Dhaka needs coordinated tree plantation to survive the scorching summers

Dhaka has been urbanised aggressively- with trees cut down indiscriminately to make way for that.

Only now, as frequent and persistent heat waves have been making the already hot tropical summers unbearable, the importance of greenery is being felt.

Urban forestry experts say tree plantation requires a scientific and coordinated approach that has long been neglected by city authorities.

As a consequence, Dhaka has not gained enough green coverage despite massive tree plantations every year, and the heavily populated city doesn’t have enough space left for urban forestry.

“It is surprising that many citizens are pressing for the immediate launch of a massive tree plantation campaign in the ongoing summer season. Saplings require continuous watering and care until their roots are established. If we plant them in the summer, we must ensure the requirements until the monsoon,” said Professor Mohammad Zashim Uddin, a professor at the Department of Botany at Dhaka University.

“But the reality is people talk about tree plantation but do not perform the due responsibility,” he added.

He said mature trees with wider canopies on the surface block the sun’s heat energy through their shades and lower the ambient temperature by vaporising moisture.

Although there are no official statistics, green campaigners have pointed to news reports on organisational declarations of planting more than two million saplings in Dhaka in the last 10 years.

Were the saplings fortunate enough to get the necessary care and nutrition to grow mature? The answer is no.

Green campaigners have observed that some organisations, including government wings, plant new saplings in the same places, and afterwards, the young trees are left almost neglected.

That is why Dhaka's greenery does not expand.

Meanwhile, the mature trees are cut down to build homes, markets, roads, and other establishments. 

According to a study titled “Present Status and Historical Changes of Urban Green Space in Dhaka City, Bangladesh: A Remote Sensing Driven Approach,” Dhaka city lost 56% of its vegetation, and its urban cover increased to 82% between 1989 and 2020.

The dwindling greenery has contributed to the increase in Dhaka city’s average summertime temperature.

An analysis of Bangladesh Meteorological Department records between 1989 and 2023 suggests that the frequency and duration of heatwaves over Dhaka are rising.

Another study titled “An Analysis of Spatio-Temporal Trends of Land Surface Temperature in the Dhaka Metropolitan Area by Applying Landsat Images” states that the land surface temperature in the Dhaka Metropolitan Area increased by 2.48 degrees Celsius in March and by 3.76 degrees Celsius in May between 1988 and 2018.

The study detected a significant warming trend for the most built-up areas.

Green campaigners fear that Dhaka city has been losing space for even planting new saplings. More than 80% of the city is now mapped as built-up areas.

According to Ahsan Rony, chief executive officer at Green Savers, the country’s renowned environment organisation, Dhaka lacks space for even the plantation of 50,000 saplings a year.

Except for private properties, there are no government-owned lands left for tree plantation.

However, the government-owned lands are under the control of different government bodies that occasionally plant trees at their own management. 

However, there is no visible coordination among them regarding tree plantation.

City corporations, having ownership of road medians, seem to be leading entities that can deal with urban forestry.

But what happens there?

City corporations' contractors work on tenders to plant trees on road medians, the only available place for forestry.

“But we see only ornamental hedge plants over there. The plants are short-lived, and their maintenance cost is high. Instead, Dhaka needs trees with large canopies to reduce atmospheric temperature and help restore biodiversity,” said Green Savers’ Ahsan Rony.

Rony believes that the selection of the trees should be done by experts. 

He recommended medicinal and fruit trees for Dhaka but emphasized on cautious plantation.

“For example, Palash, Shimul, Dumur, and other trees that shelter flocks of birds are good choices. Although, I don’t prefer the plantation of Krishna Chura on the road medians or footpaths because several casualties were recorded because of the felling of this sensitive tree,” headded.

Echoing the same, Professor Zashim said plantation of saplings, their survival up to being mature, and the creation of urban forestry need to be done systematically.

“So, under the umbrella of the Forest Department, the sole government wing having forestry experts, all stakeholders of the city authorities, and botany experts should work in a concerted way. The single platform will be mandated to set a roadmap for achieving the required green coverage, 25% of the Dhaka city territory. If it happens, we may see tolerable summers after 10-15 years,” Zashim said.

Dhaka Divisional Forest Officer SM Sazzad Hossain, said, “Outside the cities, the department operates afforestation where there are memoranda of understanding with public and private entities.”

“The department doesn’t own the city lands. With technical expertise, the department can lead Dhaka’s urban forestry. We need the crucial coordination of the city authorities first,” he added.