• 한국환경복원기술학회지
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• 제23권6호
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• pp.125-135
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• 2020

The uncontrolled urban expansion causes various social, economic problems and natural/environmental problems. Therefore, it is necessary to forecast urban expansion by identifying various factors related to urban expansion. This study aims to forecast it using a decision tree that is widely used in various areas. The study used geographic data such as the area of use, geographical data like elevation and slope, the environmental conservation value assessment map, and population density data for 2006 and 2018. It extracted the new urban expansion areas by comparing the residential, industrial, and commercial zones of the zoning in 2006 and 2018 and derived a decision tree using the 2006 data as independent variables. It is intended to forecast urban expansion in 2030 by applying the data for 2018 to the derived decision tree. The analysis result confirmed that the distance from the green area, the elevation, the grade of the environmental conservation value assessment map, and the distance from the industrial area were important factors in forecasting the urban area expansion. The AUC of 0.95051 showed excellent explanatory power in the ROC analysis performed to verify the accuracy. However, the forecast of the urban area expansion for 2018 using the decision tree was 15,459.98㎢, which was significantly different from the actual urban area of 4,144.93㎢ for 2018. Since many regions use decision tree to forecast urban expansion, they can be useful for identifying which factors affect urban expansion, although they are not suitable for forecasting the expansion of urban region in detail. Identifying such important factors for urban expansion is expected to provide information that can be used in future land, urban, and environmental planning.

• 한국습지학회지
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• 제21권4호
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• pp.298-304
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• 2019

이 논문에서는 한국의 가로수에 대한 바람 취약성을 유도하는 분석 방법을 보여준다. 몬테 카를로 시뮬레이션 방법은 도시 가로수의 파괴 확률을 결정하는 데 사용되었다. 이 확률 결과는 대구 지역의 가로수를 기반으로 4 가지 유형에 대한 바람 취약성 매개 변수를 결정하는 데 사용되었으며, 이로 인해 풍하중에서 가로수 손상 확률에 영향을 미치는 주요 요인이 직경이라는 것을 나타낸다. 또한, 선택된 4 가지 유형 중에서 높이 7m, 직경 35cm의 가로수는 손상률이 제일 낮은 반면, 높이 8m, 직경 30cm의 가로수는 가장 낮은 풍하중에서 저항하였다. 높이 7m의 가로수의 평균 손상 풍속은 직경 30cm 및 35cm에 대해 각각 43.8m/s 및 50.6m/s로 나타났으며, 높이 8m의 가로수의 평균 손상 풍속은 직경 30cm 및 35cm에 대하여 각각 38.7m/s 및 45.4m/s로 나타났다.

• Journal of Forest and Environmental Science
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• 제32권4호
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• pp.367-376
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• 2016

Urban greenery is an important component of urban environment and is fast gaining prominence especially in the developing countries. The destruction of urban trees has resulted to the degradation of the environment, thus the introduction of green Kumasi project by Kumasi Metropolitan Assembly, Ashanti Region of Ghana. The composition and diversity of urban trees gives rise to adequate management and monitoring, thus an inventory of urban trees of the Metropolis was conducted to document complete information on its density, diversity, composition and distribution. A total tree population of 1,101 was enumerated in the principal roads of the Metropolis. The ten most encountered tree species accounted for 61.04% of all the individual tree populations with Mangifera indica being dominant. The dominant families: Fabaceae, Moraceae and Arecaceae constitute 38.57% of the tree population. Diversity of the tree species was very high. The minimum diversity criteria were met on analysis of the diversity of this population. The proportion of exotic species was high with 65.71% of the trees belonging to the introduced species. It is recommended that greater emphasis should be placed on the planting of indigenous trees in future tree planting exercise.

• 한국환경복원기술학회지
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• 제21권6호
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• pp.1-13
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• 2018

Mapping radiation heat flux of urban area is essential for urban design and landscape planning. Because controlling urban geometry and generating green space are important urban design strategies for reducing urban heat, urban planner and designer need to recognize the micro urban heat distribution for adequate urban planning. This study suggests a new methodology for mapping urban radiation heat flux in a micro scale considering buildings and trees' shade. For doing that, firstly, we calculate net radiation for each urban surfaces (building, road (not shaded, building shaded, tree shaded), ground (not shaded, building shaded, tree shaded), tree (not shaded, building shaded)). Then, by multiplying the area ratio of surfaces to the net radiation, we can obtain the radiation heat flux in micro-scale. The estimated net radiation results were found to be robust with a $R^2$ of 90%, which indicates a strong explanatory power of the model. The radiation heat flux map for 12h $17^{th}$ August explains that areas under the building and tree have lower net radiation heat flux, indicating that shading is a good strategy for reducing incident radiation. This method can be used for developing thermal friendly urban plan.

• Journal of Forest and Environmental Science
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• 제37권1호
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• pp.1-13
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• 2021

The realities of Climate change and its untold implications on the livelihood of man are no longer new worldwide. In attempts to subdue the negative implications of Climate change scenario globally, several measures have being suggested and being put in place. One of such measures is urban reforestation especially in the developing nations where forest resources have extremely and uncontrollably exploited. Most of cities in developing nations are almost devoid of regularly maintained trees for whatever purpose. Thus, the enormous roles which urban tree performs are lacked in most cities. In order to subdue excessive heat in cities arising from exposure of urban land areas urban reforestation exercise needs to be embarked upon. The investigation was carried out through desk studies and review of relevant publications to examine what it entails to have a sustainable reforestation programme in cities. The study revealed that several factors need to be taken into consideration if sustainable urban reforestation will be achieved, especially in developing countries. These factors include urban soil nutrients status investigation, appropriate tree type study, public perception about the tree types, relevant legal instrument to achieve successful reforestation exercise in cities among others were found to be salient to this exercise. Urban reforestation has enormous potentials to subdue Climate change consequences, including urban renewal if adequate provision is made for its sustainability, especially in developing countries. To ensure this is realized it is recommended that relevant ministry/agency could be put in charge for the maintaining, cutting and replanting of urban tree and all that are involved in urban tree sustainability.

• Wind and Structures
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• 제22권1호
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• pp.89-106
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• 2016

With an aim to assess the wind damage to urban trees in more realistic conditions, the nonlinear dynamics of structured trees subjected to strong winds with different levels is investigated in the present paper. For the logical treatment of dynamical behavior of trees, material nonlinearities of green wood associated with tree biomechanics and geometric nonlinearity of tree configuration are included. Applying simulated fluctuating wind velocity to the numerical model, the dynamical behavior of the structured tree is explored. A comparative study against the linear dynamics analysis usually involved in the previous researches is carried out. The failure wind velocity of urban trees is then defined, whereby the failure percentages of the tree components are exposed. Numerical investigations reveal that the nonlinear dynamics analysis of urban trees results in a more accurate solution of wind-induced response than the classical linear dynamics analysis, where the nonlinear effect of the tree behavior gives rise to be strengthened as increasing of the levels of wind velocity, i.e., the amplitude of 10-min mean wind velocity. The study of relationship between the failure percentage and the failure wind velocity provides a new perspective towards the vulnerability assessment of urban trees likely to fail due to wind actions, which is potential to link with the practical engineering.

• 한국환경복원기술학회지
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• 제22권5호
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• pp.1-12
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• 2019

It is important to measure the height of trees as an essential element for assessing the forest health in urban areas. Therefore, an automated method that can measure the height of individual tree as a three-dimensional forest information is needed in an extensive and dense forest. Since airborne LiDAR dataset is easy to analyze the tree height(z-coordinate) of forests, studies on individual tree height measurement could be performed as an assessment forest health. Especially in urban forests, that adversely affected by habitat fragmentation and isolation. So this study was analyzed to measure the height of individual trees for assessing the urban forests health, Furthermore to identify environmental factors that affect forest growth. The survey was conducted in the Mt. Bongseo located in Seobuk-gu. Cheonan-si(Middle Chungcheong Province). We segment the individual trees on coniferous by automatic method using the airborne LiDAR dataset of the two periods (year of 2016 and 2017) and to find out individual tree growth. Segmentation of individual trees was performed by using the watershed algorithm and the local maximum, and the tree growth was determined by the difference of the tree height according to the two periods. After we clarify the relationship between the environmental factors affecting the tree growth. The tree growth of Mt. Bongseo was about 20cm for a year, and it was analyzed to be lower than 23.9cm/year of the growth of the dominant species, Pinus rigida. This may have an adverse effect on the growth of isolated urban forests. It also determined different trees growth according to age, diameter and density class in the stock map, effective soil depth and drainage grade in the soil map. There was a statistically significant positive correlation between the distance to the road and the solar radiation as an environmental factor affecting the tree growth. Since there is less correlation, it is necessary to determine other influencing factors affecting tree growth in urban forests besides anthropogenic influences. This study is the first data for the analysis of segmentation and the growth of the individual tree, and it can be used as a scientific data of the urban forest health assessment and management.

• 대한원격탐사학회지
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• 제39권5_4호
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• pp.1145-1153
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• 2023

도시 수목은 대기 중 이산화 탄소 흡수, 대기질 개선, 도시열섬 현상 완화 및 생태계서비스 제공과 같은 중요한 역할을 한다. 도시 수목을 효과적으로 관리하고 보전하기 위해서는 위치, 상태, 수종, 개체 수 등에 대한 정확한 공간 정보가 필요하다. 본 연구에서는 딥러닝 기반의 고해상도 도시 수목 면적 지도를 이용해 도시 지표면으로부터 수목을 분리하고, 국지적 최대값 필터링을 통해 수목의 위치를 정확하게 탐지하는 알고리즘을 제안한다. 도시의 다양한 생육 환경을 고려해 일률적인 필터 크기를 사용하는 대신, 수고에 따라 적절한 필터 크기를 선택해 수목 탐지 성능을 향상시켰다. 수원시 전역을 대상으로 구축한 도시 수목 위치 및 수고 정보는 도시 생태계의 지속가능한 관리와 탄소 저감 대책을 위한 기반이 될 것이다.

• 한국조경학회지
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• 제18권3호통권39호
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• pp.171-190
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• 1990

It is the purpose of this study to address how to manage the urban vegitation using the concept of Urban Forestry which is relatively new to Korea. When we consider the Urban Forestry as a science, We should understand it interdisciplinary subject which includes Forestry, Horticulture, Urban Planning, Landscape Design, Landuse Planning, Business and Humanities. It may say that people and tree are the fundermental components of Urban Forestry. So there are two ways of Urban Forestry Applications-How people care for trees and How trees care for People-. For the application, this study places the focus on the monetary valuation, tree inventory system and traditional forestry application to urban forest management. Pubic Relation, Communication, Ordinances and Budget are also mentioned as a part of Urban Forestry Policy. Monetary valuation of trees and forests is very important for the proper cognition of their real value. So that, they may be equated and weighed against conflicting uses which would cause to be removed or severely mutilated. A tree inventory system which is the essential part of urban tree management can provide the pertinent information about the present condition of urban tree resource. It may aid in reducing the subjectivity of tree management decisions and stimulate them to be made rapidly and can help reduce potential municipal liability by identifying serious problems in time for corrective maintenance practices to be applied for the maximize community benefits and minimimize public nuisances or hazards. Managers can derive the information from the inventory and use it for the various management plan. When we see the structure of tree inventory system as one of the data base management system, Computer is the best equipment for the efficient management plan. Public relation and communication is also important factors to care the people for urban vegetation management. Volunteer management system is a good example for the public relation and communication. Those skills are need to develop for using the priceless, valuable human resources. Budget holds the key to the execution of Urban Forestry. Good inventory can provide for efficient budgeting stratiges through it's scientific analysis for the way of maximum benefits and minimum costs. Forest can be play a vital role for the aesthetic improvement and recreation in the city. This study suggests that the traditional sivicultural application not only improve the quality of scenic beauty and recreation but also the products of timber. So it is more needed to study for strong and scientific application to urban forest management.

• 한국환경생태학회지
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• 제32권1호
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• pp.97-104
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• 2018

본 연구는 산림 우점식생 변화가 지표면 온도에 미치는 영향을 파악하고자 우리나라 대표적 혹서지역인 대구광역시를 대상으로 연구를 수행하였다. 산림 우점식생 변화 유형별 온도변화는 1990년과 2007년의 Landsat TM 영상 2scene을 분석하여 확인하였다. 토지피복유형은 산림지역, 시가화지역, 경작지 및 기타지역, 수역으로 구분하였고, 산림지역의 경우 침엽수와 활엽수로 구분하였다. 산림 우점식생 변화 유형에 따른 지표면 온도 변화를 확인하기 위해 통계분석을 실시한 결과 산림이 시가화지역으로 변화될 경우 온도는 높아지며, 유형별로 살펴보면 활엽수림이 시가화지역으로 변화된 경우 약 $0.6^{\circ}C$, 침엽수림이 시가화지역으로 변화된 경우 약 $0.2^{\circ}C$ 온도가 상승하는 것을 확인할 수 있었다. 이는 단순히 17년간 유형변화에 따른 온도 차이로 현재까지 유형이 유지된 경우와 변화된 경우를 동시에 고려할 경우 온도는 더 높은 차이를 보였다. 활엽수림의 경우 활엽수림이 유지될 때 보다 시가화지역으로 변화 될 경우 온도는 $2.3^{\circ}C$ 증가하였으며, 침엽수림의 경우 침엽수림이 유지될 때 보다 시가화지역으로 변화될 경우 $1.9^{\circ}C$ 온도가 증가하였다. 산림의 경우 시가화지역으로 변화될 때 온도가 상승하며 산림식생유형 중 침엽수가 파괴되었을 경우보다 활엽수가 파괴되었을 때 $0.4^{\circ}C$ 온도가 추가적으로 상승하는 것으로 나타났다. 도시기온 완화를 위해서는 도시림 내에서 활엽수림의 보호가 더 효율적인 것으로 확인되었다.