• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.1-28
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• 2019

This study analyzed the density and mortality rate of Korean fir at 9 sites where individuals of Korean firs were marked into the live and dead trees with coordinates on orthorectified aerial images by digital photogrammetric system. As a result of the analysis, Korean fir in each site showed considerable heterogeneity in density and mortality rate depending on the location within site. This make it possible to assume that death of Korean fir can occur by specific factors that vary depending on the location. Based on the analyzed densities and mortality rates of Korea fir, we investigated the correlation between topographic factors such as altitude, terrain slope, drainage network, solar radiation, aspect and the death of Korean fir. The density of Korean fir increases with altitude, and the mortality rate also increases. A negative correlation is found between the terrain slope and the mortality rate, and the mortality rate is higher in the gentle slope where the drainage network is less developed. In addition, it is recognized that depending on the aspect, the mortality rate varies greatly, and the mean solar radiation is higher in live Korean fir-dominant area than in dead Korean fir-dominant area. Overall, the mortality rate of Korean fir in Mt. Halla area is relatively higher in areas with relatively low terrain slope and low solar radiation. Considering the results of previous studies that the terrain slope has a strong negative correlation with soil moisture and the relationship between solar radiation and evaporation, these results lead us to infer that excess soil moisture is the cause of Korean fir mortality. These inferences are supported by a series of climate change phenomena such as precipitation increase, evaporation decrease, and reduced sunshine duration in the Korean peninsula including Jeju Island, increase in mortality rate along with increased precipitation according to the elevation of Mt. Halla and the vegetation change in the mountain. It is expected that the spatial patterns in the density and mortality rate of Korean fir, which are controlled by topography such as altitude, slope, aspect, solar radiation, drainage network, can be used as spatial variables in future numerical modeling studies on the death or decline of Korean fir. In addition, the method of forest distribution survey using the orthorectified aerial images can be widely used as a numerical monitoring technique in long - term vegetation change research.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.1-20
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• 2023

The present study has monitored the changes in the biodiversity of Dunchon-Dong ecological and landscape conservation area after the restoration of the wetland, identified and analyzed the threats to the ecosystem, and presented a management plan accordingly. In this area which was forests and rice paddies in the past, apartment reconstruction is currently underway, with some hinterland forests and wetlands remaining. When we look into the change in the floras, the total number of species was 193 in 2000 before the restoration, it decreased from 2004 to 2006, and as of 2019, it was 149, showing an increasing trend. The result of comparing the species that emerged before and after the restoration showed an increase in Cyperaceae herbs such as Carex maximowiczii and Carex dispalata growing in wetland areas within forests and Schoenoplectiella juncoides and Schoenoplectus tabernaemontani growing in areas within wetlands where shallow water is maintained. As a result of analyzing the change in the area ratio of each type of extant vegetation, the wetland native herbs formed the power at the highest ratio after the restoration. The change in the power of the wetland native herbs was on an increasing trend until 2007, after which it decreased much in 2010 and then gradually increased, showing values of 26.6% in 2000, 44.6% in 2002, 49.0% in 2005, 53.3% in 2007, 28.7% in 2010, and 37.3% in 2019. The cause of the decrease in 2010 was judged to be due to the vegetation management conducted to secure open water and remove organic matter in freshwater reservoirs. The amphibia which emerged from 2000 to 2019 was a total of 9 species including Hynobius leeshii, Bufo gargarizans, Kaloula borealis, and Rana uenoi. As a result of the changes in the emerging wild birds, the species diversity index before the restoration was 0.9922 in 2000, and the species diversity index after the restoration gradually increased to 1.2449 in 2005, 1.2467 in 2010, and 2.2631 in 2019. The amphibia and wild birds inhibiting in the Dunchon-Dong forest and wetland were judged to have increased through continuous wetland maintenance such as naturalized plant removal management, native plant maintenance, and open water securing management. For the ecosystem preservation management of the Dunchon-Dong ecological and landscape conservation area, it was suggested to minimize the impact of the Dunchon-Dong reconstruction project, reorganize the indiscriminate access roads adjacent to the wetland, and reorganize the main entrance to the wetland. For ecosystem restoration management, systematic restoration and ecological buffer planting were suggested to be carried out at the time of construction fence demolition.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.426-441
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• 2023

This study investigated the predictive accuracy of a model of landslide displacement in Jecheon-si, where a great number of landslides were triggered by heavy rain on both natural (non-clear-cut) and clear-cut slopes during August 2020. This was accomplished by applying three flow direction methods (single flow direction, SFD; multiple flow direction, MFD; infinite flow direction, IFD) and the degree of root cohesion to an infinite slope stability equation. The application assumed that the soil saturation and any changes in root cohesion occurred following the timber harvest (clear-cutting). In the study area, 830 landslide locations were identified via landslide inventory mapping from satellite images and 25 cm resolution aerial photographs. The results of the landslide modeling comparison showed the accuracy of the models that considered changes in the root cohesion following clear-cutting to be improved by 1.3% to 2.6% when compared with those not considered in the area under the receiver operating characteristics (AUROC) analysis. Furthermore, the accuracy of the models that used the MFD algorithm improved by up to 1.3% when compared with the models that used the other algorithms in the AUROC analysis. These results suggest that the discriminatory application of the root cohesion, which considers changes in the vegetation condition, and the selection of the flow direction method may influence the accuracy of landslide predictive modeling. In the future, the results of this study should be verified by examining the root cohesion and its dynamic changes according to the tree species using the field hydrological monitoring technique.

• Journal of Environmental Impact Assessment
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• v.24 no.3
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• pp.217-232
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• 2015

This study is to examine the section-based stream management with environmental characteristics and user monitoring. In Jeonjucheon, upstream section located near to Jeonju Hanok village has very good water quality and natural stream landscape. In case of mid/down streams, water quality is good and heavy concentration of facility leads to high use rates of these sections. The questionnaire consists of 5 parts: user characteristics, use behavior, citizen participation, importance rank, and Importance-Satisfaction(IS). 383 out of 454 responses with listwise deletion are used for demographic analysis and IS Analysis. In terms of citizen participation through 'ecological experience activity' and 'stream stewardship activity', 'occasional participation' shows the average of 78% in all three sections. For importance rank, the results arranged in order of priority show 'water quality' > 'green corridor' > 'trail' in up/down streams and 'water quality' > 'vegetation management' > 'trail' in midstream. Therefore, 'water quality' appears to be the most important variable among 13 variables. At last, the results of ISA indicate that all 10 variables need to be improved as satisfaction is lower than importance. In addition, 'plant management' variable falls into 'concentrate here' quadrant where importance is high and satisfaction is low.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.176-192
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• 2006

The need for a systematic drought management has increased since last countrywide drought in 2001. Naturally various studies for establishing drought plan and preventing drought disaster have been conducted. MODIS image provided by Terra satellite has effective spatial and temporal resolutions to observe spatial and temporal characteristics of a region. MODIS data products are easy for preprocessing and correcting geometrically and provide various data set in regular which are applicable for drought monitoring. In this study, Ansung river and the upstream of South Han river basin was chosen for case study to identify and assess spring drought. The multi-period MODIS image and accumulated precipitation were used to detect not only the drought year but also the vegetation change of normal year and the result were compared with various spatial data. The result shows NDVI and LSWI with is more appropriate than LST for assesing spring drought in Korea and two month cumulative precipitation has moderate relationship with drought. It is necessary to use MODIS image which has same period and same space for effective drought analysis because drought is also affected by landover and altitude.

• Korean Journal of Environment and Ecology
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• v.28 no.1
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• pp.45-54
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• 2014

This study was carried out to investigate the ecological succession sere and conservative value, and to provide the basic data in Woonsooam Valley, in Jogyesan (Mt.) (altitude 884m), Suncheon City, Korea by analysing the structure of the plant community. Fifteen plots (size is $20m{\times}20m$) were set up at an altitude of range from 255m to 495m. As a result of analysis of DCA which is one of the ordination technique, the plant communities were divided into five groups which are community I (Pinus densiflora community), community II (Quercus variabilis-Quercus serrata community), community III (Q. serrata-Q. variabilis community), and community IV (Carpinus tschonoskii-Q. serrata community) and community v(Deciduous broad-leaved forest community). We found out that the vegetation of the study site located in the South Temperate Climate Zone. The study site is found out that Q. serrata community 34.4%, part of slope in valley is the distribution that dominant species is Q. serrata-Q. variabilis community 32.1%. And in valley showed Carpinus tschonoskii community 5.5%. And Sasa borealis was dominant species in the shrub layer. We couldn't supposed that the ecological succession sere of the study site, however we should do a long-term monitoring to investigate the changes of the ecological succession each plant community, According to the index of Shannon's diversity (unit: $400m^2$), community III was ranged from 1.0102 to 1.1013, community V was 0.9945, community II was ranged from 0.7913 to 1.1503, community IV was ranged from 0.8081 to 1.0749 and community I was 0.9273.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.63-69
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• 2008

As a basic study on the creation of artificial tidal flats using dredged sediments, the pilot-scale artificial tidal flats with 4 different mixing ratio of ocean dredged sediment were constructed in Nakdong river estuary. The phragmites australis was transplanted from the adjacent phragmites australis community after construction, and then the survival and growth rate of the planted phragmites australis were measured. Also the changes of soil chemical oxygen demand (COD), ignition loss (IL), and the heterotrophic microbial numbers were monitored. The survival rate of the planted phragmites australis decreased as the mixing ratio of dredged sediment increased but there was little difference of length and diameter of the shoots. 30% of COD and 9% of IL in the tidal flat with 100% dredged sediment decreased after 202 day, however, fluctuations of COD and IL concentrations were also observed possibly due to the open system. It was suggested that the construction of tidal flats using ocean dredged sediment and biological remediation of contaminated ocean dredged sediment can be possible considering the growth rate of transplanted phragmites australis, decrease of organic matter and increased heterotrophic microbial number in the pilot plant with 100% dredged sediment. However, the continuous monitoring on the vegetation and various environmental factors in the artificial tidal flat should be necessary to evaluate the success of creation of artificial flats using dredged sediments.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.543-553
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• 2013

In Korea, there have been many studies and progresses on various types of pilot scale or commercialized field scale Best Management Practices(BMP) during the last 10 years. Runoff characteristics of diffuse pollutants from different land uses are well identified and documented. However, for the coastal area connected directly with shoreline, runoff patterns and management schemes of non-point pollution were not fully studied. Recently, coastal area is emerging as a new development axis especially in west coast side of Korea such as Incheon city and Chungnam province, thus urbanized area rapidly increased but there are no buffer zones and BMP facilities to aim at preventing direct discharge of the first flush into coastal sea and beaches. In this study, parking area in Deacheon harbor, Boryeong City in Chungnam Province was selected and rainfall runoff was monitored for two year period in order to examine run-off features from which proper type of BMP suitable for coastal area is proposed. Coastal area usually has a low ground water level and consists of plain land, so that large scale BMP such as storm water retention pond and wetland requiring great excavation works is not best management plan. In addition, monitoring study shows that storm water from the paved parking area has a high salinity compared with those in storm water from the inland. High salinity is detrimental for the vegetation. Therefore, BMP employing least vegetative cover and also in terms of maintenance is a good option such as infiltration trench and porous pavement.

• Spatial Information Research
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• v.18 no.3
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• pp.1-11
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• 2010

Recently, the construction of three dimensional spatial information of Dam reservoir area is very important part in Dam management work such as sediment survey, but it is difficult to acquire detailed terrain data because totalstation and single beam echo sounder are applied to terrain survey. This study presented method to construct detailed terrain data of Dam reservoir area using LiDAR and multi beam echo sounder. First, LiDAR survey was carried out in land zone and calibration process was applied by ground control point. And also the DEM of land zone was constructed by using algorithm, which eliminated building and vegetation class. As the result of validation of LiDAR DEM using GPS terrain survey, it was possible to construct three dimensional terrain data that was satisfied with the tolerance error of LiDAR, which was the standard error of LiDAR DEM showed as 0.108m. Also multi beam echo sounder was applied to the survey of water zone and it could construct spatial information that was satisfied with bathymetry surveying tolerance error of International Hydrographic Organization by validation with terrain survey data. And LiDAR and multi beam echo sounder data were integrated and it was possible to construct three dimensional spatial imagery information that can be applied to Dam management work such as the estimation of sediment amounts or the monitoring of terrain change by linking with high resolution orthophoto.

• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.823-833
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• 2020

In order to stably produce crops, there is an increasing demand for effective crop monitoring techniques in domestic agricultural areas. In this manuscript, a cultivation area extraction method by using deep learning model is developed, and then, applied to satellite imagery. Training dataset for crop cultivation areas were generated using RapidEye satellite images that include blue, green, red, red-edge, and NIR bands useful for vegetation and environmental analysis, and using this, we tried to estimate the crop cultivation area of onion and garlic by deep learning model. In order to training the model, atmospheric-corrected RapidEye satellite images were used, and then, a deep learning model using FC-DenseNet, which is one of the representative deep learning models for semantic segmentation, was created. The final crop cultivation area was determined as object-based data through combination with cadastral maps. As a result of the experiment, it was confirmed that the FC-DenseNet model learned using atmospheric-corrected training data can effectively detect crop cultivation areas.