• Korean Journal of Environment and Ecology
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• v.20 no.1
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• pp.52-69
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• 2006

The flora of vascular plants and the vegetation on the tidal flat was investigated in Jebudo located at Hwaseong city of Gyeonggi-do province from 2004 to 2005. Jebudo has been considered to show difference from the flora which is peculiar to island as it became semi-land by free traffic to mainland with the installation of a road which had enabled entry into the Jebudo in 1991 due to sea-splitting phenomenon. The result of the vascular plants in Jebudo were consissted of 305 taxa; 264 species, 38 varieties and 3 forms of 202 genera of 74 families. As a result of examination by distinctive survey areas within Jebudo, a tidal flat(I) region where the halophyte was being spread has been researched as 7 taxa; 7 species of 6 genera of 5 families. The taxa in Godo-Island(II) was reseached as 50 taxa; 39 species, 11 varieties and 42 genera of 24 families. The taxa in Sand dune area(III) was reseached as 61 taxa; 52 species and 9 varieties of 53 genera of 25 families. The most plant species was reseached in Mt. Tapjae (IV) reaseach area among the reseach areaes 136 taxa; 118 species, 17 varieties and 1 form of 108 genera of 55 families. The taxa in Dangje Mt.(V) was reseached as 119 taxa; 105 species, 13 varieties and 1 form of 95 genera of 45 familes. The taxa in Dongmi Mt. (VI) was reseached as 100 taxa; 85 species and 15 varieties of 83 enera of 43 families. The taxa in Paddy field(VII) was reseached as 120 taxa; 106 species, 13 varieties and 1 form of 86 genera 31 families. Especially, a Crypsinus hastatus community which is a rare plant designated by Korea forest service and a preservation plant designated by the natural environment preservation law (1998) has been discovered at a cliff of Topjae mountain near the ferry located at the northeast side. According to the result of researching halophyte communities which make up the zonation according to the environmental gradient, the communities were being formed in the order of Limonium tetragonum community, Phragmites communis community, Carex scabrifolia community, Triglochin maritimum community and Carex scabrifolia community in accordance with the order of soil particle size with breakwater as their standard.

• Korean Journal of Environment and Ecology
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• v.21 no.5
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• pp.400-414
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• 2007

This study has analyzed the vegetation structure to suggest a vegetation ecological restoration model by using the case of the afforestation for erosion control area with Pinus koreaiensis and Betula platyphylla, etc., on the hills of the Young-in mountains after its great fire in 2000. Of the area having a dimension of $1,152,404.3m^2$ selected as a survey site for the existing vegetation, the forest fire area accounted for 69.2% among which, brushwoods accounted the most for 24.67%. As a result of analysis of the 27 surveyed unit plots[unit dimension: $100m^2$] set up in consideration of the existing vegetation pattern and damaged state from the forest fire, the surveyed area was classified into 10 communities. Shrub layer's vegetation was found to be dominant in forest fire areas and the surveyed sites were classified into 5 plant communities, i.e. P. koraiensis community, Quercus variabilis community, P. thunbergii community, Q. serrata community, B. platyphylla community in forest fire areas, while non-forest fire areas were classified into 5 plant communities, such as P. densiflora community, Q. acutissima community, Q. serrata community, Q. mongolica-Q. serrata community, B. platyphylla community. Species diversity of forest fire areas was $0.3679{\sim}0.5907$ and that of non-forest fire areas was $0.5728{\sim}0.8865$. In addition, the number of the species in the forest fire areas was $5{\sim}8$ and that of non-forest areas was $8{\sim}12$; however, the population of forest fire areas$(156{\sim}456)$ was higher than that of non-forest fire areas$(61{\sim}227)$. In the analysis of growth density per layer$[of\;100m^2]$, there appeared $1{\sim}8$ trees of Q. mongolica and $3{\sim}5$ trees of Q. serrata in the upper layer species; $2{\sim}4$ trees of Q. serrata and one tree of Q. mongolica in the canopy layer. As for the characteristics of soil, acidity of forest fire areas was pH 5.45 and that of non-forest fire was pH 5.25. By setting up the middle D.B.H range of Q. mongolica-Q. serrata community as the vegetation restoration model, planting species, planting density and planting models are suggested.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.2
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• pp.67-74
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• 2010

Law-protected trees are our precious asset as natural resources with history and tradition and natural heritage which should be protected and maintained well to bequeath next generation. Law-protected trees have not only thremmatologic and genetic meaning but also environmental and emotional meaning for their value to be high. This study investigated location, vitality, wrapping condition of root area and status of maintenance of the trees to figure out their growth environment and status of maintenance in a small-middle city through survey on those of law-protected trees in Je-cheon. There showed 300 more year old trees in Je-cheon mostly and the number of trees located in flat fields was the highest. For location type, village, hill and road types were presented in the order and for degree of development, land for building was found most frequently. The average electric resistance of the formative layer was measured to be $8.4k{\Omega}$ and four trees showed bark separation. Most law-protected trees underwent tree surgery, and complete bareness of root area was observed in a tree. The root area of two trees was covered with concrete. pH of soil was recorded to be 5.0~8.4 with its average of 7.1 and electric conductivity(EC) was less than 0.5 dS/m. For status of maintenance rearing facilities were placed for 16 trees out of totally 48 ones and stone fence was done for three ones. Tree surgery was conducted for 33 trees to prevent and to treat decomposed parts of holes. Direction boards were installed for 23 trees. Based on these results, measures to manage systematically law-protected trees in Jecheon could be suggested as follows. First, a sufficient space for growth of low part of trees should be secured. Second, a voluntary management should be induced by advertising them to residents in a community. Third, rearing facilities and direction boards of law-protected trees should be placed and related education should be conducted. Fourth, through operation of the department for law-protected trees consisting of related professions and cooperation among related departments the trees should be maintained continuously.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.41-63
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• 2022

The purpose of this study is to secure objective and precise data through ecosystem monitoring, to reveal ecological characteristics through comparison and analysis with past survey data, and to accumulate basic data for diagnosing the current situation and predicting changes in the ecosystem. The target site is the 'Quercus mongolica forest on the Buksa-myeon of Namsan', which was designated as an Ecological Landscape Conservation Area (ELCA) of Seoul in July 2006. The research contents are analysis of soil environment change (1986~2016), change of actual vegetation (1978~2016), and change of plant community structure (1994~2016). A total of 8 fixed surveys (400~1,200m²) were established in 1994 and 2000. Analysis items are importance value, species and population, and Shannon's species diversity. The soil environment of Namsan is acidic (pH 4.40 in 2016), which is expected to have a negative impact on tree growth and vegetation structure due to its low capacity for exchangeable cations. Quercus mongolica forest in Namsan is mainly distributed on the northern slopes. The actual vegetation area changed from 49.4% in 1978 → 80.7% in 1986 → 82.4% in 2000 → 88.3% in 2005 → 88.3% in 2009 → 70.3% in 2016. In 2016, the forest decreased by 18% compared to 2009. While there was increased growth of Quercus mongolica in the tree layer from 2009 to 2016, the overall decline in vegetation area was due to logging and fumigation management following the spread of oak wilt in 2012. As for the changes in the plant community structure, Quercus mongolica of the tree layer was damaged by oak wilt, and the potential vegetation that can form the next generation was ambiguous. In the subtree layer, the force of urbanization tree species such as Styrax japonicus, Sorbus alnifolia, and Acer palmatum. was maintained or increased. In the shrub layer, the number of trees and species increased significantly due to the open tree crown, and accordingly, the species diversity of Shannon for woody plants also increased. In Quercus mongolica forest of Namsan, various ecological changes are occurring due to the effects of urban environments such as air pollution and acid rain, the limitation of Quercus mongolica pure forest due to oak wilt, and the introduction of exotic species, thus, it is necessary to establish a management plan through continuous monitoring.

• Korean Journal of Environment and Ecology
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• v.36 no.3
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• pp.327-337
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• 2022

Ecological restoration is considered a good means to prevent biodiversity loss in terms of the ecosystem's health and sustainability. However, there are difficulties in putting it into practice as there is no comprehensive and objective standard for the selection of plant species, such as environmental, ecological factors, and restoration goal setting. Therefore, this study developed an evaluation index necessary for selecting plant species for restoration using the Delphi method that synthesizes the opinions of the expert group. A survey with 38 questionnaires was conducted twice for experts in ecological restoration, etc., and the importance and priority of evaluation indicators were analyzed by dividing the restoration targets into inland and island regions. The result of the importance analysis showed that "native plants" had the highest average of 4.9 among the evaluation indices in both inland and island regions, followed by "seed security", "propagation", and "root growth rate". In the inland region, the index priority was analyzed in the order of "native plants", "appearance frequency", "root growth rate", "distribution range", and "seed security" in the island region, it was analyzed in the order of "native plants", "root growth rate", "appearance frequency", "distribution range", and "tolerance", showing slight differences between the two indicators. As a result of the importance and priority indicator analysis, we set the mean importance and priority of 4.1 and 2.9, respectively, in the inland region and 4.2 and 2.9, respectively, in the island region. As for the criteria of selecting plant species for ecological restoration, the "native plants" had the highest importance and priority. "Seed securing", 'viability", "topography", "proliferation", "tolerance", "soil conditions", "growth characteristics", "early succession", "distribution range", "appearance frequency", and "germination rate" were classified into subgroups of low importance and priority. The lowest indicators were "final stage of succession", "transition period", 'transition stage", "root", "reproduction", "soil", "appearance", "technology", "landscape", "climate", and "germination rate". We expected that the findings through objective verification in this study would be used as evaluation indicators for selecting native plant species for ecological restoration.

• Economic and Environmental Geology
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• v.47 no.5
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• pp.497-505
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• 2014

This study is for discrimination between asbestiform and non-asbestiform based on size characteristics of tremolite-actinolite fibers in soils from a closed asbestos mine, Jecheon, Chungcheongbuk-do, Korea. Soils and tremolite asbestos rocks were collected from a closed asbestos mine area. The dimensions of fibers with minimum $5{\mu}m$ in length and 3:1 in aspect ratio were measured using transmission electron microscopy (TEM) and compared to the known tremolite populations ranging from asbestiform to non-asbestiform. The geometric means of width of soils, asbestos rocks and National Institute for Standard and Technology (NIST) and Health and Safety Laboratory (HSL) reference samples were $1.2{\mu}m$, $0.3-0.6{\mu}m$, $1.3{\mu}m$ and $0.2{\mu}m$, respectively. The geometric means of aspect ratio of soils, asbestos rocks and NIST and HSL reference samples were 7.3, 13.7-30.1, 7.2 and 37.8, respectively. The population of tremolite-actinolite fibers from soils compared to known asbestiform and non-asbestiform tremolite was lack of thin and high aspect ratio fibers. Upper results suggest that tremolite-actinolite fibers in soils cannot be classified into a commercial grade asbestos. The tremolite-actinolite fibers do not mainly appear to be the result of contamination from distance asbestos sources by wind. For the management and control of asbestos in soils, size distributions of amphiboles should be incorporated into asbestos survey results of soils.

• Journal of Mushroom
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• v.15 no.2
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• pp.69-72
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• 2017

Diversification to develop oak pruned neck utilization technology reduction of operation cost of cheonma(Gastrodia elata) farmers is the purpose of this research, but the results of the experiment are as follows. The soil chemistry of the plantation was very weak in 2015 when the pH was 5.7, weakly acidic and EC was 0.41 (ds/m), but the faux spring area was very sunny, but at the end of May, early June, late July And so on were at a maximum temperature of $25^{\circ}C$ or more, and underground temperature fell below freezing in late January 2016. In the content of the survey of the harvested volume, treatment with a diameter of 6 to 10 cm appeared in 1,366 g total weight and in treated plots with a diameter of 20 cm or more, appeared in 1,542 g, confirming that the number and weight of the interspaces from the small neck is higher than the practice.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.411-421
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• 2014

The purpose of this study is to analyze the key factors that contribute to landslide causes through swelling clay minerals and terrain analysis in landslide sites taken place of in Yongin city, Gyeonggi-do, 2011. The study was conducted based on field survey by XRD (X-ray Diffraction), XRF (X-ray fluorescence), spectroscopic analysis on soil samples obtained from landslide sites and ASTER satellite image. Illite shows absorption features; $Fe^{2+}$ and $Fe^{3+}$ at 0.9 and $1.0{\mu}m$, broad water absorption features near 1.4 and $1.9{\mu}m$, and additional Al-hydroxyl features at 2.2, 2.3 and $2.4{\mu}m$, respectively. These absorption features are consistent with the bands 5, 6, and 7 of ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite image. Illite image was extracted using band math of $SWIR_{Illite}$. From these results, we confirmed the applicability of ASTER satellite image using identification of swelling clay minerals to landslide study.

• Ecology and Resilient Infrastructure
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• v.3 no.3
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• pp.207-211
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• 2016

This study focuses on the categorization of the phenomenon of vegetative recruitment on riparian channels, so called, the phenomenon from "white river" to "green river", and proposes for the corresponding research direction. According to the literature review and research outputs obtained from the authors' previous research performed in Korea within a limited scope, the necessary and sufficient conditions for the recruitment and retrogression of riparian vegetation may be the mechanical disturbance (riverbed tractive stress), soil moisture (groundwater level, topography, composition of riverbed material, precipitation etc.), period of submergence, extreme weather, and nutrient inflow. In this study, two categories, one for the reduction in spring flood due to the change in spring precipitation pattern in unregulated rivers and the other for the increase in nutrient inflow into streams, both of which were partially proved, have been added in the categorization of the vegetative recruitment and retrogression on the riparian channels. In order to scientifically investigate further the phenomenon of the riparian vegetative recruitment and retrogression and develop the working riparian vegetative models, it is necessary to conduct a systematic nationwide survey on the "white to green" rivers, establishment of the categorization of the vegetation recruitment and retrogression based on the proof of those hypotheses and detailed categorization, development of the working mathematical models for the dynamic riparian vegetative recruitment and retrogression, and adaptive management for the river changes.

• Journal of Biosystems Engineering
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• v.36 no.2
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• pp.79-88
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• 2011

The purpose of this study was to analyze power requirement of an agricultural tractor by major field operations. First a survey was conducted to obtain annual usage ratio of agricultural tractor by field operation. Plowing, rotary tillage, and loader operations were selected as major field operations of agricultural tractor. Second, a power measurement system was constructed with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. Third, the major field operations were experimented under fields with different soil conditions following planned operation paths. Power requirement was analyzed during the total operation period consisted of actual operation period (plowing, rotary tillage, and loader operations) and period before and after the actual operation (3-point hitch operating, forward and reverse driving, braking, and steering). Power requirement of tractor major components such as driving axle part, PTO part, main hydraulic part, and auxiliary hydraulic part were measured and calculated to determine usage ratio of agricultural tractor power. Results of averaged power requirement for actual field operation and total operation were 23.1 and 17.5 kW, 24.6 and 19.1 kW, and 14.9 and 8.9 kW, respectively, for plowing, rotary tillage, and loader operations. The results showed that rotary tillage required the greatest power among the operations. Averaged power requirement of driving axles, PTO axle, main hydraulic part, and auxiliary part during the actual field operation were 8.1, 7.8, 3.4, and 1.5 kW, respectively, and the total requirement power was about 70 % (20.8 kW) of the rated power. Averaged power requirement of driving axles, PTO axle, main hydraulic, and auxiliary hydraulic for the total operation period were 6.5, 6.0, 2.1, 0.9 kW, respectively, and total requirement power was about 52 % (15.5 kW) of the rated power. Driving axles required the greatest amount of power among the components.