Rubber plantations in Xishuangbanna. Photo: Dietrich Schmidt-Vogt / World Agroforestry Centre

China’s insatiable appetite for rubber, to satisfy its rapidly growing car market, is pushing rubber plantations into higher elevations and onto steeper slopes where rubber cultivation is no longer profitable and poses a significant threat to biodiversity.

In a new study published in PlosONE, scientists from the Kunming Institute of Botany and the World Agroforestry Centre found that the area of monoculture rubber plantations in Xishuangbanna, the second largest rubber planting area in China, increased nearly five-fold between 1988 and 2010.

The researchers call for more sustainable rubber cultivation, such as intercropping rubber with timber trees and medicinal plants in agroforestry systems. There is an urgent need, they say, for local governments to develop long-term land use strategies that balance economic benefits and environmental sustainability.

“We found that rubber now covers 22.2 per cent of the area of Xishuangbanna where in 1988 it only covered 4.5 per cent,” explains Huafang Chen, lead author of the study and GIS lab manager for the World Agroforestry Centre’s East and Central Asia region. “From 1988 to 2010, the area utilized for rubber cultivation in Xishuangbanna increased on average by 15,338 hectares per year.”

The study reveals how rubber plantations are rapidly expanding into marginally suitable areas at higher elevations and on steeper slopes, where productivity and economic value declines. By 2010, almost 30 per cent of plantations were located above 900 metres above sea-level (masl) and two-thirds of plantations are now on slopes of more than 15 degrees.

Rubber growing at high elevations in Xishuangbanna. Photo: Dietrich Schmidt-Vogt / World Agroforestry Centre

These higher elevation rubber plantations are increasingly being established in nature reserves where most of the remaining forests of Xishuangbanna are located. Xishuangbanna’s forests are particularly rich in biodiversity and have already declined from around 70 per cent in the 1970s to 50 per cent in the 2000s. Monoculture rubber plantations covered almost 10 per cent of the total nature reserve area of Xishuangbanna in 2010, an 89-fold increase on 1988.

“This disturbing pattern poses a serious threat to existing forests and biodiversity while not producing the economic returns farmers were expecting,” says Jianchu Xu, Regional Coordinator for the World Agroforestry Centre’s East and Central Asia region. “This could have a serious long-term impact on people’s livelihoods as well as on ecosystem services.”

Beijing traffic. Photo: Li Lou / World Bank (FlickR)

The study represents the first ever effort to map rubber plantations inside and outside protected areas in Xishuangbanna and their net present value for 1988, 2002 and 2010. By applying high-resolution imagery to mapping of rubber in the area, researchers were able to distinguish between young (open canopy) and mature (closed canopy) rubber plantations. The study shows 88.6 per cent mature plantations in 2010 and 11.4 per cent young plantations.

Xishuangbanna Prefecture in the southwest province of Yunnan, bordering Laos PDR and Myanmar, accounts for most of the rapid growth in China’s rubber plantations in recent years. Much of this expansion can be attributed to a rapid increase in the price of natural rubber latex; from US $130 per ton in 2000 to US $6,300 per ton in 2012.

Not surprisingly, many smallholder farmers are attracted to this seemingly lucrative industry and have converted their land to monoculture rubber production. The local government too has promoted rubber planting to improve rural livelihoods and generate economic growth. In 2008, rubber contributed to up to one-third of local government revenues and roughly half of household incomes among farmers in Xingshuangbanna.

But as this new study demonstrates, farmers may be unlikely to see the returns they hoped for.

Researchers evaluated the Net Present Value (NPV) of rubber plantations, in other words the potential economic benefits farmers can expect. They found that after 2010 when rubber plantations had expanded to less productive land at higher elevations and on steeper slopes, the percentage of plantations with positive NPV declined while the proportion of those having a negative NPV increased. In fact, 60 per cent of open canopy (young) rubber plantations in 2010 had either negative or very low NPV.

“These results, combined with declining rubber prices globally, serve as a serious warning that rubber expansion in Xingshuangbanna is no longer profitable,” notes Xu. “Farmers who have converted all their land to rubber, and farmers who are considering doing so, run the risk of losing everything if they plant outside the natural limits of the species.”

Xu says that in addition to effective and well-controlled land use policies based on sustainability, farmers need advice on the selection of land suitable for the growth of rubber.

The scientists involved in the study hope that their research will help to inform sustainable land use planning and initiatives which limit rubber expansion into unsuitable areas.

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Illustration by Zhuang-Fang Yi showing a farmer tapping rubber

This research was funded by the German Federal Ministry for Economic Cooperation and Development (BMZ) and Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) https://www.giz.de/de/html/index.html

Download the article:

Chen H, Yi Z-F, Schmidt-Vogt D, Ahrends A, Beckschäfer P, Kleinn C, Ranjitkar S and Xu J 2016. Pushing the Limits: The Pattern and Dynamics of Rubber Monoculture Expansion in Xishuangbanna, SW China PlosONE

See also: Rubber expansion threatens biodiversity and livelihoods