Despite rapid urbanization and rising concrete structures, Dhaka still retains around 1.3 million trees, according to the first-ever comprehensive tree census jointly conducted by the Bangladesh Forest Department and the U.S. Forest Service. The study, titled Urban Tree Inventory of Dhaka City, provides vital data on the density, species, distribution, and ecosystem benefits of trees across Dhaka’s 306 square kilometers.

Key Findings:

• Tree Density: On average, Dhaka South City Corporation (DSCC) has 15 trees per hectare, while Dhaka North City Corporation (DNCC) has just 7.

• Green Coverage: DSCC is 10.8% green-covered; DNCC slightly higher at 10.5%. In comparison, global cities like Toronto (27%), Atlanta (37%), and New York (21%) fare significantly better.

• Foreign Dominance: A striking 62% of Dhaka’s trees are non-native species.

• Top Species: The most common trees are mango, mahogany, and coconut, followed by banyan, rain tree, neem, jamun, jackfruit, and others.

• Air Purification Value: Dhaka’s trees collectively absorb approximately 538 tons of pollutants annually (including carbon dioxide, nitrogen oxides, and particulates), equivalent to a service worth BDT 35 crore. They also supply over 53,000 tons of oxygen each year.

• Tree-to-Human Ratio: Alarmingly, there’s only one tree for every seven residents in Dhaka.

Economic & Ecological Valuation:

The estimated market value of these trees is BDT 106 crore (USD 9 million). Beyond monetary value, they serve as crucial buffers against urban heat, pollution, and biodiversity loss. Mahogany leads in air purification, followed by black koroi, mango, and jamun.

Historical Decline:

While this is Dhaka’s first full tree census, a 2022 environmental study showed a stark decline in urban green space—from 17% in 1989 to just 2% in 2020. According to UNEP guidelines, cities should maintain at least 25% green coverage.

Urban Heat Implications:

Experts link the rising heat waves in Dhaka to diminishing tree cover and wetland loss. Areas with dense vegetation and water bodies experience noticeably cooler microclimates. In contrast, barren zones feel the full impact of extreme heat.

Dr. Ahmad Kamruzzaman Majumder from Stamford University warns that unless specific greening strategies are adopted, urban dwellers will face increasingly severe heat stress. “Dhaka’s green ecosystem had three layers: grass, shrubs, and trees. Grass and shrubs have mostly disappeared, leaving only trees—and those too are being cut down for beautification,” he said.

Future Roadmap: Mini Urban Forests

To combat urban heat and restore biodiversity, DNCC and the Forest Department signed a Memorandum of Understanding (MoU) to green road medians, footpaths, canal banks, and open lands in North Dhaka through mini urban forests. Previously, in 2023, DNCC had initiated a one-lakh tree plantation drive. Though some trees survived, many died due to lack of care.

Chief Conservator of Forests, Md. Amir Hossain Chowdhury, confirmed that the department is ready to offer technical support if DNCC provides land for greening. “Our aim is to create sustainable micro forests in the heart of the city,” he said.

Citizen Voices:

Urban residents echo the value of greenery. Goni Mia, a vegetable vendor at Mahakhali-Gulshan Link Road, recalled how large shade-giving trees were cut down recently, leaving commuters to suffer in the scorching heat. “It used to be peaceful under those trees. Now people have no shade while waiting for buses.”

In contrast, areas like Ramna Park still provide shaded walkways, bringing joy to citizens like Shahadat Hossain, a government employee, who said, “Walking under a canopy of trees brings peace and happiness.”

This landmark urban tree inventory provides policymakers with essential data to drive climate-resilient city planning. It underscores the urgent need for restoring Dhaka’s green heritage—not just for aesthetics but for survival. As climate challenges intensify, trees must be seen not as ornaments but as urban infrastructure.

Writer: Mostofa Yusuf, Prothom Alo