• 대한원격탐사학회지
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• 제21권5호
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• pp.383-392
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• 2005

Vegetation classes, especially grass and tree classes, are often confused in classification when conventional spectral pattern recognition techniques are used to classify urban areas. This paper reports on a study to improve the classification results by using an automated process of considering height information in separating urban vegetation classes, specifically tree and grass, using three-band, high-spatial resolution, digital aerial imagery. Height information was derived photogrammetrically from stereo pair imagery using cross correlation image matching to estimate differential parallax for vegetation pixels. A threshold value of differential parallax was used to assess whether the original class was correct. The average increase in overall accuracy for three test stereo pairs was $7.8\%$, and detailed examination showed that pixels reclassified as grass improved the overall accuracy more than pixels reclassified as tree. Visual examination and statistical accuracy assessment of four test areas showed improvement in vegetation classification with the increase in accuracy ranging from $3.7\%\;to\;18.1\%$. Vegetation classification can, in fact, be improved by adding height information to the classification procedure.

• 한국환경복원기술학회지
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• 제23권4호
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• pp.97-110
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• 2020

This study conducted observations at 72 traffic lights and road signs in Sejong-si, Korea from March to June 2019 in order to analyze nest-site, nest-site characteristics and feeding behavior in Tree sparrow (Passeer montanus) in urban. Feeding behavior during breeding season in 2019 was investigated at 10 Town representing traffic facilities installed on the road located in the center of the city and 10 Riverside Geumgang river's riverside road. We fitted both general linear model and regression model to our field data and estimated the spatial variation of initial date of the first feeding (i.e., being date of breeding) and the total number of caterpillar fed by parents per hour. Our results showed that the frequency of nest building on artificial structures, such as traffic lights, was about 26% higher and about 8 days earlier in the riverside. In particular, the first feeding was significantly faster when the nearest distance between nest to green field as foraging site was shorter whereas there was no significant effect of the number of nest within 50 meters on the first feeding. Number of caterpillars fed by parents was higher in the Riverside than in the Urban, and especially the number in the second brood was sharply decreased in the Urban. As we estimated average amount of caterpillars per hour to 446 traffic safety facilities in Sejong-si, it was estimated that Tree sparrows fed 18,742.8 caterpillars per hour during the breeding season. In this study, we showed that characteristics of nests built in artificial structures and feeding behavior in order to analyze effects of environmental condition in urban on life-history traits during the breeding season. Finally, we discussed the conservation of birds in urban and pest control effects.

• Journal of Forest and Environmental Science
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• 제38권1호
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• pp.64-73
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• 2022

Increasing carbon and PM_2.5 concentrations have been emerging as serious environmental issues worldwide. The purpose of this study was to quantify carbon and PM_2.5 reduction by urban parks in Gangneung, Korea. A total of 35 parks were sampled by applying a random sampling method to survey tree planting structures and the areal distribution of land cover types of urban parks. These survey data and the Green Evaluation Technique (GET) computer program were used to estimate carbon and PM_2.5 reduction by trees. Mean tree density and cover in the study parks were 3.5±0.2 tree/100 m² and 44.5±3.0%, respectively. Annual carbon uptake and PM_2.5 deposition per unit area by trees averaged 2.8±0.2 t/ha/yr and 30.2±2.8 kg/ha/yr. Gangneung's urban parks annually offset the carbon emissions by 3.4% and the PM_2.5 emissions by 3.5%. Thus, urban parks played a significant role in reducing atmospheric carbon and PM_2.5 concentrations. Total annual carbon uptake and PM_2.5 deposition of urban parks in Gangneung were about 1,338.2 t/yr and 14,433.2 kg/yr. This study is expected to contribute to raising awareness of the role and importance of urban parks regarding carbon and PM_2.5 reduction.

• 조경수
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• 통권132호
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• pp.40-46
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• 2013

• 한국환경복원기술학회지
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• 제26권1호
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• pp.47-59
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• 2023

Due to climate change and urbanization, abnormally high temperatures and heat waves are expected to increase in urban and deteriorate thermal comfort. Planting of street trees and changing the albedo of urban surfaces are the strategies for mitigating the thermal environment of urban, and both of these strategies affect the exposure and blocking of radiative fluxes to pedestrians. After measuring the shortwave and longwave radiation according to the ground surface with different albedo and the presence of street trees using the CNR4 net radiometer, this study analyzed the relationship between this two strategies in terms of thermal environment mitigation by calculating the MRT(Mean Radiant Temperature) of each environment. As a result of comparing the difference between the downward shortwave radiation measured under the right tree and at the control, the shortwave radiation blocking effect of the tree increased as the downward shortwave radiation increased. During daytime hours (from 11 am to 3 pm), the MRT difference caused by the albedo difference(The albedo of the surfaces are 0.479 and 0.131, respectively.) on surfaces with no tree is approximately 3.58℃. When tree is present, the MRT difference caused by the albedo difference is approximately 0.49℃. In addition, in the case of the light-colored ground surface with high albedo, the surface temperature was low and the range of temperature change was lower than the surrounding surface with low albedo. This result shows that the urban thermal environment can be midigate through the planting of street trees, and that the ground surface with high albedo can be considered for short pedestrians. These results can be utilized in planning street and open space in urban by choosing surfaces with high albedo along with the shading effect of vegetation, considering the use by various users.

• 한국조경학회지
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• 제27권1호
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• pp.39-53
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• 1999

This study quantified carbon uptake and emissions in urban landscape, and the role of urban greenspace in atmospheric carbon reduction for several cities of Chuncheon and Kangleung in Kangwon province. Mean carbon storage by trees and shrubs was 26.0 t (mertric tons)/ha in Chuncheon and 46.7 t/ha in Kangleung for natural lands, and ranged from 4.7 to 6.3 t/ha for urban lands (all land use types except natural and agricultural lands) in both cities. Mean annual carbon uptake by trees and shrubs ranged from 1.60 to 1.71 t/ha/yr for natural lands, and from 0.56 to 0.71 t/ha/yr for urban lands. There was no significant difference (95% confidence level) between the two cities in the carbon storage and annual carbon uptake per ha, except the carbon storage for natural lands. Organic carbon storage in soils (to a depth of 60 cm) of Chuncheon average 24.8 t/ha for urban lands and 31.6 t/ha for natural lands, 1.3 times greater than for urban lands. Annual carbon accumulation in soils was 1.3 t/hr/yr for natural lands of the study cities. Annual per capita carbon emissions from fossil fuel consumption were 1.3 t/yr in Chunceon and 1.8 t/yr in Kangleung. The principal carbon release in urban landscapes was from transport and industry. Total carbon storage by urban greenspace (trees, shrubs, and soils) equaled 66% of total carbon emissions in Chuncheon and 101% in Kangleung. Carbon uptake by urban greenspace annually offset total carbon emissions by approximately 4% in the study cities. Thus, urban greenspace played a partial important role in reducing atmospheric $CO_2$ concentrations. To increase $CO_2$ uptake and storage by urban greenspace, suggested are conservation of natural lands, minimization of hard surfaces and more plantings, selection of tree species with high growth rate, and proper management for longer healthy tree growth.

• 한국조경학회지
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• 제27권5호
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• pp.38-47
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• 2000

Carbon dioxide is a major greenhouse gas causing climate change. This study quantified annual direct and indirect uptake of carbon by urban greenspace, and annual carbon release from vegetation maintenance and fossil fuel consumption. The study area was whole Chuncheon and Kangleung, and also two districts of Kangnam and Junglang in Seoul, cities located in middle Korea. Carbon uptake by urban greenspace played an important role through offsetting carbon release by 6-7% annually in Chuncheon and Kangleung. For Kangnam and Junglang, where the population density was relatively higher, urban greenspace annually offset carbon release by 1-2%. Future possible tree plantings could double annual carbon uptake by existing trees in urban lands (except natural and agricultural lands) of a study city. Based on study results, planning and management guidelines for urban greenspace were suggested to save energy and to reduce atmospheric $CO_2$ concentrations. They included selection of optimum tree species, proper planting location from buildings, design of multilayered planting, amendment of existing regulations for greenspace enlargement, avoidance f intensive vegetation maintenance, and conservation of natural vegetation.

• 대한원격탐사학회지
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• 제22권6호
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• pp.543-551
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• 2006

산림의 효율적인 관리를 위해 최근 원격탐사 기법을 이용하여 산림에 관련된 정보를 추출하려는 노력들이 활발히 이루어지고 있다. 하지만 단일 원격탐사 데이터를 이용하는 경우 수목 인식의 정확도 및 추출되는 정보의 양적인 면에서 많은 한계를 가진다. 본 연구는 최근의 수목모델링을 위한 핵심기술들을 컬러 항공사진과 LiDAR 데이터에 적용하여 국내 환경에서의 수목 모델링을 수행하고, 그 결과를 평가하는데 그 목적을 두고 있다. 대전광역시 내에 존재하는 소규모 산림 지역 중 침엽수만으로 이루어진 단순림을 대상 지역으로 하였다. 컬러항공사진과 LiDAR 데이터를 이용하여 추정된 개체수의 정확도 평가 결과 $R^2$값이 0.77로 나타났다. 수고의 경우 집단 정확도 평가 결과 최근 변화가 일어나지 않은 지역은 측정값과 추정값의 차이가 없는 것으로 나타났고, 개별 정확도 평가의 경우 $R^2$값이 0.83으로 높은 상관도를 보였다.

• 한국환경복원기술학회지
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• 제24권4호
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• pp.15-29
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• 2021

Urban green spaces offer a variety of benefits to living things and humans. However, existing green spaces have been reduced and fragmented due to urbanization, and there is a limit to creating new large green spaces in densely developed cities. Street trees have fewer restrictions on land use, which can be a measure to secure green areas in cities. In Korea, excessive pruning is being done on some street trees for reasons such as blocking of building signboards, contact with electric wires, and restrictions on sidewalk widths. Therefore, it is necessary to quantitatively understand the relationship between the benefits provided by street trees and their structures to come up with an efficient and systematic planning and management plan for urban street trees. In this study, we quantitatively analyzed the relationship between the thermal comfort improvement by the shades of street trees and the vertical structure, planting environment, and types of street trees. To calculate the thermal comfort felt by human body, we calculated UTCI (Universal Thermal Climate Index) of each street tree. For the vertical structure of street trees, we used Terrestrial LiDAR and the point clouds of street tree's crown was sliced vertically at 1m intervals. We conducted a multiple regression analysis on the thermal comfort improvement using the variables we obtained from fields. As a result, in the case of a street tree's vertical structure, the lager the volume of tree's crown located 3-4m (β=0.298, p<.05) and 6-7m (β=0.568, p<.001) above clear length, the better the cooling effect. In addition, the thermal comfort improvement was assessed to decrease as the DBH increased (β=-0.435, p<.001). In general, the crown diameter and DBH are positively correlated, with a cooling effect occurring as crown diameter increases. In this study, the opposite result was obtained due to the small number of trees measured, so additional research is needed by increasing the number of tree samples. In the case of the planting environment, the effect of improving thermal comfort was higher in the shaded area of trees planted to the south (β=-0.541, p<.001). Since unsystematic management of street trees can deteriorate the function of them, quantitative evaluations of the vertical structure of street trees are required, which can provide specific measures for planning and management of urban street trees with thermal comfort effect.

• Ecology and Resilient Infrastructure
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• 제3권2호
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• pp.126-129
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• 2016

도시화로 인해 불투수 면적이 증가하면서 지하 침투량이 감소하고 강우 유출량이 증가하여 도시 침수 발생 가능성이 커지고 지하수 고갈 문제를 발생시키고 있다. 본 연구에서는 가로수 주위에 수분 및 영양을 공급할 수 있는 신개념 특수 가로수 보호판의 설치가 도시 내 침투량 개선에 미치는 효과를 평가하고, 시설의 배치에 따른 침투량 변화를 조사하였다. 침투관이 설치된 신개념 가로수 보호판은 토양으로는 빗물 침투량을 증가시키고 지면 위 수위 상승을 억제하였다. 따라서 개발된 신개념 가로수 보호판은 도시 도로변에서 저영향개발 (LID) 시설로서 효과적으로 적용될 수 있을 것으로 판단되었다.