• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.366-377
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• 2019

Paddy wetlands are a critical habitat for a variety of wild animals, and their rapid development and environmental changes pose a threat to the conservation of agrobiodiversity. The objectives of this study were to evaluate the habitat characteristics of anuran inhabiting paddy wetlands and identify major environmental variables affecting their distributions. The study was conducted in the Daeho reclaimed area in Dangjin, from March to October 2018. In this study, we found three anuran species (Pelophylax nigromaculatus, Hyla japonica and Pelophylax chosenicus). The environmental factors affecting the three species were identified as air temperature, humidity, water-depth, and micro-habitats. H. japonica were affected by water temperature, and P. chosenicus were affected by rice height and types of farming practices. All the three species richness was correlated with air temperature, humidity, and water-depth positively, and the three species used rice transplanted paddy fields the most. It was also found that paddy is the most preferred of the micro-habitats during the breeding season, so the survey area is considered to be used as the major breeding sites for the three species. P. chosenicus were more observed on environmental-friendly paddy fields than conventional paddy fields, which appears to be differences in their surroundings environment caused by predators and weeding. It will be needed to identify their relationship with predators, their preferred food resources and the richness and diversity of wild vegetation around paddy wetlands.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.709-720
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• 2018

In order to optimize the evaluation of biomass in crop monitoring, accurate and timely data of the crop-field are required. Evaluating above-ground biomass helps to monitor crop vitality and to predict yield. Unmanned Aerial Vehicle (UAV) imagery are being assessed for analyzing within field spatial variability for agricultural precision management, because UAV imagery may be acquired quickly during critical periods of rapid crop growth. This study reports on the development of remote sensing techniques for evaluating the biomass of winter crop. Specific objective was to develop statistical models for estimating the dry weight of barley and wheat using a Excess Green index ($E{\times}G$) based Vegetation Fraction (VF) and a Crop Surface Model (CSM) based Plant Height (PH) value. As a result, the multiple linear regression equations consisting of three independent variables (VF, PH, and $VF{\times}PH$) and above-ground dry weight provided good fits with coefficients of determination ($R^2$) ranging from 0.86 to 0.99 with 5 cultivars. In the case of the barley, the coefficient of determination was 0.91 and the root mean squared error of measurement was $102.09g/m^2$. And for the wheat, the coefficient of determination was 0.90 and the root mean squared error of measurement was $110.87g/m^2$. Therefore, it will be possible to evaluate the biomass of winter crop through the UAV image for the crop growth monitoring.

• Korean Journal of Environmental Biology
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• v.19 no.4
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• pp.313-320
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• 2001

An ecological study was conducted to determine the geographic distribution, community structure, and habitat characteristics of eelgrass, Zostera marina L. beds along the southern coast of Korea. Plants and sediment samples were collected during June 2000 and December 2000 on twenty-eight locations, including two Cheju Island stations, which were used to compare morphological characteristics with habitat types. Z. marina populations existed from the intertidal to subtidal zone, mainly in the bays along the coast and the island, the barrier reef, and the estuary where the water depth was 0.5${\sim}$8.0m. Salinity range in Z. marina beds ranged 18.2 to 34.5%$_o$. Sediments of Z. marina beds contained 49.7${\sim}$99.1% of sand and were classified into sand, muddy sand, and sandy mud. Mean grain size varied from 1.5 to 4.4 phi. Height of vegetation shoots varied from 54.7 to 171.4 cm, depending on water depth, location, substrata and habitat types. quantitative morphological features that enabled recognition of the two phonetic groups were short-narrow leaf type and long-broad leaf type. Statistical analysis indicated that biomass of individual plants and their quantitative morphological characteristics were significantly correlated.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1319-1328
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• 2011

Rhododendron brachycarpum is a evergreen broad-leaved shrub and belongs to the Ericaceae family and the Rhododendron genus. It is well known for its beautiful leaves and flowers. There are 11 species of the Rhododendron genus in Korea. It includes 3 species - Rhododendron brachycarpum, Rhododendron aureum Georgi and Rhododendron brachycarpum var. roseum Koidz. They grow naturally over 1,000 meters above sea level of the Baekdu Mountain Range in Korea. These habitats, according to investigations of 9 Rhododendron brachycarpum natural habitats, are mostly located on the slope of mountains facing north at an altitude of 1,200 m to 1,526 m above sea level with angle of inclination from 30 degrees to 45 degrees. Based on the result of vegetation analysis of dominance species in the quadrates, there are Quercus aliena, Quercus mongolica Fisch. ex Ledeb, Abies holophylla in species of upper trees, and so on. Dominant species of woody plants in tree layer are Quercus aliena, Quercus mongolica Fisch. ex Ledeb, Abies holophylla, Betula platyphylla and Veeatrum patulum Loes. fil, Erythronium japonicum, Dryopteris crassirhizoma, Paeonia japonica var. glabra Makino are founded in herbaceous plants. And we can see another result of the investigation that the flowering rates of the plants with the buds are highly ranked mountains such as Mt. Hambaek 68%, Mt. Gyebang 40%, Mt. Yagksu 9%, Mt. Gaein 7% and Mt. Seolag 0%. The results show that there are 24 over 15-year-old Rhododendron brachycarpums in Mt. Odae and are 56 under 15-year-old trees in Mt. Hambaek and are no trees in Mt. Gyebang and are 9 over 30-year-dead trees only in Mt. Taebaeg. Out of found trees, the highest tree is 7 m in height and 0.6 m in diameter. Also this result shows what are the vulnerability factors of the natural habitats. They are as follows: indiscriminate trails in mountains, damages by mountain climbers, uncareful plant collecting, the fierce competitions with other plants such as Acer pseudosieboldianum var. ishidoyanum Uyeki, Quercus aliena, Celastrus orbiculatus and damages by disease and insect, unusual temperature in natural habitats, etc. Rhododendron brachycarpums have high ornamental value and excellent pharmaceutical effect. But the areas of its habitats decrease dramatically. So we need measures to protect and their natural habitats. It is necessary that we conductfurther investigations to designate conservation area for Rhododendron brachycarpums.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.13-18
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• 2019

The DEM(Digital Elevation Model) is a three-dimensional spatial information that stores the height of the terrain as a numerical value. This means the elevation of the terrain not including the vegetation and the artifacts. The DEM is used in various fields, such as 3D visualization of the terrain, slope, and incense analysis, and calculation of the quantity of construction work. Recently, many studies related to the construction of 3D geospatial information have been conducted, but research related to DEM generation is insufficient. Therefore, in this study, a DEM was constructed using a MMS (Mobile Mapping System), UAV image, and UAV LiDAR (Light Detection And Ranging), and the accuracy evaluation of each result was performed. As a result, the accuracy of the DEM generated by MMS and UAV LiDAR was within ± 4.1cm, and the accuracy of the DEM using the UAV image was ± 8.5cm. The characteristics of MMS, UAV image, and UAV LiDAR are presented through a comparison of data processing and results. The DEM construction using MMS and UAV can be applied to various fields, such as an analysis and visualization of the terrain, collection of basic data for construction work, and service using spatial information. Moreover, the efficiency of the related work can be improved greatly.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.111-126
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• 2017

Small-scale UAS(Fusion technique of Unmanned Aerial Vehicles platform and Sensors, 'sUAS') opens various new applications in construction fields and so becoming progressively common due to the considerable potentials in terms of accuracy, costs and abilities. The purpose of this study is that the investigation of the validation on the utilization of sUAS for earth stockpile volume calculations on sites. For this, generate 3D models(DSM) with sUAS aerial images on an cone shaped soil stockpile approximately $270m{\times}300m{\times}20m$, which located at Baegot Life Park in Siheung-si, compared stockpile volume estimates produced by sUAS image analysis, against volume estimates obtained by GNSS Network-RTK ground surveying method which selected as the criteria of earth stockpile volume. The result through comparison and examination show(demonstrate) that there was under 2% difference between the volume calculated with the GNSS Network RTK data and the sUAV data, especially sUAS imaged-based volume estimate of a stockpile can be greatly simplified, done quickly, and very cost effective over conventional terrestrial survey methods. Therefore, with consideration of various plan to assess the height of vegetation, sUAS image-based application expected very useful both volume estimate and 3D geospatial information extraction in small and medium-sized sites.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.141-147
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• 2005

To clarify seed distribution in sediment and its burial properties of Suaeda japonica, the vertical and horizontal distribution of seeds, organic content of sediment, and sediment content delivered by crabs were studied in mud tidal-flat of Walgot-dong, Siheung, Gyeonggi Province, from March 1999 to October 2000. The 94% and 6% of S. japonica seeds were buried under and outside the maternal plant crown, respectively. Organic matter contents of sediment were higher at the area (17%) covered than at the one (8%) uncovered by S. japonica. In the area covered by S. suaeda, organic matter profiles of sediment showed vertical variation from 19% in surface (1 cm depth) to 14% in 6 cm depth. S. japonica seeds buried in sediment decreased from 45% in 2 mm depth to 0% in 12 mm depth. The density of crabs was higher in the vegetated area than in the non-vegetated one. Especially, the density of Cleistostoma was about 8 times higher in the former than in the latter In the vegetated area, the amount of sediment delivered by crabs was estimated to be 2,409 $cm^3{\cdot}m^{-2}$, and this could ascend the height of sediment to 2.4 mm. Consequently, it might be interpreted that plant debris (organic matters) of maternal plants and sediment delivered by crabs made the S. japonica seeds bury well. By relationship between crab distribution and vegetation, it was thought that crabs got a benefit from S. japonica.

• Journal of Korean Society of Forest Science
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• v.94 no.4 s.161
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• pp.269-276
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• 2005

This research was carried out in order to make clear population and community structure of Berchemia berchemiaefolia forest surveyed from October 1998 to October 2004 which was located in Janggok-Ri Gunwi-Gun, Kyungpook province. B. berchemiaefolia community was classified into 3 groups such as Picrasma quassioides group, Carex ciliata-marginata group and Typical group using ZM methods. In case of floristic composition structure according to crown stories, B. berchemiaefolia occupied 42.82%, 34.43%, and 5.28%, in tree layer, subtree layer and shrub layer, respectively. Importance value of Quercus variabilis, Platycarya strobilacea and Quercus serrate species was generally high. Species diversity of Picrasma quassioides group indicated 1.6669 which was highest value among the 3 vegetation groups. Population of B. berchemiaefolia showed overall the structure of reverse J type in DBH class showing the peak between 6 cm and 10 cm and reached 14 meters in height class, and the age structure of the population ranged from 11 years to 60 years showing regular distribution type. Stump sprout or/and epicormic branch made numerous stems around original stump of previous generation which was considered to be cut and disappeared by residents. Seedlings or/and saplings of B. berchemiaefolia were intensively occurred in the opened areas of forest road. Those things could be certainly considered to establish management plan of B. berchemiaefolia forest.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.564-570
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• 1997

Field experiments were carried out to investigate the effects of different residue treatment of vetch sward on soil improvement, rice growth and grain yield from 1995 to 1996. With Chinese milkvetch, pH, Ca, and Mg of paddy soil were increased in subsoil(10~20cm soil depth), and organic matter, P$_2$ $O_{5}$, and K were increased in top soil (0~10cm soil depth). Redox potential of the paddy soil with milkvetch residue was severely reduced at earlier flooding period, and recovered gradually as rice growth continued. Weeds were more abundant in the paddy with unchanged vetch stand. The most dominant weed species in the paddy soil with vetch sward residue was Echinochloa crus-galli, followed by Leersia japonica, Polygonum hydropiper in the order of abundance. Seedling establishment ratio of rice directly sown over vetch-sward was lower than in conventional tillage paddy(no-vetch, tilled) condition. Rice growth pattern, however, was not significantly affected by vetch sward treatments. The number of tillers per square meter and plant height at heading date were not significantly different among the vetch-sward treatments. Grain yield was the highest in plough of vetch vegetation, followed by conventional (no-vetch, tilled), live-mulching of vetch, vetch-removed, and vetch-desiccated by weedcide. The whole grain rice yield was the lowest in vetch-desiccated by weedcide.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.101-109
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• 2003

The study area, Kwangneung Experiment Forest (KEF) is located on the west-central portion of Korean peninsula and belongs to a cool-temperate broadleaved forest Bone. At the old-growth deciduous forest near Soribong-peak (533.1 m) in KEF, we have established a 1 ha permanent plot ($100m{\times}100m$) and a flux tower, and the site was registered as a KLTER(Korean long-term ecological research network) and DK site of KoFlux. In this site, we made a stemmap of trees and analyzed forest stand structure and physical and chemical soil characteristics, and estimated carbon budgets by forest components (tree biomass, soils, litter and so on). Dominant tree species were Quercus serrata and Carpinus laxiflora, and accompanied by Q. aliena, Carpinus cordata, and so on. As a result of a field survey of the plot, density of the trees larger than 2 cm in DBH was 1,473 trees per ha, total biomass 261.2 tons/ha, and basal area $28.0m^2$/ha. Parent rock type is granite gneiss. Soil type is brown forest soil (alfisols in USDA system), and the depth is from 38 to 66 cm. Soil texture is loam or sandy loam, and its pH was f개m 4.2 to 5.0 in the surface layer, and from 4.8 to 5.2 in the subsurface layer. Seasonal changes in LAI were measured by hemispherical photography at the 1.2 m height, and the maximum was 3.65. And the spatial distributions of volumetric soil moisture contents and LAIs of the plot were measured. The carbon pool in living tree biomass including below ground biomass was 136 tons C/ha, and 5.6 tons C/ha is stored in the litter layer, and about 92.0 tons C/ha in the soil to the 30 cm in depth. Totally more than about 233.6 tons C/ha was stored in DK site. These ground survey and monitoring data will give some important parameters and validation data for the forest dynamics models or biogeochemical dynamics models to predict or interpolate spatially the changes in forest ecosystem structure and function.