-surface data from airborne and shipborne surveys. For this reason, they are important not only in the analyses on such as plate reconstruction of tectonic boundaries and deep crustal structures, but in the studies of geothermal distribution in Antarctic and Greenland crust, related to global warming issue. It is a conventional method to compute the spherical harmonic coefficients from global coverage of satellite magnetic observations but it should be noted that inclusion of erroneous data from the equator and the poles where magnetic observations are highly disturbed might mislead the global model of the coefficients. Otherwise, the reduced anomaly model can be obtained with less corruption by choosing the area of interest with proper data processing to the area. In this study, I produced a satellite crustal magnetic anomaly map over East Asia (20° ~ 55°N, 108° ~ 150°E) centered on Korean Peninsula, from CHAMP satellite magnetic measurements about mean altitude of 280 km during the last year of the mission, and compared with the one from global crustal magnetic model (MF7). Also, a comparison was made with long wavelength anomalies from EMAG2 model compiled from all near-surface data over the globe.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.145-152
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• 2021

The purpose of this study was to determine the optimal distances between pipes to minimize the pressure loss and turbulent intensity. This was accomplished by investigating the distances between sleeve-jointed pipes and the flow changes in pipes based on variations in the Reynolds (Re) number when installing adjusting pieces for the pipes. When the thickness tp of the sleeve-jointed piping was fixed at 5 mm and the pipe lengths Lp were 10, 50, 100, and 200 mm, the correlations with the velocity of the sleeve-jointed part, pressure distribution, length of the reattachment point in the recirculation area, and Re number were analyzed. The flow characteristic of the sleeve-jointed part from a laminar to a turbulent flow region was determined by setting the Re range to 200 ≤ Re ≤ 5,000. This was done by utilizing Ansys Fluent 18.1, which is a commercial program. The enlargement and contraction ratios of the sleeve-jointed part were 1.2 and 0.83, respectively, and the turbulent intensity of the sleeve downstream edge and pressure change both increased as the Re number increased while Lp remained constant. The fact that the flow on the sleeve wall surface was disturbed by tp resulted in losses in velocity energy. Therefore, the edge of the sleeve-jointed part was also effected. When Lp was 10 mm or less, the turbulent intensity of the edge part did not change significantly as the Re number increased. The reattachment point in the recirculation area did not appear at Lp of 10 mm or less and was not affected by the vortex. In the case of 3,000 ≤ Re, the reattachment length of the wall surface of the sleeve-jointed part was nearly constant as Lp increased.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.2
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• pp.55-65
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• 2024

This study aimed to figure out diel activity patterns of water deer and wild boar, whose habitat is disturbed by human activity in a suburban area. Photographic data of water deer and wild boar collected by 18 camera traps from January 2021 to November 2022 was categorized into four diel periods (dawn, day, dusk, and night), and converted into frequencies per 100 CTD (Camera Trap-Days) for seasonal and spatial diel activity pattern analysis. Water deer exhibited intense nocturnality in fall, and wild boar did in fall and winter. During the fall, water deer's night-time capture rate was the highest (61.9%), and day-time photographic rate was the lowest (13.9%) among other seasons. During the fall and winter, wild boar's night-time photographic rate was relatively high (77.6%, 78.0%, respectively), and day-time photographic rate was relatively low (0.7%, 1.8%) in comparison with other seasons. In spatial diel activity analysis, both water deer and wild boar showed a tendency to avoid humans, especially near trails during day-time hours. The day-time photographic rate of water deer in trail-near group was 12.1% and trail-far group was 24.6%. The day-time photographic rate of wild boar was 3.4%, 5.7%, respectively. Because the diel activity patterns of wildlife reflect human disturbance, this study provides useful ecological information for developing appropriate management plans for the coexistence of water deer and wild boar in suburban areas.

• The Korean Journal of Quaternary Research
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• v.34 no.1
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• pp.1-13
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• 2024

Lagoon, attributed to the postglacial sea-level rise, has experienced rapid geomorphological changes due to increasing human impact. This study tried to infer how rapidly increasing human impact during the Holocene affects on geomorphological changes of lagoons and their surroundings, especially on Cheongchoho, Gyeongpoho and Pungho with significant changes in area and shapes. It was confirmed that the period of rapid artificial change commonly began in the 1960s to 1970s and geomorphological landscape rapidly changed since human impact intensified afterward. Intensive development not only affected on depth, area and shape changes, but also had significant impacts on water environment and biodiversity, attributed to disturbed flow between freshwater and seawater due to dredging and the installation of artificial structures. Lastly, various types of human impact were observed to be complexly interrelated, which seems to be associated with the geomorphologic process influenced by both terrestrial and marine environments. It is thought to be the result of complex interactions between humans who develop and utilize the terrain and changes in environmental conditions.