• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.3
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• pp.35-45
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• 1999

The research is to examine urban heat island effects which is resulted from urbanization using thermal infrared band of Landsat TM data and to demonstrate heat island alleviation effects of green spaces through correlation analysis of NDVI(Normalized Difference Vegetation Index) and surface temperature. According to the results, forests which are covered with natural vegetation have a high NDVI digital values, but surface temperature is very low, and urban areas which is composed of artificial paving materials have a low NDVI, surface temperature increases gradually. In summary, the analysis of relationship between NDVI and surface temperature, used in this study, is regarded as one of effective methodologies for proving heat island alleviation effects of vegetation.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.101-105
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• 2007

Lammas growth, a rare phenomenon for Korean red pine (Pinus densiflora), occurred in 2006. Lammas shoots showed higher frequency and longer length in Seoul's hotter urban center than in urban boundary or suburban forest sites. Frequency and length showed a close correlation with urbanization density and vegetation cover expressed in NDVI. Air temperature in the late summer of 2006 was more than $1^{\circ}C$ higher than an average year. Of the predominant environmental signals that modulate bud flush, only temperature changed significantly during the year. Differences in temperature between the urban centers, urban boundaries and suburban forests correlated with varying land-use density. The rise in temperature likely spurred lammas growth of the Korean red pine. Symptoms of climate change are being detected throughout the world, and its consequences will be clearer in the future. Considerate interest in the responses of ecological systems to the variable changes is required to prepare for unforeseeable crises. Monitoring of diverse ecological phenomena at Long Term Ecological Research sites could offer harbingers of change.

• KIEAE Journal
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• v.14 no.1
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• pp.31-38
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• 2014

Recently, the coverage of urban forests has been rapidly decreasing as the cities are created and expanding. Consequently, there arise urban problems such as heat island effect, urban flooding, urban desertification and so on. In this context, green roof systems is considered to be an efficient alternative to deal with these problems. However, it is difficult to apply green roof to new buildings since the majority of the buildings in cities are already constructed and the demand for new building constructions is not high enough. Therefore, it should be considered to apply green roof system to existing buildings for resolving various problems. This study evaluates heating and cooling energy consumption based on the combination of passive design factors such as wall, roof, window insulation in addition to a green roof system applied to an existing house by using an energy simulation program. Total 8 potential improvement cases are developed. Each case is applied to the same house with different insulation standard for simulations. Through the analysis of the simulated cases with the chosen test house, it is confirmed that heating energy consumption decreases as improvement cases are applied, but cooling energy consumption is relatively not much affected by each improvement case. In addition, when each improvement case is applied to already highly insulated house, the effect of thermal energy improvement decreases while the same improvement that is applied to the case with low insulated house tends to yield higher improvement rate.

• Membrane and Water Treatment
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• v.10 no.1
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• pp.99-104
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• 2019

In Korea, nonpoint pollutants have a significant effect on rivers' water quality, and they are discharged in very different ways depending on rainfall events. Therefore, preparing an optimal countermeasure against nonpoint pollutants requires much monitoring. The present study was conducted to help prepare a method for installing an automatic nonpoint pollutant measurement system for the cost-effective monitoring of the effect of nonpoint pollutants on rivers. In the present study, monitoring was performed at six sites of a river passing through an urban area with a basin area of $454.3km^2$. The results showed that monitoring could be performed for a relatively long time interval in the upstream and downstream regions, which are mainly comprised of forests, regardless of the rainfall amount. On the contrary, in the urban region, the monitoring had to be performed at a relatively short time interval each time when the rainfall intensity changed. This was because the flow rate was significantly dependent on the rainfall's intensity. The appropriate sites for installing an automatic measurement system were found to be a site before entering the urban region, a site after passing through the urban region, and the end of a river where the effects of nonpoint pollutant sources can be well-decided. The analysis also showed that the monitoring time should be longer for the rainfall events of a higher rainfall class and for the sites closer to the river end. This is because the rainfall runoff has a longer effect on the river. However, the effect of nonpoint pollutant sources was not significantly different between the upstream and the downstream in the cases of rainfall events over 100 mm.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.90-103
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• 2017

This study analyzed the surface temperature characteristics of urban green spaces under high summer temperatures to clarify the functions of green spaces in reducing urban temperatures. We obtained accurate surface temperature data using highresolution unmanned aerial vehicle images of the survey site, which was an isolated green space in the city. We analyzed differences in the surface temperature by land cover type, vegetation type, species type, and the relationship between surface temperature and vegetation volume. Based on the results, among the land cover types, wetlands and forests had low temperatures and paving areas had very high temperatures. Regarding vegetation type, broad-leaved trees had lower temperatures than coniferous trees in forests. However, in planted areas, coniferous trees had lower temperatures than broad-leaved trees. The temperature of long grass was higher than that of short grass, which suggested that the volume of grass affected the temperature. Regarding forest species type, the temperature of broad-leaved Robinia pseudoacacia forest and mixed broad-leaved forest was lower than coniferous Pinus densiflora forest. There was a slight difference in temperature between R. pseudoacacia forest and mixed broad-leaved forest. The analysis of the relationship between vegetation volume and temperature by forest species type indicated a negative correlation, where the temperature decreased with increasing vegetation volume, similar to the results of previous studies. However, we found a weak positive correlation in R. pseudoacacia forest; therefore, an increase in volume may not reduce the surface temperature depending on the dominant species.

• Journal of Environmental Science International
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• v.28 no.10
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• pp.813-829
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• 2019

We measured the amount of precipitation, stemflow, and throughfall and concentrations of nine major inorganic nutrients ($H^+$, ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$) to investigate the nutrient inputs into soil from precipitation in Pinus densiflora and Quercus mongolica stands from September 2015 to August 2016. The precipitation inputs of $H^+$, ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$ into soil were 0.170, 15.124, 42.227, 19.218, 14.050, 15.887, 22.391, 5.431, and $129.440kg{\cdot}ha^{-1}{\cdot}yr^{-1}$, respectively. The P. densiflora stemflow inputs were 0.008, 0.784, 1.652, 1.044, 0.476, 0.651, 1.509, 0.278, and $9.098kg{\cdot}ha^{-1}{\cdot}yr^{-1}$, and those for Q. mongolica were 0.008, 0.684, 2.429, 2.417, 2.941, 1.398, 2.407, 0.436, and $13.504kg{\cdot}ha^{-1}{\cdot}yr^{-1}$, respectively. The P. densiflora throughfall inputs were 0.042, 21.518, 52.207 27.694, 20.060, 24.049, 37.229, 10.241, and $153.790kg{\cdot}ha^{-1}{\cdot}yr^{-1}$, and those for Q. mongolica were 0.032, 15.068, 42.834, 21.219, 20.294, 20.237, 24.288, 5.647, and $119.134kg{\cdot}ha^{-1}{\cdot}yr^{-1}$, respectively. Of the total throughfall flux (i.e., stemflow + throughfall flux) of the nine ions for the two species, ${SO_4}^{2-}$ had the greatest total throughfall flux and $H^+$ had the lowest. The net throughfall fluxes of the ions for the two species had various correlations with the precedent dry period, rainfall intensity, rainfall amount, and pH of precipitation. The soil pH under the Q. mongolica canopy (4.88) was higher than that under the P. densiflora canopy (4.34). The difference in the soil pH between the two stands was significant (P < 0.01), but the difference in soil pH by the distance from the stems of the two species was not (P > 0.01). This study shows the enrichments of inorganic nutrients by two representative urban forests in temperate regions and the roles of urban forests during rainfall events in a year.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.80-96
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• 2023

The expansion of human activities and road development has led to the loss and fragmentation of ecological spaces, which is a negative factor for biodiversity. In particular, urban areas where land use and land cover have rapidly changed into urbanization zones are regions where ecological spaces are lost and isolated, making it difficult for wildlife to inhabit. Furthermore, the loss and fragmentation of ecological spaces due to urbanization can have a negative impact on ecosystem services. Therefore, to enhance biodiversity and ecosystem services in urban and national land, it is necessary to establish a practical ecological axis that reflects the current status of the city. Thus, this study analyzed the connectivity of ecological spaces and forest axis that can be used for spatial planning related to urban ecological axis of local governments in Daegu and Gyeongsangbuk-do. The ecological connectivity was analyzed by dividing the Daegu-Gyeongbuk region into 31 local government units, distinguishing between forests and natural areas using land cover data. Subsequently, the study area was divided into 20,483 hexagonal grids of 1 square kilometer each, and the restoration effects for ecological fragmentation within 100 meters were spatially clustered to visualize priority restoration areas. The forest axis was derived by considering regional conditions such as land cover, building area, slope, and others to connect 1,534 forests of 100 hectares or more. The research results are expected to be used as fundamental data for spatial planning, goal setting, and the selection of restoration areas for improving ecological connectivity.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.06a
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• pp.1-5
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• 2003

In order to prepare a basis for ecological restoration of the Seoul Metropolitan area, ecological diagnoses on soil physico-chemical properties and vegetation structure were carried out. Land use patterns, actual vegetation, and biotope patterns were also investigated based on aerial photograph interpretation and field checks. I formulated landscape elements overlaying those data and evaluated the ecological value of each element. Soil pollution was evaluated by analyzing soil samples collected in each grid on the mesh map, divided by 2km $\times$ 2km intervals. Soil samples were collected in forests or grasslands escaped from direct human interference. Soil pollution evaluated from pH, and SO$_4$, Ca, Mg, and Al contents of soil was more severe in the urban outskirts than in the urban center. Those soil environmental factors showed significant correlation with each other. Vegetation in the urban area was different in species composition from that in suburban areas and showed lower diversity compared with that in the suburban areas. Successional process investigated by population structure of major species also showed a difference. That is, successional trend was normal in suburban areas, but that in urban areas showed a retrogressive pattern. The landscape ecological map of Seoul indicates that the urban center lacks vegetation and greenery space is restricted in urban outskirts. Such an uneven distribution of vegetation has caused a specific urban climate and thereby contributed to aggravation of air and soil pollution, furthermore causing vegetation decline. From this result, it was estimated that such uneven distribution of vegetation functioned as a trigger factor to deteriorate the urban environment. I suggested, therefore, a restoration plan based on landscape ecological principles, which emphasizes connectivity and even distribution of green areas throughout the whole area of the Seoul to solve this complex environmental problem. In this restoration plan, first of all, I decided the priority order for connection of the fragmented greenery spaces based on the distances from the core reserves comprised of green belt and rivers, which play roles as habitats of wildlife as well as for improvement of urban environment. Next, I prepared methods to restore each landscape element included in the paths of green network to be constructed in the future on the bases of such preferential order. Rivers and roads, which hold good connectivity, were chosen as elements to play important roles in constructing green network by linking the fragmented greenery spaces.

• Journal of Environmental Impact Assessment
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• v.27 no.3
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• pp.279-290
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• 2018

The importance of monitoring and assessing the status of urban forests in the aspect of urban forest management is emerging as urban forest edges increase due to urbanization and human impacts. The purpose of this study was to investigate the status of vegetation condition of urban forest edge that is affected by different land cover types using $NDVI_{max}$ images derived from FSDAF (Flexible Spatio-temporal DAta Fusion). Among 4 land cover types,roads had the greatest effect on the forest edge, especially up to 30m, and it was found to affect up to 90m in Seoul urban forest. It was also found that $NDVI_{max}$ increased with distance away from the forest edge. The results of this study are expected to be useful for assessing the effects of land cover types and land cover change on forest edges in terms of urban forest monitoring and urban forest management.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.97-104
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• 2018

This study investigated the effect of forest type changes in Daegu, the hottest city in Korea, on the land surface temperature (LST). The LST change by forest type was analyzed by 2scene of Landsat TM image from 1990 to 2007. The land cover types were classified into 4 types; forest areas, urban areas, cultivated areas and other areas, and water areas. The forest areas were further classified into the coniferous tree areas and the broadleaf tree areas. The result of the statistical analysis of the LST change according to the forest type showed that the LST increased when the forest was changed to the urban area. The LST increased by about $0.6^{\circ}C$ when a broadleaf tree area was changed to an urban area and about $0.2^{\circ}C$ when a coniferous tree area was changed to an urban area. This was the temperature change as the result of the simple type change for 17 years. The temperature change was larger when considering both cases of the forest type being retained and changed. The LST increased by $2.3^{\circ}C$ more when the broadleaf tree areas were changed to the urban areas than when broadleaf trees were maintained. The LST increased by $1.9^{\circ}C$ more when the coniferous tree areas were changed to the urban areas than when the coniferous tree areas were maintained. The LST increased by $0.4^{\circ}C$ more when the broadleaf tree areas were destroyed than when the coniferous tree areas were destroyed. The results confirmed that the protection of broadleaf trees in urban forests was more effective for mitigating climate change.