A Study on Planting Techniques to Enhance the Function of Urban Wind Ventilation Forest: In the Case of Wind-Connecting Forest, Seocho-gu, Seoul
Article information
Abstract
Background and objective
This study was conducted to develop Connecting Forest planting technique suitable for urban structure and target site conditions on Banpo-daero Street in Seocho-gu.
Methods
Through simulation analysis of planting techniques by type (computer climate model: ENVI-met), the street types were classified into the following categories: bare ground type (1), currently planted with Platanus occidentalis (square pruning) (2), a type that can realistically create a strip green (3), and a type that grows the tree canopy and applies Platanus occidentalis and a strip green in the center of the road (4).
Results
In the case of creating a 2-meter-wide band green on the existing street trees in the first row, and multi-layered vegetation using the step-by-step arrangement method of small tree + shrub + herbaceous plants, the temperature of up to 0.15°C rise in the roadway area and the temperature of up to 0.12°C went down in the sidewalk area, and PMV (Predicted Mean Vote) was reduced by up to 1.32 in the multi-layer trench planting area. Particulate matter was concentrated, resulting in an increase of about 40~80μg/m3 in roadways and sidewalks. In the case of the ideal planting arrangement of the route applying the original tree tree tree street + the green belt 2m + the central green zone, the effect of reducing the maximum 1.6°C in the roadway area and 0.3°C in the sidewalk area was shown, and the result of lowering the temperature throughout the target area was derived. arise from street trees, trench planting and trees in Green Area at the Center Line the concentration of particulate matter in the roadway area increased to about 150μg/m3, and the concentration of particulate matter in sidewalks and residential areas decreased. Through simulation analysis, we planted street trees with large trunk widths that are favorable for shade formation (Platanus occidentalis) and maintained the unique tree shape, oval, rather than square pruning, and the composition of the strip greenery consisted of multi-layered plantings based on the terraced layout method by introducing tree species with excellent particulate matter reduction capabilities.
Conclusion
This study is meaningful in analyzing the function of connecting forests, which play an important role in urban wind ventilation forests, which are created as a solution to improve the urban environment, such as reducing particulate matter in the city and mitigating heat waves, and suggesting planting techniques that can improve their function.
Introduction
The frequency of heat waves is increasing due to climate change (Intergovernmental Panel on Climate Change(IPCC) 2007), which directly leads to an increase in natural disasters (National Institute of Meteorology 2018). The Korea Forest Service is promoting various urban forest creation projects (particulate matter blocking forests, reduction forests, and wind ventilation forests) through 'the 2nd Urban Forest Basic Plan (2018–2027)' to improve the environment, including climate mitigation and air purification. Urban forests, including street trees, are known for their effective role in regulating the microclimate by blocking, absorbing, and purifying pollutants in the air and reducing temperatures in urban centers. Therefore, the creation of green spaces in urban areas where air pollution is intensifying and the heat island phenomenon is severe is attracting attention in terms of improving air quality.
The concept of wind ventilation originates from the German word "Ventilationbahn" first used by Kress (1979) and now refers to the utilization of a network of green areas, cities, water, and open spaces to allow fresh air from the mountains or sea to flow into a city. Mayer et al. (1994) proposed to categorize urban wind ventilation into four types:(1) normal wind ventilation, (2) polluted wind ventilation, (3) cold and fresh wind ventilation, and (4) wind ventilation related to biometeorology. Previous studies on the environmental control functions of greenery (urban forests) include temperature reduction (Jo et al. 2003), carbon dioxide absorption, noise reduction (Park and Kim 1995), and particulate matter reduction. Nowak et al. (2000) created a modeling of the particulate matter blocking effect of street greenery, and several studies using the modeling showed that the particulate matter blocking effect of street greenery is very high. Lee et al. (2019) showed that urban landscape trees adsorb PM and affect airflow. Kim et al (2002) confirmed the temperature reduction through trees by comparing the temperature in the phyllosphere layer and the temperature on the bare ground, and Jung et al (2015) confirmed that the temperature reduction effect is greater in the multilayer structure of the street structure, and suggested the criteria for creating street greenery for temperature reduction effect. Lim et al (2022) analyzed the effect of improving the thermal environment of urban space by road orientation and street tree planting type in summer using ENVI-met. Hong (2020) used ENVI-met to determine how the concentration of particulate matter generated by roads spreads to neighboring living areas according to the type of urban development. Baek (2020) used ENVI-met to analyze how to create Connecting Forest that can mitigate and reduce heat waves and particulate matter generated on roads. Although there have been many studies comparing and verifying the effectiveness of urban street connectivity forests, there is a lack of research on planting structures and planting techniques suitable for the actual structure and current conditions of the target site. Previous studies have been conducted on materials, structures, and temperatures, including studies on road materials and temperatures, tree species and temperatures in plant cover layer, and the type and temperature reduction of horizontal green areas (trees + subtrees + shrubs) but this study has been conducted on urban structures and planting techniques (according to green space structure).
This paper compares and analyzes the planting structure and techniques of each type in the target site and proposes realistic planting techniques to improve the function of urban forests. A planting structure suitable for the characteristics of the target site was selected and a planting technique is able to improve the function of particulate matter reduction and temperature reduction, which is the function of urban wind-connecting forest.
Research Methods
Research framework
The research system was carried out in the following order: selection and typification of research sites, current status survey, analysis and simulation, design, effect analysis, and design optimization. Four types of analysis scenarios were used to compare and analyze the temperature and Predicted Mean Vote (PMV) of driveways, sidewalks, and residential areas, and the effectiveness of blocking and reducing particulate matter (Fig. 1).
Study area
Seocho-gu has utilized its geographical features with a high percentage of greenery to effectively bring clean air from the mountains outside the city into the city center, improving the structure of the base greenery, planting species that reduce particulate matter, and creating wind ventilation that connect roads and street forests to build an environment that actively responds to climate change. The Connecting Forests were selected along Bangbae-ro, Banpo-daero, Seochojungang-ro, Seocho-daero, and Hyoryeong-ro, and a detailed basic plan was implemented. This study selected Banpo-daero, a major connecting forest in the Seocho-gu 'Seoripul Wind-Connecting Forest Road Creation Project' as the study site.
The study site was Banpo-daero Street, a connecting forest that runs from Umyeonsan Mountain in Seocho-gu to the Hangang River. Banpo-daero is an eight-lane, 40-meter-wide, 4.7-kilometer-long road with public facilities and residential facilities such as apartment houses adjacent to it. The sidewalk width of about 5 meters is planted with square-pruned Platanus occidentalis on a 1,500 mm × 1,500 mm tree protection board on the road side. The street tree species is a Platanus occidentalis, which is managed in the form of a tree with a height of 12 meters, a trunk of 5 meters by 5 meters, and a basement of 4 meters due to square pruning (Fig. 2).

Study area (Source: https://map.kakao.com).
Data composition
Using a 1/1,000 scale topographic map of the target site, the urban structure (roads and sidewalks, scale and height of surrounding buildings, finishing materials, etc. To simulate (ENVI-met), a survey area of 250 m × 150 m was set up, and the street status, tree species, height, basement, tree trunk diameter, and tree trunk width were investigated.
Analytic simulation
ENVI-met (ver. 5.0.3), a three-dimensional computerized microclimate analysis model, is a version that can input urban structures such as buildings and vegetation in three dimensions more accurately than the previous version, and has increased the number of input data types to reflect the actual environment. Physical structures such as roads, sidewalks, side roads, building wall and roof materials, and wall and rooftop greenery were built based on spatial information open platform maps to reflect the actual environment. In addition, since roads and sidewalks are affected by shadows from neighboring buildings, surrounding commercial and residential areas were included. To verify the effectiveness of heat island mitigation, we selected July 22, 2021, the highest temperature in Seocho-gu in 2021, as the simulation date. The wind was set to blow along the road, and the time period was set to 6 hours from 13:00 to 18:00 to verify the temperature and particulate matter reduction effect along Banpo-daero. To verify the effectiveness of reducing particulate matter, we selected 16:00 to 19:00 on May 8, 2021, when the highest level of particulate matter in Seocho-gu was recorded. The climate of Seoul, South Korea is a climate in which high summer temperatures and high concentrations of fine dust appear differently. In order to clearly distinguish the improvement effects for each item, a simulation was conducted by dividing the date with the highest temperature and the date with the highest concentration of fine dust. Predicted Mean Vote (PMV) is an index that quantifies thermal comfort by considering meteorological factors such as temperature, wind speed, humidity, and average radiant temperature, as well as human activity and clothing as subjective factors (American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 1989; ASHRAE 2005; Baek 2020). The PMV simulation was also applied to the Banpo-daero using ENVI-met (ver. 5.0.3). The same criteria as the microclimate analysis model were applied, and simulations were conducted for each scenario based on 13:00, when the temperature is high and the sun's altitude is high. Human body index, clothing, and body metabolism were analyzed by entering the most commonly used ISO 7730 standards (Basic settings of the ENVI-met program) for a typical human in 1984(Baek 2020). The source of particulate matter was set to be generated from vehicles in the driveway area. It is selected based on the day when the particulate matter level in Seocho-gu, the target area, was highest on the Seoul Air Quality Information Site, and on May 8, 2021, particulate matter(PM10) in Seocho-gu was 442μg/m3 (Average daily concentration) and particulate matter (PM2.5) are 114 μ g/m3 (Average daily concentration). The average value of fine dust over time was applied to the concentration of particulate matter (PM10) used in the simulation (Table 1).
Scenario overview
The analysis scenario of the target site was conducted in four stages, and type (1) was set as bare ground before planting trees on Banpo-daero, and type (2) was typified as the current planting status of the target site. Type (3) is a type of plan that introduces planting structures and techniques that can be realistically applied to the current target site, and type (4) is a type that applies the ideal plan of a multi-layered street green Connecting forest with a central green area along Banpo-daero as a Connecting forest creation technique for the Wind-Connecting Forest Road Creation Project in Seocho-gu. To analyze the effect of changing the planting technique, structure, and type of connected forest, each tree was set in the same form(Shape and size of Platanus occidentalis and shrub species) (Fig. 3).

Simulation model for each type of Banpo-daero street (3D). A, Banpo-daero Street Tree Type (1) Simulation Model(3D); B, Banpo-daero Street Tree Type(2) Simulation Model(3D); C, Banpo-daero Street Tree Type (3) Simul’ation Model(3D); D, Banpo-daero Street Tree Type (4) Simulation Model(3D).
The planting type of type (1) was set as a boulevard along Banpo-daero excluding the trees planted in the target site from the current land use and urban status, and the trees in the surrounding residential areas such as greenery and parks reflected the current status. The horizontal structure of Banpo-daero is a flat structure.
Type (2) is a type that applies the planting type, planting species, planting structure, and green cover rate (10.2%) of the current target site (along Banpo-daero) as it is. The physical structure of the target site, such as driveways, sidewalks, side roads, wall and roof materials of surrounding buildings, and wall and rooftop greening, and the specific planting status through field surveys were applied to the design model. A 1,500 mm × 1,500 mm tree protection board is installed at the end of the sidewalk on the sidewalk side of Banpo-daero, and Platanus occidentalis are planted as street trees, and in some places they are removed and covered with pavement for access to adjacent commercial buildings. In addition, the tree is pruned in the form of square pruning, which has been continuously implemented by Seocho-gu for five years since 2018, and is built as a model by applying a tree shape of 12 meters high, 5 meters wide by 5 meters long, and 4 meters below ground.
Type (3) reflects the planting type, tree species, planting structure, and green cover rate of the current site, and the actual case of the site that was created as a Connecting forest based on a street tree of Platanus occidentalis that applied square pruning to the street greening of Banpo-daero was applied as a planting plan model (green cover rate of 20%). The planting type, technique, structure, and species type of the horizontal banded greenery in the recently created Seoul Connecting Forest project were applied as the planting plan.
Type (4) is composed of the most ideal planting type, planting species, and planting structure (20% green cover) from the basic plan for the Seocho-gu wind ventilation connection Forest. It was planned as a median green and a multi-layered street forest. In consideration of the 30-meter road and 5-meter sidewalk width, traffic conditions, and traffic safety zones, a 2.0-meter strip greenery was secured along both sides of the road, and a central bus lane and median greenery were introduced in the center of the road. In particular, the street forest, which are Platanus occidentalis, were not pruned to a square shape, but the large and wide original tree trunks were applied. The banded greenery was applied in a terraced arrangement to increase the density of the vegetation structure by placing plants densely in the middle and front in line with the road and the main wind direction in the city center to prevent the spread of pollutants to the commercial and residential areas on both sides of the road, while the central greenery was planned to allow good airflow by excluding lower shrubs.
Results and Discussion
Verify effectiveness with simulations
Temperature
The results of the comparison between type (1) and type (2) showed that the planting of street trees on the streets of the city center resulted in a temperature reduction effect on the driveway and sidewalk areas, as well as the surrounding commercial and residential areas. In addition, it was confirmed that the temperature difference becomes larger at times when the sun is at a high altitude, and the formation of shadows due to street trees has a significant effect on temperature reduction. In the comparison of type (2) and type (3), the composition of horizontal greenery increased the temperature of the driveway area by up to 0.18°C, and the sidewalk area decreased the temperature by up to 0.12°C. This is believed to be due to the high temperature heat generated from the roadway moving to the sidewalk along the wind direction, which increased the temperature, as confirmed by the effect of creating a strip green area using the cascading method by Baek (2020). The comparison of type (2) and type (4) showed that the temperature in the center of the road was reduced by up to 1.06°C by creating a central green zone. In addition, the planting of a central green zone in the center of the road significantly reduced the temperature not only in the road area but also in the sidewalk area and residential area as the sun's altitude was lowered. By keeping the square-pruned Platanus occidentalis in their original conical shape to increase the area of the tree canal, and by creating a belt green zone with a terraced layout of street trees + multilayer plantings, the temperature reduction effect can be expected not only in the sidewalk but also in commercial and residential areas. However, the high temperature of the driveway area is concentrated in the driveway along with the wind, so it should be improved by planting techniques that fit the urban structure of the target area. In closed spaces due to neighboring buildings, the spread of high temperatures should be reduced by terracing, and in intersections and wide open spaces, low shrubs or flowering plants should be planted in the belt green to disperse the heat outside with the wind.
PMV (Predicted Mean Vote)
The results of the comparison between type (1) and type (2) showed that planting street trees on the streets of the city center reduced the PMV by about 0.25 in the driveway and sidewalk areas, and about 0.3 in the commercial and residential areas. Comparing type (2) and type (3), the results showed that the PMV was reduced by up to 1.32 or more by planting square-pruned Platanus occidentalis and strip greenery in a terraced arrangement. However, the reduction was only seen in the green zone under the street trees, and the reduction was not evident across the roadway, commercial and residential areas. In the comparison of type (2) and type (4), the PMV index of up to 1. 56 was lowered by creating a central green zone in addition to the original tree type and the banded green zone in a terraced arrangement. In particular, the reduction effect of the central green zone was significant on the roadway, and as a result, not only the surrounding sidewalk area but also the surrounding shopping malls and residential areas were reduced. The creation of a banded green zone with street trees and multi-layered plantings of Platanus occidentalis along Banpo-daero reduced PMV in the roadway, sidewalk, commercial and residential areas. The creation of a central green zone in the center of the road and the planting of Platanus occidentalis would greatly reduce the PMV of the entire site, but it is difficult to create in reality. Therefore, by maintaining the original conical shape of the trees and increasing the area of the tree trunks to form shade as wide as the tree trunk, and creating a strip green area of multi-layered plantings, PMV will be greatly reduced in the driveway and sidewalk areas.
Particulate matter
The results of the comparison between type (1) and type (2) show that the difference in PM2.5 concentration between the two types is 436.95–350.74 μ g/m3 across the entire site due to the planting of street trees in the city center. The concentration of particulate matter increased in the driveway area, and the concentration of particulate matter also increased in the surrounding commercial and residential areas. This is judged to be due to the fact that the wind speed is slowed down due to the square pruning of the Platanus occidentalis and the concentration is increased due to the inability to spread the particulate matter due to the stagnation of the wind. As a result of the comparison between type (2) and type (3), the difference in particulate matter concentration between the square-pruned Platanus occidentalis and the terraced green space is 348.91–58.36 μ g/m3. The result of creating a banded green area with a row of Platanus occidentalis and a lower terraced layout resulted in the concentration of particulate matter in the driveway area. In the comparison of type (2) and type (4), the difference in particulate matter concentration is 351.54 ~ −500.62 μ g/m3 by creating a central green area with the original tree type, which is Platanus occidentalis, a banded green area with a terraced arrangement, and a central green area. The concentration of particulate matter in the roadway area was further increased due to the street trees, strip greenery, and central greenery trees, but in the sidewalk area and commercial and residential areas, the concentration of particulate matter decreased significantly as the distance from the roadway area increased.
By creating a banded green area with a multi-layered planting method of terraced layout along Banpo-daero with street trees, the effect of reducing particulate matter can be expected throughout the entire site. However, since pollutants are concentrated and stagnated in the road, it is necessary to improve this by applying planting techniques that fit the urban structure of the target site. In spaces that are closed due to surrounding buildings, it is necessary to reduce the spread of particulate matter on the roadway by creating a belt green with a terraced layout, and in intersections and wide-open spaces, it is necessary to create a belt green that fits the urban structure by planting low shrubs or flowering plants in the belt green so that particulate matter can be dispersed with the wind on the road (Fig. 4).
Synthesis
At 13:00 of the result of comparison between type (1) and type (2) shows that, the temperature of the roadway area was reduced by 0.34°C, the sidewalk area was 0.58°C, and the temperature of the commercial and residential area was reduced by 0. 69°C and PMV (Predicted Mean Vote) was reduced by 1 or more, but at 18:00, particulate matter increased due to a decrease in wind speed. At 13:00 of the result of comparison between type (2) and type (3) shows that, the temperature of up to 0.15°C rise in the roadway area and the temperature of up to 0.12°C went down in the sidewalk area, and PMV (Predicted Mean Vote) was reduced by up to 1.32 in the multi-layer trench planting area. At 18:00, particulate matter was concentrated, resulting in an increase of about 40~80μg/m3 in roadways and sidewalks. Finally, at 13:00 of the result of comparison between type (2) and type (4) shows that, the effect of reducing the maximum 1.6°C in the roadway area and 0.3°C in the sidewalk area was shown, and the result of lowering the temperature throughout the target area was derived. At 18:00, arise from street trees, trench planting and trees in Green Area at the Center Line the concentration of particulate matter in the roadway area increased to about 150 μg/m3, and the concentration of particulate matter in sidewalks and residential areas decreased. This study analyzed the effect of planting structure on the target site by categorizing the planting structure to improve the function of particulate matter and temperature reduction, which are the main functions of the Connecting Forest (Table 2). When comparing type (1) and type (2) of Banpo-daero, it was found that street tree planting has a significant effect on reducing the temperature and PMV indicators of the street environment. It was determined that the high heat generated from the roadway moved to the sidewalk along the wind direction and increased the temperature. Through the comparison of type (2) and type (3), it was analyzed that in a situation where a certain size of street trees provide shade, the composition of the strip green under the street trees has a small effect on temperature reduction, but it is possible to feel significantly more comfortable in the street trees and the strip green in terms of PMV. In the comparison between type (2) and type (4), the area of the street tree canopy became larger, and the planting of a Platanus occidentalis in the center of the road created shade as wide as the canopy, resulting in a large temperature difference in the driveway area, and the temperature and PMV were reduced in the sidewalk area. The effect of planting street trees across the roadway and sidewalk area, as well as the surrounding commercial and residential areas, reduced the temperature, and the creation of a strip greenery with a cascading arrangement of street trees + multi-layered plantings further increased the temperature reduction effect on the surrounding area. As can be seen in type (4), if the square-pruned Platanus occidentalis are kept in their original shape to increase the area of the tree canopy, it is judged that a greater effect than the current effect will be seen in terms of temperature and PMV in the driveway, sidewalk area, and surrounding areas.
However, the effect of reducing particulate matter was different in the driveway and sidewalk areas and the surrounding commercial and residential areas. Compared to type (1), the concentration of particulate matter increased in the driveway area due to wind, whereas in type (2), type (3), and type (4), the introduction of street trees, terraced green areas, and central green areas resulted in the concentration of particulate matter in the driveway area, and the concentration increased in the sidewalk area. This was due to the effect of blocking wind due to trees rather than the effect of reducing particulate matter through trees planted along the roadside, which increased the concentration of particulate matter in the driveway.
Therefore, it is judged that if the entire belt green within the street route is created in a terraced layout, particulate matter will be concentrated in the driveway and sidewalk areas, so it is recommended to reduce the spread of particulate matter in closed spaces due to surrounding buildings by using a terraced layout, and to plant low shrubs or grasses in the belt green at intersections and wide-open spaces so that particulate matter can be dispersed with the wind. In addition, in sections where particulate matter is concentrated due to the creation of urban wind ventilation connecting forests, it is judged that it is necessary to reduce the concentration of particulate matter in the city center by introducing artificial reduction facilities such as particulate matter collectors in addition to reducing particulate matter through trees.
Developing a connecting forest planting technique
Growing street trees and planting Platanus occidentalis in the center of the road can significantly reduce the temperature and improve PMV in the driveway and sidewalk areas, but if it is difficult to create a green area in the center of the road, it is judged that it is first necessary to widen the width of the tree by managing the original tree shape of the street tree, the Platanus occidentalis. In addition, as a way to improve the ability to reduce particulate matter, multilayer plantings based on the terraced layout method should be used in street environments with narrow sidewalks and building fronts to create a water wall through small trees and shrubs planted in addition to existing street trees to prevent the spread of high temperatures and particulate matter in the driveway to sidewalks and commercial and residential areas. On the other hand, in street environments with wide sidewalks and building fronts, such as intersections, the planting technique of planting a water wall in the strip green area should be avoided, and a low planting structure should be created so that high temperatures and high particulate matter in the driveway can spread outside the sidewalk area by introducing low trees. Therefore, in order to improve the temperature control function of street forests and the function of blocking and reducing particulate matter, the existing square-pruned Platanus occidentalis on Banpo-daero, which is a destination that matches the main wind direction, are maintained in their original tree shape, a band greenery with a terraced layout is created, and tree species with excellent particulate matter reduction capabilities are selected and planted, and a planting technique that considers the urban structure to regulate the flow of wind inside the road is proposed as follows. In addition, Pinus densiflora for. multicaulis, Acer pseudosieboldianum, and Cornus officinalis are planted for small trees that have good growth and excellent particulate matter reduction capabilities in the urban street environment, and Euonymus japonicus, Viburnum erosum, and Spiraea prunifolia for. simpliciflora, Weigela subsessilis, Rhododendron yedoense, Euonymus alatus, Buxus microphylla var. koreana are planted for shrubs, and Pachysandra terminalis and Liriope platyphylla were selected as ground cover plants (Fig. 5).
Conclusion
In this study, we selected Banpo-daero, a major connecting forest in Seocho-gu, to reconfirm its function as a wind forest and a connecting forest according to the characteristics of the target site, and to propose planting structures and techniques to improve its function. In addition, we analyzed the changes in temperature and particulate matter using ENVI-met, a microclimate analysis model, to present a realistic planting design plan for each target site to improve its function.
Banpo-daero Road is a connecting forest, focusing on the role and function of temperature reduction and particulate matter blocking and reduction, and analyzed the planting structure of the terraced layout method as a target site that matches the presence or absence of street trees, the form of pruning, the composition of the strip greenery, and the prevailing wind direction. Through simulation analysis, we planted street trees with large trunk widths that are favorable for shade formation (Platanus occidentalis) and maintained the unique tree shape, oval, rather than square pruning, and the composition of the strip greenery consisted of multi-layered plantings based on the terraced layout method by introducing tree species with excellent particulate matter reduction capabilities. The creation of a banded green area with a terraced layout resulted in an increase in temperature and concentration of particulate matter in some areas of the driveway, which was determined to be the result of concentration along the driveway in the area of the driveway that matches the main wind direction. In areas with narrow sidewalks or narrow spacing between neighboring buildings, we created a water wall with high-tree shrubs to block high temperatures and particulate matter in the wind and driveway areas, and in areas with wide spacing between intersections and neighboring buildings, we used low shrubs or covering plants such as grasses to induce the spread of high temperatures and particulate matter in the wind and driveway areas. This planting technique, which takes into account the urban structure of the target site, will enhance the role and function of temperature reduction and particulate matter blocking and reduction. As a limitation of this study, there is a limitation of the study that did not take into account the changes in fine dust concentration and temperature when deriving the results of the roadside PMV simulation. In addition, the statistical verification of the results of this study was insufficient due to the lack of establishment of detailed data for various types of Wind-Connecting Forests. This study is meaningful in analyzing the function of connecting forests, which play an important role in urban wind ventilation forests, which are created as a solution to improve the urban environment, such as reducing particulate matter in the city and mitigating heat waves, and suggesting planting techniques that can improve their function.
Notes
This paper is a revised and expanded version of the master's thesis of Geun-Ki Kim, University of Seoul, Republic of Korea, 2023.