Hyderabad: City planners and biodiversity experts in Canada and the US have reinvested to revive native plant species because the ornamental and ‘fast-growing’ variants fail in the face of climate change.
Indian cities, especially Hyderabad, may face such an eventuality, experts said, because the trees planted in urban areas are non-sturdy, nursery-bred varieties.
“The saplings for mass tree plantation drives come from forest nurseries which maintain 3-4 varieties for economic reasons. The same species is planted over large areas. How will there be biodiversity,” asked Dr Thulsi Rao, an expert on urban biodiversity.
Fast growing varieties like gulmohar and copper pod (Konda chinta or Pachha Sunkesula; Peltophorum pterocarpum), which have ornamental qualities, are considered invasive.
Though they provide green cover, they break easily.
“Trees not only provide green cover, they are home to animals, reptiles and birds. Different trees attract different species,” said Mr Uday Krishna of Vata Foundation. He said a rain tree (Albizia saman), which can spread over 40 sq. m. can host up to 2,500 species, making it ideal for urban forest biodiversity. “They began saying that the branches give way easily and stopped planting them,” Mr Krishna said.
If only 10 species of trees are planted on a 100 acre parcel of land, the number and variety of birds, animals and reptiles would reduce in the space. “That is why you don’t see so many bird species now,” said Mr Ravi Jillapalli, wildlife photographer and University of Hyderabad scholar. Such unscientific urban forestry has taken away the habitat of the sparrow.
Fruit trees have been replaced by ornamental ones which barely attract birds. “Would you find a custard apple tree often,” an expert at the urban biodiversity department said. Municipalities don’t opt for fruiting trees to avoid people demanding ownership.
Environmentalists say introducing alien varieties may lead to the extinction of natural species. A report on flora in the state says that 77 varieties were lost by 2010 in Hyderabad.
“The University of Hyderabad campus had a natural forest, which we encroached into. Now in the name of urban forestry they are felling existing trees and planting weaker ones with nobody to take care. Where will the rabbits, the deer hide,” Mr Jillapalli said.
Mr Krishna said that trees were deliberately categorised as non-relocatable and felled.
Dr Thulsi Rao said urban forests were being reduced to parks, and no land was devoted to biodiversity. “We have identified a spot from the Biodiversity Park to Durgam Cheruvu to be developed as an urban forest. But our town plans don’t support green spaces....