Manja, or the glass-coated string used for flying kites, not only poses threat to humans, animals and birds but also to trees. A study by the country’s oldest botanical garden has revealed that it poses a great threat to trees. But how can a snapped string struck in a tree kill the tree? Apparently, it does so by allying with the creepers in the garden.
A research paper by three scientists of the Acharya Jagadish Chandra Bose Indian Botanic Garden, located in West Bengal’s Howrah district, illustrates in detail how the manja, in collusion with climbers, does the damage. “The abandoned, torn kite strings act as an excellent primary supporting platform for the tender climbers, giving easy passage to reach the top of the trees. Lateral branches from the top of the climber and other accessory branches from the ground reaches the top taking support of the first climber, completely covers the treetop, thus inhibiting the penetration of sunlight,” says the research paper.
The paper, authored by C.M. Sabapathy, Basant Kumar Singh and Arabinda Pramanik, states that the string intertwined with climbers slowly brings about the death of trees in the botanical garden.
The scientists have identified at least 15 creepers — which include species like Antigonon leptopus (Mexican creeper) Bignonia unguis-cati ( cat’s claw) Cocculus villosus (broom creeper), Dioscorea bulbifera (air potato), Operculina turpathum (wood rose) and Mikania micrantha (bitter vine) — that can climb even tall trees with the support of manja entangled in its branches.
Take the case of Bentinckia nicobarica – a rare palm only endemic to the Nicobar islands of the country. A creeper on its own cannot do any harm to a palm tree. But climbers like wood rose and bitter vine can throttle the tree to death.
“Some of our important trees have died in the garden. We are trying to remove these vines from the endemic pine trees so that they can survive. In seven out of 10 cases, it is found that these noxious weeds are reaching the top of other trees only due to these strings,” Mr. Singh said.
Other important trees like Strychnous nux-vomixa (kuchla tree), a medically important tree, and Swietenia mahagoni (Indian mahogany) have also been affected by the creepers.
The AJC Bose Indian Botanic Garden is the biggest and oldest botanic garden in the country spread over 273 acres and plays host to 1,400 species of trees — mostly rare and endangered and some of them being endemic to India.
The research paper has been accepted by Indian Journal of Biological Sciences . The three authors have also pointed to the adverse impact of the manja on the birds as well as the water bodies of the botanic garden.
