Impact of urban tree morphology on reducing surface flow in Hue City, Vietnam Open Access

Climate, topography, vegetation, and their interactions strongly influence the hydrological cycle on Earth. This issue has attracted extensive research to provide a basis for developing solutions to mitigate urban flooding. Vegetation, including urban trees, is considered a cost-effective solution to intercept rainfall, increase evaporation of rainwater, and enhance rainwater infiltration into the soil. The ability of trees to perform these functions depends on various factors, such as tree characteristics (species, size, canopy density, leaf area index (LAI), leaf structure, and root system); soil volume available for tree growth; soil structure and composition; rainfall events, and precipitation characteristics. Urban trees help intercept rainfall and increase the amount of rainwater evaporating through their canopy. Tree canopies directly block rainfall and enhance the evaporation of rainwater accumulated on leaves (Xiao et al. 2000; Yang et al. 2019). Zabret et al. (2017) stated that depending on tree species, rainfall characteristics, and the time of year, the reduction in rainfall intensity beneath the canopy can range from 25 to 70% (Zabret et al. 2017). Asadian & Weiler (2009) measured the rain interception ability of two deciduous tree species in British Columbia, Canada, and concluded that, on average, urban trees can intercept 50–60% of rainfall. Research findings indicate variations in rainfall interception capacity among tree species (Asadian & Weiler 2009). According to the research, the interception rate for coniferous trees ranges from 20 to 40%, while for deciduous trees, it is from 20 to 25% (Geiger et al. 1995). Researchers discovered that coniferous trees demonstrate a higher percentage of rainfall interception capacity of 30%, while deciduous trees intercept only about 20% of precipitation (Kuehler et al. 2017). Experimental data measuring runoff from three plots with tree cover showed that trees reduced the runoff coefficient from asphalt surfaces by 38% in summer and 43% in winter (Armson et al. 2013). Experiments involving urban tree arrangements, including garden trees, demonstrated a feasible reduction in runoff from 9.1 to 21.4% (Inkiläinen et al. 2013).

The structural diversity of urban trees is also one of the key factors contributing to differences in their ability to reduce surface runoff (Zabret 2013). Trees with stiff, rough-textured leaves intercept more rainfall than soft, smooth leaves (Xiao et al. 2000). The LAI impact was analyzed in detail by Yang et al. (2019) by evaluating four tree species: Ginkgo biloba, Aesculus turbinata, Saccharina japonica, and Zelkova serrata. Their results showed that smaller leaves more effectively intercept rainfall than larger leaves. Tree bark plays the most significant role in rainfall interception. After conducting experiments on leaves, branches, and the bark of 10 common urban tree species in Shanghai, the study concluded that coniferous trees intercept more rainfall than broadleaf trees (Wang et al. 2023). The root system of trees contributes to enhancing rainwater infiltration. According to a greenhouse experiment, rainwater infiltration increased by an average of 63% in areas with trees compared to areas without trees (Bartens et al. 2008).

The ability of soil to absorb rainwater varies depending on root distribution density. Trees with deep root systems improve water infiltration the most, followed by trees with moderate and shallow root distributions (Xie et al. 2020). The research findings above indicate that urban trees' morphological characteristics significantly influence their ability to intercept, evaporate, and absorb rainwater. Additionally, this capability is affected by climatic conditions and soil types in tree-covered areas.

Xiao et al. (2000) and Guevara-Escobar et al. (2007) stated that in regions with high total rainfall, seasonal heavy rain, and short-duration intense storms, the ability of trees to intercept rainfall decreases (Xiao et al. 2000; Guevara-Escobar et al. 2007). On the other hand, in areas with high temperatures, rainwater evaporates faster, whereas high humidity levels reduce the evaporation rate. Researchers and practitioners must base the study and use of trees to reduce surface runoff on climate conditions, soil characteristics, and tree species traits. Around the world, experts have proposed and implemented numerous models and projects utilizing trees to reduce surface runoff, such as:

– The project by the US Center for Watershed Protection (2017) utilized best management practices with trees, developing urban greenery based on a scientific system (Center for Watershed Protection 2017). Due to its high feasibility in 2017, the project received funding from the National Urban and Community Forestry Advisory Council of the US Forest Service.

– The water balance model calculates the average annual runoff for locations with mature trees planted on grass or impermeable surfaces and without trees. The model includes four hydrologic soil groups and five tree types at 31 sites across 11 climate zones (Hynicka & Caraco 2017).

– An experiment measuring throughfall using standard rain gauges was placed under tree canopies and in areas without trees. Researchers collected measurements over 24 months during rain events and applied a formula to the recorded data to calculate the rainfall intercepted by the trees (Venkatraman & Ashwath 2016).

– The MIDS calculator, developed by the Center for Watershed Protection (2018), is widely used in the United States to estimate the rainwater storage capacity of urban trees. The calculation considers tree morphology, location, and soil characteristics. In the MIDS model, designers configure trees as tree trench systems (tree boxes) and implement them with or without drainage pipes beneath the planting box (Center for Watershed Protection 2018).

Reducing stormwater runoff through urban trees has become an important ecosystem service, attracting significant research and investment, especially in developed countries. However, in Vietnam, research on the application of this approach remains largely unexplored. Urban tree studies in Vietnam have mainly focused on aesthetics, landscape design, microclimate improvement, and management organization (Lang et al. 2023). Other areas of study include species composition and tree diversity, which Vietnamese Standards have formalized. However, quantitative analyses of urban trees' environmental impacts are scarce, and almost no studies or experiments have examined the role of trees in flood mitigation. Recently, Lang et al. (2023) applied the MIDS method to evaluate the reduction in stormwater runoff capacity due to changes in tree species along Ly Thuong Kiet Street, Hue City, highlighting the importance of selecting tree species that balance landscape enhancement and stormwater management (Lang et al. 2023). Another study by Lang et al. (2024) analyzed the impact of tree pit size on water infiltration along Dong Da and Ly Thuong Kiet Streets in Hue City (Lang et al. 2024).

Hue City, which has the highest urban tree density in Vietnam, contains over 64,000 street trees, numerous lakes and ponds, and the northern area of the Perfume River, where the UNESCO World Heritage Site stands. However, localized flooding remains a major annual challenge (Lang et al. 2023). Despite implementing various infrastructure solutions, authorities have not fully resolved the issue. In the context of climate change, the increasing frequency of extreme rainfall and the expansion of impervious surfaces due to urbanization are exacerbating localized flooding. (In the past, the Hue Citadel rarely experienced flooding, but it has become more frequent.) This situation has driven the search for additional solutions to address the issue, aiming to minimize damage to the landscape, environment, and economy, particularly in the tourism sector, which is the key strength of Hue – the Heritage City. Additionally, to provide and supplement scientific evidence on the role of urban trees in flood mitigation, this article compiles and analyzes research findings from multiple perspectives that influence the capacity of trees to reduce surface runoff. The study gathers data from reliable research, experiments, and high-credibility methodologies from various authors to raise awareness and encourage Vietnamese scientists to engage in evaluating and applying tree-based solutions for flood reduction.

Based on regional geographical characteristics and careful consideration of methods, techniques, and available research infrastructure, this study continues to apply the MIDS method. Researchers have widely used this technique across multiple US states, demonstrating its effectiveness and publishing the results. Moreover, it provides a straightforward evaluation process, requires minimal monitoring time, and suits large-scale studies in areas facing frequent localized flooding.

As urban roads continue to increase, researchers have developed more systematic findings, reinforcing conclusions that serve as a foundation for proposing practical solutions. This process, in turn, shifts the perspectives of policymakers and the public in urban planning, design, and interactions with urban greenery.

This study builds upon previous research, expanding the study area and focusing on the following key aspects:

• – Establishing the scientific basis for utilizing urban greenery to mitigate stormwater runoff in Hue and Vietnam – a strategy that has received limited research and application.

• – Quantifying and assessing the ability of urban trees to reduce surface runoff based on the current urban greenery in three streets north of the Hương River (a historic preservation area) and two streets south of the Hương River (a new urban development zone).

• – Evaluating the variation in runoff reduction among different streets under study.

• – Determine key long-term factors that decrease the effectiveness of urban trees in runoff reduction despite being common and challenging to mitigate within the study area.

Studied streets in the north: Dang Thai Than Street (751 m long and 15 m wide), Mai Thuc Loan Street (853 m long and 18 m wide), and Nguyen Chi Dieu Street (652 m long and 15 m wide).

Studied streets in the South: Tran Quang Khai Street (700 m long and 13 m wide) and Ben Nghe Street (440 m long and 23 m wide).

All these streets suffer severe flooding in the rainy season, with Tran Quang Khai Street being the worst affected (floodwater levels of 0.5–0.8 m, prolonged duration).

Hue City receives some of Vietnam's highest rainfall, with intensities reaching 26 mm in 10 min, 67 mm in 30 min, and 120 mm in 60 min. The region's sandy loam soil has moderate to high water retention but compacts easily, reducing infiltration, especially after consecutive rainy days. The weathered soil layer has poor to moderate water regulation capacity.

• Primary data: Includes survey data on soil characteristics, topography, and the development status of urban greenery along major roads: Nguyen Chi Dieu, Mai Thuc Loan, Dang Thai Than, Ben Nghe, and Tran Quang Khai (Table 1 and Figure 1).

• Secondary data: Includes information on soil, topography, green ecosystems, Geographic Information System (GIS), MIDS methodology, water absorption capacity of tree roots, and the impact of vegetation on surface runoff collected from previous studies and reports from relevant authorities. Additionally, meteorological and hydrological agencies in Hue City and the surrounding areas gathered rainfall, flow velocity, and flood frequency data.

Urban tree data includes species count, trunk diameter (1.3 m height), total height, canopy diameter, area (CP), and LAI. Additional LAI data (1932–2000) show deciduous trees with LAI values of 3.5 (small), 4.1 (medium), and 4.7 (large). The estimation for canopy water interception is 2.2 mm for conifers and 1.1 mm for deciduous trees. The drip line determines the canopy diameter, representing full-grown coverage. Sandy loam soil (Group A) in the study area has a wilting moisture content of 0.05 and a field capacity (FC) of 0.45.

Like An Giang, evaporation in Hue City ranges from 3.6 to 4.6 mm/day in the rainy season (avgerage 4.1 mm/day). The evaporation ratio is 20% (Lindsey & Bassuk 1991).

Tree planting before 2009 and after 2010 followed individual placement along major roads, with surface and underground areas of 2.25 m² each.

Soil drainage: The planting medium depth (DM) is 0.83 m, ensuring 24-h drainage at an 8.46 mm/h infiltration rate. FC and n, followed by MID, are 0.14 and 0.45 (USDA Forest Service 2018).

• – Data on the development of urban trees along the streets: The collected information includes species of trees, quantity, diameter at 1.3 m height (cm), overall height (m), canopy diameter (m), canopy area (m²) (CP), and LAI (Table 2).

• – Other data inherited from research results around the world include:

Other data from global research include the LAI of trees, derived from studies on global leaf area between 1932 and 2000 (Scurlock et al. 2002). The trees on the studied street are deciduous, with an LAI of 3.5 for small trees, 4.1 for medium-sized trees, and 4.7 for large trees. Water intercepted by a tree canopy may evaporate or be slowly released so that it does not contribute to stormwater runoff. A simplified interception capacity (I_c) value for deciduous and coniferous tree species gives an interception credit: I_c coniferous = 2.2 mm; I_c deciduous = 1.1 mm.

The diameter of the tree canopy is measured at the drip line (d), expressed in metres, representing the canopy projection (CP), which indicates the apparent canopy area when fully grown. The hydrological soil group of the study area is A (sandy loam), with the water contents at the wilting point and FC at 0.05 and 0.45, respectively.

The evaporation rate (E_rate) per unit of time in Hue City, similar to An Giang, ranges from 3.6 to 4.6 mm/day during the rainy season, with an estimated average of 4.1 mm/day.

The research by Lindsey & Bassuk (1991) sets the evaporation ratio (E_ratio) at 0.20, or 20% (Lindsey & Bassuk 1991).

Before 2009 and after 2010, planners planted urban trees along the main roads as individual specimens. They placed the trees in an environment with a surface area of 2.25 m² (AM), with an equivalent area below ground (AB) of 2.25 m².

The depth of the environment (DM) is 0.83 m (this depth corresponds to the depth necessary to achieve a 24-h drainage time with the specified soil infiltration rate of 8.46 mm/h). FC and n, followed by MID, are 0.14 and 0.45, respectively (USDA Forest Service 2018).

This method uses survey results and data from related projects and studies to enable the research team to analyze, evaluate, and provide comprehensive assessments of the study area. The data, which the team collects, synthesizes, analyzes, and evaluates, is based on the following sources: government regulations regarding drainage management; the current state of drainage systems, flooding situations, and flood mitigation efforts in urban areas along the roads of Hue City; and studies on planning, designing, and managing sustainable green drainage systems, with a particular focus on Hue City.

To calculate the credit for evapotranspiration, use the rooting depth as the media depth. This depth corresponds to the thickness of the designed media and the underlying soil into which tree roots can grow.

Survey results show that, in practice, urban trees planted along streets are typically isolated, planted in a medium with a surface area (AM) of 2.25 m² and an equivalent bottom area (AB) of 2.25 m².

The depth of the medium (DM) is 0.83 m, corresponding to the necessary depth to meet a 24-h drainage time at a specified soil infiltration rate of 8.46 mm/h.

The FC and porosity of the medium (n) according to MIDS are 0.14 and 0.45, respectively (USDA Forest Service 2018). Along streets, planners plant isolated trees in more prominent mediums, with a surface area (AM) of 3.24 m² and an equivalent bottom area (AB) of 3.24 m².

Additionally, there are 19 big growing media, each containing two or three trees, with dimensions of AM = 16.2 m², AB = 16.2 m², and DM = 0.83 m.

(***) Evapotranspiration volume from trees (VET):

The study used global leaf area data from 1932 and 2000 to calculate trees' LAI values (Scurlock et al. 2002). The LAI values for streetside trees are 4.7 for large trees, 4.1 for medium-sized trees, and 3.5 for small trees.

The study by Lindsey & Bassuk (1991) set the evaporation ratio (E_ratio) at 0.20, or 20% (Lindsey & Bassuk 1991).

The evaporation rate in Hue City ranges from 3.6 to 4.6 mm/day during the rainy season, with an average of 4.1 mm/day.

(****) The volume intercepted by the canopy (VI):

The MIDS calculation provided the values of VI, V_infb, and VET for each tree and the number of trees in each group on the studied streets. Table 3 presents the results.

The results indicate that the 341 trees across five studied streets help reduce stormwater runoff, retaining a total of 1,132.39 m³ of water, an average of 3.32 m³ per tree, which is relatively minor. However, runoff reduction varies significantly between streets (Table 3).

Key reasons include:

• (i) Differences in tree density. More trees generally lead to more significant runoff reduction. For instance, Dang Thai Than Street, with 122 trees, retains 351.27 m³ of water, whereas Tran Quang Khai Street, with just 32 trees, retains 122.54 m³.

However, Table 3 shows that tree count rankings do not align with runoff reduction rankings. For example:

• – The street with the most trees has 3.8 times more trees than the one with the fewest, yet its runoff reduction is only 2.8 times higher.

• – Across other streets, tree count differences range from 1.56 to 2.0 times, while runoff reduction differences range from 1.39 to 1.79 times (Table 3).

• (ii) Diversity and complexity of urban tree morphology

Variations in Pc, LAI, and I_c indices reflect differences in tree size, canopy cover, and species, affecting the impact of tree quantity and the direct role of trees in evaporation and rainwater interception.

Additionally, Pc and LAI values fluctuate due to both natural and human factors:

• – Natural factors: Storms and strong winds can break branches, uproot trees, or damage canopies.

• – Human factors: Pruning for storm prevention reduces canopy cover and interception capacity.

Key findings:

• – Evaporation accounts for the most considerable rainwater loss (647.62 m³), surpassing interception by 2.8 times and infiltration by 2.6 times. Enhancing evaporation processes is crucial for mitigating local flooding.

• – Urban trees in the study area have limited infiltration capacity due to unsuitable tree pit design and soil conditions:

Regardless of tree size, existing pits are too small (2.16–3.24 m²/tree). Most trees exceed 9 m in height, requiring significantly larger pits.

The soil lacks a structured composition, reducing infiltration and root expansion.

Current tree planting primarily serves aesthetic and shading purposes rather than flood mitigation. The loamy sand used in tree pits is highly compacted, further limiting infiltration, especially during heavy rainfall.

Challenges and solutions: With climate change increasing extreme rainfall, eco-friendly solutions, such as urban trees, one of Hue's key strengths, are urgently needed. However, several challenges hinder their flood mitigation potential:

• – Limited land availability restricts space for trees to maximize infiltration.

• – Storm-related conflicts in tree management: Balancing canopy preservation (Pc and LAI) for flood mitigation with pruning for storm resilience remains a challenge.

• – Infrastructure conflicts: Integrating trees with underground drainage, power lines, and fibre optic cables requires technical expertise.

• – Tree species selection: Multi-functional trees need long-term research and interdisciplinary collaboration.

Trees significantly impact the hydrological cycle in general and on reducing surface runoff in particular. Many studies have confirmed this and consider it a viable solution to mitigate localized flooding. This study applied the MIDS method to evaluate the ability of urban trees to reduce surface runoff along five streets in Hue City and confirmed their effectiveness. However, in the study area, the capacity of trees to reduce stormwater runoff was not high and varied across different streets.

The main reasons for this issue include:

• (i) The number of trees decreased by 84 over the past 10 years due to the region's frequent exposure to typhoons, a weather phenomenon that has intensified with climate change.

• (ii) Changes in tree morphology, notably the LAI and canopy cover (Pc), have shown a negative trend (declining) due to extreme weather events and human activities.

• (iii) Small tree pit sizes and non-structural soil use hinder water infiltration. These factors affect the changes in three key processes – evaporation, interception, and infiltration – and ultimately impact the ability of trees to mitigate surface runoff.

The study results indicate that tree quantity is not the most crucial factor in cases where Pc and LAI values are very low or negligible. Tree quantity statistics alone do not provide a comprehensive quantification of the value of urban greenery. Reports on urban trees and their environmental impact would be more meaningful if they focused on biological and morphological characteristics.

Maintaining high Pc and LAI values presents a significant challenge in a region frequently affected by typhoons. Storm-related tree damage occurs probabilistically, but biological and structural measures can help mitigate its impact. However, the widespread practice of pruning and trimming trees during the storm season to prevent breakage and hazards to people remains the most challenging issue. Authorities and residents often conduct this practice extensively and simultaneously, precisely when high Pc and LAI values are most crucial. The reliance on inherited and generalized LAI and I_c values for each tree group is a limitation of this study. The more specific and detailed these values are, the more precise the differentiation, leading to more accurate assessments. These indices should be calculated for each tree to effectively use urban trees to mitigate localized flooding in a specific area. Applying Statistical Package for the Social Sciences (SPSS) to analyze correlations between variables (such as tree quantity, morphological characteristics, and soil structure) and the level of surface runoff reduction provides a foundation for designing tree-planting scenarios tailored to this goal in the context of climate change.

The study results suggest that policymakers in Vietnam and the public should adopt a multipurpose perspective on urban trees, recognizing their role in improving the microclimate, cultural landscape, and aesthetics and mitigating flooding. However, trees alone are not a sufficient solution for controlling stormwater runoff. Integrating trees with ponds and reservoirs is a promising direction for future in-depth research to enhance the feasibility of green solutions for managing stormwater runoff. Based on the research findings, to achieve practical application, the proposed hypothesis for leveraging Hue City's strengths in surface runoff control is as follows:

Integrating urban tree solutions with a detention pond system to reduce localized flooding amid increasing urbanization and climate change.

Hue City has the advantage of abundant greenery and numerous ponds and lakes, which provide favourable conditions for extending water retention time, reducing surface runoff, and achieving the following goals: delaying localized flooding after heavy rainfall, minimizing flood depth, and reducing the number of inundation points.

Urban tree solution design: Select tree species, preferably evergreen species, with high wind resistance and high Pc and LAI indices. Optimize spatial arrangement: Ensure appropriate aboveground and underground space for stable tree growth. Increase tree cover through multi-layered vegetation (canopy trees and shade-tolerant plants).

Detention pond solution design: Utilize existing ponds and lakes to calculate water retention capacity for each rainfall event. Studies on low-impact development highlight the superior benefits of urban trees in the hydrological cycle, microclimate regulation, soil conservation, and biodiversity protection. This paper demonstrates how street trees mitigate surface runoff, reducing localized flooding, preventing soil erosion, and controlling soil and water pollution. Trees achieve this by intercepting rainfall, reducing its intensity, enhancing infiltration, and absorbing stormwater while lowering nutrient loads.

Research on the capacity of urban greenery to mitigate localized flooding and stormwater runoff has significant implications for environmental protection and climate change adaptation. Integrating vegetation into urban infrastructure reduces flood risks, enhances air quality, preserves biodiversity, and fosters a healthier living environment for urban residents. Moreover, in the context of climate change, where precipitation patterns and extreme weather events have become increasingly unpredictable, green infrastructure as a natural solution for stormwater management is of growing importance. This aligns with previous studies, such as that of Abed-Elmdoust et al. (2016), which emphasize the necessity of understanding and adapting to shifts in precipitation patterns to ensure the sustainability of hydrological systems. Additionally, identifying critical locations within river networks, as proposed by Sarker et al. (2019), can be applied to urban planning to optimize tree-planting locations, maximizing flood mitigation effectiveness and environmental protection (Sarker et al. 2019).

Globally, strategies for mitigating localized flooding have evolved, with urban trees playing a crucial role in reducing stormwater runoff. Studies across diverse geographic regions have demonstrated their effectiveness in flood mitigation. Despite engineering interventions, Hue City continues to experience localized flooding. Given its high urban tree density, integrating green infrastructure presents a valuable opportunity for flood mitigation. This study evaluates the capacity of urban trees along five streets in Hue to reduce stormwater runoff, focusing on three key hydrological processes: infiltration, evapotranspiration, and rainfall interception.

Using the MIDS methodology, the study finds that urban trees contribute to runoff reduction, with an estimated total volume of 1,132.39 m³ and an average reduction of 3.32 m³ per tree. While this volume is relatively modest, it underscores the role of urban trees in flood mitigation. Among the three hydrological processes, evapotranspiration accounts for the largest share (647.62 m³), exceeding rainfall interception by 2.8 and infiltration by 2.6.

Multiple factors influence the capacity of urban trees to mitigate runoff, which varies across different streets. Tree quantity plays a significant role, as streets with more trees exhibit greater stormwater runoff reduction. For example, Dang Thai Than Street, with 3.8 times more trees than Tran Quang Khai Street, shows 2.8 times greater runoff reduction. However, tree morphology also contributes independently to runoff reduction. The ranking of streets by tree count does not align precisely with their runoff reduction capacity, indicating that additional factors, such as canopy structure and leaf area, significantly influence stormwater management. While tree density varies by a factor of 1.56–3.8 across different streets, the corresponding differences in runoff reduction range from 1.39 to 1.79 times, highlighting the importance of tree morphological characteristics.

Additionally, Pc and LAI indices strongly affect interception and evapotranspiration rates. However, frequent pruning, as a preventive measure or in response to storm-related damage, results in relatively low Pc and LAI values for most trees in the study area. Small tree pits and the absence of structured soil further constrain infiltration. Although fibrous root systems could enhance infiltration, inadequate planting conditions limit this process.

Consider the following recommendations to enhance the role of urban trees in flood mitigation. Reducing the spacing between tree pits and implementing continuous planting strips would expand the soil area while improving wind resistance by allowing tree canopies to support each other. The use of structured soil in tree pits could enhance infiltration capacity. Selecting tree species with moderate mature heights and robust fibrous or taproot systems would minimize the need for extensive pruning during storm seasons. Integrating flood mitigation principles into urban tree planning and ensuring national policies and standards (QCVN) incorporate tree design criteria for stormwater management.

This study employs LAI and Ic values derived from MIDS for specific tree groups in the study area. However, certain morphological characteristics, such as bark texture and leaf structure, were not analyzed, which may introduce limitations in quantifying their hydrological impact. Future research should refine these assessments using theoretical and experimental approaches to improve accuracy in frequently flooded urban areas. Additionally, statistical analysis using SPSS will examine correlations between tree morphology, soil composition, and soil volume to further evaluate their contributions to flood mitigation. These findings provide a foundation for recommending optimal tree species selection and improving urban green infrastructure strategies.

L.P.C.L. conceptualized the study, rendered support in data curation, formal analysis, and funding acquisition, investigated the work, developled the methodology, contributed in project administration, resources, and software, supervised the work, validated the process, visualized the process, wrote the original draft, wrote and reviewed and edited the article. N.H.S. conceptualized the study, rendered support in data curation, formal analysis, and funding acquisition, developed the methodology, contributed in project administration, resources, supervised the work, validated the process, visualized the study, wrote the original draft, wrote and reviewed and edited the article. L.N.H. conceptualized the study, rendered support in data curation, formal analysis, devloped the methodology, and project administration, wrote the original draft.

This research would like to thank the support of the Hue University under the Core Research Program, Grant No. NCM.DHH.2023.03.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.