HONOLULU (May 22) – The unrestricted expansion of rubber plantations in the uplands of mainland Southeast Asia could have devastating environmental effects, according to an article in the May 22 issue of Science, the influential weekly journal of the American Association for the Advancement of Science.
Written by Alan Ziegler of the National University of Singapore, Jefferson Fox of the East-West Center in Hawaii and Jianchu Xu of the Kunming Institute of Botany, the article notes that rubber plantations – which largely feed China's tire manufacturing industry – are expanding rapidly throughout the mountainous areas of mainland Southeast Asia.
More than 500,000 hectares, or 1.23 million acres, already may have been converted to rubber in the uplands of China, Laos, Thailand, Vietnam, Cambodia, and Myanmar, the authors report. By 2050, they say, the area of land dedicated to such farming systems could more than double or triple – vastly reducing biodiversity and potentially having severe consequences on water resources in the region.
Fox and his colleagues write that much of the region's uplands that have been converted to rubber have historically been associated with the traditional farming practice of "swidden," or shifting cultivation – often referred to negatively as "slash-and-burn" farming – that has widely been blamed for tropical deforestation.
"In fact," Fox wrote in an earlier publication, "shifting cultivation, rather than being the hobgoblin of tropical forest conservation, may be ecologically appropriate, culturally suitable, and under certain circumstances the best means for preserving biodiversity in the region. The real threat to these tropical forests is posed by the steady advance of large-scale permanent and commercial agriculture."
In their Science article, Fox and the other authors write that "clinging to the perception that swidden cultivation is a destructive system that leads only to forest loss and degradation, governments in Southeast Asia have tried to control or terminate it through bans, declaration of forest reserves, forced resettlement, monetary incentives, and crop substitution yet such policies have not always improved environmental conditions."
In fact, they say, such policies have sometimes provided an excuse for the development for large scale commercial cultivation of single crops. "In the case of rubber, homogeneous monocultures with myriad negative environmental consequences have emerged," they write. "Erosion has accelerated and stream sediment loads have increased where repetitive cultivation is performed on steep slopes without appropriate conservation methods; permanent conversion of hill slopes and road building have increased the risk of landslides; irrigation of cash crops in the dry season has desiccated streams; and use of pesticides and fertilizers to sustain commercial agriculture has reduced water quality."
Fox and his co-authors conclude by recommending that "a substantial increase in natural reserve areas could help to reduce the threats to biodiversity and carbon stocks. Another possible strategy involves paying upland farmers to preserve forest resources. A more realistic approach may be to promote diversified agroforestry systems in which cash crops such as rubber and oil palm play important roles, but are not planted as monocultures."
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The EAST-WEST CENTER is an education and research organization established by the U.S. Congress in 1960 to strengthen relations and understanding among the peoples and nations of Asia, the Pacific, and the United States. The Center contributes to a peaceful, prosperous and just Asia Pacific community by serving as a vigorous hub for cooperative research, education and dialogue on critical issues of common concern to the Asia Pacific region and the United States. Funding for the Center comes from the U.S. government, with additional support provided by private agencies, individuals, foundations, corporations, and the governments of the region.