• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.274-283
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• 2015

The reservoir shores seem to be vulnerable to biological invasion. The purpose of this research was to find out the floristic composition of alien plants and their relationship between environmental factors on reservoir shorelines in Korea. We investigated flora of alien plants and environmental factors of geomorphology, hydrology, water quality and soil on the shoreline of a total of 35 reservoirs with different water level managements. There were 56 species of alien plants, which was 15% of the total plant species identified in the study of reservoirs. A total of 57% of these alien species were the species which were introduced shortly after opening the port from 1876 to 1921 in Korea. More than 80% of the alien plants on the reservoir shores originated from America and Europe. The current distribution of Ambrosia trifida and Paspalum distichum were restricted in the central part and the southern region of the Korean Peninsula, respectively. The water level fluctuation, flood frequency at the median water level, water pollution index, coverage of rock exposure and mean degree of shoreline slope were determined as important environmental factors that have an effect on the characteristics of shoreline alien flora. Our results suggest that the reservoir shore was in danger of being invaded by alien plants due to the water level management and other human disturbances. For effective conservation of the reservoir ecosystem, periodic monitoring systems are required for the early detection of alien species on the reservoir shore.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.433-442
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• 2017

As a result of the Four-River Restoration Project in Korea, the habitat of endangered plant species of Aster altaicus var. uchiyamae and Polygonatum stenophyllum, which had been natively grown in the riparian zone of Namhan River, was destroyed and artificial replacement habitats were created. In this study, Habitat Suitability Index (HSI) was used to determine whether the replacement habitats are suitable for each species or not. From October 2015 to July 2016, Habitat Evaluate Procedures (HEP) were conducted on two replacement habitats of A. altaicus var. uchiyamae (Gangcheonsum and Sum-River) and on two replacement habitats of P. stenophyllum (Gangcheonsum and Youngjuk) in the Namhan River watershed. As evaluation parameters for A. altaicus var. uchiyamae habitat, habitat matrix (ratio of unburied gravel), height above the ordinary water level, soil nutrients, and light conditions were selected and for P. stenophyllum habitat, soil texture, light conditions, and coverage of companion species were selected. HSI was applied to evaluate the suitability of each replacement habitat. According to the result of the evaluation, replacement habitats of A. altaicus var. uchiyamae and P. stenophyllum located in Gangcheonsum have relatively high HSI values as 0.839 and 0.846, respectively. On the other hand, replacement habitats of A. altaicus var. uchiyamae in Sum-River and P. stenophyllum in Youngjuk zone have HSI value of 0, indicating unsuitable habitats for these species. This is the first attempt to apply HSI for plant species in Korea and proved the usefulness of HSI on plants.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.745-756
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• 2013

This study was carried out to suggest an experimental base to maintain the sustainability of extensive green roof as considering moisture demand by the type of the green roof plant before construction. The changes of soil moisture content, chlorophyll content, coverage of Sedum kamtschaticum and Dianthus chinensis var. senperflorens in two type of perlite soil and mix soil, were investigated under the condition of no rainfall and no irrigation during one month. The result shows that with the increase of stress time, soil moisture content and chlorophyll content on leaf were in a downward trend; After 30 days, Soil moisture content were lowest in 10 cm depth perlite soil system planted Dianthus chinensis. and 20 cm depth mix soil system planted Sedum kamtschaticum had the highest soil moisture. Generally soil moisture contents of soil system planted Dianthus chinensis var. senperflorens were lower than that of soil system planted Sedum kamtschaticum. In 10 cm depth soil system, state of plant growth was better than 20 cm depth soil system both perlite soil and mix soil type. It can be confirmed.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.168-178
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• 2017

In order to prevent major and chemical accidents, some of the plants which would like to install and operate hazard chemicals handling facilities must submit Off-site Consequence Analysis due to recent arisen leak accidents since 2015. A lot of chemical industrials choose gas detectors as mitigation equipment to early detect gas vapor. The way of placement of gas detectors has two methods; Code-based Design(CBD) and Performance-based Design. The CBD has principles for gas detectors to be installed with consideration for the place that is expected to accumulate gas, and the leak locations according to legal standards and technical guidelines, and has a possibility to be unable to detect by these rules to locate gas detectors by vapor density information. The PBD has two methods; a Geographic Method and Scenario based Method. The Scenario-based Method has been suggested to make up for the Geographic Coverage Method. This Scenario-based Method draw the best optimum placement of gas detectors by considering leak locations, leak speed information, leak directions and etc. However, the domestic placement guidelines just refers to the CBD. Therefore, this study is to compare existing placement location of gas detectors by the domestic CBD with placement locations, coverages and the number of gas detectors in accordance with the Scenario-based Method. Also this study has measures for early detecting interest of Vapor Cloud and suitable placement of gas detectors to prevent chemical accidents. The Phast software was selected to simulate vapor cloud dispersion to predict the consequence. There are two cases; an accident hole size of leak(8 mm) from API which is the highst accident hole size less than 24.5 mm, and a normal leak hole size from KOSHA Guide (1.8 mm). Detect3D was also selected to locate gas detectors efficiently and compare CBD results and PBD results. Currently, domestic methods of gas detectors do not consider any risk, but just depend on domestic code methods which lead to placement of gas detectors not to make personnels recognize tolerable or intolerable risks. The results of the Scenario-based Method, however, analyze the leak estimated range by simulating leak dispersion, and then it is able to tell tolerable risks. Thus it is considered that individuals will be able to place gas detectors reasonably by making objectives and roles flexibly according to situations in a specific plant.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.481-488
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• 2006

The field scale experiment was performed to examine the performance of the constructed wetland for nonpoint source (NPS) pollution loading reduction. Four sets (0.88 ha each) of wetland and pond system were used. After three growing seasons of the wetland construction, plant coverage increased to about 90% even without plantation from bare soil surfaces at the initial stage. During the start up period of constructed wetlands, lower water levels should be maintained to avoid flooding newly plants, if wetland plants are to start from germinating seeds. The average removal rate of $BOD_5$, TSS, T-N and T-P during the first two years was 5.6%, 46.6%, 45.7%, and 54.8%, respectively. The $BOD_5$ removal rate was low and it might be attributed to the low influent concentration. The early stage of wetland performance demonstrated the effectiveness of water quality improvement and was satisfactory for treating polluted stream waters. From the first-order analysis, T-P was virtually not temperature dependent, and $BOD_5$ and TSS were more temperature dependent than T-N. A pond-wetland system was more effective than a wetland-pond or a wetland alone system in water quality improvement, particularly to reduce T-P. Overall, the wetland system was found to be an adequate alternative for treating a polluted stream water with stable removal efficiency and recommended as a NPS control measures.

• Korean Journal of Environment and Ecology
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• v.15 no.4
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• pp.379-393
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• 2002

Thirty-six plots (each size 100m2) have been set up and surveyed to investigate the plant community structure and the ecological density of Pinus densiflora for. eracta(Chunyang-type) community in Seobyeok-ri, Chungyang-myeon, bonghwa-gun, Kyeongsangbuk-do. Four communities, Community I (large DBH class), Community II (large DBH class), Community III (middle DBH class), Community IV(small DBH class), were classified into by mean DBH and mean height. Pinus densiflora for. eracta dominate in canopy layer, Fraxinus sieboldiana and Quercus mongolica dominate in understory layer, Rhododendron Schlippenbachii and R. mucronulatum dominate in shrub layer. It turned out that thefour communiteis had low species diversity(0.4320~0.9487; unit: 400$m^2$) and high similarity. By the result of ecological density analysis. the mean basal area was proportionated to mean DBH (cm) size. By the result of simple regression analysis between mean DBH(cm), mean distance(m), and the number of individual were as follow: Ecological distance(m) = 0.0934$\times$ DBH(cm) +0.6117, Number of individual=242.47$\times$ DBH(cm)$^{-1.009}$, Ecological distance=9.643$\times$No. of individua $l^{-0.7016}$. In addition to four communities were suitable to the growth of Tricholoma matsutake because average species were about 30~50 years old, litter layer was 0.5~2.5cm and the ratio of coverage shrub was 20% .

• Korean Journal of Environment and Ecology
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• v.17 no.3
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• pp.201-209
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• 2003

This study was carried out to select proper species fur early stage replantation in forest road cut-slope. From one to fifteen years elapsed forest roads in four regional areas of Gyeongsangnam-do and Jeollanam-do, sample plots were selected, and their vegetations and environmental factors were investigated. Invaded species and plant coverage have increased with elapsed years. The occurrence rate of herbs have decreased, while the occurrence of trees have increased with elapsed years. The ordination analysis showed that distribution of species was influenced by the elapsed year, the slope angle of the cut-slope, elevation, and the direction angle of the cut-slope. Dactylis glomerata, Poa pratensis, Amorpha fruticosa, Lespedeza sp., Artemisia princeps var. orientalis, Duchesnea chrysantha, Miscanthus sinensis, Pueraria thunbergiana, Zanthoxylum schinifolium, Rhus chinensis, and Weigela subsessilis were considered as proper species for replantation in forest road cut-slope, besides the species used already. Seventy seven family, 190 genus, 233 species, 38 variety, and 271 species in total were counted as invaded plant species in the survey zone. Naturalized plants were 18 species. Invaded species are, with high frequency first, Rubus crataegifolius, Artemisia princeps var. orientalis, Zanthoxylum schinifolium, Pueraria thunbergiana, Pinus densiflora, Lespedeza maximowiczii, Lysimachia clethroides, Lespedeza bicolor, Youngia denticulata, Miscanthus sinensis, and Erigeron annuus.

• Journal of Plant Biology
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• v.28 no.2
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• pp.165-175
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• 1985

The natural forest vegetation of the Piagol, Mt. Chiri, was classified into five major communities, i.e. Quercus mongolica, Carpinus laxiflora, C. tschonoskii, Q. serrata and Fraxinus mandshurica community. C. tschonoskii, C. laxiflora and Q. mongolica characteristically were dominated in the range of 500∼700 m, 700∼900 m and 900∼1,400 m in altitude, respectively. Abies nephrolepis and Rhododendron schlippenbachii in the ridge of Nogodan-Nalnaribong, and F. mandshurica and Q. serrata in the Yongsuam ravine were found as the dominant species. The transition between C. tschonoskii and C. laxiflora communities was relatively wide. The boundary between F. mandshurica, in the conglomerated zone, and the other communities surrounding its community was fairly abrupt. In Q. mongolica community, the canopy was relatively opened and the oak young tree of undergrowth was fairly dense. In the community of C. laxiflora and C. tschonoskii, the species composed of their understory was rich while their coverage was lower than that of Q. mongolica community. Shannon's diversity index was decreased in order of C. tschonoskii, C. laxiflora and Q. mongolica community, while their Simpson's dominance index increased conversely. Judging by the DBH-class distribution showing the negative exponential curve, these communities were considered as the climax forest. In Polar Ordination used samples (quadrats), the vegetation of the Piagol was divided into five groups, which was coincided with five communities classified by Braun-Blanquet system. In the ordination, the first axis and the second axis may be considered soil conditions and thermal conditions, respectively. It seems that two different methods, phytosociological method in macro level and ordination techniques in micro level, are useful for the vegetation classification.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.227-232
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• 2014

Ageratina altissima is an invasive plant species known to threaten native plant communities in Korea. A. altissima is thought to invade shady forests from disturbed open areas; however, uncertainty remains as to how shade and litter depth might affect establishment. A study of A. altissima distribution characteristics in areas adjacent to trails was undertaken at Mt. Umyeon in Seoul, Korea. Increasing densities of A. altissima were found to correlate with greater light availability and decreasing litter depth (p < 0.001) within 10 m distance from trail locations and on ridges rather than further within forests and valleys. The effects of soil moisture content, soil gravel content and soil pH on distribution were not found to be significant, suggesting that A. altissima is adaptable to a broad range of soil conditions. Results indicate that forest areas close to trails may be particularly susceptible place to A. altissima invasion, demonstrating the need to carefully consider implications for A. altissima expansion in trail management.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.1
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• pp.79-91
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• 2005

Wetland systems are widely accepted natural water purification systems around the world in nonpoint sources pollution control. Constructed wetlands have become a popular technology for treating contaminated surface and wastewater. In this study, the field experiment to reduce nonpoint source pollution loadings from polluted stream waters using wetland system was performed from June 2002 to March 2004, including winter performance using four newly constructed wetlands. The Dangjin stream water flowing into Seokmun estuarine lake was pumped into wetlands, and inflow and hydraulic residence time of the system was $500m^{3}{\~}1500m^{3}/day\;and\;2{\~}5$ days respectively. After 3 years operation plant-coverage was about $80~90\%$ from zero at initial stage even with no plantation. Average water quality of the influent in growing season was BOD_{5}\;3.96mg/L$, TSS 22.98 mg/L, T-N 3.29 mg/L, T-P 0.30 mg/L. The average removal rate of four wetlands for $BOD_{5},\;TSS,\;T-N\;and\;T-P$ in growing season was $24\%$, $62\%$, $54\%$, and $51\%$, respectively. And average water quality of the influent in winter season was $BOD_{5}$ 4.92 mg/L, TSS 12.47 mg/L, T-N 5.54 mg/L, and T-P 0.32 mg/L, respectively. The average removal rate of four wetlands for them was $-21\%$. $23\%$, $33\%$, and $53\%$, respectively. The reason of higher BOD_{5} effluent concentration in winter season might be that low temperature restrained microorganism activity and a organic body from the withered plant and algae was flown out. Except the result of $BOD_{5}$, the effectiveness of water quality improvement in winter season was satisfactory for treating polluted stream waters, and $BOD_{5}$ variation was within the range of background concentration. Performance of the experimental system was compared with existing data base (NADB), and it was within the range of general system performance. Overall, the wetland system was found to be satisfactory for NPS control such as improvement of polluted stream water.