• Journal of Environmental Impact Assessment
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• v.19 no.3
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• pp.231-245
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• 2010

The the purpose of this study was to analyze of the vegetation structure and phytosociological changes in the area adjacent to GeumJeong Mountain Fortress for fifteen years. The result of this study was as follows; Of the 8 quadrates, site of the North Gate 2 was having a highest in the number of extinct trees, 15 kinds. This is probably due to trampling effect caused by climbers' steps. Site of the West Gate 1 and South gate 1 each had 8 kinds of extinct trees, respectively. The number of newly appeared trees was highest at site of the North Gate 1, (8 kinds) followed by the sites of South gate 1 and South gate 2, respectively (5 kinds). The highest decrease in number of tree species was observed in North Gate 1, therefore, there is a strong relationship between vegetation diversity and the number of users of the available spaces. In order to revitalize the unstable vegetation structure of the Area Adjacent to GeumJeong Mountain Fortress, Robinia pseudo-acacia has to be well maintained in the shrub tree layer, and vines, such as Smilax china, Humulus japonicus, and Pueraria thungergiana, should be removed. To recover natural vegetation, dead leaf layer should be protected, and more shrub trees need to be planted. In the understory and shrub tree layer, multi layer tree planting is highly recommended to recover natural vegetation and increase tree diversity. In order to improve bad soil condition caused by trampling effect of recreational users, special treatments to the soil structure are required, such as mulching and raking soil. Also, depending on its soil damage from users trampling, the areas in the park should be divided into usable areas and user limited areas by the sabbatical year system. To improve the soil acidity due to acidic rain, soil buffering ability should be improved by activating microorganisms in the soil by using lime and organic material.

• Journal of Ecology and Environment
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• v.47 no.2
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• pp.49-62
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• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.5
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• pp.27-43
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• 2019

This study applied the LANDIS-II model to the forest vegetation of the study area in Yeongdong-gun, Korea to identify climate effects on ecosystems of forest vegetation. The main purpose of the study is to examine the long-term changes in forest aboveground biomass(AGB) under three different climate change scenarios; The baseline climate scenario is to maintain the current climate condition; the RCP 4.5 scenario is a stabilization scenario to employ of technologies and strategies for reducing greenhouse gas emissions; the RCP 8.5 scenario is increasing greenhouse gas emissions over time representative with 936ppm of $CO_2$ concentration by 2100. The vegetation survey and tree-ring analysis were conducted to work out the initial vegetation maps and data for operation of the LANDIS model. Six types of forest vegetation communities were found including Quercus mongolica - Pinus densiflora community, Quercus mongolica community, Pinus densiflora community, Quercus variabilis-Quercus acutissima community, Larix leptolepis afforestation and Pinus koraiensis afforestation. As for changes in total AGB under three climate change scenarios, it was found that RCP 4.5 scenario featured the highest rate of increase in AGB whereas RCP 8.5 scenario yielded the lowest rate of increase. These results suggest that moderately elevated temperatures and $CO_2$ concentrations helped the biomass flourish as photosynthesis and water use efficiency increased, but huge increase in temperature ($above+4.0^{\circ}C$) has resulted in the increased respiration with increasing temperature. Consequently, Species productivity(Biomass) of trees decrease as the temperature is elevated drastically. It has been confirmed that the dominant species in all scenarios was Quercus mongolica. Like the trends shown in the changes of total AGB, it revealed the biggest increase in the AGB of Quercus mongolica under the RCP 4.5 scenario. AGB of Quercus mongolica and Quercus variabilis decreased in the RCP 4.5 and RCP 8.5 scenarios after 2050 but have much higher growth rates of the AGB starting from 2050 under the baseline scenario. Under all scenarios, the AGB of coniferous species was eventually perished in 2100. In particular they were extinguished in early stages of the RCP 4.5 and RCP 8.5 scenarios. This is because of natural selection of communities by successions and the failure to adapt to climate change. The results of the study could be expected to be effectively utilized to predict changes of the forest ecosystems due to climate change and to be used as basic data for establishing strategies for adaptation climate changes and the management plans for forest vegetation restoration in ecological restoration fields.

• Korean Journal of Environment and Ecology
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• v.17 no.2
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• pp.123-132
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• 2003

This ecological study investigated the vegetation changes of abandoned salt field, 21 plots(1${\times}$lm, 1${\times}$2m) set up by the methods of Braun-Blanquet and Elenberg in a coastal island, Gasado, Jindogun, from July to September,2002. The vascular plants of abandoned salt field in the surveyed site identified 17 families and 48 species. Of these species, halophytes and mesophytes were 20(42%) and 28(58%) species. In addition, the disturbance to this habitat led to the change of halophytes in abandoned sald field, exotic plants was distributed 23 species, which included Dactylis glomerata, Conyza canadensis, Oenothera odorata, Cosmos bipinnatus, etc., in the group of, mesophytes were 20(71%) species, vegetation communities were classified into 3 community types, i.e. the halophyte grassland community(Limonium tetragonum community, Suaeda japonica community, Spergularia marina community), the wetland grassland community(Phragmites communis community, Carex scabrifolia community, Phaceturus latifolius var. angustifolius community), and the mesophyte grassland community(Erigeron bonariensis community, Daucus littoralis var. koreana community). Each communities was described the structual, distribution and changes of the vegetation in the abandoned salt field, the vegetation table and actual vegetation map were prepared.

• Journal of Korea Water Resources Association
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• v.49 no.1
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• pp.73-81
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• 2016

This study investigates the development of lower channels and sediment sorting processes in the vegetated channels with the mixed sediment. The sediment discharges fluctuate with time and decrease with vegetation density. The bed changes with irregular patterns, and the sediment particles in the vegetated zone at the surface of bed are fine. The dimensionless geometric mean decreases with vegetation density. The fine sediment particles are trapped by vegetation, and the bed between main steam and vegetated zone increases. Moreover, the particle sizes are distributed irregularly near the zone. The hiding functions decrease with dimensionless particle size. However, the functions increase with vegetation density, which is confirmed by decreasing sediment discharge with vegetation. The lower channel is stable and the migration decreases in the condition of $0.5tems/cm^2$. However, the migration of the lower channel in the condition of $0.7stems/cm^2$ increases due to the increased sinuosity and new generated channels in the sedimentated vegetation zone.

• Korean Journal of Remote Sensing
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• v.40 no.1
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• pp.9-18
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• 2024

Small streams, despite their rich ecosystems, face challenges in vegetation assessment due to the limitations of traditional, time-consuming methods. This study presents a groundbreaking approach, combining unmanned aerial vehicles(UAVs), convolutional neural networks(CNNs), and the vegetation differential vegetation index (VDVI), to revolutionize both assessment and management of stream vegetation. Focusing on Idong Stream in South Korea (2.7 km long, 2.34 km² basin area)with eight diverse revetment methods, we leveraged high-resolution RGB images captured by UAVs across five dates (July-December). These images trained a ResNeXt101 CNN model, achieving an impressive 89% accuracy in classifying vegetation cover(soil,water, and vegetation). This enabled detailed spatial and temporal analysis of vegetation distribution. Further, VDVI calculations on classified vegetation areas allowed assessment of vegetation vitality. Our key findings showcase the power of this approach:(a) TheCNN model generated highly accurate cover maps, facilitating precise monitoring of vegetation changes overtime and space. (b) August displayed the highest average VDVI(0.24), indicating peak vegetation growth crucial for stabilizing streambanks and resisting flow. (c) Different revetment methods impacted vegetation vitality. Fieldstone sections exhibited initial high vitality followed by decline due to leaf browning. Block-type sections and the control group showed a gradual decline after peak growth. Interestingly, the "H environment block" exhibited minimal change, suggesting potential benefits for specific ecological functions.(d) Despite initial differences, all sections converged in vegetation distribution trends after 15 years due to the influence of surrounding vegetation. This study demonstrates the immense potential of UAV-based remote sensing and CNNs for revolutionizing small-stream vegetation assessment and management. By providing high-resolution, temporally detailed data, this approach offers distinct advantages over traditional methods, ultimately benefiting both the environment and surrounding communities through informed decision-making for improved stream health and ecological conservation.

• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.19-24
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• 2009

In order to analysis the variation in vegetation area caused by topographical change at Jinudo in the Nakdong estuary, we used aerial photographs of Jinudo from 1998 to 2006. To extract an accuracy shoreline from these aerial photographs, a tide calibration was performed. We also estimated the annual variation in topographic area and vegetation area, and then analyzed the relationship between them by a correlation analysis. The following results were obtained: 1) The calibrated shoreline distance of Jinudo from 1998 to 2006 was estimated to have a range of (-)1,927 cm to (+)4,671 cm. 2) Annual changes in the topographic area and vegetation area in Jinudo have been increasing gradually from 1998, and the correlation coefficient between topographic area and vegetation area is 0.97. 3) The estimated topographic areas were with following order: southern (III), eastern (IV), northern (II) and western (I), while for the vegetation area, the order was southern (III), northern (II), eastern (IV) and western (I). 4) The vegetation area of the southern region (III) of Jinudo had the largest size among the regions, and was calculated to be $4.3{\sim}5.4$ times larger than the eastern region (IV).

• Journal of Korea Water Resources Association
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• v.46 no.9
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• pp.909-919
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• 2013

This study examines the hydraulic characteristics, the channel changes, the behavior of bars, and bank stability by means of laboratory experiments. Three sets of laboratory experiments are conducted to elucidate the influence of riparian vegetation of the channels with erodible banks. Flow velocity is decreased in the vegetated zone, the mobility of lower channels is decreased. The double Fourier analysis of the bed waves shows that 1-1 mode (alternate bar) is dominant at the initial stage of the channel development. As time increases, 2-2 and 2-3 modes (central or multiple bars) are dominant due to the increased width to depth ratio. As the vegetation density is increased, the number of bars are increased, bank stability increases. The variation of sediment discharges is affected by vegetation density. The braided intensity is decreased with vegetation density. As the vegetation density is increased, the correlation coefficient of bed topography and bed relief index is increased.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.437-441
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• 2009

The modern times is as special as from the river, the river is very important of our life. The importance to preserve the river environment has been issued and the river developing method is being changed to use potential function of nature as well as flood control. Essential element of the river restoration is a vegetation. The flow resistance by vegetation along the river banks is greatly increase the flood stage. Therefore, the flow resistance due to vegetation in the river and roughness coefficient changes to understand the hydraulic characteristics is an important elements in the river restoration. The purpose of this study is to analyze the flood stage and the aspects of riverbed changes due to the corridor restoration with river vegetation. In order to simulate the flood stage and riverbed changes, HEC-RAS, RMA-2, and SED-2D model were applied for the upstream and downstream in study reaches, respectively.

• The Korean Journal of Ecology
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• v.21 no.4
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• pp.389-399
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• 1998

this study was focused on the effects of fire on spatial change of vegetation landscape in rural region. Fire types recognized as erown fire, severe surface fire and light surface fire in order of increasing intensity were described in a fire map. GIS was introduced to understand the relationship between fire types and topographic conditions or vegetation types. We also investigated land-use type and regeneration strategies after burning. Fire intensity depended on topographic conditions and vegetation types. Special land-use type in this area was collection of edible mushroom (Tricholoma matsutake). Mushrooms had been obtained from Pinus densiflora forests existing as edaphic climax or managed artificially. Regeneration strategy in burned areas was to make sprouts from burned oak stumps. A higher density and growth rate of sprouts, as compared to those on unburned areas, facilitated vegetation succession from P. densiflora forest to oak forest and consequently led to change of landscape pattern.