A single species

THE evergreen, coastal conocarpus erectus, also called the conocarpus tree, isn’t native to Pakistan. It’s known for its dense foliage, fast growth and high tolerance for harsh environmental conditions. It can withstand humidity, saline soil, drought, strong coastal winds and high urban pollution. It is particularly attractive to cities facing environmental stress. The tree can reach heights of six to over seven metres within a few years. It has narrow leaves, a compact canopy and small button-like flowers, which is why it’s sometimes called the ‘buttonwood tree’.

In 2008, the then Karachi mayor, Mustafa Kamal,introduced this tree to rapidly increase the city’s green cover in response to growing urbanisation, dust pollution and rising temperatures. At that time, Karachi was expanding rapidly, with large sections lacking tree cover. The conocarpus tree was selected because it grows quickly, requires relatively little water, and can survive the coastal climate. Thousands of these trees were planted along roads, highways, parks and public spaces across Karachi.

For many residents, this plantation drive was initially seen as a sign of improvement. Within a few years, many previously barren roadsides began to look greener. The tree’s dense foliage created thick green hedges along major roads, giving the city a more landscaped appearance. In elite residential areas, particularly in neighbourhoods such as DHA and Clifton, conocarpus trees were also widely used as boundary hedges in elite homes, planted in rows to create walls for privacy, shielding houses from traffic and neighbouring properties. Because they grow quickly and remain evergreen, they are a popular landscaping choice for both municipal authorities and private property owners.

Views on removing conocarpus trees have been mixed.

However, the large-scale planting of a single species soon attracted criticism from environmentalists and urban planners. A main concern was the ecological risk of monoculture, — the dominance of a single tree species across large urban areas. Experts argued that planting only one type of tree can reduce biodiversity and make urban ecosystems vulnerable to disease or pests that could wipe out entire tree populations. It was pointed out that the trees produce large root systems that can damage underground infrastructure, such as water pipelines.

Besides, some health experts claimed that pollen from the tree contributes to allergies and respiratory problems. The criticism led to a debate in Karachi about whether it was the right species for large-scale urban planting. As a result, in 2020, the Sindh government said that there would be no new conocarpus plantations and existing trees in some areas would gradually be removed or replaced. But the removal process wasn’t rapid or systematic. In many areas of the city, the trees were not fully uprooted, with stumps left behind. The contractors responsible for the removal reportedly claimed that the wood retrieved was valuable and that timber from the cut trees was sold for crores of rupees. Still, the overall process remained unclear to many citizens, and there was little public communication explaining the exact reasons for the removal. Official plans suggested that the removed trees would be replaced with a wider variety of native and flowering species better suited for ecological diversity — such as neem, amaltas, gulmohar and kachnar. These trees are known not only for providing shade but also for brightly coloured seasonal flowers.

However, many residents say this replacement hasn’t been visible on a large scale. While some new saplings have appeared in certain locations, the promised widespread replanting has remained limited. If the replantation pro­­gramme had been implemented on a lar­ger scale in 2020, Karachi’s landscape may have appeared very different today. Such diversity could have improved the city’s microclimate, while also making urban spaces more visually vibrant.

Public views of the tree’s removal have also been mixed. Some people working in areas where these trees were cut claimed that the dense hedges sometimes hid illegal activities such as drug use, making certain spaces difficult to monitor. Others strongly opposed the cutting, arguing that the trees provided much-needed shade for roadside businesses such as tea stalls and khokas. Without the trees, some residents feared the empty space might be occupied by informal structures or shanties.

Many citizens have suggested that the Sindh government should launch extension programmes encouraging citizens to plant suitable trees and that the Sindh Forest Department should provide saplings at subsidised costs. If such efforts were implemented consistently, Karachi could gradually develop a more diverse and sustainable urban forest.

Arif Hasan is an architect.
Hamna Syed is a researcher.
www.arifhasan.org

Published in Dawn, March 24th, 2026

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