• Korean Journal of Environmental Biology
• /
• v.37 no.1
• /
• pp.109-118
• /
• 2019

This study was carried out to investigate the vegetation of wetland and terrestrial lands in Jangdo wetland conserved area in Korea and to analyze the characteristics of the vegetation changes in the recent years. From the plant community, there were evergreen broad-leaved forests of the Machilus thunbergii, Castanopsis cuspidata, and Machilus thunbergii-Castanopsis cuspidata communities. Moreover, there were deciduous broad-leaved forests of the Salix koreensis, Mallotus japonicus, Mallotus japonicus-Pueraria thunbergiana and Celtis sinensis communities. Additionally, there were shrub forests of the Rosa multiflora-Rubus hirsutus, grassland of Molinia japonica-Miscanthus sacchariflorus and Miscanthus sacchariflorus-Imperata cylindrica communities, and plantation forest of the Pseudosasa japonica community. The area of the wetland vegetation (15%) was much narrower than that of the terrestrial land vegetation (85%). Comparing these results with those of the past 10 years, the wetland plant communities decreased by one-third and the proportion of neutral or dry plant communities increased. In order to mitigate landization succession of the wetland and maintain native wetland vegetation in this area, the expansion of the Salix koreensis community must be controlled to a suitable scale. In addition, it is urgently required to remove the invasive non-wetland plants, such as Pseudosasa japonica and Pueraria thunbergiana.

• Korean Journal of Plant Taxonomy
• /
• v.49 no.1
• /
• pp.70-89
• /
• 2019

In this study, we investigated the flora of Jeonggwangsan Mt. (Yongin, Korea) from May of 2015 to September of 2016. Through 14 independent field investigations, we identified a total of 367 taxa of vascular plants, including 89 families, 234 genera, 323 species, six subspecies, 34 varieties, and four formae. Eight taxa were endemic to Korea, while 27 were naturalized in Korea. Nineteen taxa were the floristic regional indicator plants in Korea: four in Rank VI, four in Rank III, two in Rank II, and nine in Rank I. A total of 59 taxa were designated as controlled Korean biological resources, requiring special permission for export to outside countries. Two taxa were listed on the Red List of Korea, including one Near Threatened (NT) taxon (Hololeion maximowiczii Kitam.) and one Least Concern (LC) taxon (Iris minutoaurea Makino).

• Journal of the Korean Institute of Landscape Architecture
• /
• v.47 no.1
• /
• pp.49-56
• /
• 2019

Urban green spaces have been contributing to the improvement of environmental, mental, and physical health for humans. In addition, recent studies showed the potential role of vegetation in reducing the amount of crime in inner-city neighborhoods at the micro-scale level. However, little is known about the positive role of urban green areas in improving urban safety at the regional level. The purpose of this study is to examine the relationship between urban green areas and actual outdoor crime rates, while also considering socio-demographic factors. The study area is the city of Austin, Texas, USA, which consists of 506 block groups. This study utilized socio-demographic factors based on U.S. Census data and vegetation-related factors utilizing GIS and ENVI software. For analyses, the analysis of variance (ANOVA) and an ordinary least square (OLS) regression were utilized. The results from ANOVA showed that yearly crime rates per acre for areas having 0%~25% trees in their neighborhoods were 0.46% and 1.05% higher than those of having 25%~50% and >50% trees in the neighborhoods, respectively. The results from the OLS regression represented that income, NDVI and park rates in neighborhoods were negatively associated with the crime rate per acre, whereas the percentage of minorities and the percentage of teenage school dropouts were positively associated with the crime rate per acre. This study implies that urban green areas may help to improve the safety of urban areas.

• Korean Journal of Environment and Ecology
• /
• v.35 no.2
• /
• pp.193-203
• /
• 2021

As endangered species are gradually increasing due to land development by humans, it is essential to secure sufficient protected areas (PAs) proactively. Therefore, this study checked priority conservation areas to select candidate PAs when considering the impact of land development. We determined the conservation priorities by analyzing four scenarios based on existing conservation areas and reflecting the development impact using MARXAN, the decision-making support software for the conservation plan. The development impact was derived using the developed area ratio, population density, road network system, and traffic volume. The conservation areas of endangered species were derived using the data of the appearance points of birds, mammals, and herptiles from the 3rd National Ecosystem Survey. These two factors were used as input data to map conservation priority areas with the machine learning-based optimization methodology. The result identified many non-PAs areas that were expected to play an important role conserving endangered species. When considering the land development impact, it was found that the areas with priority for conservation were fragmented. Even when both the development impact and existing PAs were considered, the priority was higher in areas from the current PAs because many road developments had already been completed around the current PAs. Therefore, it is necessary to consider areas other than the current PAs to protect endangered species and seek alternative measures to fragmented conservation priority areas.

• Economic and Environmental Geology
• /
• v.55 no.2
• /
• pp.197-207
• /
• 2022

This study investigated spectroscopic exploration of Myeonsan formation, the titanium(Ti) ore hostrock, in Joseon supergroup based on machine learning technique. The mineral composition, Ti concentration, spectral characteristics of Myeonsan and non-Myeonsan formation of Joseon supergroup were analyzed. The Myeonsan formation contains relatively larger quantity of opaque minerals along with quartz and clay minerals. The PXRF analysis revealed that the Ti concentration of Myeosan formation is at least 10 times larger than the other formations with bi-modal distribution. The bi-modal concentration is caused by high Ti concentrated sandy layer and relatively lower Ti concentrated muddy layer. The spectral characteristics of Myeonsan formation is manifested by Fe oxides at near infrared and clay minerals at shortwave infrared bands. The Ti exploration is expected to be more effective on detection of hostrock rather than Ti ore because ilmenite does not have characteristic spectral features. The random-forest machine learning classification detected the Myeonsan fomation at 85% accuracy with overall accuracy of 97%, where spectral features of iron oxides and clay minerals played an important role. It indicates that spectral analysis can detect the Ti host rock effectively, and can contribute for UAV based remote sensing for Ti exploration.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.1
• /
• pp.28-34
• /
• 2004

This study was performed to evaluate the characteristics of the carboxymethylated substrate from high reactive autohydrolyzed cellulose (HRC) and those of commercial α-cellulose (CAC) and refiner mechanical pulp (RMP). Saccharification rates of HRC substrate were achieved over 70% with 12 hr hydrolysis, about 90% with 24 hr, and 99.5% with 72 hr. CMCase and avicelase activities of cellulase onozuka were 4.09 ㎛ G/mg·min and 14.0 ㎛ G/mg·min, respectively. There were no any significant changes in cellulase activities with this substrate. The saccharification rates of CAC and RMP were very low, 57% and 38% with 72 hr, respectively. Those lignin-zero autohydrolyzed substrates, HRC and CAC, were highly carboxymethylated at the high alkali concentration, near 30%, for 3 hr. reaction, and resulted in 1.13-1.15 of D.S., besides 0.85 of D.S. from RMP. Water solubilities of carboxymethylated substrates were increased with an increase of D.S., 98-98.5% from HRC and CAC and 31.5% from RMP. RMP which has low specific surface area showed lower water retention values, compared to high values of 435 and 321% from CAC and HRC, respectively. There were no direct relationship between surface area and swelling ratio of the substrates.

• Korean Journal of Environment and Ecology
• /
• v.35 no.2
• /
• pp.181-192
• /
• 2021

This study surveyed visitors' perceptions of Mudeungsan National Park's Seoseokdae Trail Section (STS) on the visitor reservation system (VRS). Data were collected from 248 visitors to STS selected through convenient sampling in May 2019. The majority (86.9%) of the respondents rated their overall experience in STS as either "no problem at all" or "little problem". Moreover, 43.0% of the respondents were aware of the VRS. The most popular information source for VRS was the Internet (49.7%), followed by other people (18.4%) and broadcasting media, e.g., TV (17.7%). While 69.9% of the respondents thought that implementation of VRS would be effective in improving managerial conditions of the STS, respondents perceived that "cumbersome reservation procedures" (79.3%) of the VRS operation was the most important problem, followed by "unfairness associated with Internet familiarity gap" (78.7%) and "deprivation of the opportunities to visit freely" (76.3%). The support for VRS implementation was higher among higher-aged, married, higher-educated, more frequent STS visitors, Gwangju residents, and solo visitors than the other groups. The "knowledge level about VRS" and "the awareness level about potential problems associated with VRS operation" negatively influenced the support for the implementation of VRS, while "the perceived managerial effectiveness of VRS" positively influenced it.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.2
• /
• pp.9-18
• /
• 2004

This study was carried out to find the efficient methods for preventing resin exudation from spruce board during high temperature environment service.In the dry-air oven test, in-use temperature related to resin exudation of 110℃ could be obtained by the appropriate kiln drying without any special treatment, and the in-use temperature of the radio-frequency/vacuum (RF/V)-dried boards was about 20℃ higher than that of the conventional kiln-dried boards.In the autoclave test, resin exudation was not found from any board dried in the conventional kiln and in the RF/V kiln after the low pressure steam explosion (SE) treating, while for the control resin exudations were more severe in the autoclave test above 130℃ than in the dry-air oven test. It, therefore, would be suggested that resin exudation during high temperature service condition can be prevented more effectively by super-heated steaming green boards than by high-temperature drying boards with low moisture.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.4
• /
• pp.58-65
• /
• 2004

This study was performed to investigate the protease activity from fruit body of Sarcodon aspratus and its features. The specific protease activity was increased with the increasing purification steps, 2.62 times by desalting, 17 times by CMC column chromatography, 113.8 times by DEAE-Sephadex A-50 column chromatography, and 728.3 times by Sephadex G-75 column chromatography. Proteases were identified as two different enzymes having different isoelectric points at pH 4.35 (its recovery rate 8%) and pH 4.7 (its recovery rate 3.5%). Those proteases were purified by 3,025 folds and 3,257 folds in terms of specific activity. Two proteases having different isoelectric points had similar enzymatic properties. This protease was estimated to be 43,000 daltons of molecular weights by SDS-PAGE. This protease with optimum pH 4 was almost stable in the pH range of 4~7. Optimal temperature of protease activity was 40 to 50℃, and the protease activity was completely inhibited at 70℃ for 30 min.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.5
• /
• pp.12-19
• /
• 2004

This study was performed to investigate the optimum condition of protease production from submerged culture of oak mushroom (Lentinula edodes, Sanlim No. 5) and its enzymatic features. Among several combinations of media, the combination of wheat bran, corn flour, water and corn oil (WB+CF+W+ CO) yielded 84.8 U/g of maximum protease activity. This combination of ingredients, in spite of not being particularly protein-rich in comparison to the other media, allowed for good growth of the fungus and maximal protease production. Comparison of different growth medium liquids indicated that demineralized water afforded the best growth of the fungus and the highest protease activity. Acetate buffer and acidified water negatively affected The protease production peaked around 72 hr of incubation, and decreased thereafter. The molecular weights of produced protease were about 45,000 by Sephadex G-75 chromatography. The pH optimum for protease activity was 4, while maximal activity incubated at 37℃ for 1 hr was observed between pH 4~6. The optimum temperature of this protease was 55℃, and the enzyme was active over a broad temperature range (30~60℃), indicating that this protease would be suitable for a wide range of applications where. different pH and temperature are necessary, such as digestive aids, food industry, beer and tannery industries.