Rapid expansion of plantations could lead to devastating effects
Amresh Gunasingham, Straits Times 11 Jun 09;
THE rapid expansion of rubber plantations in South-east Asia in the last decade could have a devastating effect on the environment, scientists here have warned.
More than 500,000 hectares of regional mountainous forests - about eight times the size of Singapore - have already been converted to rubber plantations, noted Associate Professor Alan Ziegler from the National University of Singapore (NUS) Department of Geography, who led a study on the matter.
By 2050, the expansion of plantations in the highlands of south-west China, Laos, Thailand, Vietnam and Myanmar is expected to double or triple. These findings were published in the May 22 edition of the prestigious journal Science.
Agreeing with the study, Professor Richard Corlett, from the Department of Biological Science at NUS, said: 'What used to be a landscape consisting of patches of forest, irrigated rice and a variety of other crops is now just uniformly rubber.'
In the report, Prof Ziegler noted that the unrestricted expansion of rubber in mountainous regions in mainland Southeast Asia could have devastating environmental effects.
With fewer trees, there are far fewer plants to absorb excess carbon dioxide from the atmosphere, accelerating the effects of global warming. Deforestation also causes erosion and landslides, while growing only rubber destabilises regional water systems as the plants tend to suck up excess water.
There is also a threat to biodiversity.
Said Dr Koh Lian Pin, a research fellow at ETH Zurich - the Swiss Federal Institute of Technology: 'If this trend continues, it could mean the decline of numerous species of native plants and animals, many of which are already on the brink of extinction.'
Roughly a quarter of the world's species of animals and plants lives in this region.
Experts attributed the trend to rising crude oil prices and a burgeoning demand for rubber products, particularly in China.
Crude oil, which is used to make synthetic rubber, hit a peak of nearly US$150 last year, causing the demand for natural rubber to go up, Dr Koh explained.
Prof Corlett added: 'Rubber seems to be the most valuable crop in the region.'
In the report, Prof Ziegler called for more areas to be designated as forest reserves.
'A substantial increase in natural reserve areas could help to reduce the threats to biodiversity and carbon stocks,' he wrote.
He also called for the adoption of 'diversified agroforestry systems', where cash crops such as rubber and oil palm play important roles, but are not planted as monocultures.
Instead, they will co-exist alongside native species of plants, reducing the threat to ecosystems.
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