Bangladesh’s Smaller Cities Outperform the Capital in Urban Tree Canopy Benefits, Study Finds

A new study of Bangladesh’s city corporations has revealed a striking paradox at the heart of the country’s urban greening: some of its smallest and most peripheral cities are delivering far greater environmental benefits per resident than the sprawling capital region. The research, published in the journal Discover Sustainability, used a standardized canopy assessment tool to quantify how much tree and vegetation cover exists across Bangladesh’s major urban centers, and then translated that cover into concrete ecosystem services, including air pollutant removal, carbon sequestration, and stormwater management. The findings expose deep regional disparities in who gets to breathe cleaner air, enjoy cooler streets, and benefit from urban nature, and they point to significant gaps in the country’s environmental legal framework that may be perpetuating those inequities.

The research team, led by Md. Uzzal Hossain of the Department of Botany at the University of Barishal, together with colleagues from geology, law, and other disciplines, assessed land cover and ecosystem service provision across all of Bangladesh’s city corporations. These administrative units represent the country’s largest and most politically significant urban areas, from the dense megacity of Dhaka to smaller regional centers such as Barishal and Sylhet. Studies of this kind have been notably scarce in Bangladesh, despite the country’s acute vulnerability to urban heat, flooding, and air pollution, making the new analysis one of the most comprehensive baselines yet assembled for the nation’s urban forests.

Methodologically, the study relied on i-Tree Canopy, a widely used software tool developed by the United States Forest Service that estimates land cover composition and ecosystem services from randomly sampled points overlaid on aerial imagery. Rather than measuring every tree individually, the tool generates statistical estimates of the proportion of land under different cover classes, such as trees and shrubs, grass and herbaceous vegetation, bare soil, buildings, roads, and other impervious surfaces. Those cover percentages are then combined with established models of tree physiology and local environmental data to estimate how much pollution the canopy filters, how much carbon dioxide it absorbs and stores, and how much rainfall it intercepts before it overwhelms drainage systems. The authors are careful to note that these are model-based estimations rather than direct empirical measurements, and they caution that results should be interpreted comparatively, within the acknowledged limitations of the methodology, rather than as precise field measurements.

The land cover results alone tell a vivid story of uneven urban ecology. Grass and herbaceous coverage, one of the key indicators of green space, ranged from a high of 47.08 percent in Cumilla to a low of just 8.31 percent in Sylhet, a nearly sixfold difference between cities in the same country. Trees and shrubs emerged as the dominant green cover class across the city corporations, but the quantity and distribution of that woody canopy varied enormously. In densely built and rapidly industrializing cities, impervious surfaces have consumed the space that vegetation once occupied, leaving residents with a fraction of the green infrastructure available elsewhere.

When the researchers converted canopy cover into ecosystem services, the geographic pattern became even more pronounced. Barishal, a peripheral city in the country’s south, led all city corporations in air pollutant removal, filtering an estimated 1,026.75 tons per square mile per year, and in carbon sequestration, absorbing roughly 36.21 kilotons per square mile per year, while also performing strongly in stormwater management. By contrast, Dhaka South, the heart of the capital, along with the neighboring industrial cities of Gazipur and Narayanganj, showed significant ecological deficits. These are precisely the areas where population density, traffic volume, and industrial emissions make the need for urban canopy greatest, meaning that the cities generating the most pollution and heat are the ones least equipped by vegetation to mitigate it.

The study also translated ecosystem services into monetary terms on a per capita basis, a metric that highlights the equity dimension of urban greening. Barishal again ranked first among the city corporations, providing ecosystem services with an estimated monetary value equivalent to 386.60 dollars per unit area per capita, the highest in the country. This figure reflects not only abundant canopy but also a favorable ratio of green infrastructure to population. In the capital and its bordering industrial cities, the same calculation revealed the highest levels of spatial inequity in the study: large populations sharing a depleted resource base, so that the per capita flow of benefits from urban nature shrinks to a fraction of what residents of smaller cities enjoy.

These findings carry particular weight in the context of Bangladesh’s breakneck urbanization. The country’s major cities have expanded rapidly over recent decades, absorbing wetlands, farmland, and vegetated land into built-up areas. Dhaka’s population growth has famously outpaced its infrastructure, and satellite cities such as Gazipur and Narayanganj have become hubs of garment manufacturing and other industry, with corresponding pressure on land and air quality. The new data suggest that this growth has not been accompanied by proportional investment in green infrastructure, and that the environmental burdens of urbanization, from flooding to air pollution, fall hardest on the residents of the most degraded landscapes.

Beyond the ecological accounting, the research team turned to the legal and policy architecture that governs urban green space in Bangladesh, and here the diagnosis is sobering. Reviewing the relevant policy frameworks, the authors found a critical implementation gap in the government’s administrative tools, the practical mechanisms, regulations, and enforcement processes that would translate environmental commitments into protected and expanded canopy on the ground. In other words, the problem is not necessarily an absence of environmental law or policy language, but a failure of implementation that allows inequity in ecosystem service distribution to persist and widen. The authors argue that closing this gap is essential if Bangladesh is to meet its commitments under the Sustainable Development Goals, particularly those relating to sustainable cities, health, and climate action.

The study’s authors frame their results as a direct input for distributive environmental justice, the principle that the benefits and burdens of environmental conditions should be shared fairly across populations. By identifying which city corporations suffer the greatest ecological deficits and the highest spatial inequity, the analysis gives policymakers a prioritized map for intervention: where to plant, where to protect existing canopy, and where regulatory enforcement needs strengthening. The authors call for innovative, multidisciplinary, and technology-based policymaking, suggesting that tools like i-Tree, remote sensing, and geospatial analysis could be institutionalized within government planning processes to monitor green cover and hold authorities accountable over time.

For a country on the front lines of climate change, the stakes of urban canopy extend well beyond aesthetics. Trees and shrubs intercept rainfall that would otherwise contribute to the chronic waterlogging that paralyzes Bangladeshi cities during monsoon season, filter the particulate pollution that ranks among the world’s most severe, and sequester carbon while cooling streets that regularly reach dangerous temperatures. The new study demonstrates that these services are not distributed by chance but reflect historical patterns of development, planning, and enforcement, and that they can be quantified, compared, and managed. Whether Bangladesh’s policymakers use this evidence to redirect resources toward the ecologically depleted capital region and its industrial satellites, or whether the gap between cities like Barishal and Dhaka South continues to widen, will be a test of the country’s commitment to equitable, sustainable urban development.

Subject of Research: Distribution of urban tree canopy and ecosystem services across Bangladesh's city corporations and its links to environmental legal policy

Article Title: Urban tree canopy and ecosystem services distribution in city corporations linking environmental legal policy of Bangladesh

Article References: Hossain, M. U., Sourov, M. J. I., Saha, S. C., Marium, A., Rahman, M. G., & Sony, S. K. (2026). Urban tree canopy and ecosystem services distribution in city corporations linking environmental legal policy of Bangladesh. Discover Sustainability. https://doi.org/10.1007/s43621-026-04803-4

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04803-4

Keywords: urban tree canopy, ecosystem services, i-Tree Canopy, Bangladesh, Dhaka, Barishal, air pollutant removal, carbon sequestration, stormwater management, spatial inequity, environmental policy, sustainable development goals