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A Chinese invader, hired by India - Tree capturing Himalayan region by poisoning plants: Scientists

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By G.S. MUDUR in Delhi
  • Published 27.12.07

New Delhi, Dec. 26: Not just the Chinese army, a tree with roots there is also facing grave allegations of capturing Indian territory.

The tree, native to China and east Asia and introduced in India for the extraction of vegetable oil, is cornering terrain for itself in the Himalayan region by poisoning local plants, scientists have warned.

Named Sapium sebiferum and growing in Himachal Pradesh and Uttarakhand, the tree shows the key hallmarks of an invasive species, scientists at the Institute of Himalayan Bioresources Technology (IHBT), Palampur, said.

“This plant has the ability to alter the habitat around itself, making it unsuitable for other plants,” Sanjay Uniyal, a plant ecologist at IHBT told The Telegraph.

Although the exact extent to which the tree has spread in the western Himalayas still remains unassessed, studies by Uniyal and his colleagues indicate that it has successfully established itself in the sub-Himalayan tracts of India and poses a threat to native plants.

Preliminary surveys by the IHBT scientists have revealed seedlings and saplings of Sapium sebiferum where this tree was not present earlier.

In a report in the journal Current Science from the Indian Academy of Sciences, Uniyal and his colleagues cautioned that like other invasive species, Sapium sebiferum has high potential for spread — it produces fruits and seeds every three or four years, and a single mature plant produces 100,000 to 150,000 high-viability seeds.

Uniyal said IHBT had no information of when this plant was introduced in India. But forest scientists believe it was brought to function as a multipurpose agroforestry and economically important tree.

The scientists point out that the tree, commonly known as the Chinese Tallow, has been dubbed an invasive species in several countries, including the US where it has spread across several southeastern states.

Uniyal said Sapium sebiferum is an allelopathic plant that can dramatically change local habitats by adding certain substances in the soilthat are harmful to local plants.

“Allelopathic substances may be produced by the leaves or the roots of invasive species,” said K.V. Sankaran, a senior scientist with the Kerala Forest Research Institute, Peechi. “These are essentially plant toxins that prevent growth of other plants.”

Forest ecologists tracking the spread of invasive species in India said Sapium sebiferum is not yet classified as invasive, but this could be only because of lack of data on its spread.

“Many plants that we think were always here are actually alien species from other lands,” said Akhilesh Rabhubanshi, an ecologist at the Banaras Hindu University, who has been studying invasive species in the Vindhyan region.

The pale green annual herb, Parthenium hysterophorous, entered India sometime in the early 20th century through contaminated cereals, but was recorded in 1956.