Karachi’s Orangi, Baldia and Korangi are great neighbourhoods to live in if you like being surrounded by many different types of trees. Ironically because they are poor neighbourhoods, the city government ignores them when planting trees, which is why the people do it themselves. This means these neighbourhoods have many more types of trees, which is a good thing.
Otherwise experts warn that a monoculture of planting just one type of tree is spreading in Karachi. That tree is the Conocarpus erectus.
In a study published in January in the journal Urban Forestry & Urban Greening, Zafar Iqbal Shams and other researchers from the Institute of Environmental Studies at the University of Karachi explain the patterns they found.
They went by town and linked the width of roads to the types of trees planted. The experts defined the roads as wide (24m or greater), medium and narrow. The wide ones are main roads generally managed by KMC and the town administrations manage the narrow and medium roads. However, people also grow and care for plants outside and close to their homes.
Karachi’s streets are dominated by the Conocarpus erectus (over 25%), followed by Neem (15%). You will find the Conocarpus mostly on wide and medium roads. Overall, Karachi has 23 families, 46 genera and 62 species of trees on its streets.
During the last 10 years, many trees were removed to widen streets so traffic would flow better. Countless more were uprooted as urban infrastructure came up or the timber mafia struck. According to the study, several major streets do not have any trees. In fact, thousands of large canopy trees on the central roads of Gulshan Iqbal and North Nazimabad were removed over the last few months to widen them and for the construction of the BRT.
The experts found that Lyari, the most populated, oldest and poorest towns, had the highest percentage (80.9%) of treeless strips. The rich North Nazimabad and lower-middle income Kemari town did not have any treeless strips. The experts defined each strip as 100m. Lyari Town had the lowest number of trees per 100m strip and Keamari had the highest.
There were higher densities of trees in richer towns such as North Nazimabad and Gulshan Iqbal compared to the poorer Lyari and Baldia. But Gulshan Iqbal, a town of high to higher income residents, had one of the lowest diversities because just a single type, the Conocarpus erectus, was overplanted on 75% of its streets.
The experts found that the civic agencies ignored poorer neighbourhoods. Towns with rich residents had more trees mainly because these neighbourhoods had high real estate land value and better roads and sidewalks. The civic agency seldom took interest in massive tree planting on the streets of poor residents.
The number of trees in affluent towns such as North Nazimabad and Gulshan Iqbal was 10 times greater than places like Lyari and Baldia.
This was the case with Gulshan Iqbal which is centrally located and has higher land value. The civic agency pays more attention to it. It gave it better roads and sidewalks and did more tree planting, with a preference for exotic species. The civic agency preferred planting exotic species, because they grow faster. Planting just one type of tree has lower maintenance costs, but in the long run may be riskier if that species gets diseased and has to be removed.
The agency generally removes all the trees, while planting one or two species of its choice. This is why Orangi had the highest diversity but the lowest number of trees. This is why some rich towns did not have species diversity.
Lyari not only had the fewest trees but the least types of trees, which shows that the people who live there and the local government both ignore it. The experts did point out, however, that perhaps Lyari had fewer trees because there wasn’t enough space to plant them.
Towns on the edge of Karachi with poorer neighbourhoods, such as Landhi and Bin Qasim had fewer exotic trees.