• Korean Journal of Environment and Ecology
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• v.30 no.2
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• pp.228-242
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• 2016

This research was conducted for understanding the evergreen forest community structure of the Bijin Island. The island was worth of vegetational value because of the representative warm temperate species such as Castanopsis cuspidata was distribute there. According to the results of community classification by TWINSPAN and DCA, the Bijin Island evergreen forest were classified by 9 communities, such as C. cuspidata, C. cuspidata-Pinus thunbergii, Neolitsea sericea-Camellia japonica, Platycarya strobilacea, Quercus serrata-Decidus broad-leaved, Alnus firma, P. thunbergii. Due to the C. cuspidata, N. sericea, Ca. japonica etc. were still dominated at canopy and under-canopy layer, so the evergreen forest will be sustain current conditions for a while if there is no artificial disturbances that were caused by human. Pl. strobilacea community will be expected to replace N. sericea and also Q. serrata-Decidus broad-leaved community will be changing caused by mutual competition. Normally, in the way of the succession process of the warm temperate forest, P. thunbergii will be expect via deciduous broad-leaved to evergreen forest such as Machilus thunbergii, C. cuspidata var. sieboldii, and N. sericea. In case of species diversity index, P. thunbergii comm.(1.2739), Q. serrata-Decidus broad-leaved comm.(1.2325), Decidus broad-leaved comm.(1.1807), and A. firma comm.(1.0854) are relatively high, while C. cuspidata and N. sericea-Ca. japonica that was dominated by evergreen species at canopy layer and P. thunbergii that was damaged by fire are relatively low(0.7380~0.8416). Soil pH was 4.72~6.33, electric conductance was 0.035~0.128dS/m, and content of organic matter was 3.4~17.4%.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.118-134
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• 1994

This study was conducted to investigated the plant community structure and to revaluate the part of plant ecosystem on statement of environmental impact assessment in Muju resort golf course, Solch'on area, Tokyusan National Park. The actual vegetation was comprised of Pinus densiflora-Quercus mongolica-Q. serrata community(33.21%), Q. spp. community(27.30%), P. densiflora community(20.68%) and high mountain marsh(4.93%) etc., which communities were the major vegetation and the forest vegetation was came to being a peculiar to environmental condition. The degree of green naturality 8, 9 was covered 93% in survey area, and so this result reflect the stability of ecosystem. There was all the difference between the statement of environmental impact assessment of development concerned and this study result in the estimation of degree of green naturality. The plant community were divided into six groups in fifty-four plots by DCA and the dividing groups were P. densiflora, P. densiflora-Q. mongolica, P. densiflora-Q. serrata-F. mandschurica-B. davurica, Q. mongolica-Q. serrata-P. densiflora, Q. mongolica-Q. variabilis, Salix koreansis- B. davurica community. Except P. densiflora forest in survey site, the ecological succession trend of the other communities was seemed to be from P. densiflora to Q. spp.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.91-101
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• 2000

The emission sources of volatile organic compounds (VOCs) are wastewater treatment plants. sanitary landfills, automobile industries, and so on. The VOCs are harmful to human beings because of their toxicity and carcinogenicity, and cause the serious air pollution problem producing ozone ($O_3$) as a result of photochemical reaction. To investigate the emission of VOCs from wastewater treatment plant, aeration basins at the City of Los Angeles' Hyperion Treatment Plant were selected and measured flux was compared with calculated flux. For compounds commonly associated with wastewater (DCM, TCM, PCE, UM, DCB, UND) and not expected in vehicle exhaust or ambient air coming off the ocean, concentrations immediately downwind of the aeration basins were a factor of ten or higher than those measured in the upwind air. The airborne flux of less degradable or non-biodegradable compounds, e.g., DCE, DCM, TCA, DCA, TCM, PCE, DCB, through an imaginary plane at the downwind side of the aeration basins was in agreement with the estimated flux from measured liquid phase concentrations. Henry's constant. aeration rate, and an assumption of bubble saturation. For several compounds (PCE, DCE, TCA), the ratio (measured flux/calculated flux) is almost unity.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.539-551
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• 2019

The purpose of this study is to understand the vegetation structure and ecological characteristics of the coastal forest Pinus thunbergii community in Busan Metropolitan City (BMC) and to establish reference information for the management of the coastal forest in BMC in the future. We set up 97 plots with an area of $100m^2$ each for the analysis and investigation of the vegetation characteristics. The analysis using the TWINSPAN and DCA techniques found seven community groups: Pinus thunbergii-Quercus aliena community, Pinus thunbergii-Eurya japonica(1) community, Pinus thunbergii-Eurya japonica(2) community, Pinus thunbergii-Quercus serrata community, Pinus thunbergii-Camellia japonica(1) community, Pinus thunbergii-Camellia japonica(2) community, and Pinus thunbergii-Eurya japonica-Camellia japonica community. According to the analysis of vegetation structure, Pinus thunbergii was a main dominant species at the canopy layer in all sites while Eurya japonica and Camellia japonica were dominant species at the understory layer. Pinus thunbergii-Quercus serrata community is predicted in the forest succession because of the competition between Pinus thunbergii and Quercus serrata in the canopy layer and the understory layer. As such, it is necessary to observe changes by continually monitoring this community. Tree species with strong salinity tolerance, including Pinus thunbergii, have formed community groups because of the environmental characteristics of coastal forests, strong with salinity tolerance species are forming community groups. Therefore, all community groups except for the Pinus thunbergii-Quercus serrata community will maintain the current vegetation structure unless drastic environmental changes occur.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.1-12
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• 2020

Low-Orbit satellite mobile networks can provide services through miniaturized terminals with low transmission power, which can be used as reliable means of communication in the national public disaster network and defense sector. However, the high traffic environment in the emergency preparedness situation increases the new call blocking probability and the handover failure probability of the satellite network, and the increase of the handover failure probability affects the QoS because low orbit satellites move in orbit at a very high speed. Among the channel allocation methods of satellite communication, the FCA shows relatively better performance in a high traffic environment than DCA and is suitable for emergency preparedness situations, but in order to optimize QoS when traffic increases, the new call blocking and the handover failure must be minimized. In this paper, we propose LEO-DBC (LEO satellite dynamic beam width control) technique, which improves QoS by adaptive adjustment of beam width of low-orbit satellites and call time of terminals by improving FCA-QH method. Through the LEO-DBC technique, it is expected that the QoS of the mobile satellite communication network can be optimally maintained in high traffic environments in emergency preparedness situations.

• Korean Journal of Environment and Ecology
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• v.36 no.5
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• pp.507-524
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• 2022

In this study, we revealed the location environment and community structural characteristics after extensively investigating Korea's warm-temperate island areas and categorizing vegetation through TWINSPAN analysis. Based on it, this study aims to suggest the direction of the vegetation restoration plan for warm-temperate forests by deriving a restoration strategy for each vegetation type. The vegetation types were clearly divided into eight types, and communities I through IV were good evergreen broad-leaved forests dominated by Machilus thunbergii and Castanopsis sieboldii. On the other hand, communities V through VIII were Pinus thunbergii forest, deciduous broad-leaved forest, and artificial forest, and retrogressive succession vegetation in the warm-temperate areas. The environmental factors derived from the DCA analysis were altitude (average temperature of the coldest month) and distance from the coastline (salt tolerance). The distribution pattern of warm-temperate forests has been categorized into M. thunbergii, C. sieboldii and Cyclobalanopsis spp. forest types according to the two environmental factors. It is reasonable to apply the three vegetation types as restoration target vegetation considering the location environment of the restoration target site. In communities V through VIII, P. thunbergiiand deciduous broad-leaved formed a canopy layer, and evergreen broad-leaved species with strong seed expansion frequently appeared in the ground layer, raising the possibility of vegetation succession as evergreen broad-leaved forests. The devastated land where forests have disappeared in the island areas is narrow, but vegetation such as P. thunbergii and deciduous broad-leaved forests, which have become a retrogressive succession, forms a large area. The restoration strategy of renewing this area into evergreen, broad-leaved forests should be more effective in realizing carbon neutrality and promoting biodiversity.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.413-421
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• 2022

This study was conducted to identify the vegetation structure of the Abies nephrolepis forests by analyzing species composition in Mt. Doota and Mt. Cheongok in the Gangwon region with the phytosociological method. In order to perform a field investigation, 18 survey areas with an area of about 400 m2 were set up for the stands where A. nephrolepis grow wild. Communities were classified through TWINSPAN and visualized using DCA (Detrended Correspondence Analysis). Species diversity analysis, importance value analysis, and DBH class analysis were employed to identify the characteristics of each community. As a result, the A. nephrolepis forests in Mt. Doota and Mt. Cheongok have been classified into 4 communities; GroupI, II, III and IV. GroupIis Quercus mongolica-A. nephrolepis competitive forest dominated by Q. mongolica and A. nephrolepis in the order. Group II is A. nephrolepis-Betula ermanii competitive forest dominated by A. nephrolepis, Sorbus commixta, and B. ermanii in the order. Group III is dominated by A. nephrolepis, but is expected to have competition between A. nephrolepis and Q. mongolica in the future due to the mass occurrence of Q. mongolica saplings. A. nephrolepis, S. commixta, and Q. mongolica are the dominant species in Group IV, and A. nephrolepis is the major dominant species in all layers. The species diversity of the A. nephrolepis forests in Mt. Doota and Mt. Cheongok is lower than other A. nephrolepis forests in Mt. Seorak, Maruguem, and Mt. Odae. It is necessary to establish conservation measures and to continuously monitor the A. nephrolepis forests in Mt. Doota and Mt. Cheongokis due to the harsh environment and the competition that may occur between A. nephrolepis and deciduous trees such as Q. mongolica in the future.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.662-675
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• 2022

This study was intended to investigate and analyze the current status of the plant community structure in order to provide basic data for the systematic conservation and management of the Buxus sinica area appearing on the ridgeline connecting the Gyeokjabong(Mt.) and Keungiljae, on Bogildo Island. In consideration of location characteristics such as density, topography, and direction of B. sinica appearing in the shrub layers, a total of 26 sites were set as the survey area for representative vegetation communities or areas with changes in topography. According to DCA and TWINSPAN, it was classified into 6 communities, namely Carpinus turczaninovii-Deciduous broad-leaved, C. turczaninovii, C. turczaninovii-B. sinica, C. turczaninovii-Evergreen broad-leaved, Q. acuta, and D. trifidus-Q. acuta. The community dominated by C. turczaninovii maintains the status quo for the present moment, however, Q. acuta will dominate the surrounding area in the long term, so Q. acuta has high succesion potential. In the case of the Q. acuta and D. trifidus-Q. acuta communities, Q. acuta, known as the climax species of warm-temperate forests, will maintain dominant status. In a case of B. sinica, the community dominated by C. turczaninovii will remain in good status due to the topographical conditions, but the community dominated by Q. acuta growth difficulties are expected due to the high coverage. In the relationship between environmental factors and vegetation distribution, analysis showed that only soil pH affect vegetation distribution. Furthermore, the soil acidity (pH) was 3.78-5.30, the electrical conductivity was 0.186-0.543 dS/m, and the organic matter content was 2.25-2.89%.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.19-35
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• 2022

In this study, the forest vegetation structure in the Maruguem (ridge line) area from Yuksipryeong to Cheonwangbong, Baekdudaegan, was analyzed using vegetation classification, importance values, species diversity, and NMS. Data were collected using 373 quadrates in a Braun-Blanquet vegetation survey conducted from May to October 2020. Vegetation was classified into nine vegetation units, which were verified using DCA analysis. Vegetation units 1-5, which were grouped by sub-alpine region, showed high importance values, mainly for sub-alpine vegetation, such as Abies koreana, Picea jezoensis, Pinus koraiensis, and Betula ermanii. In Maruguem, which is not high above sea level, importance values for species such as Pinus densiflora and Quercus serrata were high due to the topographical characteristics of the ridge. The A. koreana community (vegetation unit 1-5), which had a relatively high average elevation, had higher species diversity compared with that of other vegetation units. According to NMS analysis, for abiotic environmental factors, there was a positive correlation between vegetation units 1, 2, 4, and 5 and elevation. Overall, this study describes all low-elevation area vegetation (P. densiflora and Lindera erythrocarpa) to high-elevation area vegetation (A. koreana and P. jezoensis) as well as the characteristics of the Baekdudaegan ridge vegetation that did not include valley vegetation.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.127-142
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• 2024

This study aimed to understand the interrelationships between tree species in plant communities through Plant Social Network (PSN) analysis using a large amount of vegetation data surveyed in an island area belonging to a warm-temperate boreal forest. The Machilus thunbergii, Castanopsis sieboldii, and Ligustrum japonicum, which belong to the canopy layer, Pittosporum tobira and Ardisia japonica, which belong to the shrub layer and Trachelospermum asiaticum and Stauntonia hexaphylla, which belong to the vines, appearing in evergreen broad-leaved climax forest community, showed strong positive association(+) with each other. These tree species had a negative association or no friendly relationship with deciduous broad-leaved species due to the large difference in location environments. Divided into 4 group modularizations in the PSN sociogram, evergreen broad-leaved tree species in Group I and deciduous broad-leaved tree species in Group II showed high centrality and connectivity. It was analyzed that the arrangement of tree species (nodes) and the degree of connection (grouping) of the sociogram can indirectly estimate environmental factors and characteristics of plant communities like DCA. Tree species with high centrality and influence in the PSN included T. asiaticum, Eurya japonica, Lindera obtusiloba, and Styrax japonicus. These tree species are common with a wide range of ecological niches and appear to have the characteristics and survival strategies of opportunistic species that commonly appear in forest gaps and damaged areas. They will play a major role in inter-species interactions and structural and functional changes in plant communities. In the future, long-term research and in-depth discussions are needed to determine how these species actually influence plant community changes through interactions